The New York Times, by John Noble Wilford

By John Noble Wilford

Something out there beyond the farthest reaches of the known solar system seems to be tugging at Uranus and Neptune. Some gravitational force keeps perturbing the two giant planets, causing irregularities in their orbits. The force suggests a presence far away and unseen, a large object that may be the long-sought Planet X.

Evidence assembled in recent years has led several groups of astronomers to renew the search for the 10th planet. They are devoting more time to visual observations with the 200-inch telescope at Mount Palomar in California. They are tracking two Pioneer spacecraft, now approaching the orbit of distant Pluto, to see if variations in their trajectories provide clues to the source of the mysterious force. And they are hoping that a satellite-borne telescope launched last week will detect heat ''signatures'' from the planet, or whatever it is out there.

The Infrared Astronomical Satellite was boosted into a 560-mile-high polar orbit Tuesday night from Vandenberg Air Force Base, Calif. It represents an $80-million venture by the United States, Britain and the Netherlands. In the next six or seven months, the telescope is expected to conduct a wide-ranging survey of nearly all the sky, detecting sources not of ordinary light but of infrared radiation, which is invisible to the human eye and largely absorbed by the atmosphere. Scientists thus hope that the new telescope will chart thousands of infrared-emitting objects that have gone undetected - stars, interstellar clouds, asteroids and, with any luck, the object that pulls at Uranus and Neptune.

The last time a serious search of the skies was made it led to the discovery in 1930 of Pluto, the ninth planet. But the story begins more than a century before that, after the discovery of Uranus in 1781 by the English astronomer and musician William Herschel. Until then, the planetary system seemed to end with Saturn.

As astronomers observed Uranus, noting irregularities in its orbital path, many speculated that they were witnessing the gravitational pull of an unknown planet. So began the first planetary search based on astronomers' predictions, which ended in the 1840's with the discovery of Neptune almost simultaneously by English, French and German astronomers.

But Neptune was not massive enough to account entirely for the orbital behavior of Uranus. Indeed, Neptune itself seemed to be affected by a still more remote planet. In the late 19th century, two American astronomers, William H. Pickering and Percival Lowell, predicted the size and approximate location of the trans-Neptunian body, which Lowell called Planet X.

Years later, Pluto was detected by Clyde W. Tombaugh working at Lowell Observatory in Arizona. Several astronomers, however, suspected it might not be the Planet X of prediction. Subsequent observations proved them right. Pluto was too small to change the orbits of Uranus and Neptune; the combined mass of Pluto and its recently discovered satellite, Charon, is only one-fifth that of Earth's moon.

Recent calculations by the United States Naval Observatory have confirmed the orbital perturbation exhibited by Uranus and Neptune, which Dr. Thomas C. Van Flandern, an astronomer at the observatory, says could be explained by ''a single undiscovered planet.'' He and a colleague, Dr. Robert Harrington, calculate that the 10th planet should be two to five times more massive than Earth and have a highly elliptical orbit that takes it some 5 billion miles beyond that of Pluto - hardly next-door but still within the gravitational influence of the Sun.

Some astronomers have reacted cautiously to 10th-planet predictions. They remember the long, futile quest for the planet Vulcan inside the orbit of Mercury; Vulcan, it turned out, did not exist. They wonder why such a large object as a 10th planet escaped the exhaustive survey by Mr. Tombaugh, who is sure it is not in the two-thirds of the sky he examined. But according to Dr. Ray T. Reynolds of the Ames Research Center in Mountain View, Calif., other astronomers ''are so sure of the 10th planet, they think there's nothing left but to name it.''

At a scientific meeting last summer, 10th-planet partisans tended to prevail. Alternative explanations for the outer-planet perturbations were offered. The something out there, some scientists said, might be an unseen black hole or neutron star passing through the Sun's vicinity. Defenders of the 10th planet parried the suggestions. Material falling into the gravitational field of a black hole, the remains of a very massive star after its complete gravitational collapse, should give off detectable X-rays, they noted; no X-rays have been detected. A neutron star, a less massive star that has collapsed to a highly dense state, should affect the courses of comets, they said; yet no such changes have been observed.

More credence was given to the hypothesis that a ''brown dwarf'' star accounts for the mysterious force. This is the informal name astronomers give to celestial bodies that were not massive enough for their thermonuclear furnaces to ignite; perhaps like the huge planet Jupiter, they just missed being self-illuminating stars.

Most stars are paired, so it is not unreasonable to suggest that the Sun has a dim companion. Moreover, a brown dwarf in the neighborhood might not reflect enough light to be seen far away, said Dr. John Anderson of the Jet Propulsion Laboratory in Pasadena, Calif. Its gravitational forces, however, should produce energy detectable by the Infrared Astronomical Satellite.

Whatever the mysterious force, be it a brown dwarf or a large planet, Dr. Anderson said he was ''quite optimistic'' that the infrared telescope might find it and that the Pioneer spacecraft could supply an estimate of the object's mass. Of course, no one can be sure that even this discovery would define the outermost boundary of the solar system.

By John Noble Wilford

In its first days of operation, a new telescope orbiting the earth has returned infrared images showing previously unobserved features of distant galaxies and revealing cosmic ''maternity wards'' where clouds of interstellar gas and dust appear to be in various stages of giving birth to stars.

In just one minute of observation, moreover, the Infrared Astronomical Satellite, which was launched Jan. 25, collected more information on infrared emissions from the Large Magellanic Cloud, the nearest galaxy to our own Milky Way, than had ever been obtained in the years of looking through instruments on the ground, in balloons or high-altitude aircraft.

Infrared radiations are invisible to the human eye, and such radiations coming from space are virtually undetectable on the earth because they are mostly absorbed in the atmosphere.

The pattern of intense infrared, or heat, emissions from one region of the Large Magellanic Cloud, a nebula of dense dust and gas known as Tarantula, appeared to confirm predictions that it was a region where many new stars were forming, according to astronomers on the project. Further analysis may resolve a scientific debate as to whether the nebula has recently spawned a cluster of massive stars, each 10 to 100 times heavier than the sun, or a single ''monster'' star thousands of times more massive than the sun.

In the satellite's first 12 hours of operation, its 22-inch telescope also gathered data on at least 20 other galaxies, some of which are barely visible to optical telescopes.

Astronomers hailed the spacecraft's early performance in interviews last week at the Jet Propulsion Laboratory in Pasadena, Calif., and at a news conference yesterday at Chilton, England, the primary tracking station for the mission.

Dr. Gerry Neugebauer, an astronomer at the California Institute of Technology and one of the chief project scientists, said the spacecraft was ''working extremely well,'' that the telescope's pointing accuracy exceeded expectations and that the vehicle should be able to operate at least 10 months, three months longer than originally expected.

First Full Map of Heavens

The one-ton spacecraft is circling the earth from pole to pole once every 103 minutes at an altitude of 560 miles. Its goal is to scan 95 percent of the sky and produce the first comprehensive map of perhaps a million objects in the heavens - dust clouds, stars and galaxies - as active infrared emitters that could be signaling clues to the dynamic processes involved in the birth and death of stars.

Looking in areas closer to home, it should also detect the heat ''signatures'' of thousands of asteroids that have never been seen and search for the long-suspected 10th planet, a body that is assumed by many astronomers to exist beyond the orbits of Neptune and Pluto.

For making its observations, the spacecraft has an array of 62 detectors at the base of the telescope that are capable of sensing infrared radiation in four wavelengths. The detected radiations are converted to electronic data, recorded on board and then transmitted to the ground each time the spacecraft passes within radio range of the Chilton tracking station. On the ground, the digital data are then processed by computers and displayed as graphs showing highs and lows of infrared intensities or as images that are color-coded to characterize different radiation levels.

New Window on Universe

So far, the telescope had seen ''no major discoveries or unexpected things,'' Dr. Harm Habing, an astronomer at the Huygens Laboratory in Leiden, said at the news conference. But by opening a new window on the universe, observing clearly for the first time in infrared wavelengths of the electromagnetic spectrum, the telescope is expected to find many stars and galaxies that had gone undetected and probe the center of the Milky Way, where vast amounts of dust obscure the countless objects that make the region a source of so much mysterious energy.

Dr. Neugebauer said trying to do infrared astronomy from ground-based telescopes, as in the past, was like ''trying to do optical astronomy during the daytime.''

The project is an $80-million multinational endeavor in which the United States built the telescope and is managing operations, the Netherlands built the spacecraft and three other scientific instruments and Britain is tracking the spacecraft and collecting its radioed data.

Nebula Nicknamed Tarantula

One of the first infrared images released yesterday showed features in a bright nebula of the Large Magellanic Cloud that is officially designated 30 Doradus, but that is nicknamed the Tarantula because long, separated filaments of the nebula give it a spider-like appearance. The nebula is 155,000 light years from the earth, a light year being the distance light, traveling at 186,000 miles a second, covers in a year.

The image was reconstructed at the Jet Propulsion Laboratory from electronic data transmitted by the spacecraft, with different false colors applied to accentuate gradations of infrared intensities. White denotes the brightest infrared sources; blue, the faintest.

Dozens of the infrared objects that appear in the image are from areas where nothing can be seen with optical telescopes. Most of these sources, project astronomers said, are probably newly forming stars still shrouded in the cloud of gas and dust from which they are condensing.

According to Dr. B. Tom Soifer, a senior research associate at the California Institute of Technology, spacecraft sensors set to detect different wavelengths of infrared radiation have most likely observed three different stages of stellar evolution occurring in the Tarantula region. Instruments sensitive to the longest wavelengths, he said, detected what appear to be ''molecular clouds just deciding to collapse and form stars.'' Medium wavelengths revealed the matter coalescing into denser features. Then, in the shortest infrared wavelengths, Dr. Soifer said, the images show stars that have just formed.

Theory holds that gravitational collapse causes the clouds of dust and gas to coalesce and form new stars. Once the new stars are massive enough and hot enough, thermonuclear reactions begin and they glow in the visible portion of the spectrum. In the early stages of their evolution, however, when they are cooler, they radiate mainly in the infrared.

Dr. Soifer said the new images confirmed that the Tarantula was indeed ''an active region of star formation.'' As the survey progresses, the data will be compared with observations of star formations in other regions and other galaxies before astronomers expect to draw any conclusions about the nature of star birth or other celestial phenomena.

By John Noble Wilford

A grayish-brown chunk of rock, a meteorite found on the ice of Antarctica four years ago, has sent a shock wave of excitement through the laboratories of planetary science. Its drab appearance belies its apparently exotic provenance. The rock very likely comes from Mars.

If scientists are right about this, and the evidence is becoming more and more persuasive, the meteorite would assume an importance in the history of science comparable to that of the first Moon rocks returned by the Apollo astronauts. It would be the first known object from another planet to reach the Earth. It would afford scientists their first chance to study in detail the chemistry and geology of Mars.

Tests on pieces of the meteorite have recently erased most uncertainty about its Martian origin. After an analysis of gases trapped in the meteorite, Dr. Robert O. Pepin, a University of Minnesota physicist, emerged from his laboratory last week and exclaimed: ''It's from Mars. I don't think there's any doubt.''

Later, checking his enthusiasm, Dr. Pepin modified his assessment, saying: ''The evidence is extremely strong, but still not conclusive.''

That seems to be the attitude of most scientists who have examined the meteorite and will be comparing notes Thursday at the annual Lunar and Planetary Science Conference in Houston. The rock's volcanic history, age and chemistry all suggest that it originated on Mars. The only serious problem, according to scientists, is the question of how the rock could have escaped Mars.

Dr. Donald D. Bogard, a geologist at the Johnson Space Center in Houston, custodian for this and other rare meteorites, said ''impressive geochemical evidence'' had now moved physicists to think hard about ''circumstances in which you can get fragments of Mars.''

One promising idea is that an asteroid hit Mars with such force that it not only tore rocky fragments out of the surface but it also turned permafrost to steam, and that helped to propel the rocks to velocities that enabled them to break free of Martian gravity.

Such imaginative thinking follows several years of detective work in which scientists followed a trail of clues extracted from the meteorite itself to make a case for a likely Martian connection. At first they were sure only that this was a most unusual meteorite.

The 17.5-pound rock, eight inches in diameter, was picked up in 1979 at the Elephant Moraine near Antarctica's McMurdo Sound by a team of American scientists. They were there under the auspices of the National Science Foundation, the Smithsonian Institution and the National Aeronautics and Space Administration. They were there to harvest meteorites, which are relatively plentiful on the coastal slopes of Antarctica and usually in a well-preserved condition. University of Chicago scientists have identified a meteorite found in Antarctica last year as coming from the Moon. They could be reasonably sure because they had the Apollo samples for comparison.

Two of the rocks in the collection from 1979, the one under study now and a similar one, were identified as members of a class of meteorites known as SNC, for shergottites, nakhlites and chassignites. (They are so named for the places where the pieces were first found: at Shergotty, India; Nakhala, Egypt, and Chassigny, France.) Of the 10,000 or so meteorites in the hands of scientists and collectors, fewer than a dozen are SNC meteorites.

Early diagnostic tests on the rock from Elephant Moraine, labeled EETA 79001, produced the first clues that this was different from most meteorites. It was young as meteorites go - 1.3 billion years old, according to radioactive dating. Meteorites almost invariably date back to the beginning of the solar system 4.6 billion years ago. Since the rock appeared to be volcanic, moreover, it must have come from a body that had been geologically active as recently as 1.3 billion years ago.

Some Possible Sources Ruled Out

Asteroids, the usual source of meteorites, would have cooled much earlier because they are relatively small. Lavas have not flowed on the Moon in more than 3 billion years, according to Apollo findings. Besides, asteroids and the Moon have no atmospheres, and this rock appeared to have formed in an oxidizing environment.

It seemed almost terrestrial. But, no, an examination of cosmic-ray imprints on the rock revealed that it had spent at least two million years as a separate body in outer space. Scientists found it hard to imagine that a piece of the Earth could have escaped into orbit and then fallen back again.

Scientists then began to think of possible planetary origins. Venus was ruled out. It would be virtually impossible for something to break out of the dense Venusian atmosphere. Anything from Mercury would have been drawn in toward the nearby Sun. The massive outer planets would probably have precluded the escape of any rocks from their vicinities. Attention turned to Mars.

In the meteorite, among flecks of yellow and dark tan, are many glassy fragments. Viewed through a microscope, they resemble broken pieces of a beer bottle. Dr. Bogard recently decided to analyze some of the glass for any trapped gases.

For there were signs in its radioactive components that the rock had been subjected to a violent shock 180 million years ago. The shock was from the event, scientists reason, that dislodged the rock from its parent body. The event might have been an asteroid impact, which would have heated the rock and driven some of the surrounding atmosphere into it.

Sure enough, Dr. Bogard found trapped in the glass some so-called noble gases - neon, argon, krypton and xenon - strikingly similar in abundance to those of the Martian atmosphere, as determined by Viking missions to Mars in 1976. Scientists then abandoned lingering notions that the rock might be terrestrial and gave even more serious thought to Mars.

A couple of pebble-sized pieces of the rock were shipped to Dr. Pepin at the University of Minnesota for what might be a decisive test. Nitrogen in the thin Martian atmosphere exists in a distinctive pattern, as Viking observed. There is a higher concentration of a relatively heavy form, or isotope, of nitrogen than is found on the Earth or apparently anywhere else in the solar system.

Although there is more of a lighter isotope, nitrogen-14, than the heavier isotope, nitrogen-15, in the Martian atmosphere, the ratio is remarkably different from that on the Earth. Viking measurements indicate 60 percent more nitrogen-15 in the Martian atmosphere than in Earth's atmosphere. The distinctive ratio serves as an isotopic signature for identifying Martian atmosphere.

To look for the signature Dr. Pepin and his associates, Dr. Richard Becker and Dr. Urs Frick, heated tiny samples of the rock to boil the gases out of the glass and to identify and measure them in a mass spectrometer. The apparatus was developed by Dr. Frick, a Swiss geophysicist. It can examine tiny samples from such minute amounts of gas, the scientists said, because of modifications that achieve a sensitivity for the instrument a thousand times greater than ordinary spectrometers. They began the test early last week.

The meteorite sample, no more than one-thousandth of an ounce, was wrapped in platinum foil and placed at the bottom of a glass tube. A heating coil surrounded the tube. At first the sample was subjected to temperatures of a few hundred degrees Fahrenheit to drive off ordinary nitrogen gas. Then the temperature was raised in steps up to 1,200 degrees. A computer took note of the invisible vapors.

''The results are ambiguously positive,'' Dr. Pepin announced after the test. They were positive, he said, because the spectrometer detected 15 percent more nitrogen-15 than would be found in a sample from the Earth's atmosphere. They were ambiguous because he needed a measurement of close to 60 percent to match the Viking data from Mars.

Discussing the results later with Dr. Alfred O. Nier, another Minnesota scientist, who headed a Viking atmospheric science team, Dr. Pepin said the problem might be some ''contamination'' from ordinary nitrogen that the rock absorbed during processing in the laboratory. Or it could be, Dr. Nier suggested, that the Martian atmosphere was different 180 million years ago, when the glass trapped the gas, from what it was at the time of the Viking missions.

If Dr. Pepin was disappointed, he did not betray it. ''That rock just 'smells' like Mars,'' he remarked. As the geochemists marshaled their evidence, physicists addressed the question of how the rocks could have achieved the velocity of 3.1 miles a second necessary to fly off Mars. Many scientists doubt that a rock can be accelerated to such an escape velocity without breaking apart. And if it could, why then have there apparently not been many fragments blasted free of the Moon, with its lower gravity, and sent hurtling to the Earth?

Steam-Catapult Theory

An explanation may be the permafrost that is believed to lie beneath the surface of Mars. An asteroid blasting the surface could vaporize permafrost and create a sort of steam catapult, which would impart an additional burst of energy to rocky debris flying away from the impact.

Dr. Thomas J. Ahrens of the California Institute of Technology will report on the dynamics of this hypothesis at this week's conference in Houston. Dr. George Wetherill of the Carnegie Institution suggested the steam-catapult idea but still has doubts about its validity.

Definitive proof that scientists now have in their hands pieces of Mars, Dr. Bogard said, may have to await the return of Martian samples by spacecraft. The United States has no plans for such an undertaking.

By John Noble Wilford

After the United States and the Soviet Union in 1967 ratified a treaty outlawing nuclear weapons in space, most of the world relaxed under the assumption that its newest frontier was not likely to become a battleground. But military planners and weapons technologists on both sides, never relaxing, quietly pursued visions of space wars fought with non-nuclear weapons.

They have designed and in some cases tested satellites to hunt and destroy other satellites. They have conducted extensive research in space-based laser and particle-beam weapons - reality catching up with the deadly ray guns of science fiction.

Even though the feasibility of such non-nuclear weapons has yet to be proved, President Reagan called attention to them last week in a speech urging American scientists ''to turn their great talents'' toward developing powerful advanced missile-defense systems that could protect the United States against nuclear attack. He did not specify the weapons he had in mind, but White House aides acknowledged that they involved earth-based and space-based lasers and particle-beam technologies.

Spending Is Up Sharply

Nor did Mr. Reagan call for any immediate crash program for their development and testing. Spending on such systems has already increased sharply, from $200 million for laser work in 1980 to $1 billion annually for laser and particle-beam projects. And this is only part of the growing budget for space military operations in general. In the next five years the Reagan Administration plans to increase military space spending, now about $8.5 billion a year, by more than 10 percent a year, a greater rate of increase than for the rest of the Defense Department budget.

Almost from the beginning of the space age, in 1957 when the Russians launched the first Sputnik, space has been a realm of considerable military activity, but of the passive kind. The United States and the Soviet Union both use satellites for such applications as early warning against nuclear attack, intelligence gathering, navigation, weather forecasting and long-range communications. More than 40 American satellites now in orbit perform these functions.

Thirty seconds after a Soviet intercontinental ballistic missile lifts out of a silo, for example, American satellites with infrared sensors are supposed to be able to pick out its telltale heat trail. Data on the missile's speed and course are transmitted to communications satellites that relay the information instantly to computers and display terminals in an Air Force command center buried in Cheyenne Mountain near Colorado Springs. Further tracking of the missile is also reported by satellite communications.

In addition, Vela satellites 60,000 miles out in space watch for nuclear detonations. Several satellites with highly sensitive cameras are continuously transmitting photographs and other data disclosing military dispositions by friend and potential foe. Satellite reconnaissance, it is generally agreed, has had a stabilizing effect on global politics because it has enabled each adversary to verify the other's conformance to the first strategic arms treaty. The satellites presumably minimize the chances of surprise and miscalculation.

The Space Treaty

In 1967 the Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, Including the Moon and Other Celestial Bodies, commonly referred to as the Outer Space Treaty, was signed by 107 nations, including all of the countries active in space. The treaty, which was drafted by the United Nations Committee on Peaceful Uses of Outer Space, governs all activities in the exploration and use of outer space. One provision bans the stationing of ''weapons of mass destruction'' in orbit or on the moon.

One reason the Soviet Union and the United States were willing to agree to the treaty was that they did not see any advantage to having nuclear weapons in space and had determined that orbiting nuclear bombs seemed much less practical than ballistic missiles.

The common definition of ''weapons of mass destruction'' is nuclear bombs or warheads, and the research, development and deployment of the kind of non-nuclear weapons now being discussed for placement in outer space would not appear to be restricted by the terms of the Outer Space Treaty.

While reaffirming a commitment to peaceful uses of space, President Reagan said in a directive on space policy last July, ''The United States will pursue activities in space in support of its right to self-defense.''

What the Administration apparently had in mind was outlined last year in a five-year plan, a document known as a Defense Guidance. Space operations, the document said, ''add a new dimension to our military capabilities.'' The document further ordered ''the prototype development of space-based weapons systems so that we will be prepared to deploy fully developed and operationally ready systems should their use prove to be in our national interest.''

Concern About Soviet Efforts

This reflected a growing concern among American military analysts over presumed Soviet advances in space weaponry. Since 1968, the Russians have been testing a non-nuclear anti-satellite system, or ASAT, which they have used to intercept target vehicles they have sent into space. Small satellites are sent into orbit to hunt a target satellite, hover near it, then explode, shattering the victim craft with shrapnel.

The Air Force has countered with an American ASAT that is scheduled for its first tests in late summer. By all accounts, it is expected to have more capacities and flexibility than the Soviet version. The American anti-satellite weapon is a small homing missile, launched into space from a high-flying F-15 aircraft. It seeks out its target with infrared sensors, then explodes near the target or collides with it at high speeds. The Pentagon has directed that the first anti-satellite systems be ready for use by 1987.

The impending tests are a point of contention between arms-control advocates and the Administration. Forty-five members of Congress recently sent a letter to President Reagan calling on him to ''refrain from testing this ASAT until we have tried in good faith to negotiate a ban on such weapons.''

Hope for Mutual Restraint

Dr. Richard Garwin, a physicist at the International Business Machines Corporation and a longtime Government adviser on military matters, has said the Russians ''show every sign of being willing to give up further testing of their ASAT's'' if the United States agrees to do the same.

Perhaps the most effective weapon against the current generation of satellites is in hand. It is an ordinary nuclear warhead that can be exploded in space. Such an explosion generates an electromagnetic pulse that damages or destroys unprotected electronics in satellites at great distances. The problem is that the pulse might wipe out a nation's own satellites as well as the enemy's.

But President Reagan's ''vision of the future,'' as expressed in his speech Wednesday night, extended to technologies that are not yet in hand and, according to many scientists, may not be feasible until well into the next century, if ever. These are the technologies of laser and particle-beam weapons.

The earliest potential space application of lasers, conceivable in the next 5 to 10 years, would be to attack enemy satellites or defend friendly satellites. Harold Brown, Secretary of Defense in the Carter Administration, wrote recently that a system of space-based lasers to intercept ballistic missiles, which Mr. Reagan was talking about, ''would probably not be feasible before the next century, if ever, and would cost on the order of $100 billion.''

Countermeasures Expected

Moreover, Mr. Brown said, ''by the time it was deployed, countermeasures against it would be possible, at lower cost, to prevent the system from operating as a successful ballistic missile defense.''

The most advanced laser under consideration is one that works by combining fluorine and hydrogen to produce energy in the form of light. This light is concentrated by mirrors in the weapon until it emerges as an intense, highly focused laser beam. A brief pulse of 200 billion watts, which might be possible, could vaporize metal and produce destructive shock waves.

Dr. Garwin, the longtime Government adviser, said there was ''no indication'' that ''you can make a big enough laser and point it accurately enough.'' He is sure, he said, that ''I can destroy the system of concentrated large laser satellites and if I'm going to have a war in which I undertake to attack the U.S., I'm certainly going to have arranged space mines next to the laser satellites to destroy them pre-emptively.''

Particle-beam weapons are at a more rudimentary stage of development than lasers. Such weapons would use streams of charged or neutral atomic or subatomic particles, accelerated to intense energies, to disable or destroy spacecraft or ballistic missiles. The rays of both weapons would reach a target at or near the speed of light.

Report on Soviet Effort

A 1977 article in Aviation Week and Space Technology, a respected trade weekly, reported evidence that the Russians had built a giant particle-beam projector on the ground. The Pentagon, however, said it doubted that the Soviet Union was even close to developing a weapon that could disable missiles.

The atmosphere has a scattering effect on a beam shot from the ground into space. And a major obstacle to deploying a particle-beam weapon in space is the problem of generating enough power to produce a deadly beam. One shot would consume tons of chemical fuel. The only possible practical alternative, scientists suggest, is to operate the weapon with a controlled thermonuclear plant, and this fusion technology is apparently many years away from being operational.

Because of the many uncertainties about laser and particle-beam weapons, scientists generally felt that President Reagan was raising false hopes by suggesting the possibility of their serving as an effective missile defense. Dr. Wolfgang K.H. Panofsky, a Stanford University physicist, said experts in these exotic technologies may be embarrassed by suggestions that the time is ripe to accelerate research, saying, ''The practitioners in the field are not anywhere near as gung-ho as the President's speech implies.''

But many scientists who criticized the speech nonetheless said they approved of continuing research and development efforts to explore space-based weapons to prevent a ''technological surprise'' by the Soviet Union.

By John Noble Wilford

On Anacapa Island, off the California coast near Santa Barbara, the brown pelicans are nesting in profusion among the volcanic rocks this spring, a welcome sight to ornithologists who had once feared for their fate. Their eggs are firm and more thick-shelled than in years past. The early hatchlings feed lustily on the regurgitated anchovies in their parents' baggy gular pouches.

All is not completely well in this large breeding colony of pelicans, scientists report, but it is better than anyone dared hope a decade ago. Indeed, the 3,000 pelicans that came to Anacapa to breed this year symbolize one of the most striking success stories in ecology. After some 40 million years of survival, the brown pelican species seemed headed toward the brink of extinction, a victim primarily of mankind's heavy use of pesticides. But measures to curb pesticides appear to have saved the pelicans.

''The recovery of the pelicans is a major accomplishment in ecology today,'' said Dr. Ralph W. Schreiber, curator of ornithology at the Los Angeles County Museum of Natural History. ''There are so many failures that it's good to have a success story.''

Dr. Schreiber, an authority on pelican behavior, believes a case can now be made for removing these large marine birds from the Government's endangered species list, though other experts caution that the bird's existence remains threatened by polluted waters and human invasions of their habitats. An ornithologist with the Office of Endangered Species, Jay M. Sheppard, said the removal of pelicans from the list is being considered, but no action is expected soon. He could not recall when a bird species had made a comeback warranting such action.

In any event, scientists plan to continue studying and monitoring the pelican as a useful early-warning system of trouble lurking in the coastal ecosystem. As long as the brown pelicans in plentiful number are there standing solemn watch at docks, stretching their absurd physiognomies, taking flight like the prehistoric pterodactyls, gliding gracefully and making their headlong kamikaze dives for fish - as long as the pelicans inhabit the warmer coasts of North America, it is a sign that the waters still abound in fish and plankton and are relatively free of insidious pollutants.

A decade ago, the prognosis for the brown pelican in North America was grim. These birds had vanished from Louisiana, the Pelican State, and were seldom seen anymore along the Texas coast. Few, if any, chicks were hatching in California; only eight chicks hatched on Anacapa in 1971. The pelicans seemed to be holding their own in Florida, but barely, and the prospects were none too bright. And so the brown pelican, that wonderful bird whose ''beak will hold more than his belican,'' in the words of the limerick, went on the endangered species list in 1973.

At the time, biologists already suspected pesticides as a major cause of the pelican's plight. Sometimes the effect was direct, poisoning the birds or their food supply. In other cases, sublethal doses of chemicals interrupted pelican reproduction.

Investigations found that endrin, a pesticide used for boll weevils and sugar-cane borers, was responsible for massive fish kills in the Mississippi River delta beginning in the late 1950's. This coincided with the catastrophic decline in the pelican population along the Louisiana and Texas coasts, from 50,000 to almost zero. Pelicans fish for a living, and the fishing was poor.

In an effort to bring the birds back, conservation agencies took young pelicans from Florida and set them up in colonies in Louisiana. By 1975, a population of almost 500 birds was established, but suddenly some 300 of them were found dead. Analysis determined they had lethal residues of endrin in their bodies. The pesticide was not only killing their food supply, it was poisoning the pelicans, too.

Dr. Schreiber doubts that pelicans will ever again thrive in Louisiana and Texas, despite the introduction of birds from Florida, because of diminished food supplies, oil spills and the loss of natural habitats to real estate development.

Effect on Reproduction

The effect of pesticides on pelican reproduction has been more subtle, though potentially disastrous, as Dr. Robert W. Risebrough, a University of California biologist, discovered when he visited Anacapa Island in 1969. He found only 12 intact eggs in the colony's 300 nests; a pelican usually lays three eggs in a breeding season, each one twice the size of a chicken egg. All around were the remains of crushed and collapsed egg shells.

Pelicans, Dr. Risebrough concluded, shared a problem that was also threatening the future of bald eagles, peregrine falcons and other bird species. Pesticides in their food were causing these birds to lay eggs with shells so thin that they collapsed while being laid or during incubation. Upon further study, DDT was identified as the prime suspect. Insecticide residues found in pelican eggs were almost totally those of DDT and its metabolic products.

For some reason, scientists soon found, pelicans are particularly sensitive to DDT-caused eggshell thinning. The chemical gets in plankton that is eaten by the small fish that pelicans consume, and at each step up the food chain, the chemical seems to become more concentrated. Although the actual mechanism is not fully understood, Dr. Schreiber explained, a metabolic product of DDT, known as DDE, seems to block the process that transports calcium from the bloodstream through to the shell.

The problem was more acute in the California breeding colonies than elsewhere, scientists said, because large amounts of DDT wastes were being dumped in Los Angeles by the Montrose Chemical Company.

Shells Still 20% Thinner

A few years after the use of DDT was banned in this country, in 1972, and after the company curtailed its dumping, pelicans resumed laying viable eggs on Anacapa. Dr. Daniel W. Anderson, professor of wildlife biology at the University of California at Davis, said a graduate student, Franklin Gress, recently visited the island and estimated 1,500 pairs of pelicans were nesting there. Though most of the cream-colored eggs looked durable, the shells were still about 20 percent thinner than normal.

''The pelican is recovering,'' Dr. Anderson said. ''The population in California is increasing, but it's probably only half of what it was before the 1950's. Reproduction rates are still not what they should be, which is about one hatchling per breeding pair. I'm for being cautious about taking the pelican off the endangered list. A lot of things can happen.''

One cause for lingering concern is the continued presence of pesticide residues in many adult pelicans. Many of the birds seen along the California coast breed on islands in the Gulf of California, near the agricultural regions of Mexico where DDT is still being used.

Another concern is over the pelican's sensitivity to fluctuations in its food supply. More than any other environmental factor, the availability of food is decisive in pelican breeding. Studies show that a hungry pelican is not an amorous pelican. The birds mate and nest only when they store up sufficient energy reserves for egg production and survival through the one-month incubation period.

Florida Birds Have Varied Diet

Pelicans in Florida feed on more than 30 species of small fish, which Dr. Schreiber said probably accounted for the greater population stability there. On the Pacific Coast the pelicans eat only anchovies. Consequently, commercial fishermen and conservationists have recently been eyeing each other suspiciously. The former view pelicans as competitors. The latter fear human overharvesting of anchovies will doom the pelicans. But so far, Dr. Anderson said, conflict has been avoided through Federal regulations limiting the commercial anchovy catch.

Food shortages, whether natural or man-induced, have had some severe effects on breeding pelicans in California and Mexico, according to Dr. James O. Keith, a research biologist with the United States Fish and Wildlife Service. Pesticide residues in the pelicans may aggravate the problem.

Writing in the spring issue of Oceanus, a publication of the Woods Hole Oceanographic Institution, Dr. Keith noted that in ringdoves without DDT residues, a 10 percent reduction in food was sufficient to keep 50 percent of the birds from ever attempting to breed. In birds with DDT residues, the same reduction of food kept all pairs from breeding. This suggested ''a similar pattern in brown pelicans,'' Dr. Keith said, because food shortages are common in their lives and DDT is still found in their bodies.

Among Best-Studied Birds

It was the prospect of losing these birds forever that led scientists to learn more about them. The brown pelican is now among the best-studied birds in the world.

Dr. Schreiber, for example, while a graduate student at the University of South Florida, studied the mating and nesting behavior of pelicans in Tampa Bay. He observed one male staking out a territory. The crown of its head, usually white, had turned yellow, a transformation marking its readiness to mate. It communicated its inclinations to a nearby female by repeated sideways movements of its head and long bill.

Once the female was won over, and their bond sealed, the two pelicans spent two weeks collecting sticks and grass for their nest while pausing frequently for copulation. After the eggs were laid, the two took turns on the nest for the month-long incubation. They fed the hatchlings for another three months; normally only one of the three eggs leads to a surviving bird. And for the surviving young birds life was a struggle through the first year; normally three-fourths of them perish.

Many fail to master the diving techniques that pelicans depend on for catching fish. Pelicans who get the diving knack, catching and eating 20 percent of their body weight in fish each day, usually live long lives of 25 to 40 years. However, more than 700 pelicans in Florida, about 5 percent of the population there, die each year from entangling mishaps with fishing hooks and lines.

The brown pelican, which exists solely in the Western Hemisphere, is the only one of the seven pelican species to dive for its food. The others swim along, more like ducks, and gulp down fish.

By John Noble Wilford

Out there, far, far away where Earth is a mere pinpoint of light and the Sun is a pale disk of diminishing consequence, a hardy little spacecraft cruises on and on into the unexplored. No machine of human design has ever gone so far. Pioneer 10 has traveled to the reaches of Pluto, a distance it achieved yesterday, and is advancing toward the edge of the solar system.

From out there, now 2.7 billion miles away, Pioneer's eight-watt radio transmitter sends faint messages back to Earth every day, whispers of discovery. The transit time of these reports, traveling at the speed of light, is 4 hours and 16 minutes. And by the time the signals arrive at tracking antennas, they have all but vanished, their strength reduced to 20-billionths of a watt.

But scientists with the patience to extract the signals out of the background noise and to decipher their messages are learning for the first time what it is like in the outermost solar system. It is cold and dark and empty, as they knew it must be. A tenuous wind of solar particles, the million-mile-an-hour solar wind, still blows outward. Cosmic rays race inward. A virtual vacuum it may be, but nothingness, it seems, is a relative condition.

If the spacecraft survives long enough and the scientists are clever enough, more exciting discoveries could lie ahead for Pioneer 10. It might be able to detect gravity waves, which have been theorized but have never been observed. It might locate the source of the mysterious force tugging at Uranus and Neptune, a gravitational force suggesting the presence of some as yet unseen object - perhaps the long-sought Planet X or a dim companion star to the Sun. The spacecraft may also function long enough to report back the answer to the question, Where does the solar system end and interstellar space begin?

''We are constantly entering unexplored territory,'' says Dr. Aaron Barnes, an astrophysicist at the Ames Research Center in Mountain View, Calif., where the Pioneer mission is directed. ''We really don't know what we'll learn.''

Travel was never more broadening. When Pioneer 10 was launched March 3, 1972, from Cape Canaveral, Fla., no spacecraft had ventured farther than Mars. Pioneer made its way safely through the asteroid belt, a region littered with rocky debris between Mars and Jupiter. It flew within 81,000 miles of Jupiter's cloudtops on Dec. 2, 1973, returning the first close-up images of the Sun's largest planet. The pictures revealed the cyclonic forces of the Great Red Spot roiling Jupiter's dense hydrogen and helium atmosphere. Pioneer made the first detailed observations of Jupiter's powerful radiation belts and discovered that the planet's sphere of magnetic influence extended to the orbit of Saturn, a distance of half a billion miles.

Pioneer had by then accomplished its mission and exceeded its designed 21-month lifetime. The 500-pound craft had been blasted by Jovian radiation and pelted with micrometeoroids. ''No one dreamed then we'd still be hearing from Pioneer today,'' recalls Dr. James A. Van Allen of the University of Iowa, one of the mission's scientists.

Still Pioneer kept going, its nine-foot dish antenna always cocked in the direction of Earth. It dutifully kept sending home a travelogue on interplanetary space as it crossed the orbit of Saturn in 1976 and the orbit of Uranus in 1979.

Pioneer 10 had now made believers out of its creators, the engineers for the National Aeronautics and Space Administration and the spacecraft manufacturer, TRW Inc. Like the little engine that could, this was the little spacecraft that could probably push on to the frontier of interstellar space and still be living to tell the tale.

After more than 11 years in flight, according to Richard O. Fimmel, the project manager at NASA's Ames Research Center, all the craft's scientific instruments, except the magnetometer, are working normally. He estimates that deep-space antennas should maintain communications with Pioneer for eight more years, out to a distance of five billion miles. That is when the craft's radioisotopic power unit will no longer be generating enough electricity for operations.

Leaving Realm of Known Planets

Right now Pioneer is, in effect, leaving the realm of the known planets. At 5 P.M. yesterday the craft, traveling 30,613 miles an hour, sped farther out than Pluto. It was then almost 2.8 billion miles from the Sun; Earth is 93 million miles away from the Sun. At the time, however, Pluto was on the other side of the Sun.

On June 13, Pioneer's outbound trajectory will cross Neptune's orbit, 2.81 billion miles from the Sun. Normally Pluto is the outermost planet, but because its orbit is highly elliptical, unlike the roughly circular orbits of the other planets, Pluto is now nearer to the Sun than Neptune and will be for the next 17 years.

Each day flight controllers at Ames typically send Pioneer a message when they arrive at work. By quitting time eight and a half hours later, which is the round-trip communications time, they receive Pioneer's reply.

They also receive about 16 hours of scientific data each day from the spacecraft, mainly information defining the extent and behavior of the heliosphere, the Sun's extended atmosphere. Blowing away in all directions from the Sun is the solar wind, an electrically charged gas composed of protons (hydrogen nuclei) and electrons that stream out from the Sun's corona. The wind carries along with it the Sun's magnetic field.

It is as if the Sun is blowing a pressure bubble out into space, a tear-shaped magnetic bubble that acts as a barrier against intrusions by most particles from the interstellar medium. The bubble is streamlined by the motion of the solar system through this interstellar gas. At the solar system's leading edge, so to speak, the bubble is blunted. In the opposite direction, the bubble forms a long tail. Pioneer 10 is traveling down the tail of the heliosphere.

Before Pioneer, some scientists believed the boundary, the heliopause, might be just beyond Jupiter. But the spacecraft is six times that far out and has yet to encounter the boundary.

The spacecraft's instruments indicate the heliosphere ''breathes'' in and out once every 11-year solar cycle, as reported by Dr. John Simpson, a Pioneer experimenter from the University of Chicago. When the Sun is most turbulent, which last occurred in 1980, shock waves from its magnetic storms seem to persist throughout the heliosphere for as long as a year. The effect may be to change the bubble's shape.

Moreover, at the time of maximum solar activity, the bubble seems to be more impervious to cosmic rays from out in the galaxy. Pioneer's detectors found the cosmic-ray particles half as numerous then.

For the rest of Pioneer's working lifetime, scientists will be monitoring the data for signs of the boundary crossing. Scientists are not sure what to expect. Dr. Barnes says Pioneer would probably encounter changes in the outside temperatures and discernible turbulence as the solar wind was buffeted by the incoming interstellar gases. The speed of the solar wind should drop suddenly from supersonic to subsonic. Dr. Van Allen, however, doubts ''anything dramatic'' will be observed at the heliopause.

Other spacecraft, Voyager 1 and Pioneer 11, may find a sharper boundary. Though not as far from Earth as Pioneer 10, they are traveling in an opposite direction, toward the blunt edge of the bubble. Dr. Edward C. Stone of the California Institute of Technology, Voyager's chief scientist, believes the spacecraft should encounter a kind of bow shock caused by the solar wind slamming into the dominant and relatively stationary interstellar environment. It may even be possible to hear the boundary crossing. Energies produced by the interactions may give off whistling noises that Voyager will radio back to Earth.

Because of its great distance away, Pioneer 10 could give scientists their first evidence of the existence of gravity waves. According to Einstein's General Theory of Relativity, cataclysms in the universe, collapsing or exploding stars, should send waves of gravitational radiation across the galaxies. Dr. John Anderson of the Jet Propulsion Laboratory says that a painstaking analysis of radio transmissions from Pioneer to Earth might reveal the jiggling effects that a gravity wave would have on the craft or Earth itself.

Possible Discovery at the Edge

Accordingly, Pioneer 10 may lead scientists to the discovery of some massive object toward the edge of the solar system. It may be, as some astronomers suspect, a ''brown dwarf'' star, a celestial object that was not quite massive enough for its thermonuclear furnace to ignite. Since most stars are paired, it is not unreasonable to assume that the Sun might have such a dim companion.

Or the force could be from a 10th planet, the long-sought Planet X. Evidence assembled in recent years has led several groups of astronomers to renew the search for a large planet out beyond Pluto and Neptune.

Someday, of course, even the durable Pioneer 10 will lose touch with those who sent it off on its long journey. The little radio that has already transmitted more than 126 billion bits of scientific data will go dead. Sensors will lose sight of the Sun.

Even then, silent and derelict, Pioneer 10 will cruise on and on, the first human artifact to leave the solar system. About once every million years, as nearly as anyone can calculate such things, the craft might expect to come close to another star system. It might then be found by other intelligent beings.

With that eventuality in mind, Pioneer's makers indulged in an act of infinite hubris. They attached a plaque engraved with images of a man and a woman, the location of Earth and some points of basic science - possibly the little spacecraft's ultimate message.

By John Noble Wilford

Where ships of a future day may sail, there is no air smacking of salt. There is no air at all. But a ''breeze'' does blow, a gentle force. Imperceptible though it may seem, nothing to flutter the pennant on a tall mast, this force may someday send ships scudding through interplanetary space.

The force is the light of the sun, sunbeams and nothing more. Photons of sunlight have no mass but they do have momentum. They exert a pervasive pressure that can push against gossamer sails in the vacuum of space. Square sails like huge kites or long crisscrossed sails could be spread out hundreds of feet, miles perhaps, to deflect the light as if it were wind. The force of sunlight beating on the thin plastic sails should be enough to carry ships out to the moon, to asteroids and comets, to the distant planets.

Solar sailing may be only a concept to build a dream on, something for another century. No government deems it worthy of financial support. But a growing number of enthusiasts, many of them engineers, are seeking to put the dream to flight in two or three years. They believe in solar sailing enough to raise money from private sources and invest their own time and talent, setting up a veritable cottage industry to develop models and prototypes of sailing rigs with which to test the dream.

Their efforts in the United States have reached the point, they say, where they are almost ready to send a small sailing craft out 1,000 miles to check out the concept. If the square sail is unfurled properly and passes performance tests, the craft might then be directed toward a swing around the moon, a leisurely voyage of more than two years. Work on this venture is being directed by the World Space Foundation, a nonprofit corporation based in Pasadena, Calif.

Engineers in Czechoslovakia are also doing theoretical studies and building model sails to study the dynamics of such craft. Similar efforts in France have emboldened engineers there to challenge the world to an unmanned race of solar sailing craft to the moon, a regatta the likes of which Newport never envisioned.

The moon race may or may not come about. Many officials of the National Aeronautics and Space Administration are still skeptical about the sail's future. The believers, however, hope that interest generated by a successful demonstration flight would be, according to Dr. Louis D. Friedman, ''so strong that the naysayers will be suppressed in favor of the dreamers.'' Dr. Friedman is executive director of the Planetary Society, a public-membership organization based in Pasadena that seeks to stimulate support for planetary science and exploration.

One of the believers, Chauncey Uphoff of NASA's Jet Propulsion Laboratory in Pasadena, defines the rationale in support of solar sailing. Low-cost transportation, he notes, is essential for the development of any new frontier. To be truly effective, the transportation system should use fuel available on that frontier, like the wood-burning locomotives that crossed the American West and the sailing ships that crossed the Atlantic.

Accordingly, Mr. Uphoff says, ships that sail by the energy from sunlight - the one plentiful ''fuel'' in interplanetary space - should provide a relatively low-cost means for long-duration voyages of exploration and, ultimately, the hauling of cargoes between extraterrestrial ports of call.

The fundamental principle of solar sailing was predicted by James Clerk Maxwell in the 19th century. According to his theory of electromagnetism, if light was indeed a form of electromagnetic radiation, it should exert a force on anything from which it was reflected. Einstein later theorized that although photons, the elemental bundles of light, had no mass, energy was equivalent to mass and thus an object like a photon could have energy and momentum without having mass.

Seizing on this, two Soviet visionaries of space flight, Konstantin Tsiolkovsky and Fridrikh Tsander, published in the 1920's the first known descriptions of how the photon energy of the sun could move a reflecting sail in space. A 1951 article in Astounding Science Fiction Magazine, entitled ''Clipper Ships of Space,'' advanced the idea of a 100-ton spaceship, a ''light-jammer,'' powered by a three-mile sail. The first technical discussion of solar sailing in an American scientific journal came in 1958 when Richard L. Garwin, a physicist at I.B.M. and Columbia University, wrote of it as ''a practical method of propulsion within the solar system.''

A study by the Battelle Memorial Institute in Columbus, Ohio, found solar sailing to be feasible, and this led to further analysis by the Jet Propulsion Laboratory in the middle 1970's. Engineers there were investigating possible missions to rendezvous with Halley's comet when it passes nearby in 1985-86. They liked the idea of a sail design known as the heliogyro.

Instead of one main sheet, this sailing rig would consist of an array of 12 sail ''blades,'' mounted much like helicopter blades. Each blade, a paper-thin plastic coated with an aluminum film for greater reflectivity, would be 26 feet wide and 3.75 miles long. The slow rotation of the array would produce enough centrifugal force to support and stiffen each blade, eliminating the need for heavy spars, stays and winches. And the blades could be pitched to different angles to turn the ship with respect to the sun.

This and all other solar-sailing rigs would ''tack'' to fly either in toward the sun or out toward the farther reaches of the solar system. But unlike a sailboat, which tacks by managing wind force against water resistance, a solar sailer would manage light pressure and its own orbital velocity. As each photon bounces off the sail, the reversal of its momentum shows up as a reaction force perpendicular to the sail. To go toward the sun, the sail is set to reflect sunlight forward in the direction of its orbit. The resulting reverse force slows the craft and allows solar gravity to pull it spiraling in toward the sun or any intermediate destination. The process is reversed to sail outward to Mars, the asteroids or the outer planets.

The greater the sail surface and proximity to the sun, the greater the reflectivity pressure or energy thrust. At best, the thrust developed by a solar sail is so small as to seem insignificant. But unlike fuel-limited chemical propulsion systems, the sail would be providing thrust constantly throughout the trip, for years on end, gathering velocity until a fairly small craft might attain speeds of up to 124,000 miles an hour.

No one bought the idea of a solar sail for a Halley's Comet flight, and eventually the United States dropped the whole comet excursion because of the budgetary squeeze.

Dr. Friedman, who had headed the study at the Jet Propulsion Laboratory, and Robert L. Staehle, an engineer on the team, never abandoned the idea. Dr. Friedman left the laboratory to direct the Planetary Society. Mr. Staehle, who still works at the laboratory, and some friends established the World Space Foundation to give private citizens a chance to ''support and participate in space exploration.''

One of the foundation's primary undertakings has been the solar sail project. Working weekends and nights, several dozen engineers from the Jet Propulsion Laboratory and several aerospace companies in the Los Angeles area designed a square sail with four spars like the crosspieces of a kite and with triangular vanes at two corners for orienting the sail.

Mr. Staehle said last week that the foundation has held preliminary talks with NASA and the European Space Agency to arrange passage for the test sail on a space shuttle flight or Europe's Ariane rocket. The sailing craft would have to be boosted up at least 1,000 miles to get away from the drag of atmospheric gases from the earth.

At that altitude, the light stainless-steel spars and stays, rolled up inside the spacecraft like a carpenter's rule, would be paid out slowly, unfurling the accordion-folded sail until it was stretched full and wrinkle-free.

By now, the foundation has spent more than $100,000 on solar sailing, part of it from a grant by the Charles A. Lindbergh Fund. Mr. Staehle estimates that the demonstration flight would cost from $2 million to $12 million, depending on how much of the materials and launching services are donated. Hughes Aircraft Company, for instance, recently gave the project a surplus rocket motor.

If the test goes well, Mr. Staehle said, the foundation hopes to get the Government interested in grander ventures. A mission to return a soil sample from Mercury might be more easily accomplished with sails than rockets. Another sailing ship might visit a number of asteroids, in the manner of a Captain Cook going from island to island in the Pacific. Or a ship might sail the heavy freight to Mars, getting it there in time for use by the first astronauts, who would arrive by faster, smaller rocket-powered craft. Someday perhaps, if dreams take flight on sunbeams.

Tennyson, when he ''dipp'd into the future,'' saw a vision that seemed to anticipate solar sailing through space. In ''Locksley Hall,'' the poet ''Saw the heavens fill with commerce, argosies of magic sails.''

By John Noble Wilford

Huckleberry Finn, shrewd in so many ways, had trouble understanding the symbolic nature of maps. In “Tom Sawyer Abroad,” Mark Twain writes of Tom and Huck’s being up in a balloon, wondering if they passed over Illinois. Huck insists they have not, and Tom asks Huck how he can be so sure. “I know by the color. We’re right over Illinois yet,” Huck says. “And you can see for yourself that Indiana ain’t in sight.”

''What's the color got to do with it?'' asks Tom.

''It's got everything to do with it. Illinois is green, Indiana is pink. You show me any pink down here, if you can. No, sir; it's green.''

''Indiana pink? Why, what a lie!''

''It ain't no lie; I've seen it on the map, and it's pink.''

This is too much for Tom. ''Seen it on the map! Huck Finn, did you reckon the states was the same color out of doors as they are on the map?''

Huck, unfazed, sticks to his literal-minded view of cartography. ''Tom Sawyer, what's a map for? Ain't it to learn you facts?''

Huckleberry Finn's delightful confusion came to mind not long ago when the National Aeronautics and Space Administration displayed some of the latest, most striking mapping images of the world as seen from space. They were produced by the new technologies of remote sensing and electronic data processing that have been transforming the ancient art and science of mapmaking. Remote sensing, by airborne and spaceborne radar and by instruments known as multispectral scanners, provides a new means of gathering prodigious amounts of information, rapidly and repeatedly, for making and revising maps. It complements and to some extent replaces aerial photography and the labors of foot-slogging surveyors, which can provide greater detail of topography but which cannot provide as comprehensive coverage in as short a time. And the enormous appetite of computers for ingesting and digesting data makes it possible to convert remote-sensing images into maps. In a growing number of instances, computers are replacing conventional paper maps with digital maps in the computer's memory. While the information can be used to print out a more or less conventional-looking map, the big advantage of this system is that it can store in digital form information that can be quickly changed to take new geographical features into account and can be used immediately to produce a totally revised map or a map showing only specific features in a region, such as, say, all the four-lane highways in Pennsylvania.

These new technologies have made it possible for the first time to map the entire world, from pole to pole, and expose every part of every land to continuous scrutiny. They are the basis for the ''spy-in-the-sky'' satellites deployed routinely by both the United States and the Soviet Union, satellites that supply military strategists with the means to locate with incredible accuracy potential targets for missile attack.

On the other hand, these same technologies tend to be stabilizing influences on world affairs because of their value in monitoring conformance with arms-control agreements and reducing the chances that one side will act hastily through miscalculation of the other's capabilities or intentions.

But the application of these technologies goes far beyond military reconnaissance. Mapping from space affords a new view of the world and its natural resources, with ecological, economic and political implications that are now only beginning to be appreciated. The new technology can help in the search for new sources of minerals and petroleum, in taking inventory of crops and their condition and in determining the depth of snow cover as a way of predicting floods. For Huck Finn it would have been sufficiently flabbergasting to contemplate NASA's new remote-sensing multispectral scanner, particularly its color images. No colors in the images are true to the out-of-doors, or even to usual maps (see illustration, page 49). Much of Indiana runs to pink or red, which would have been satisfying to Huck, but so does Illinois. So do all surfaces of the earth covered with vegetation. And the Mississippi River appears deep blue, a misrepresentation that Huck, with his experience rafting the muddy waters, would have found laughable. Elsewhere, urban sprawl is delineated in smudges of grayish-blue. Bare land shows up as white, green or brown, depending on soil conditions; some clays rich in iron oxides stand out in yellow and orange. Variations of other hues denote differences between clear and polluted water, deciduous and coniferous forest, rice and soybeans, healthy and diseased crops. This is the world as it looks through the electronic eyes of a robot beholder, the Landsat spacecraft, which carries the scanner. More than one million of these images have been produced since the first of four Landsats was launched into earth orbit in 1972, an output that constitutes an extraordinary portfolio of all parts of the world seen in great detail in all seasons, including hitherto largely unmapped areas such as the Arctic and central Asia. The shapes of the land may be familiar: the continents and coastlines, the boot of Italy and the hook of Cape Cod, the deltas of the Nile and the Mississippi. But there is more there than ordinarily meets the human eye.

''These are not just pretty pictures,'' Samuel W. Keller, a NASA official, explained at a showing of Landsat 4 imagery. Technically, they are not photographs at all. They are multispectral images. Photography, with an Instamatic or the sharpest telescopic lens, ordinarily makes pictures of features by registering their reflections of light visible to the human eye. Landsat's scanning sensors not only see visible light in the yellow and red wavelengths but also detect radiation in the region of the electromagnetic spectrum beyond red and thus beyond the rather limited perception of the human eye. This is known as the near-infrared region. Hence Landsat's multispectral vision, and its unusual ability, as Huck would say, to ''learn you facts.''

Since different objects - animal, vegetable and mineral -reflect sunlight in different ways, each is said to have a ''spectral signature.'' Sandstone reflects light in the infrared differently from shale, wet soil differently from dry soil, corn differently from wheat, and so forth. These otherwise invisible signatures are discernible, after careful analysis, from the image data produced by Landsat and processed by computers on the ground. In this processing, what is essentially invisible is made visible through the use of ''false'' colors that give these images such an unfamiliar aspect.

Sometimes the effect approaches or, depending on taste, surpasses modern art. In a test of the other new method of looking at the earth from afar, the imaging radar system carried by the space shuttle Columbia profiled great swaths of land with remarkable results (see illustration, left). In this system, radio signals are bounced off the earth and the returning echoes are processed into images. Rugged mountains and sinuous valleys stand out in the radar imagery as on a three-dimensional relief map. A mosaic of the Great Salt Desert of northern Iran, when processed in false color, seems to cross the boundary from science to Willem de Kooning and Jackson Pollock. It becomes a painting fluent with marbled, swirling patterns in burnt orange and blue, ancient sediments in reality, and spreading patches of strong red and blue, the dry salt and clay deposits.

Esthetics aside, the new technologies are changing the look of maps in a more fundamental way. Nowhere is this better illustrated than in the electronic maps that will be carried and consulted by the cruise missiles. These maps no more resemble familiar paper maps than a computer data tape does the Gutenberg Bible.

Like a traveler on a more innocent journey, the cruise missile will have tucked in its onboard computer a ''map'' of the route it is to follow and of its ultimate target. This is a magnetic tape containing in digital form such map information for the route as ground elevations and coastlines as well as forests, large buildings, antennae, power lines and other vertical obstructions. The Defense Mapping Agency is well on the way to converting to digital form the maps for more than half of the world's land surface. That is, existing maps are being disassembled and their components - contour lines, roads, bodies of water, cities, etc. - identified by number codes. This is called digitizing. New mapping data come not only from Landsat but also from what the Pentagon calls ''other sources,'' which presumably include the even more sophisticated secret digital-imaging reconnaissance satellites (KH-11, or Keyhole). These data originate as electronic pulses that translate to computer numbers, and so are more readily incorporated in the agency's digital data bank. Digitizing has been a monumental task, and will cost more than $1 billion by the time it is completed.

With one of these ''memorized'' maps, according to the Defense Mapping Agency, a cruise missile should be able to fly many hundreds of miles at tree-top level, to avoid radar detection, and find its target with astonishing accuracy. For much of the flight the missile follows a preset course. Then, at specified points, the missile's radar altimeter senses the ground below and compares its readings with the ''map.'' The missile thus ''sees'' where it is and, if necessary, adjusts its course to the next checkpoint. The winged missile, obeying messages from its map and radar, undulates with the contours of the land. The closer it gets to the intended target, the more frequently it consults the map. Although much about the final approach is classified secret, and critics question the missile's reliability and vaunted accuracy, some arms experts in Washington say that the cruise missile is supposed to have a 50 percent chance of delivering its nuclear warhead to within four to six feet of a target.

Looking to the future, Maj. Gen. Richard M. Wells, director of the mapping agency, says, ''Our goal is an all-digital capability, all the way from acquisition of data to their publication as maps or other uses.'' By the 1990's, perhaps, the D.M.A. would have the whole world reduced to computer digits and stored in a vast library of magnetic and optical disks. Conceivably, each time a highway was extended a few miles, a new housing complex went up or a forest was cut down, some computer numbers would be added or revised. It would always be possible to have an up-to-date world cartographically. ORRIS M. THOMPSON, A RESEARCH cartographer at the United States Geological Survey in Reston, Va., shies away from using the word revolution to describe cartography’s new-found capabilities. ''Almost at any time in the last 40 years,'' he says, ''you could have looked at what was happening in mapping and called it revolutionary. It's an evolution rather than a revolution. All those gadgets and systems are the result of long, sweaty hours, a little progress here and there, with one thing building on another every day.'' His view reflects the temper of most cartographers, who emphasize the incremental nature of what has occurred in their profession. Aerial photography, for example, may be said to have begun in 1858 with a feat by Gaspard-Felix Tournachon, a Paris photographer who called himself Nadar. He loaded his wet-plate apparatus into the basket of a balloon and cast off to an altitude of some 250 feet, where he succeeded in taking a picture of an entire village. Honore Daumier, the artist, drew a caricature of a balloonist with a caption saying that Nadar had elevated photography to the ''highest'' art.

World War I brought together the airplane and photography, leaving no doubt that the two technologies had a joint future. Aerial photographs, like the new radar and multispectral images, are not in themselves maps. They are the raw material of maps. Converting them to maps requires a number of complex mathematical steps to determine scale and pin down the elevations, longitudes and latitudes - the precise locations -of features in relation to each other and to the rest of the world. This procedure, known as photogrammetry, is yielding to varying degrees of automation today, but it used to involve hours upon hours of work with stereoscopic plotting instruments. Overlapping photographs of the same terrain, each seen from a slightly different perspective, produce a three-dimensional model from which map information can be extracted.

When the space age dawned, in 1957, little thought was given to its potential impact on mapping. Many experts assumed that the earth's atmosphere would probably have a blurring effect and preclude map-quality photography from space. The early astronauts soon proved them wrong.

As he approached the end of his Mercury orbital flight in 1962, John H. Glenn Jr. remarked, ''I can see the whole state of Florida just laid out like on a map.'' He could see whole what generations of mappers had had to piece together from the ground or low-altitude aircraft. Even more revealing, and tantalizing, to mappers was L. Gordon Cooper Jr.'s experience on the last Mercury flight, in 1963. More than 100 miles over Tibet, the astronaut reported, ''I could detect individual houses and streets.'' Comparing existing maps, years out of date, with some pictures he had taken, cartographers easily identified unmapped mountains in Tibet, mislocated lakes and the perimeters of ancient lake beds. From this came a revised map of Tibet and a growing impatience to exploit space flight's mapmaking potential.

This led, after years of bureaucratic infighting and budget constraint, to the Landsat program. The Defense Department had already developed and deployed advanced remote-sensing instruments on its various reconnaissance satellites. These included telescopic cameras with such sharp eyes that they could discern not only missile sites and troop movements but the painted lines in parking lots and, it is said, even the license-plate numbers on Moscow automobiles. More recently, military satellites, like Keyhole, have replaced photography with electronic sensors that detect variations in light intensity and convert these into images of extraordinary clarity. But these are secret programs, and the technology that was cleared for use on the Landsats was purposely not as good as it could have been, since it was intended as a basically nonmilitary tool. The Pentagon did not want the Russians to know what the United States could actually see from space.

Three virtually identical Landsats were launched, in 1972, 1975 and 1978, under the direction of NASA's Goddard Space Flight Center in Greenbelt, Md., and their performance measured up to the most optimistic predictions. From 570-mile-high polar-crossing orbits, the spacecrafts' multispectral scanners produced a continuous stream of images. All types of specialists eagerly pored over the incoming images and liked what they saw. They liked the comprehensive and repetitive coverage. Each image, taken along a 115-mile-wide swath, covered 13,000 square miles of land surface; an airplane would have had to snap 1,000 pictures to encompass an equal amount of land. With some 30,000 images, moreover, a Landsat could record the whole world every 18 days.

The broad view appealed to geologists, even to those who had been skeptical at first. ''I didn't have great hopes for this electronic stuff,'' recalls Dr. Paul D. Lowman Jr., a Goddard geologist who felt more comfortable with ''real'' photography. But in no time Dr. Lowman discovered in the Landsat imagery many previously unmapped fractures branching off the San Andreas Fault in California. Other geologists revised maps of mountain ranges and spotted areas of extensive fracturing in Alaska that may be associated with mineral deposits. Oil and mining companies rushed to buy the images; some major oil discoveries, it is rumored, can be attributed in part to Landsat data.

Agronomists established that they could take quick inventories of crops. In early tests, they found that Landsat images could discriminate among 29 separate types of vegetation in Arizona and could tell the difference among California fields that were fallow, freshly plowed, newly sown or bearing crops. The Government now routinely uses Landsat data in forecasting the Soviet Union's trouble-plagued wheat production. More than 100 nations, some with their own receiving stations, make use of Landsat data to keep track of their crops, forests and water resources as well as to produce some of the first reliable maps of their hinterlands.

Mapmakers, like the geologists, had their initial doubts about Landsat. ''God knows, I was a skeptic, but I was dead wrong,'' says Dr. Alden P. Colvocoresses, another research cartographer at the Geological Survey. A wholehearted convert now, he displays on his office wall the chart showing a previously unmapped Indian Ocean reef that was detected by Landsat. It bears the name Colvocoresses Reef. He rhapsodizes about a tiny island off Labrador that Landsat put on the map for the first time. It bears the name Landsat Island. He concedes that surveys from aircraft produce images with clearer detail, at resolutions of a few feet or inches. But Landsat, he notes, covers more ground more quickly and more often; three images, taken in less than one minute, brought forth a photo map of New Jersey. Dr. Colvocoresses also concedes that it is impossible to extract contours from Landsat imagery. He emphasizes, instead, the satellites' usefulness in map revision. Once an area has been topographically mapped by more conventional means, the major mapping problem is not land forms, which change little, but keeping up with changes in cultural, or man-made, features such as roads and buildings, which change too rapidly for ordinary mapmakers.

The first two Landsats have long since ceased operations. Landsat 3 stopped functioning in March and was put in standby mode. Last July it was joined by another, Landsat 4. This spacecraft is even more to the cartographers' liking. The spatial resolution of its imaging systems is three to four times better than that of the previous Landsats, and it can observe more subtle variations in light intensities reflected from the land. Each of the sensors in its primary imaging system has a gray scale of 256, compared with 64 for the earlier Landsats. That is, each of its sensors responds to 256 variations in light intensity and encodes the results in electronic digits, each number representing a picture element, or pixel. All the pixels are assembled through computer processing to create the images.

Landsat 4's enhanced capability comes from its new set of sensors known as the thematic mapper. In addition to its greater resolution and sensitivity to light contrasts, the instrument can see more because it measures reflected light in six wavelengths, four of them infrared, as well as in a thermal channel for taking surface temperatures. In cartography, a thematic map is intended to serve some special purpose or to illustrate a particular subject, in contrast to a general map on which a wide variety of phenomena appear together. The theme can be soil or vegetation distribution, glacial flows or snow cover, geologic faults, land-use patterns, all of which are the stock in trade of Landsat mapping.

With the thematic mapper, Landsat images reveal in finer detail street patterns, individual buildings and specific aspects of fields such as soil variability. In new images of the Washington area, for example, bridges, streets, airport runways and even bike paths, through computer enhancement processing, are discernible; the Capitol shows up as a blue rectangle surrounded by red, the false-color for vegetation and not a political or fiscal statement. ''Where there is a difference in the succulence of vegetation, we can discriminate that and we could not do that before,'' says Dr. Vincent V. Salomonson, the chief Landsat scientist. ''This allows us to separate corn from rice and rice from soybeans, and so on.''

Landsat's future is uncertain, however. The Reagan Administration wants to turn Landsat over to private enterprise, even though remote-sensing experts warn that a viable commercial market for Landsat data is at least a decade away. The Communications Satellite Corporation, the logical purchaser, agreed to buy Landsat only if the Government would throw the weather satellites into the deal. An announcement of this proposal last March provoked a tempest of Congressional protest, leaving the fate of the Landsat program much in doubt. As observant as Landsat is, its images are virtually useless to topographic mappers interested in the texture of the land. For this, they are looking with rising expectations to a sophisticated version of radar flown in aircraft and more recently in spacecraft. The system, known as side-looking imaging radar or synthetic-aperture radar, involves sending pulses of ultrahigh-frequency radio signals toward a target and then detecting the faint echo that is reflected back to the aircraft or satellite. A rough surface will reflect more radio energy than smoother surfaces. Mountainous terrain and lava flows, for instance, will show up as bright sources in a radar image. Analysis of the time it takes signals to make their round trips gives a measure of the relative elevations of various ground features. The echoes are recorded on film in a holographic fashion and are then transformed, using lasers, into images that give the illusion of three dimensions. The final product is a photograph from which maps, particularly geologic and topographic maps, can be fashioned.

In the 1960's, imaging radar was introduced to military aircraft for all-weather targeting and reconnaissance work. Another of radar's attributes is that it can function night or day and see through clouds. The most ambitious and successful cartographic application of this technology came in the 1970's when Brazil, with the help of American contractors, conducted an airborne radar survey of the poorly mapped Amazon Basin, more than half of the nation's territory. A previously unmapped river, several hundred miles long, was discovered, and a region marked out as a national forest reserve was found to be savanna.

The first civilian imaging radar carried into earth orbit was aboard an oceanographic satellite named Seasat, which was launched in 1978. Although Seasat operated less than four months, because of a malfunction, scientists and cartographers saw enough in the data to be encouraged and amazed. The survey confirmed that the surface of the ocean has contours like the land. At some places it is as much as 600 feet higher than in others. These bulges and dips occur because of gravitational differences resulting from an unequal distribution of mass in the earth's interior or, in more subtle instances, because of corresponding hills and valleys of the ocean floor beneath. A seamount two miles high raises the ocean surface above it about three feet. Taking this information from Seasat, scientists at the Jet Propulsion Laboratory in Pasadena, Calif., constructed a map of the world's sea floors that will likely serve as a guide to future explorations and provoke some revised thinking about global geology. Similarly, Dr. William F. Haxby at Columbia University's Lamont-Doherty Geological Observatory is perfecting what he calls ''geotectonic imagery'' from Seasat data, a technique that yields maps of submarine mountains, ridges, trenches and basins in almost dry-land detail.

A similar radar system, designed primarily to survey land, rode in the cargo bay of the space shuttle Columbia on its second mission in November 1981. Some of the resulting images were overlaid with Landsat images to highlight the complementary nature of the technologies, a mixing of radar's sharp view of terrain relief and Landsat's multispectral view of surface chemistry, as in the kinds of rocks and vegetation. The combined images in false color can be dazzling, as well as informative.

But the most arresting discoveries to come out of the preliminary analysis were the shuttle radar's observations beneath the Sahara sands. In extremely arid regions, it was found, the radar signals penetrated 6 to 10 feet - sometimes 15 feet - below the surface through loose, dry sand, often until they hit bedrock. Crossing over the Sudan and southern Egypt, the Columbia's radar produced images revealing buried traces of rivers that once flowed there and carved out valleys as broad as those of the present Nile. Carol S. Breed of the Geological Survey in Flagstaff, Ariz., was the first to see this. Geologists later bored holes into the desert and confirmed the existence of an ancient drainage system and found buried sites of human settlements from the time when the Sahara was less arid. Reporting the discovery in the journal Science, the team of radar experts concluded: ''The potential for mapping ancient drainage patterns - and, by inference, potential sources of near-surface ground water - is sufficient to arouse excitement among earth scientists, who now have a new means of exploring the deserts of the earth.''

One of the scientists, Dr. Charles Elachi of the Jet Propulsion Laboratory, says that in future experiments from the space shuttle the imaging radar system will be tested in different radio frequencies and at different viewing angles. The oblique angle of the radar beam, like the angles of early or late sunlight, produces more sharply etched images of mountains and other relief. A more advanced version of the radar is to be flown on a shuttle mission next year. With soaring confidence in radar's mapping potential, Dr. Elachi declares: ''We have the technology and the ideas. We have the platform, the space shuttle. With two or three shuttle flights in polar orbit, we could map the topography for the whole world.'' What is happening with multispectral sensing and radar may be evolutionary, as the Geological Survey's Morris Thompson suggests, but the way the new mapping information is being handled by computers approaches the revolutionary. It represents more than an increment of progress; it is a vaulting stride toward capabilities that would have been inconceivable a short time ago. This not only changes the way map information is gathered, but the way maps are produced, by automation, and the very definition of what a map is.

Digitization is the key. Most of the satellite map data arrive in the form of a computer's numerical language, a stream of digits. But existing maps must be converted to digits, a process akin to unmaking a map. So far, it has been a largely semi-manual process. To convert a map into numerical form, an operator moves a hand-held sensor over the surface of the map to encode contours, boundaries and other features. More fully automated digitizing systems are coming into use at the Geological Survey and the Defense Mapping Agency. A paper map or certain images, placed on a rotating drum, are scanned by light-sensing devices that reduce the entire contents to digital form and store this in a computer. A typical topographic map is thus broken down into approximately 1.1 million data points, and that merely for elevations. Technicians then call up the map images on video screens for editing or revising. Maps extracted from the digitized data can be generated at any scale desired.

The Geological Survey last year completed its first digital cartographic data base, a set of standard magnetic computer tapes that contains the outlines of boundaries, roads and railroads, streams and other basic map features for the entire United States. A single tape of selected features for one of the 21 regions sells for $100; the entire data set costs $6,300. The first of the survey's topographic maps to be produced by computer, a five-color chart of the Birch Tree, Mo., area, was published last August.

Even more extensive is the Defense Mapping Agency's effort along these lines. This little-known organization, with 9,000 employees, primarily in Washington and St. Louis, started in 1974 to computerize the entire world, looking toward the ''all-digital'' production of maps. Often the information was never converted to maps in the conventional sense. The data became terrain models used in training simulators so that pilots could ''see'' what they were ''flying'' over. Or the digitized map data became critical elements in the ''smart'' guidance systems for cruise missiles or the Pershing 2 missiles. A canister containing several digital maps for routes to several potential targets is loaded into the missile, and just before launching, the missile is ''told'' which map to follow. Because these military projects had priority, much of the agency's effort to achieve a more generalized computerized mapping capability was sidetracked until now.

It was probably just as well, for the D.M.A. was facing what appeared to be an insurmountable data storage problem. To convert the map of the world to digits and store it on magnetic tape would have required a building five-eighths of a mile cubed just to hold the tapes, according to Lawrence F. Ayers, a deputy director.

A few years ago, Morris Thompson wrote about the changes in cartography between 1950 and 1975 and sought to forecast what surveying and mapping would be like in the year 2000. Distance measurement in surveying, he noted, passed in that time from steel-tape techniques to electronic systems based on lasers, and by 2000 both technologies should be supplanted by a guidance system mounted on land vehicles, boats or aircraft. Starting at a point of known position and elevation, the surveyor proceeds with the instrument from point to point along the surface to establish automatically positions and elevations needed for preparing accurate maps from images of the surface. The Defense Mapping Agency says these systems are already providing ''unprecedented relative positioning accuracies.'' Mr. Thompson also wrote that by 2000 the ''classical form of maps, in which features are represented by lines and symbols, will be supplemented or replaced to a large extent by photo-image maps or sensor-image maps.'' This would be facilitated by cartographic information compiled and stored in digital form at central data banks. Moreover, he predicted, the principal data-gathering machinery for much mapping would be spacecraft carrying arrays of high-resolution sensors.

Mr. Thompson says he would not significantly revise any of his predictions. ''Remote sensing, satellites and computers are the future of cartography,'' he states, and to a remarkable extent the future has already arrived.

The new maps being produced from the new technologies may make the world more comprehensible, perhaps more manageable, but no less wondrous. It has always been thus with maps that seek to reduce the world to a scale more susceptible of human comprehension.

By John Noble Wilford

The space shuttle Columbia landed safely today, but almost eight hours late, after a cascade of malfunctions struck and spread concern for the spaceship's critical navigation system.

The six-man crew rode the winged spaceship carrying the Spacelab to a landing here at 6:47 P.M., Eastern standard time. This brought to a successful conclusion the longest shuttle mission, a 10-day flight, and the first test of the European-built Spacelab as an orbital research facility.

At the moment of touchdown, Mission Control told the crew: ''Columbia, welcome home. Beautiful landing!''

For a time, however, there was doubt as to when the Columbia would be coming home, today or possibly a day later. The suspense built in the morning, the result of a mysterious sequence of failures. A thruster firing jolted the spaceship. A computer failed and then another computer failed. These were computers handling guidance and navigation functions. Finally, a navigation measuring system also shut down. Lieut. Gen. James A. Abrahamson of the Air Force, the National Aeronautics and Space Administration's shuttle chief, said there was concern that ''this was a kind of problem that would ripple through all'' the computers and other systems. After hours of troubleshooting, Mission Control in Houston decided it was safe to attempt the landing, even though engineers still did not understand the source of the malfunctions. At a news conference here, General Abrahamson said tests showing that one of the key computers used in navigation had survived without flaw gave flight controllers the confidence to proceed with the landing plans. This suggested that the problems were not necessarily widespread. General Abrahamson emphasized that at no time did Mission Control feel that the situation bordered on ''a potential disaster.'' Nonetheless, he said, ''We were going to be very careful, and we were.''

The two pilots and four scientists aboard the Columbia remained cool through the day. The crew members were John W. Young, Maj. Brewster H. Shaw Jr. of the Air Force, Dr. Owen K. Garriott, Dr. Robert A. R. Parker, Dr. Byron K. Lichtenberg and Dr. Ulf Merbold of West Germany. This is the largest crew to fly in a spacecraft.

The descent from orbit apparently went without flaw, despite the earlier equipment problems. But just as Mr. Young brought the nose wheels of the Columbia to the ground, one of the suspect computers failed again.

When the Columbia came to a stop, John Blaha, the spacecraft communicator at Mission Control, said to the crew: ''We've got some good news and bad news. The good news is we've got lots of beer waiting for you. The bad news is we drank it eight hours ago.''

The spaceship was originally scheduled to land at 10:58 A.M. This was a one-day extension of the mission decided on because of the Columbia's smooth performance, until the final hours, and because the spacecraft had ample reserves of fuel and oxygen.

This was the first time in nine flights that a space shuttle had failed to land on time because of mechanical problems. The third flight, in 1982, and the seventh flight, last June, had to stay aloft longer than planned because of weather conditions at their landing sites.

The flight of the Columbia had been remarkably free of trouble until the multitude of malfunctions struck this morning. It was 5:13 A.M., Eastern standard time. The Columbia was 155 miles up in orbit when an automatic firing of jet thrusters in the nose rocked the spaceship. Nothing quite so jarring had ever occurred on a shuttle. Mr. Young, the commander, estimated that the force was 19 or 20 times greater than the normal force of the earth's gravity.

'It Was Really an Impact'

''It really hit the vehicle hard,'' Mr. Young reported to Mission Control. ''It was really an impact. It was probably as high a magnitude type thing as we have seen.''

At precisely the same time, the computer handling the spaceship's guidance and navigation systems shut down. This was the No. 1 general purpose computer, one of four identical computers on board that bear the burden of controlling the craft's complex systems. Any one of the four is capable of taking over for the others. In addition, a fifth, independent computer is available as a backup system.

The No. 2 computer immediately took over from the troubled No. 1 computer. Five minutes later, in another thruster firing, the No. 2 computer also shut down, apparently because it became overloaded. For about one minute, the Columbia had no computer-operated guidance and navigation capability.

Mission control then commanded the No. 3 computer to the rescue. It had been turned off during the problem; the No. 4 computer was handling the spaceship's environmental control systems and other tasks.

Flight controllers were mystified. They ordered the No. 2 computer back on, and it worked. They tried to restart No. 1, but it did not work. It was presumed dead. The No. 2 computer resumed its guidance and navigation duties, as the No. 3 computer was switched off; it held the vital re-entry programs and had to be kept available for any updating of those instructions.

Officials Are Baffled

Still, no one understood the cause and nature of the malfunctions, or whether they were linked or independent problems. Mission Control decided to postpone the landing. Theoretically, it would be possible to land the shuttle without the computers but it is believed that, in practice, a human pilot could not execute commands fast enough to make the maneuvers necessary for reentry into the earth's atmosphere.

''We need time to better understand the problem before we commit to reentry,'' Mission Control told the crew.

Two more landing opportunities were available in the evening, at 5:17 or an orbit later at 6:47. Mr. Blaha, the spacecraft communicator at Mission Control, asked Mr. Young if he had any preference.

''I have no druthers,'' Mr. Young replied, though he noted that the later landing would give him a chance to take a nap. He had been up all night at the controls.

Mr. Young had one suggestion, though. ''I recommend we close the forward R.C.S.,'' he said, referring to the reaction control system thrusters, ''and not run any more of those rascals.''

While hundreds of engineers at Houston analyzed data from the Columbia's computers, searching for clues to the malfunctions, another gremlin struck. This time it was one of the three inertial measuring units that failed. This system senses the spaceship's acceleration, position and angle of attack to provide reference data needed by the computers in issuing commands to the propulsion system.

Major Shaw, who had taken over the controls while Mr. Young slept, reported at about 9 A.M. ''fault signals'' from the inertial unit. Attempts to restart the system were futile.

Soon afterward, Mission Control elected to wait and attempt the landing on the final opportunity of the day. Even though the cause of the problems ''is not obvious with analysis,'' Mr. Blaha told the crew, it was decided to go ahead with ''deorbit preps.''

Flight engineers readjusted the computers so that if the No. 2 machine failed again, the No. 5 computer would take over immediately and guide the ship home. The interconnections between the various machines were also adjusted to ''minimize the impact'' on them if No. 2 should fail.

At 5:14 Mission Control announced the decision to return to the earth as planned. Gary Coen, the flight director, was chain-smoking.

The Columbia was out of radio contact when it began its descent. At 5:52, while over the Indian Ocean. It would be almost 45 anxious minutes before Mission Control would know if the computers were working and navigating the Columbia through the many thruster firings and body-flap settings necessary to keep it on course. It was out of range of any tracking stations.

By the time word came, the Columbia was off the west coast of the United States. Mission Control began receiving tracking data at 6:31. All was well.

By John Noble Wilford

When the countdown nears the final few minutes, a hush settles over Cape Canaveral. It is dark, a couple of hours after midnight on Aug. 30, and as if in response to some vestigial mammalian instinct, the senses grow more acute. The air smells of damp subtropical decay and, one imagines, sleeping alligators. I am peering across the lagoon out to the palmetto and to the sandy flats running to the Atlantic shore, three miles away, where the space shuttle Challenger stands on its truncated pyramid like a monument bathed in ceremonial light.

Its image shimmers in and out of focus. Sometimes in the dense, humid air the xenon-lighted Challenger looks like a mirage, which gives it a mythic aspect. We are looking and waiting for the greater light, the sudden dawn of ignition.

Waiting for the moment of launching, in the hushed atmosphere of anticipation, I never fail to sense something beyond sight and smell, something else - echoes. The echoes of the old days of spaceflight, the struggling days and glory days when we first became a spacefaring people.

Hard as it is for some of us to believe, on Oct. 1, the National Aeronautics and Space Administration will be marking the 25th anniversary of its creation, and so I am even more attuned to the echoes from the past. Over the years, I have seen 30 crews of astronauts embark on space voyages and dozens of tests of new rockets and launchings of craft to provide new communications links, survey the earth and the heavens and probe the planets.

Back in the early days, waiting for liftoff was more often than not an exercise in futility. Some gizmo would balk at the last minute, and the launching would be scrubbed until another day, another week. Once, frustrated reporters were reduced to writing about the murder of a local cocktail waitress, calling it ''the only successful shot fired here in weeks.'' Or the rocket would take off in the wrong direction and have to be destroyed in midair. People from those days still talk of a missile called Snark, which had the unhappy habit of taking off and plunging into the nearby Banana River so often that they began speaking of the Snark-infested waters.

In time, however, the countdowns usually went like clockwork and the destinations kept getting farther and farther away from the Banana River. It was no longer achievement enough just to get something in orbit. On the strength of the raw, gravity-defying power of the Saturn 5 rockets, whose rattling reverberations still echo in the mind, we reached the moon. Our automated surrogates ventured out to Mars, Jupiter, Saturn and beyond. We saw these worlds for the first time as worlds, not as baubles of reflected light in the sky. One of the spacecraft we bade farewell to at Cape Canaveral more than a decade ago, the hardy Pioneer 10, has cruised beyond the outermost planets, bound for interstellar space.

These were achievements to match the exuberant rhetoric of those early days. Reaching for a metaphor for the new experience in unfamiliar realms, President John F. Kennedy in 1962 spoke of space as ''this new ocean'' and of those who set sail on it as spacefarers embarking on ''one of the great adventures of all time.'' This generation, he added, ''does not intend to founder in the backwash of the coming age of space.'' The words breathed of romance and daring, of new frontiers to test the resolve of a people shaped by the experience of mastering frontiers.

T-minus-31 seconds and counting. Thirty-one seconds to go. The computers are running everything now. The thunderstorms have passed, the sky is opening up after a 17-minute rain delay, and everyone expects the launching to be flawless. Down the line. A piece of cake. Those fuel cells and auxiliary power units might send off a few alarms in the cockpit. Not to worry. A few heat-shielding tiles might fly loose during ascent. The shuttle will endure such things.

It is a tested machine. A fantastic flying machine, the astronauts say. The shuttles, the world's first reusable spaceships, have been flying since April 1981. Part rocket, part spacecraft and part airplane, they represent an attempt to make travel on the new ocean more economical and more routine.

When development of the shuttles began in 1972, the nation had changed and so had its language of expectations. Another President, Richard M. Nixon, heeding the more constrained spirit of the time, had said: ''With the entire future and the entire universe before us, we should not try to do everything at once. Our approach to space must be bold - but it must also be balanced.''

Some of the first tentative steps toward exploring commercial prospects in space were taken by the Carter Administration. It was perhaps inevitable, given the nature of people and their approach to new frontiers, that after the period of exploration there would follow a period devoted to possible exploitation. First, we went out to space, and now, in a sense, we are trying to embrace it and bring space down to earth. We may be left for a time with only the echoes of the testing and exploring times, but - with a sigh, perhaps - we must accept the fact that the American civil space program is growing to maturity. It has passed through the joys and crises of precocious childhood and now is being called upon to do grown-up things, like earn a living and establish permanent roots in space.

The leaders of NASA are striving to reshape the agency to respond to the railroad metaphor and also maintain the can-do fervor that has motivated its best engineers and managers. It is not an easy task. If the agency does not get into step with the new economic and political realities, especially regarding its relations with industry and the military, it could wind up on the periphery of the space enterprise it did so much to mobilize. Already, the Defense Department's space operations have surpassed NASA's in annual spending - $8.5 billion, compared with NASA's $7 billion - and the Reagan Administration plans to increase military space spending by more than 10 percent a year over the next five years, a greater rate of increase than for the rest of the department. The Commerce Department's National Oceanic and Atmospheric Administration has assumed the operations of weather and earth-resource survey satellites. And years ago, in the first and as yet only profitable commercialization of space, private industry took over communications satellites.

If, on the other hand, the agency does not continue to have challenging goals, it could lose many of its best engineers and managers. NASA is already much smaller than in the Apollo days, with a workforce of 21,000 compared with 36,000 in 1966. Many of the brightest engineers, attracted to NASA during the Apollo Project, now hold critical middle-level management positions; without new challenges, they would be tempted to leave. There are signs that the ''brain drain'' is beginning.

By background, today's NASA leaders seem suited to the new era of exploitation. Unlike previous administrators - two university presidents, a lawyer-politician, an engineer and a physicist - the present NASA administrator, James M. Beggs, is a former business executive. He was the executive vice president of General Dynamics Corporation just prior to taking the job in 1981, but before that had held management posts at NASA and the Department of Transportation. The deputy administrator, Hans Mark, is a former Secretary of the Air Force. The associate administrator for space flight, who runs the shuttle program, is General Abrahamson; he had overseen the F-16 jet-fighter development. Though there have been businessmen and generals in NASA's management before, now they seem to be there with the mission of establishing stronger ties with business and the military.

When Mr. Beggs took over, he set himself one major long- range goal: to win approval for NASA to embark on the space-station project. In announcing preliminary plans for the station this summer, Mr. Beggs said: ''It will open up commercial opportunities we have not dreamed of; it should improve our national security; provide more sophisticated science, and be a source of international cooperation. If the United States does not take this step, we will lose our pre-eminence in space.'' That is, the station was to be the centerpiece in NASA's response to Administration pressures for economic and military exploitation of space - as well as to the agency's own institutional momentum. Such an undertaking would keep NASA where its engineers like to be, doing the big project.

Anyone who saw the movie ''2001: A Space Odyssey'' has a notion of what an orbiting space station could be like: a huge white-spoked toroid slowly revolving in the great beyond, inhabited by astronauts and engineers who operate instruments of high technology and dispatch craft to the more distant reaches of space. A space station was high on NASA's post-Apollo planning agenda, but nothing came of it except the experimental Skylab, operated in 1973-74. Plans for a more ambitious station had to be set aside in favor of the shuttle, which NASA engineers accepted because they had to, budgets being what they were, and also because they envisioned it as the ferry that would someday shuttle back and forth between earth and the space station.

The White House is expected to make a decision on the space station very soon, perhaps early enough so that NASA, if the decision is favorable, could get some start-up money in next year's budget. But NASA's immediate plans are more modest than the 2001 station. According to a NASA task-force study, the core of the station would be a large cylindrical ''house,'' where four to six astronauts, engineers and scientists would live, conduct their work and operate the rest of the station.

This habitat would be equipped with ports into which the shuttles would dock. Attached to the habitat would be additional chambers for prototype orbital factories - places for processing metal alloys, crystals for electronics, drugs, vaccines and other industrial products that presumably could be made better, or only, in the microgravity vacuum of space.

Extending out from the habitat, at the end of long girders, could be the antennas, solar-power panels and other modules containing experiments. Another platform for experiments, uninhabited, could fly nearby so that it could be serviced by the astronauts and yet be free from the vibrations and contaminations of the main station. If development were to begin next year, Mr. Beggs said, the basic elements of the station could be aloft by 1991 at a cost of $9 billion.

Later, the station could be added to, module by module, beam by beam, much like a Tinkertoy set, until it accommodated from 12 to 18 people and spread out like an orbital industrial park and service station for refueling and overhauling satellites and inter-orbital tugs. A second space station, probably uninhabited, might also be placed in a polar orbit for earth sensing and for military reconnaissance and command operations. So far, however, the Pentagon has been cool to NASA's space-station plans. It is supporting NASA but says it has not identified a single military job that could be done better by a space station than by conventional spacecraft. In time, more active Pentagon backing may be vital to the project, as it was in winning continued financial support for the shuttle.

By 1991, the Soviet Union will probably have its own large space station in orbit. For the last decade, Soviet efforts have focused on flights of its small Salyut stations, each of which has remained in orbit several years and served as home for crews for as much as six months at a time. The Salyut 7, now in orbit, was doubled in size last June by the addition of a module, and at the time, Soviet officials reiterated their goal of creating ''long-lasting, manned orbiting space stations.''

But NASA officials are not stressing Soviet competition so much as the prospects of inaugurating an extraterrestrial industrial revolution through the space station and other programs. ''No longer is it a question of whether space has commercial promise,'' said Mr. Beggs, ''but rather how best to proceed to maximize that promise for national economic well-being. I think that is a very significant point in the history of this agency and the history of this nation.''

In keeping with the Administration's goal of getting private investors more involved in space, NASA announced recently that a 1986 shuttle mission would be devoted entirely to industrial experiments. A NASA- funded study found that 84 companies were interested in doing 244 experimental and commercial projects in orbit. The first working example, which has already been on four shuttle missions, was a separation process known as electrophoresis. Developed by the McDonnell Douglas Corporation in conjunction with Johnson & Johnson, it successfully tested methods of making ultrapure pharmaceutical products, such as vaccines and a possible replacement for insulin.

For the first time, moreover, private companies are putting venture capital into space flight other than satellite communications. Fairchild Industries plans to build its own small unmanned orbital platforms, to be deployed by the shuttle, and to rent space to other companies for research and manufacturing. A West German company, Messerschmitt-Bolkow- Blohm, has already built a similar craft. A group of Texas investors is testing a private space-launching rocket. Three young graduates of the Harvard Business School recently set up their own company, Orbital Systems Corporation, and received from NASA exclusive rights to develop and market a propulsion system for launching satellites from the shuttle. And several large companies are interested in the Reagan Administration's plan to allow private industry to buy Delta, Atlas and Titan rockets and launch them for hire.

A standard arrangement to get private industry thinking space is an exclusive joint-endeavor agreement between NASA and a company with an idea that has commercial potential. The agency offers the company a free ride on the shuttle for as long as its work is in the research-and- developmental stage. Three companies have signed such deals and several dozen others have expressed interest. When the manufacturing process reaches a production stage, the company begins paying a hauling fee, which could be as much as $5 million for each shuttle flight. Shuttle fees run about $42 million for a payload that takes up the full cargo bay. A customer can reserve the entire 60-foot- long bay or part of it, and pay accordingly. These fees are expected to increase substantially in 1985 to reflect the true costs of the shuttle flights.

Other arrangements are being negotiated on a case- by-case basis. Such high-risk research-and-development ventures also enjoy substantial tax deductions for the investors. There have been some exploratory talks about having a private company pay for an additional shuttle in return for an arrangement with NASA to be the shuttle marketing agent.

There are, of course, critics and skeptics of the new plan for NASA. They fear that NASA may be overselling the prospects for significant commercialization. NASA, they feel, lacks sufficient assurance of funding to carry out the projects that are envisioned as justifications for the space station. At the same time, it wants to jump into another big engineering endeavor that could, as with the shuttle in the 1970's, wreck chances for a more balanced program of science exploration and commercial activities.

They also believe the Reagan Administration is being hasty in its moves to turn over some segments of space activities to private industry. A recent study by the National Academy of Public Administration, composed of 294 scholars and Government administrators, recommended against a transfer any time soon of the space shuttles to full operation by a private company.

A proposal by the Reagan Administration to hand over to private industry all weather satellites and the Landsat earth-resource survey satellites, now operated by the National Oceanic and Atmospheric Administration (after they were developed and tested by NASA), has run into heavy opposition in Congress. Critics charge that, in the case of the weather satellites, the Government would be setting up a private monopoly whose sole customer would be the Government itself. They say the Landsat divestiture makes even less sense. According to a study prepared under Government contract by Earth Satellite Corporation and Abt Associates, an organization of research and development consultants, only substantial subsidies and Government- guaranteed data purchases could produce a profit for a private earth-resource survey company for many years to come.

A source of deeper concern is the shuttle itself. As successful as the flights have been, it remains to be seen whether the shuttles can live up economically to their advance billing. In the original projections, the four-shuttle fleet was expected to fly 560 missions over a 12-year period, with each vehicle being able to land, be serviced and take off again in two weeks. This was a totally unrealistic prediction, it turns out, conceived in part to justify the shuttle to Congress and the public. The more often the shuttles flew, the less each flight should cost - a matter of overhead divided by volume. ''That was the phoniest Mickey Mouse economic analysis that ever went on record,'' said Richard D. DeLauer, Under Secretary of Defense for Research and Engineering.

Shuttle officials have long since abandoned predictions of two-week turnarounds. Their present goal is a total of 24 launchings a year by 1988 for the fleet of four shuttles, 30 by 1990 and 40 by 1992. A recent study by the National Research Council concluded that the chances of reaching 30 launchings by 1990 were ''impossible or highly improbable'' because of engine- maintenance and other refurbishment problems. Still, General Abrahamson foresees a ''crossover point'' in shuttle launching-rate economics around 1988. He said that with a higher launching rate, higher customer fees based on realistic costs and more efficient operations, the ''loss-leader part of the program'' should then be behind NASA. Unless the shuttles pull out of the red and can produce annual revenues of at least $2 billion, as Mr. Beggs has forecast, NASA may be hard put to support a more aggressive program in the future. Although NASA has received modest budget increases in recent years, to pull out of its 1970's doldrums, its current annual budget of $7 billion has less than 40 percent of the purchasing power of its allocation in 1966, the high point of the Apollo mobilization, when there was enough money not only for going to the moon but also for initiating the spectacular planetary expeditions. Skeptics, particularly scientists, say from bitter experience that if anything has to go to finance the space station, it will likely be NASA's science programs.

NASA will be making its push for accelerated space- station funding at the same time it is supposed to be reviving its planetary exploration program. After a lapse of six years, in which no major new planetary missions were authorized, the Administration this year finally approved a program to send a spacecraft to map cloud-shrouded Venus by radar in 1988. On the drawing boards are missions in the 1990's to orbit Mars to study the planet's geology and climate, to visit the vicinity of a comet and asteroid, and to probe and map Titan, the large satellite of Saturn. Other proposals include missions to bring back samples of Martian soil, collect fragments of a comet and to orbit the moon to prospect its resources for exploitation.

Under a plan developed earlier this year by a committee of leading scientists, such expeditions could be supported with an investment of $300 million a year over the next two decades, less than 5 percent of NASA's budget. That would be half again as much as planetary exploration's current budget, but considerably less than spending a decade ago. Reaction to the plan has been favorable at both NASA and the White House.

Not to have a commitment to future missions would be to turn away from one of the most exciting enterprises of our time - our voyages of discovery in the solar system. Shuttles and space stations may expand human activities in space, but the little craft that visit other worlds with their cameras and inquiring sensors expand our knowledge and inspire a sense of wonder about our place in the universe. While the shuttles make their increasingly routine freight runs in the years to come, Voyager 2 will be flying by Uranus and out to Neptune, and the orbiting space telescope, scheduled to go into operation in 1986, will be extending our vision of the universe.

Scientists have also noted that NASA's budget crunch during the shuttle buildup cost dearly in missed opportunities. A ''grand tour'' of the planets, with craft far more sophisticated than the Voyagers, was canceled. The United States pulled out of an expedition, with the European Space Agency, to orbit the poles of the sun. No American satellite will be going out to rendezvous with Halley's comet in 1985-86, as had been proposed, leaving such explorations to Europe, Japan and the Soviet Union. Even the shuttle suffered. The original plan, abandoned because of costs, was to make it a completely re-usable vehicle, and thus more economical to operate, instead of having to replace its booster rockets for each launching, which is now the case.

NASA's leaders have sought to reassure scientists of their commitment to scientific exploration in the space- station era. They note, for example, that the station would be a key element in the mission to obtain samples of Martian rock. The samples might be returned there to be processed so that Martian microorganisms, if any exist, would not contaminate Earth. The station could also be a port of embarkation for manned flights back to the moon or to Mars. ''If such a base were in orbit by the year 1991,'' wrote Mr. Beggs in the journal Spectrum, ''the United States would be back on its way to the moon by the year 2000.''

Out of this time of transition for NASA, for all the emphasis on the practical aspects of exploiting space, may emerge a larger vision of what America should aspire to in space. We can now contemplate greater aims because we have the technology, thanks in large part to Apollo in the 1960's and the shuttle development in the 1970's.

George A. Keyworth 2d, President Reagan's science adviser, went to Washington two years ago with discouraging words for NASA's ideas about big ventures. But he has changed his mind. Mr. Keyworth has decided it is time to return to a bolder approach to the space program and to ''inject a new sense of vision into U.S. space exploration.'' Space, he says, is ''a place to be careful, but not to be timid.'' Some of the less- timid initiatives he has in mind include the development of shuttle-like vehicles to fly from the space station, which he sees as eventually becoming a transportation hub, the development of colonies on the moon and the launching of astronauts from the space station to Mars.

These words sound like echoes from the glory days earlier in NASA's first 25 years. Whether the spirit of Apollo can ever be rekindled is questionable. NASA no longer has the political clout it had then, and the nation is probably in no mood for what might seem to be technological extravagance. But we are a spacefaring people now - our travels have only begun.