Space Exploration: Portrait of a Planet

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The picture was grainy and ill-defined, a blur of white curving across a black background. It would take months of painstaking analysis to determine what it really showed. But one quick glance gave the scientists at Caltech’s Jet Propulsion Laboratory the most important message of all: from 135 million miles in space, their spacecraft, Mariner IV, had sent home the first closeup portrait man has ever made of the far-off planet Mars.

While all the world watched and waited, the ambitious timetable of U.S. space exploration had been put to its most demanding test. And the high, undulating whine of JPL’s computers seemed to change subtly into a cry of exaltation. Mariner had made it.

This was the triumphant climax of an eight-month experiment. The picture pulsing back across the far reaches of space marked the final payoff. For those pictures, JPL’s boss, Physicist William Pickering, and his crew had sweated out Mariner’s launch from a Cape Kennedy rocket pad; the agile combination of men and computers in the Pasadena lab had solved complex equations of trajectory with split-second precision; the members of the Mariner team had kept a close watch as they monitored their spacecraft’s every signal.

By week’s end, three pictures were made public. The second and third shots, like the first, showed broad, desertlike areas but few outstanding surface markings. The first photo had been snapped from a distance of 10,500 miles, catching the planet at 11 a.m. Martian time. Through a slight trajectory miscalculation, Mariner was 500 miles off its intended course and caught Mars in a slightly different pose than expected—the camera focused on a 192-mile segment in the Martian area known as Phlegra. The next shots were made as Mariner swept past the eastern edge of Trivium Charontis in the direction of the southern polar cap.

Where the first and second pictures overlap, there is a twelve-mile-wide dark spot that JPL picture analysts believe is genuine and not a camera smudge—but what it is, they are not sure. The third picture, snapped from 9,500 miles out, is the most interesting one so far. The contrasts are sharper, bringing out the first distinctive features to be seen in the Mariner pictures: some faint suggestion of shallow craters similar to those on the moon, and a long depression that could be a valley.

More pictures are on the way. They may reveal much more of what Mars looks like because they will cover areas generally thought to have a more varied terrain. Unlike the first shots, the later pictures were made in afternoon lighting, and shadows should bring out sharper contrasts. It will be weeks, though, before they are released.

Historic Journey. Remarkable as those photographs were, they tended for a few excited moments to hide the rest of a remarkable feat. Without a single snapshot to show for its travels, Mariner IV would still have earned its place in the annals of science. In its 325-million-mile, 228-day flight, it had charted interplanetary reaches never before explored by man and set an impressive record for long-distance communication. All during its trip, Mariner sent back valuable scientific information about the solar wind, cosmic dust, magnetic fields and deep-space radiation. In the vicinity of the red planet it scouted the hazards that astronauts will meet when they try to land there. It gave earthbound experts their most accurate estimates of the planet’s structure and mass; it beamed radio signals through the Martian atmosphere to study its density and looked for signs of a magnetic field.

Mariner started its historic journey on Nov. 28, 1964, only three weeks after Mariner III failed because it could not jettison its protective shroud. A powerful Atlas-Agena rocket lofted the 575-lb. Mariner IV through Earth’s atmosphere, then kicked it loose to take off on its own like a great flying windmill. The spacecraft, freed from a cocoon-like covering, unfolded the four solar panels that powered its instruments by converting the sun’s energy into electricity. With those panels deployed, it measured 22 ft. 7½ in. across and 9½ ft. to the top of its antenna. Curving into a wide-swinging, elliptical orbit that was precisely plotted in advance, the ship set out to intersect the orbit of Mars at a predetermined time.

The ship was a space scientist’s dream laboratory—crammed to capacity. Its four panel blades shone purple from the thin sapphire-glass coating that protects their 28,224 tiny solar cells from radiation damage. Its silvery octagonal body, made of magnesium and aluminum alloy, carried 138,000 components, including 31,696 delicate electronic components ranging from a computer to a small, lO½-watt radio transmitter. It was programmed and equipped to send to Earth a continuous stream of reports on 39 scientific and 90 engineering measurements. Crowded into the spacecraft were a new type of helium gas magnetometer to study magnetic fields, an ionization chamber and Geiger counter to measure galactic cosmic rays, a collector cup to measure the solar wind’s barrage of protons, a cosmic-ray telescope and cosmic-dust collector —plus the all-important TV camera. “I don’t think you could improve the payload,” said one of the project scientists. “It’s a damn near perfect mix of experiments.”

Incredible Balance. One compartment of the spaceship housed a piece of equipment that did nothing but take up space and use electric current. It was a dummy ultraviolet light photometer. In ground tests before launch, the real one developed a disturbing habit of high-voltage arcing that not only blew out the photometer but also disrupted the TV system. Unable to replace the instrument and unwilling to risk ruining Mariner’s picture mission, the engineers decided to leave the instrument behind. Since the ship was designed to carry the photometer, a replica was made of exactly the same weight; it was polished to give off the same reflection and engineered to absorb the same electric current, lest an incredibly delicate balance be upset.

Although detailed instructions for nearly all of Mariner’s maneuvers were programmed in advance and stored in the on-board computer, the journey still had its moments of suspense and anxiety. The first trouble came only 16 hours after launch, when two solar pressure vanes—flaps hinged to the end of the solar panels—stuck in an up-tilted position. Unless corrected or compensated for, this fault would have been enough to head the ship on a course that would have taken it 400 miles farther away from Mars than was anticipated.

Other malfunctions plagued the early days of flight. The solar plasma probe equipment, designed to detect the low-energy protons of the solar wind, was thrown off kilter because of a defective metal clamp. A tube in the ionization chamber conked out, causing a power failure that eventually ruined the whole experiment. Mariner’s roving navigation eye also got it into trouble. The bright, bluish-white star Canopus was supposed to serve as Mariner’s polestar, but other bright objects began to confuse Mariner’s sensor. Once it tracked the wrong star for ten days until a command from JPL directed it back to Canopus. With another command, the engineers solved the Canopus problem by shutting the brightness gate, a mechanism that caused the sensor to begin searching for its assigned star whenever it was fixed on a light considerably brighter or dimmer than Canopus. Sometimes a speck of dust reflecting the sunlight would accidentally trigger the maneuver. “The dust’s effect on the sensor,” says John Casani, Mariner systems manager, “really threw us for a loop.”

Ultimate Accuracy. Despite such “glitches” (a spaceman’s word for irritating disturbances), Mariner handled its difficult assignment without a hitch. On Dec. 5, when it was 1,267,613 miles out, Mariner received a command from JPL to fire its rocket motor for the first and only correction of its trajectory. The ultimate accuracy of the encounter with Mars depended on this operation; hopefully it would correct for the drag of the pressure vanes and any other factors that were taking Mariner from its planned course.

Such a maneuver is based on the solution of complex mathematical equations involving all the intricacies of space mechanics. Computers at JPL took into account Mariner’s speed and trajectory, its location in relation to the point in Mars’s orbit where the encounter should take place, and the influence of the sun, the Earth and Mars itself. Then they calculated the thrust needed to get the ship where it had to be at the proper time. Without correction, Mariner would have strayed 150,000 miles away from target. After the mid-course maneuver, it was aimed well within its programmed 10,000 miles. A second mid-course correction, though possible, was never needed.

On Feb. 11, JPL signaled for a checkout of Mariner’s photographic apparatus. The commands turned on and then turned off power to the tape recorder, and pointed the TV camera as it would have to be when it got close to Mars. Everything functioned well. Recalling the dust problem with Canopus sensors, JPL engineers decided to remove the TV lens cover then, instead of waiting until the final encounter. If there was any dust on the cover, they did not want it shaken loose to endanger the sensors at a critical moment.

Planning for Trouble. Well past mid-point in its journey, the spaceship was sailing along smoothly. No problems, only precedents. On April 29, when Mariner reached a straight-line distance from earth of 66 million miles, it surpassed the record for long-distance space communications set two years ago by the unsuccessful Russian Mars 1 probe.

So uneventful was the flight that it began to worry Mariner Project Manager Dan Schneiderman. He was afraid that his 200-man control team might begin to take the mission too much for granted. Determined to guard against the danger, he busied his men with practice Mars encounter exercises all through the final few weeks of the flight. Working with a duplicate of the ship that was far out in space, Schneiderman’s team manned their posts and computed answers to a nerve-racking sequence of simulated problems. They dealt with every imaginable glitch, from premature starts of the camera to unprogrammed movements of the scan platform that was designed to pick up the planet and tell the TV camera when to start functioning. Every decision the team made was fed into a duplicate Mariner in the laboratory, just as radioed commands might later be sent into space. The difference was that on these practice runs results could be checked, tactics could be changed.

As the real test approached last week, the months of calm gave way to hours of apprehension. So much could go haywire in such a complex operation, so much could happen to delicate instruments during such a long journey through the hazards of space. JPL statisticians had already calculated that there was only a 17% chance of getting photographs. To be sure, the JPL crew knew that the mission had already produced significant scientific results, but they also realized that only a set of pictures would mean real success. “It’s a failure without the pictures,” said John Casani. “You’re judged on the success of the most difficult part of the mission. That’s the pictures, and if we don’t get them, then we’ve failed.”

Alarm in Analysis. On encounter day—July 14—JPL technicians arrived at their control center at dawn. They were filled with nagging doubts. The TV and tape-recording equipment had not been tested since February, and if something did go wrong, there would be no time to correct it because it would take 24 minutes for radio signals traveling at the speed of light to make the round trip between Mariner and the control station. Just to be on the safe side, JPL control sent a series of four last-minute direct commands to back up the programmed instruction. It was the first time the lab had talked to its ship in five months, and Mariner answered like a good boy.

The first command was sent when Mariner was still 107,000 miles away from Mars. This turned on the camera’s shutter mechanism, started the scan platform searching with a wide-angle sensor for light from Mars, and turned on the tape recorder’s power. Everything was going unbelievably well. Newsmen and families of the scientists gathered in JPL’s Von Kármán Auditorium to await the cryptic reports from the primary tracking stations at Johannesburg in South Africa, Woomera in Australia and Goldstone in California.

At 4:55 p.m., P.D.T., the wide-angle sensor detected the edge of Mars. Twenty-three minutes later, the narrow-angle sensor also picked up Mars. Presumably, the picture-taking sequence had begun. At 5:30 p.m., Jack James, Assistant Deputy Director of JPL in charge of lunar and planetary projects, grinned broadly as he received a report by telephone. Goldstone, he told newsmen, had just verified that the tape recorder was running. The chances of getting pictures were excellent. Mariner’s cheering section broke out in applause.

The elation soon turned to despair. JPL control began receiving conflicting signals about the performance of the two-track, continuous-loop tape recorder. “There is alarm in the analysis team,” James announced. The signals hinted that something was wrong with the recorder’s stop mechanism. Quite possibly it was not cutting off for a 24-second interval between each picture. If so, the tape would have run through its two tracks twice as fast as it should have; it would have recorded only half of the 21 pictures. The confusion was compounded when a disembodied voice over the intercom announced: “All indications are that all was normal during the recording sequence.”

Thin & Dusty. For hours no one would know for sure. While the JPL crew waited anxiously, Mariner swooped around the back side of Mars. It was out of touch with Earth for 54 minutes. During this maneuver, it performed one additional and highly important experiment. Mariner beamed radio signals back to Earth through the atmosphere of Mars. By examining the changes in amplitude and frequency of the radio waves as they arrived on Earth, scientists hoped to get a better idea of what Martian atmosphere was like.

From this experiment they soon learned that the air enveloping Mars is extraordinarily thin, about the density of Earth’s atmosphere at altitudes of 93,000 ft. to 102,000 ft. Air pressure on the surface of Mars, estimates JPL Physicist Dr. A. J. Kliore, is between 10 and 20 millibars compared with Earth’s average of 1,000. The Martian atmosphere is now believed to have only 1% to 2% the density of Earth’s, and may also be far more turbulent. Being so thin, the Martian air would have to blow with tremendous velocity to kick up the dust storms thought to be characteristic of the red planet.

From the millions of measurements Mariner had already sent back, other scientists also began to draw their part of the portrait of the planet. Some preliminary conclusions:

> The magnetic field of Mars is almost nonexistent, about 1/1,000 to 1/10,000 that of Earth’s.

> Mars does not appear to have any radiation belts similar to Earth’s Van Allen belts.

> Heavy solar radiation slips through the planet’s thin atmosphere to bombard its surface, but the level is not likely to be so high as to make all life impossible.

Garbage Collection. From these findings, scientists on the Mariner project could only draw a bleak, forbidding picture of Mars. They were surprised not to find signs of a magnetic field, but their instruments simply did not show any change in measurements during the encounter. Since most scientists believe that the Earth’s magnetic field results from the motion of a hot liquid metal core, they now assume that Mars and Earth have basically different internal structures. Mars, in fact, may be more like the moon, which also lacks a magnetic field. “If there are any Martian men, they do not use a compass with any effectiveness,” cracked Dr. James Van Allen of the State University of Iowa, who heads one of the Mariner scientific teams.

Discoverer of the Earth’s radiation belt that is named after him, Dr. Van Allen (TIME cover, May 4, 1959) was particularly interested in the possibility of trapped radiation in the vicinity of Mars. But Mariner’s instruments could not find any. Thus, man should be able to orbit Mars for long periods of time without heavy shields against radiation. And despite the high level of radiation on the surface of the planet, scientists say that it does not appear to be enough to discourage exploration. Man could probably visit Mars without wearing special radiation protection.

Before approaching Mars, scientists report, Mariner recorded ten solar flares (eruptions on the sun that spew out streams of particles), two of which were not noted on Earth. The cosmic dust team, nicknamed “the garbage collectors” because the dust is essentially waste material, also made an interesting discovery. They had expected the rate of dust to increase as the spacecraft traveled farther from Earth. It did—for a while. Then it abruptly diminished. “We are theorizing,” says W. M. Alexander of the Goddard Space Flight Center, “that Earth and Mars act as sweepers of these dust particles, attracting them to the planets and cleaning out large paths along their orbits.” No one knows how they do it.

Mariner also looked for two near-Earth phenomena. It failed to find any evidence of the giant tail of Earth’s magnetic field that is supposed to stretch thousands of miles out into space. In another experiment, Mariner measured the shock wave caused by solar pressure against Earth’s magnetic field. The wave turned up three times at distances of 138,000 to 154,000 miles from Earth. This indicated, the scientists concluded, that the magnetic field around Earth is constantly expanding and contracting.

Turning Heart. Still, for many tense hours last week, the overriding question at JPL control was not Mariner’s confirmed scientific coups but what it had done during the photo sequence. The suspense ended when Mariner broke its silence on schedule and began playing back the bits of digital code representing the pictures it had taken the day before. “When I saw that little printout tape and knew we had a picture,” says Caltech’s Dr. Robert B. Leighton, chief experimenter of the picture team, “my heart turned around.”

His emotion was understandable. That printout tape, with its endless rows of digits, told the men who could read it that Mariner seemed to be obeying the intricate orders built into it so many months before. According to plan, shortly after the scanning mechanisms sighted the planet, automatically activating the photo system, the six-inch vidicon tube focused through a reflecting telescope and took its first picture. It was programmed to take one picture every 48 seconds. Each picture was made up of 200 lines—compared with 525 lines on commercial TV screens. And each line was made up of 200 dots. The pictures were held on the tube for 25 seconds while they were scanned by an electron beam that responded to the light intensity of each dot. This was translated into a numerical code with shadings running from zero for white to 63 for deepest black.

The dot numbers were recorded in the binary code of ones and zeros, the language of computers. Thus white (0) was 000000, black (63) showed up as 111111. Each picture—actually 40,000 tiny dots encoded in 240,000 bits of binary code—was stored on magnetic tape for transmission to Earth after Mariner had passed Mars. More complex in some respects than the direct transmission of video data that brought pictures back from the moon, the computer code was necessary to get information accurately all the way from Mars to Earth.

Because of the great distance and the craft’s weak 10½-watt radio transmitter, it took 8 hr. 35 min. to transmit the coded data that made up one picture. And by the time the signals reached a tracking station, they were no stronger than one-billionth of one-billionth of a watt. Those faint whispers were picked up by big-dish antennas and amplified a thousand times as they were piped through a liquid helium maser. So slow was the transmission rate that no complete picture could be received at any one tracking station. As the Earth’s rotation carried one station out of range, another moved into position to collect the rest of the message.

Computers on Earth digested the pictures, digit by digit, and “developed” them by translating the numerical values into the correct shades of light to be projected onto a photographic film. All told, Mariner was programmed to take and transmit up to 21 such pictures of Mars. But excited Mariner engineers could not wait for the first transmission to be completed before they sneaked their first look. They processed the half picture received by the Johannesburg and Madrid tracking stations even before Goldstone, which had taken over tracking when the others lost contact, could supply its half of the tape.

The pictures were not as clear as JPL engineers had hoped for, but certainly better than they had feared. Over the next few months the Mariner picture team will experiment with various methods to highlight the most meaningful images: they will try to clean up the signals, check and recheck for errors in transmission, and exaggerate certain features by changing the contrast. In the coming few weeks the team expects to get a second and possibly third replay of Mariner’s tape. The replays will be compared with the first run in an effort to eliminate any picture distortions owing to false radio signals. JPL eventually plans to construct a model of the photographed portion of Mars—less than 1% of the planet’s total surface.

Eloquent Tribute. As the pictures are printed and reprinted, the data examined and reexamined, the measurements studied and restudied, the monumental achievement of Mariner IV will expand steadily. Its success already adds up to an eloquent tribute to one of the most skillful and resourceful teams ever gathered together in the pursuit of scientific knowledge. William Pickering’s spacemen of JPL have more than earned their rank in the vanguard of U.S. space exploration. Among their leaders:

> Jack N. James, 44, expert in radar guidance control and organizing genius of the JPL team, was recently promoted to the job of Assistant Deputy Director of JPL in charge of lunar and planetary projects. He headed the group that built Mariner II in the incredibly brief time of eleven months, also organized the Mariner IV team.

> Dan Schneiderman, 43, electrical engineer and Mariner IV project director, had to make the final decisions on any hair-raising problems during the Mars encounter. He has worked on the Corporal and Jupiter missiles, was systems manager of the Mariner II Venus probe. His ideal: “To remain a virgin in outlook, not litter my mind with dogma.”

> John Casani, 33, Mariner IV’s meticulous systems manager, has a reputation among his colleagues as being the man who knows the most about every part of the spacecraft.

> Richard Sloan, 34, a Caltech-educated physicist, was in charge of the scientific instruments aboard Mariner IV. Before joining JPL for the Ranger moon shot, he did basic research on low-temperature physics at Caltech. He believes man shows his nobility by action. Says Sloan: “Tears streamed down my face when Roger Bannister broke the four-minute mile.”

> — Nicholas A. Renzetti, 50, a Columbia Ph.D. in physics, was responsible for directing communications to and from Mariner IV.

> Robert B. Leighton, 45, a Caltech physics professor and textbook author, is in charge of interpreting the photographs. He has made himself familiar with Mars by taking pictures of the planet through Earth-bound telescopes.

Restless Curiosity. Led by Physicist Bill Pickering, whose own career runs through the history of U.S. space flight, those men have fashioned the most ambitious and successful space adventure yet. Mariner’s pictures, Pickering was the first to admit, will add little if anything to the ancient argument over the possibility of life on Mars. But all the other data the spacecraft collected may yet supply many answers.

Man has been waiting for those answers for centuries as he has gazed into the heavens and wondered if he is alone in the universe. Of the planets nearest to Earth, Venus may be too hot for habitation; besides, it is constantly shrouded in clouds that make observation difficult. In 1962 the scientific information sent back by Mariner II (TIME cover, March 8, 1963) cast serious doubt that Venus could support life.

The red planet of Mars seemed far more promising as a likely place to start looking for planetary neighbors. Observations made by optical telescopes suggested a surface swirling with dust storms. Frost-covered polar caps could be picked out, along with marked seasonal variations, and dark regions that might well indicate vegetation of a sort. A Martian day (24 hr. 37 min.) is similar in time to Earth’s, but there the apparent similarities end. Mars has a year of 687 days. It has little more than half the diameter and a shade more than one-tenth the mass of Earth. Any Martian life would probably have to survive in arid wastelands and an atmosphere that has little or no oxygen and only traces of water vapor.

According to currently accepted theories, if life does exist on Mars, it is probably of a very low order—moss, perhaps, or lichen or fungus. Nonetheless, cartoonists and science fictioneers still picture a planet inhabited by little green men with floppy antennae sprouting out of little green heads. Serious astronomers, as well, have gone in for elaborate speculations. In 1877, the respected Italian astronomer Giovanni Schiaparelli set off a surge of imaginative theories when he reported seeing canali, or channels, on the surface of the planet. This led to speculation that Martians might be tapping their polar regions to irrigate their vast deserts.

Other observers fancied that the canals might be the remains of a great civilization that disappeared as the planet dried out, victim of a weak gravity that could not hold moisture. A Russian astronomer even suggested that the two small moons of Mars—Deimos and Phobos—might be artificial satellites by which Martians eons ago sought to escape their dying planet. At the turn of the century one of the Boston Lowells, Astronomer Percival Lowell, long a believer in Martian life, finally despaired of finding it. “To our eventual descendants,” he wrote, “life on Mars will no longer be something to scan and interpret. It will have lapsed beyond study or recall.”

Mars may, indeed, have seen better times. But Lowell did not reckon with man’s great leap in technology, his relentless assault on his physical boundaries—the mighty rockets and the miniaturization, the electronic computers and the sophisticated guidance and tracking systems that proliferated after World War II. They are providing man for the first time with the capability to match his restless curiosity.

Still Sweating. Many eminent scientists believe that man will eventually find life on Mars, and New Zealand-born Dr. Pickering is among them. “I’ve always felt we’ll find some form of life on Mars,” says he, “and I look forward to the day when we’re landing capsules there and searching for life.” Space scientists have much to learn before they launch those exploratory capsules, but Pickering’s Mariner has already taught them valuable lessons.

And that voyage is far from over. At week’s end, JPL men were sweating out the glitches that might mar the final pictures, even while they made plans for gathering still more valuable information from their far-traveling craft. Past Mars now, its pictures taken and its programmed experiments over, the purple-winged ship is curving off into a perpetual orbit of the sun. By Oct. 1, Mariner will be 195 million miles away from Earth, its signals too weak to monitor. In September 1967, though, after a trip that will have taken it as far as 250 million miles away, it will be back within 30 million miles of Earth. It will be within radio range once more. Perhaps by then it will have even more to tell about the mysteries of space. For after learning so much about the planet Mars, Mariner IV will remain in space as a versatile man-made planet.