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Lunanauts Move Easily on the Moon

At last man was seeing before his eyes answers to a host of riddles that had perplexed and divided scientists and intrigued other mortals. Could man perform at the moon’s ⅙ g (⅙ of earth’s gravity)? Would he sink into a sea of soft, smothering dust? Would fatigue quickly claim him?

And what about the lunar material? Would it be young or old, hard or soft, black or brown or gray? Would it be volcanic? Would it duplicate material on the earth? Would it tell the story of a hot moon or a cold moon?

Obviously the lunanauts had little difficulty performing in ⅙ g. After gingerly testing the soil and the best ways of moving, they frolicked about like colts, or—as Apollo 8 Astronaut Bill Anders remarked—like a pair of Texas jack rabbits. They tried two-legged kangaroo jumps; that technique proved tiring. They floated across the long-shadowed scene in a lazy lope, six to eight feet at a stride, with both feet in the air most of the time. It felt like slow motion, Armstrong reported, but it was a comfortable way to cover ground—if they remembered to plan their stops three or four steps ahead.

At times they seemed, in their bulky suits, like dancing bears; at other times they were marionettes. And now and then it was a ballet, with a graceful pas de deux.

Their exuberance was seen not only in their lively actions but also in Armstrong’s excited query right after Aldrin came down the ladder: “Isn’t it fun?”

But it was hard work too, with many scientific observations to make and tasks to perform in a tightly limited schedule.

As for the surface, at least in the Sea of Tranquillity, the Eagle crew said it was somewhat slippery and described the soil as seeming like graphite, or soot, or almost like flour. It stuck to their boots, but because of the moon’s lack of air, it never billowed up to hamper work.

They said that their boots pressed in only a fraction of an inch in most places, although on the edges of small craters they sank as much as six or seven inches and tended to slip sideways.

In fact, the two men discovered a strange paradox: When they planted the United States flag in the lunar soil, they had to press hard to force the staff down, yet it would fall over easily. The soil showed great resistance downward, but little sideways. Aldrin found that he could pound a core tube only about five inches deep, even with repeated blows.

The men remarked on the variety of the moon rocks. The surface of some showed vesicles, or tiny pits, formed by gas bubbles as the rock cooled. Some were pitted with little glassy craters as though they had been struck by BB shot.

Colors varied from chalky gray to ashen gray, with hints of tan or cocoa brown at times, depending on the angle of view.

Moon Rocks Hold High Priority

In every direction, the lunar surface was pocked with thousands of little craters and many larger ones, five to fifty feet across and littered with angular blocks.

It had been decided in advance that the most important single thing the astronauts could do—scientifically speaking—would be to bring back samples of the moon.

Shortly after stepping onto the surface, Armstrong took a “grab sample,” or contingency sample, scooping it up into a Teflon bag on the end of a light collapsible rod. The pole he discarded, but the bag of soil he rolled up and—with some difficulty—tucked into a pocket above his left knee.

As Astronaut-scientist Don Lind commented in Houston during the flight, “He is certainly going to get back in the spacecraft with his pants on, so we will have this sample for sure.”

With a specially made aluminum scoop on an extension handle, and with a pair of long aluminum tongs, Armstrong later gathered a larger quantity of the dark lunar soil and representative samples of the lunar rocks. These he put into two boxes, each formed from a single piece of aluminum. A ring of soft metal, indium, lined the lip of each box; when the box was closed and the straps drawn tight around it, a knifelike strip around the edge of the lid bit deeply into the indium, thus helping to seal the samples in a vacuum and to protect them against contamination.

All told, the astronauts brought back about 48 pounds of lunar material. In addition, they undertook to gather a bit of the sun. To be sure, it was a very small sample, less than a billionth of an ounce at best, but presumably it was enough to tell a great deal about the solar furnace. The sample was gathered by trapping particles of the solar wind.

Swiss Scientists Count Sun Particles

The solar wind is an ionized, or electrified, gas constantly streaming away from the sun at speeds of 200 to 400 miles a second. Ordinarily we do not detect the wind on earth, because the magnetosphere—the magnetic field around our planet—deflects the electrified gas. We see its effects only when a little of the solar wind occasionally leaks into the magnetosphere in the polar regions, becomes accelerated by some process that scientists do not yet understand, and causes the brilliant aurora high in the atmosphere.

The moon lacks a strong magnetic field, so the solar wind flings against it a steady barrage of atomic particles that, scientists believe, may slowly erode the lunar rocks. The device to trap these infinitesimal particles is ingeniously simple, compared to other more sophisticated instruments designed for lunar research. It amounts to little more than a strip of aluminum foil about a foot wide and four and a half feet long that Aldrin unfurled and hung on a slender mast stuck into the moon near the lunar module.

This sheet was left exposed to direct sunlight for an hour and 17 minutes, then rolled up like a window shade and stored inside one of the lunar sample boxes. Scientists hope that during exposure the sheet received the full force of the solar particles. Many of them—perhaps as many as 100 trillion—may have embedded themselves in the foil, penetrating several times their own diameter—as much as a millionth of an inch.

As this is written, Swiss researchers led by Dr. Johannes Geiss are attempting to extract the solar particles at the University of Bern and the Federal Institute of Technology in Switzerland.

Their technique is to melt and vaporize the foil in an ultrahigh vacuum. Then, in a device known as a mass spectrometer, the atomic particles of the gases they are seeking may be separated according to their mass. The process faintly resembles that of the cream separator which drives the heavier milk particles to one outlet and the lighter cream particles to another.

Unmanned satellites outside our atmosphere have already investigated the solar wind, and from these studies scientists have found that it holds particles of hydrogen, helium, and probably oxygen. Theoretically it should also contain particles of all the other chemical elements making up the sun—some 92 in all. The Swiss researchers do not expect to detect all these; rather, they seek to measure the gases helium, neon, and argon, known as “noble gases” because they normally do not react with other substances.

Dr. Geiss hopes to find isotopes, or varieties, of these elements in the foil-trapped solar wind sample. Knowledge about the proportions of such isotopes will add to our understanding of the origin of the solar system. Particularly it may tell us something of how the earth and its atmosphere were formed.

Unique Instruments Gleam Like Jewels

The solar wind collector came back to earth with the astronauts, but two other important scientific instruments were left behind on the moon. One is a seismometer, a device for detecting tremors and quakes. The other is a super-mirror to reflect laser beams sent up from earth. Together they form the EASEP, or early Apollo scientific experiments package.

I was privileged to see these two instruments a few days before they were placed aboard the lunar module. As befits all hardware going on moon flights, they were kept in a “clean room,” where all dust is carefully filtered out. Before going in, I had to thrust my shoes into a mechanical brusher to remove dust, then cover my clothing with a white nylon gown and my hair with a nylon cap.

The two instruments stood in solitary splendor in the middle of the floor, completely dominating an otherwise nearly empty room. A barrier surrounded them, keeping me at a discreet distance. Lights bathed the scene from a high ceiling, reflecting on white walls and an aluminum floor. I felt as though I were in a sultan’s treasury, looking at his crown jewels. And, in truth, the two devices shone and glittered like jewels—the seismometer because of its amber-gold thermal covering, and the reflector because of the crystalline beauty of its 100 glistening prisms.

Inside the golden cylinder at the heart of the seismometer were mechanical combinations of booms, hinges, and springs that respond to vibrations, and electronic devices to record the intensity of the vibrations and transmit the information by radio to earth. Two large solar panels, producing as much as 40 watts, could provide the necessary electric power during the two-week-long lunar day. During the moon’s night the instrument was to fall silent, but nuclear heaters, fueled with radioactive plutonium 238, would keep the transmitter warm.

Device to Measure Lunar Tides

Dr. Gary V. Latham of Columbia University’s Lamont-Doherty Geological Observatory, the principal investigator for the seismometer experiment, told me that this kind of instrument has given us most of what we know about the earth’s interior, and should do the same for the moon.

“However, the lunar seismometer is ten to a hundred times more sensitive than those we use on earth,” he explained. “The moon fortunately lacks the constant vibrations from ocean tides, wind, and traffic that plague instruments on earth.

“With this device—actually four seismometers in one package—we should be able to detect the impact of a meteorite the size of a garden pea half a mile away on the moon.

“Also, in time we should be able to tell if there are small tilts in the surface caused by tides in the lunar material itself. If a rigid bar 300 miles long were lifted at one end by one inch, this seismometer could record it.

“And the instrument can record tremors about one million times smaller than the vibration level that a human being can feel.”

I asked Dr. Latham how he could tell the difference between a moonquake and a meteorite impact.

“It’s not easy,” he admitted, “but that’s about the same problem seismologists have been facing for years in deciding whether a tremor on earth is caused by a quake or by a nuclear test in some remote place. We can do it because the waves caused by a bomb or an impact are richer in high-frequency vibrations than those caused by a quake.”

On the moon, Buzz Aldrin opened an equipment bay on the back of the lunar module and lifted out the two instruments—weighing a total of nearly 170 pounds—as though they were light suitcases. He carried them easily, with both arms bent at the elbows so the packages would not chafe his suit. He deployed the seismic package about 60 feet away from Eagle while Armstrong set up the laser reflector nearby, where they would presumably not suffer from the blast of the ascent engine.

A few minutes later, a radio command from earth uncaged the seismometers and turned on their transmitter. Immediately—to the joy of scientists on earth—the instruments began recording the footfalls of the astronauts on the moon.

Inked Squiggles Record Moon’s First Visitors

In the control center at Houston, I watched signals coming in from the seismometers. Inked pens traced endless lines on long strips of paper issuing from strip-chart recorders; heated styluses did the same on waxed paper on drum recorders.

Dr. Latham explained that when the lines were straight, the moon was quiet. When the pens and styluses began to vibrate and trace squiggly lines, something was happening on the moon. The nature of the squiggles and their amplitude suggested to Dr. Latham and his colleagues what was happening. For example, rapid vibrations of the pens, tracing designs like fuzzy caterpillars, recorded the movements of the astronauts.

The moon seems to be quieter internally than earth—but the instruments have nonetheless recorded trains of high-frequency waves lasting from one to nine minutes. These, say the scientists, may be landslides, perhaps in West Crater. It is a new enough crater for such slides to be expected from the stresses caused by constant shifts from extreme heat to extreme cold.

The seismometers also seemed to detect several fairly strong shocks with lower frequencies than the landslide tremors. At first these appeared to be moonquakes. But peculiarities in the signals have led the seismologists to suspect that the “tremors” may have been caused by venting of gases from the lunar module, or by abnormalities within the instruments themselves. Only further experiments will tell.

The Apollo 11 seismometers survived the oven heat of one lunar noon and the bitter cold of one lunar night, but the electronics in their command receiver gave out from overheating on the second noon. Dr. Latham expects the instruments carried on future missions to last longer because they will be protected with a heat-radiating thermal blanket.

Laser Hits a Far-off Target

As soon as Neil Armstrong had put the laser reflector in place and carefully aimed it at earth, scientists began firing powerful pulses of ruby laser light at it. The second and third largest telescopes in the world (after Mount Palomar’s)—the 120-incher at Lick Observatory, on Mount Hamilton, California, and a brand-new 107-incher at McDonald Observatory, Fort Davis, Texas—were used to concentrate the beams. Light passing backward through one of these telescopes spreads out to a spot only a few miles wide by the time it hits the Sea of Tranquillity.

At first no detectable light returned; the brilliance of reflected sunlight obscured whatever laser light might be struggling back. But shortly before lunar night, the telescope at Lick began to pick up signals, and McDonald has since detected them repeatedly.

Unlike the seismic package, the laser reflector has no moving parts and requires no power supply. It consists simply of a hundred fused-silica prisms, each about the width of a silver dollar, set in an aluminum frame 18 inches square. Each prism is the corner of a cube. When light enters and strikes one face, it must, by the laws of optics, bounce off two other faces as well, and then come right back out on itself.

Professor Carroll O. Alley, Jr., of the University of Maryland, who is in charge of the experiment, showed me one of the prisms. As I looked into it, the image of my eye filled the corner where the three planes intersected.

“Now tilt the reflector a few degrees in each direction,” suggested Professor Alley.

To my surprise, my eye kept looking straight back at me no matter which way I tilted the piece of silica. It was uncanny that I could not escape its fixed stare.

“That’s why the corner reflector works so well for our purposes,” explained Professor Alley. “These prisms are the most accurate reflectors ever made in any quantity. Yet, of course, the beam is severely attenuated in its half-million-mile round trip.”

How much, I wondered.

“We send out about 10 billion billion photons [units of light],” he said. “If we are lucky, 10 photons will return to our detector. That’s far too few for the eye to see, but our instruments can measure them.”

Knowing the speed of light, and timing the round trip (about 2½ seconds) to an accuracy of one billionth of a second, Professor Alley and his colleagues can figure the distance to the reflector with an exactness never before possible. They expect to refine that distance, as measured at any given moment, to an error of only six inches—and that’s exactly the point of the experiment.

“Once we can determine the moon’s distance from two observing spots on earth simultaneously,” Professor Alley continued, “then by simple calculation we can find out exactly how far apart those two spots lie. If distances between observatories in Europe and the Americas tend to increase over a period of years, then we will have strong evidence that those continents are slowly drifting apart, as many scientists now believe.”

Within a decade the laser experiment will also help scientists check on how fast the moon is receding from the earth, examine the wobble of the earth on its axis, and test new theories of gravity.

Professor Alley expects that the reflector will continue to give good results for at least ten years, maybe a hundred. During that time anyone can use it who has the appropriate laser and telescope equipment. It is truly an international experiment.

Even before Armstrong and Aldrin had finished their observations, photography, and scientific chores, the flight controllers in Houston were getting nervous that the two men would overstay their time on the surface of the moon.

At one point Armstrong loped some 200 feet to photograph the smaller of the two craters he had overflown. “When he returned he was really puffing,” one of the men in the control room at Houston told me later. And when the Apollo commander hauled the rock-sample boxes through Eagle’s hatch with a line-and-pulley arrangement, the exertion sent his pulse up to 160 beats a minute—four beats faster than it had been during the lunar landing.

Those Who Follow Will Stay Longer

But the controllers’ fears were groundless. Armstrong entered the LM and locked the hatch just two hours and 20 minutes after he had stepped out of it, almost exactly according to plan. He did not feel particularly tired.

“It was nothing at all like the exhaustion after a football game,” he said later.

In fact, the metabolic rate for both men stayed considerably lower than expected. Half their oxygen supply remained unused in their portable life-support packs, as did ample water and battery power. For that reason, the astronauts of Apollo 12 were given permission to stay substantially longer on the moon.

When Aldrin and Armstrong re-entered Eagle, one incident aroused momentary apprehension among TV watchers back on earth. One of the backpacks, which barely cleared the hatch entrance, struck a circuit breaker just inside and snapped its end off. It was needed to arm the ascent engine—a necessary step before the engine could be fired to get the men off the lunar surface.

Fortunately, the circuit breaker could still be pushed in. More important, there were other ways in which the astronauts could arm the engine. Almost everything in Apollo can be accomplished in two or more ways for safety’s sake.

Before leaving the moon, the two men opened the hatch once more and jettisoned their backpacks and other items not destined for return to earth. (The lunar seismometers dutifully recorded the impacts.)

Million-dollar Museum on the Moon

Any future explorers who reach Tranquillity Base will find an expensive museum. There remain the two lunar instruments, the United States flag (which does not, incidentally, constitute a territorial claim by the United States), Eagle’s descent stage with the plaque on one leg announcing that “We came in peace for all mankind,” and a symbolic olive branch in gold.

And scattered about lie a million dollars’ worth of discarded items that had to be left behind to save weight and space: cameras, backpacks, tools, lunar overboots, bags, containers, armrests, brackets, and other miscellaneous gear.

In addition, the crew left an Apollo shoulder patch commemorating the three astronauts—Gus Grissom, Ed White, and Roger Chaffee—who died on January 27, 1967, in a spacecraft fire, and medals honoring two Soviet cosmonauts who have lost their lives—Yuri Gagarin and Vladimir Komarov.

A final memento carried messages of good will from leaders of 73 nations. Etched on a 1½-inch disk of silicon by the same process used for making miniaturized electronic circuits, the messages have been reduced in size 200 times and are invisible to the naked eye.

Eagle’s climb back into orbit took less than eight minutes of firing by the ascent engine. Mike Collins, who had been the solar system’s most isolated man in his orbiting command module, watched his companions return with undiluted joy. Eagle started as a pinpoint of light as its tracking beacon flashed, but grew rapidly in size till it swung grandly into position for rendezvous.

For a few moments during docking, the two craft failed to align themselves properly, but skillful jockeying by the pilots solved the problem. Then Collins floated into the tunnel between Eagle and Columbia to shake hands with his colleagues.

The three men, reunited in the command module, set the ascent stage adrift in lunar orbit, where it will remain indefinitely, and began the 60-hour journey home. As uneventful as the trip out, the coast back ended on July 24 with a fiery but totally successful reentry in the Pacific, 950 miles southwest of Honolulu.

Emerging from the blackened command module, the three men began a period of earthly quarantine. Wearing biological isolation garments—coveralls with gas masks—they went immediately from the helicopter to a specially adapted vacation trailer known as the mobile quarantine facility. Carried by ship to Hawaii and thence by plane to Houston, they entered living quarters in the Lunar Receiving Laboratory, where they underwent the most intensive medical scrutiny.

None of the tests of the men or of the lunar samples they brought back revealed any organisms that could harm life on earth—or indeed any organisms at all. So, late on August 10, the three Apollo crewmen were released to their families and a waiting world.

What Did Apollo Mean?

Amid all the excitement and hyperbole, what was the real significance of Apollo 11?

In a minor sense, perhaps, it was the coming of age of the space program, for it was the 21st manned space flight for the United States, as well as the 21st launch in the Saturn series. And if life begins at 40, that too is symbolic, for the day after the flight began marked the 40th anniversary of Robert Goddard’s first launching of an instrumented rocket, complete with thermometer, barometer, and camera.

Apollo 11 was in addition a momentous adventure, the most widely shared adventure in all history.

It was, as well, a technological triumph of the highest order, made possible only by the sustained effort during the past decade of hundreds of thousands of persons and the expenditure of some 22 billion dollars.

It involves so complex a technology that no one man can begin to comprehend what lies behind it: the tons of blueprints, the 20 thousand contractors; the 20 million pages of manuals, instructions, and other material printed monthly by the Kennedy Space Center alone; the rocket and spacecraft encompassing more than five million separate parts; the engines—most powerful in the world—that gulp 15 tons of kerosene and liquid oxygen a second and get five inches to the gallon; the telemetry that during launch sends back to Houston each second enough information to fill an encyclopedia volume.

Man’s Long Reach to the Unknown

But above all, Apollo 11 was a triumph of the human spirit. As Buzz Aldrin said in a TV broadcast while coming home from the moon, “This has been far more than three men on a voyage to the moon ... This stands as a symbol of the insatiable curiosity of all mankind to explore the unknown.”

At the President’s dinner honoring the astronauts shortly after their release from quarantine, Neil Armstrong brought tears to the eyes of many when he said, in a voice filled with emotion: “We hope and think ... that this is the beginning of a new era, the beginning of an era when man understands the universe around him, and the beginning of the era when man understands himself.”

But with all the congratulations, and all the pride of accomplishment, Buzz Aldrin struck perhaps the finest note of all when, on the way home from the lunar conquest, he read to a listening world this moving passage from the eighth Psalm of the Old Testament: “When I consider thy heavens, the work of thy fingers, the moon and the stars, which thou hast ordained; What is man, that thou art mindful of him?”

Kenneth F. Weaver was Assistant Editor of the magazine at the time when this article was published.
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