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Дата изменения: Thu Oct 16 01:00:21 1997 Дата индексирования: Tue Oct 2 04:35:26 2012 Кодировка: Поисковые слова: mercury surface |
Apollo 12 Animations |
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For NASA, 1969 was a roller coaster year. The first half was full of feverish activity as thousands upon thousands of people did whatever was necessary to make sure that the first landing was achieved. But then, with the triumph still fresh in everyone's mind, it was time to look at what the future might hold in store. Unfortunately, it soon became evident that not only would the feverish pace of Apollo have to slow but also that the program might have to end.
For four years, the NASA budget had been shrinking from the peak it had reached in 1965. A decrease was, of course, inevitable because, during the peak years, NASA had to undertake a number of expensive projects simultaneously. There was the development of the Saturn V, the CSM, and the LM, and the construction of the launch pads and the Vehicle Assembly Building at the Cape and all of the new facilities at Manned Spacecraft Center in Houston. So it wasn't surprising that spending at the 1965 level couldn't be sustained. But there was an expectation that, once the landing was a reality, the budget would stabilize at a level that would let the lunar program continue. And there were even some who thought that a Mars program was in the cards. However, soon after the 1968 election, the incoming Nixon Administration had ordered a review of NASA's list of future programs; and the major implication of that review was that, while the nation had been committed to the Kennedy goal, it was the politics of space that had opened the public purse and not an overwhelming interest in the space program itself. Certainly, President Nixon was no great fan of the program and, now that the race with the Russians had been won, NASA's budget was headed for levels that would not only force long postponements of such cherished dreams as a space station, a lunar base, and missions to Mars, but also threatened the continuation of Apollo itself. In September 1969, the White House announced that lunar exploration would not continue beyond Apollo 20.
Although the Nixon decision was a blow to NASA, the consequences were not all bad. In light of shrinking budgets, NASA immediately announced that the remaining Apollo schedule would be stretched. Money could be saved by conducting launches only twice a year. Salaries and other personnel costs dominated the NASA budget and, by stretching the schedule, the agency would have to employ only enough people, particularly at the Cape, to prepare and perform one mission at a time. Stretchout also meant that planners, engineers, scientists, and astronauts had more time to assimilate experience and data between missions and, as well, it gave NASA a chance to complete hardware and procedures modification that would make the last few missions spectacularly productive. Of great importance were LM design changes which would allow an increase in landing weight from eight tons to nine and that, in turn, meant that the LM's flown late in the series would be able to carry an electric-powered, wire-wheeled dune buggy called the Lunar Rover, and also greater stores of oxygen, cooling water, and electric power for longer visits. The combination of the Rover and an expanded-capacity backpack would let the crews stay on the Moon long enough to conduct three 7-hour EVA's and, during each of them, venture as far as ten kilometers from the LM.
Early in Apollo, NASA sketched out a sequence of missions which would lead to the first landing. "A" missions were unmanned tests of the launch vehicles and the Command Module; "B" missions were unmanned tests of the LM; "C" missions (Apollo 7) were manned, earth orbital tests of the Command Module; "D" missions (Apollo 9) were LM/CSM tests in earth orbit; "E" missions (none were flown) were tests in high earth orbit; "F" missions (Apollo 10) were lunar orbit tests; and the "G" mission was the landing. In 1968, NASA added three other mission types to the list: "H" missions (Apollo 12, 13, and 14) would be subsequent flights to other landing sites using the basic equipment; "I" missions (none flown) would be lunar orbit-only science flights; and "J" missions would be the longer visits that LM design changes would make possible. With Rovers at their disposal, each of the J-mission crews would be able to visit a variety of geologic features scattered around the local countryside, collect far greater quantities of rock and soil than walking astronauts could hope to carry, make use of an impressive number of tools carried on the Rover, and also give the research teams back on Earth a mobile experiment platform. In general, the J-missions promised a significant increase in productivity. However, before such impressive missions could be attempted, NASA had to demonstrate that crews could achieve pinpoint landings, work a full-day in the stiff suits and, if necessary, walk several kilometers back to the LM from a disabled Rover.
For Apollo 12, the site selection committee picked an interesting spot on the Ocean of Storms (Oceanus Procellarum), about 1500 kilometers west of Tranquillity Base. Although, as Don Wilhelm's details in To a Rocky Moon, the Apollo 12 site wasn't the first choice of the geologic community, it did have several things going for it. First, it was a reasonably level site. There were a number of large craters surrounding the target point, but otherwise the area presented no more in the way of hazards than those that Armstrong and Aldrin had faced. Second, the astronauts would be able to collect rocks and soil samples from another of the great lunar plains and, most interestingly to the geologists, from a place covered with ejecta from the young, prominent crater Copernicus which lies some three hundred kilometers to the north. And third, with an eye toward a dramatic demonstration of pinpoint targeting, if Apollo 12 Commander Pete Conrad and his shipmate Alan Bean landed close enough, they would be able to walk over to the Surveyor III spacecraft and even bring pieces of it back to Earth.
On April 19, 1967, the Surveyor landed on the inner slope of a fairly large crater, a fact which greatly reduced the immediate photographic return but which, ironically, made identification of the precise landing spot a relatively easy matter. From trajectory data, NASA knew where each of the Surveyors had landed to within a mile or two but, because each of the spacecraft was no bigger than a modest-sized lunar boulder, unambiguous identification in orbital photographs was all but impossible. However, details in the Surveyor photographs could be compared with details in the Lunar Orbiter pictures so that, in principle, the landing sites could be pinpointed. Ewen Whitaker, now retired from the University of Arizona's Lunar and Planetary laboratory, was a member of the Surveyor team and had the responsibility of identifying the landing sites. As the first pictures came in from Surveyor III, it was immediately apparent that the spacecraft had landed in a crater. It was a relatively featureless crater but there were a number of good-sized rocks scattered around, particularly to the north of the spacecraft. One pair of large rocks looked as though they were almost touching each other and it seemed to Whitaker that he might be able to find them when he started to examine the appropriate Orbiter pictures through the microscope. Within a couple of days, he was sure he had them; the rocks looked like mere pinpricks through the microscope, but there were other rocks visible as well and they made a pattern which matched up nicely with the Surveyor III pictures. Whitaker had found the crater.
A couple of years later, when the Apollo site selection committee was looking for a good place for the first precision landing, the Surveyor III site came easily to mind. Along with the other factors, the site offered NASA engineers a golden opportunity to examine spacecraft parts which had been exposed to lunar conditions for a relatively long period of time - thirty one months in this case - information which would someday be of use in designing space stations and lunar bases. If all went well, Conrad and Bean would be able to visit the Surveyor, photograph it, and then strip off a few components to bring back to Earth.
Surveyor Crater is a member of a distinctive cluster of craters. When viewed from the approach trajectory, the cluster looks not unlike a Snowman, with Surveyor Crater forming the fat torso. By using Lunar Orbiter photos and, as well, photos returned by the prior Apollo crews, NASA was able to construct a fairly realistic model of the landing site so that, during training in the LM simulators, the view out Conrad's window - actually a TV picture of the model - looked enough like the real thing that, at pitchover, Conrad would have a comfortable sense of deja vu.
"I'm trying to cheat and look out there," he said. "I think I see my crater."
He wasn't absolutely sure but, seconds later, at pitchover, there was no doubt. "Hey, there it is! There it is! Son-of-a-gun! Right down the middle of the road!"
Bean glanced up and saw the Snowman, too. "Outstanding!", he said. The scene looked just like it had in the simulator. There was the Snowman,. Indeed, it seemed for a moment that Intrepid was going to land right in the center of Surveyor crater.
Conrad was delighted. "I can't believe it! Amazing! Fantastic!"
Bean fed him the numbers and, at four hundred feet altitude, Conrad took over manual control. He'd picked out a good spot west of the crater and short of the Snowman's Head beyond. He angled north to fly around Surveyor Crater and then south to avoid another, far shallower feature. There were very few boulders in the area and, as they got lower, the LM exhaust began kicking up a lot of dust. During the last few moments, Conrad lost sight of the ground and had to rely on his simulator training to make a blind touchdown.
Although Conrad was sure of where he was going to land during the approach, once he was down he wasn't sure exactly where he was. He'd lost track of the landmarks while he concentrated on rocks that he could see through the dust so that he could see if he was moving left or right, forward or back. But he knew he was close, certainly within a couple hundred meters of the target.
Fittingly, it was Dick Gordon, traveling overhead in the Command Module Yankee Clipper, who nailed down the landing coordinates. As he made his second post-landing pass, he put his eye to the sextant in hopes of getting a glimpse of the LM, a feat that Collins had never managed. Of course, Gordon had a real advantage in that he knew where Intrepid was supposed to be. As he picked up the Snowman, it wasn't long until he spotted the LM's fifty-meter shadow.
"I have him," he said. "He's on the Surveyor Crater; he's about a fourth of a Surveyor Crater diameter to the northwest...I'll tell you, he's the only thing that casts a shadow down there."
In seconds, he was directly overhead. "The Intrepid is just on the left shoulder of the Snowman. He is looking at me. He is about a third of the way from the Surveyor Crater to the [Snowman's] Head."
Then he really got excited. "I see the Surveyor! I see the Surveyor! Hey! That's almost as good as being there."
Now there was no doubt. Not only had Gordon seen the LM but he'd seen the Surveyor itself. Conrad and Bean had landed right on target and, thanks to Ewen Whitaker, they'd even been sent to the right crater! This was going to be fun.
Although they'd gotten a bit behind the planned timeline while trying to figure out where they'd landed, Conrad and Bean were models of efficiency once they got started donning the backpacks. With luck, the process could be completed in under two hours and that's just about how long it took. They made a few minor mistakes when, out of eagerness, they occasionally relied more on memory than on the detailed checklists. However, thanks to the checklists, they were able to get back on track after only a few minutes of wasted effort. Finally, about four-and-a-half hours after touchdown, they made one final check to be sure that they had good, airtight suits and then radioed Houston for permission to depressurize the cabin.
"Houston, are we Go for EVA?"
"Stand by, Intrepid. We'll be right with you," said CapCom Edward Gibson.
Conrad couldn't quite believe what he'd just heard. "Stand by?! You guys ought to be spring-loaded!"
But, of course, Houston wasn't going to keep the explorers waiting long. Once all the status boards had been checked a final time, the Gibson radioed permission. "Intrepid, You're Go for EVA."
Pete Conrad is not a tremendously tall person. The one-meter jump down from the bottom rung of the ladder had always seemed a bit intimidating, but now it gave him a chance to set the tone for the mission. The time for historic phrases had past; now it was time to have fun. "Whoopie!" he said as he made the plunge. "Man, that may have been a small one for Neil, but that's a long one for me." (Readers interested in the story behind this episode should consult either the Apollo 12 Lunar Surface Journal or Andy Chaikin's A Man on the Moon.)
Bean soon joined Conrad on the surface and, once they'd both had a chance to get used to walking and a chance to savor the sight of the Surveyor sitting so close by, they got busy deploying the scientific gear. As on Apollo 11, there was a TV camera, a seismometer, and a laser reflector. And they also had a more-sophisticated solar-wind analyzer and a number of other physics packages that made up the ALSEP (Apollo Lunar Surface Experiments Package) that had gotten bumped off Apollo 11. Most of the equipment, together with a central power station and transmitter, was stowed in two compact packages tucked away in the Descent Stage. Bean lifted them down with a pulley and attached them to the ends of a carrying bar - which would double as a radio antenna mast - in dumbbell fashion. The complete ALSEP weighed 250 pounds on Earth, but only about 40 pounds on the Moon, and Bean had no particular trouble hauling the load to the deployment site about one hundred fifty meters west of the LM. The two experiment packages tended to bounce up and down as he walked and that made gripping the bar a little difficult; but, generally, he and Conrad had very few problems with this first major set of tasks.
The lesson? "Never come to the Moon without a hammer."
A second equipment problem involved the electric cables which connected the various units to the Central Station. Although the cables were fairly stiff, on Earth they tended to lie flat to the ground, held down by their own weight. However, on the Moon, the cables hardly seemed to notice the weak gravity and retained loops and bends they had acquired during storage inside the LM - loops that stood up from the ground rather like sections of a frozen garden hose. There were no disastrous tripping episodes during Apollo 12, but the need to dodge cables slowed the work.
Avoiding cables was a matter of watching one's feet or, from a more practical point of view, of watching the other guy's feet. The suits were bulky enough that, although the astronauts had to lean far forward to balance, they rarely saw their own feet and had a tough time keeping clear of obstacles. The suits also slowed the work in other ways. Because the inflated suit was stiff, it was difficult to flex the knees enough to kneel. The most practical way to grab or manipulate objects close to the ground was to use long-handled tools. However, the tools themselves were sometimes awkward to use and, as Conrad commented, it all would have gone a lot quicker had they been able to reach down easily. It was only later, during the second EVA, that he and Bean discovered a couple of handy tricks.
Within three hours of leaving the LM, the astronauts had finished deploying the scientific equipment. They had gotten about a half an hour behind the nominal time line but were otherwise well pleased. They were both relaxed - with heart rates dipping down into the 80s - and Conrad would have whistled while he worked, had whistling been possible at 3.7 psi suit pressure. The only thing that had gone really wrong during the EVA was the loss of the TV camera. This was the first color TV camera to be landed on the Moon and, unfortunately, it quit working while Bean was moving it away from the LM. As was suspected at the time, he accidentally pointed it at a bright reflection off the LM and burned out the target in the vidicon imaging tube. As Bean said in technical debriefings with the engineers once he got home, the root cause was the fact that he hadn't been able to train with an actual flight camera. Development of the camera had lagged and NASA took delivery just a short while before the launch. In the interim, Bean had trained with a mockup and never paid attention to the camera's limitations. Fortunately, the loss of the TV wasn't critical from a technical point of view. Conrad and Bean both took plenty of photographs. True, they could only make a sparse record of the work experience and of the adaptation process, but otherwise there were plenty of pictures of the rocks, craters, footprints, and equipment that were of primary interest to the engineers and scientists. Nonetheless, things were going so well and the crew was obviously having such a good time - joking, laughing, humming, and singing - that the lack of a picture was a real frustration to those of us who had taken the Wednesday morning off from school or work to watch the coverage.
When Conrad first went out to the ALSEP site to scout out a deployment area while he waited for Bean, he had noticed a couple of meter-sized, conical mounds and was eager to take a look. Were these volcanic features? Or something else? On their way out to Middle Crescent, Conrad and Bean finally had a chance to take a close look and they quickly decided that the mounds were probably big clods of compacted soil which had been thrown out by the Head Crater impact. They took pictures and collected a few samples and then moved on. Along the way, they found beads of glass lying out on the surface, and, at Middle Crescent Crater, hints of bedrock exposed in the inner walls. Twenty minutes didn't give them much time for careful consideration or comment; it was very much a matter of jog, stop, take a minute to marvel, take a few pictures, grab a sample, and jog again. But the hurried pace didn't really matter. If nothing else, the jaunt gave them some practice for the serious geologizing they would do during the second EVA. And, besides, it was all fun. Indeed, it took several reminders from Houston before they started back to the LM.
On the way back to the spacecraft, Conrad and Bean made good time, covering the two hundred meters in about five minutes. Despite a couple of stops to pick up irresistible rocks, they managed a net speed of about 2.5 kilometers per hour. On the second EVA, they planned to extend their range to about 400 meters and the short run proved that, should something need tending in the spacecraft, they'd have no trouble getting back in a hurry. Their heart rates had risen to only about 120 beats a minute and, although they were both a bit tired, they clearly had plenty of physical and mental reserves. They were happy and pleased with their performance.
Conrad and Bean didn't sleep well. The hammocks and the heater made for an easier night than the Apollo 11 crew had, but nobody had been able to do anything about the excitement. Bean took a sleeping tablet but it didn't help much. In the morning, Conrad reported that they'd gotten about five hours of sleep but, in reality, they'd hardly slept at all. An hour ahead of the scheduled wake-up call, it was they who called Houston. They were eager to get outside again. After a quick meal, they got busy preparing themselves, their suits, and the LM for the day's activities. Two and a half hours after calling Houston, they were out on the surface.
During the entire second EVA, Pete Conrad was like a man possessed, constantly aware of the timeline and the list of tasks yet to be done, single-minded in his determination to complete everything on the checklists that they wore on their sleeves. He knew that they would have to keep moving. Not counting the time they took to load the backpacks wit