SP-4208 LIVING AND WORKING IN SPACE: A HISTORY OF SKYLAB

 

17
 
THE LAST MISSION
 
Changes to the Mission.
An Error in Judgment.
Activation.
Getting to Work.
First Month's Accomplishment.
A Comet for Christmas.
Carr Calls for an Assessment.
Around the World for 84 Days.
Coming Back.

 

 

[312] While the second crew set new records for productivity in orbit, the third crew spent long days in Houston's simulators. Bean and his colleagues had enjoyed first priority in using the limited training facilities until they left for the Cape. Only toward the end of July, with just over three months remaining before scheduled launch, did Carr's crew have uninterrupted use of the trainers. Besides practicing rendezvous, dock ing, and reentry procedures-tasks which took up most of their time- they rehearsed extravehicular activity in Huntsville's big water tank, sat through hours of simulations at the ATM console, and familiarized them selves with the 50-odd pieces of experiment hardware they had to operate.

 

CHANGES TO THE MISSION

 

As if this were not enough, mission planners and experimenters devised more tasks for the last crew. After looking at early results, astronomers asked for new solar observations. Medical experts required extra measurements and photographs. Planning for these new experiments was sometimes faulty; the crew would later complain that training for some of them had been totally inadequate.

Late in the summer, Headquarters program officials determined to use Skylab as a platform for observing a comet discovered by a Czech astronomer, Lubos Kohoutek, in March 1973. Its early discovery, nine months before perihelion, gave astronomers more time than they normally had to prepare for observing a comet (see app. F). Since the newcomer would swing around the sun in late December, Carr's crew would be in an excellent position to observe it.1 Using Skylab for comet-watching meant that new, complex maneuvering procedures had to be added to the training schedule.

The new experiments were a recognizable addition to the third crew s work load. What no one seemed to recognize was that the second crew had raised everyone's expectations for the last mission. In a press....

 


[
313]

Removing the first of eight damaged stabilization fins from the Saturn IB that would carry the third crew to Skylab.

Removing the first of eight damaged stabilization fins from the Saturn IB that would carry the third crew to Skylab. The work delayed the launch five days, until 16 November 1973. 73-H-1105.

 

....conference on 2 October 1973, JSC Skylab manager Kenneth S. Kleinknecht enthused over the second crew's accomplishments, which showed, he said, that man "was able to do more than we thought he could do." Management was retaining the option to extend the last mission to 70 days, and since this would cost around half a million dollars a day, flight planners would have to supply enough work to justify it. The chief of Houston's Orbital Assembly Project Office observed that the remarkable productivity of the second crew was "indicative of what we can expect in the future." The manager of the JSC Missions Office then outlined recent changes to plans for the last flight. There would be 28 man-hours of experiment work per day and 12 new Joint Observing Programs for the ATM. Ten to 14 earth-resource passes had been added to the 20 already planned, and the crew would take some additional medical measurements. Continuing the handyman tradition established on the first two missions, the last crew would recharge the coolant in a refrigeration system and troubleshoot the earth-resources microwave antenna, which had failed.2

Throughout October training and launch preparations went smoothly, aiming for a liftoff on 11 November. Five days before that, however, inspection of the Saturn IB launch vehicle disclosed cracks in each of its eight stabilizing fins. The cracks, probably caused by stress corrosion' might well have caused the fins to be ripped off as the rocket passed through maximum aerodynamic pressure early in flight. Replacement fins, flown in from NASA's Michoud, Louisiana, facility, were installed where the Saturn sat, atop the 39-meter "milkstool." Special work platforms, much like painters' scaffolds, were swung from the [314] mobile launcher down to the base of the rocket. The repair crews had to work some 1 2-hour shifts, but the job was completed on 12 November. Launch was rescheduled for the 16th.3

The major uncertainty clouding the third mission was the possibility of motion sickness during the first days in orbit. After the second crew's unfortunate experience, NASA's top managers had become gravely concerned. A group of NASA and outside medical experts, convened in late October to evaluate the data on space malaise, recommended medication upon reaching orbit. After Carr and his crewmates objected, because both of the favored drugs had undesirable side effects, it was agreed that the commander would delay his medicine until after rendezvous was complete. On the second and third days all three astronauts were to take the capsules routinely; thereafter, only if symptoms appeared. They were instructed to restrict head movements as much as possible and to spend the first night in the command module, since moving around in a large space seemed somehow conducive to motion sickness. The astronauts agreed- somewhat reluctantly, because they were not convinced that even the medical experts fully understood the illness.4

 

AN ERROR IN JUDGMENT

 

Skylab's last mission roared into the Florida sky at 9:01 a.m. EST, 16 November 1973. The launch and early phases of flight were routine except to the all-rookie crew; on their first pass over the United States, mission commander Lt. Col. Gerald P. Carr told Mission Control that the spacecraft windows were smudged where the three delighted first-timers had been looking out. On the fifth revolution, between Australia and Guam, Carr sighted the workshop; within 10 minutes he had closed to about 30 meters. He maneuvered the Apollo spacecraft in with great precision, but once again the docking gear gave trouble. After two unsuccessful attempts, Carr hard-docked the command module to the multiple docking adapter almost exactly 8 hours after launch.5

That done, the crew was out of touch with Houston for 41 minutes between Bermuda and Carnarvon, Australia, so they started straightening up the command module, stowing the gear used during rendezvous and docking. First, however, Carr and scientist-pilot Edward G. Gibson took their antinausea pills. Pilot William R. Pogue had already attended to that, but too late. A few minutes before ground contact was established, he asked Gibson to hand him a vomit bag. Gibson complied, and as he and Carr went ahead with their chores, Pogue said, "I think I'm going to go slow for the next few minutes." It was not enough; weightlessness had done its work, and Pogue vomited-not very much, but he was quite nauseated. Houston came back on the communications circuit just before 6 p.m. and reiterated the physicians' warning about entering the work- [315] shop. Before launch, Carr had requested a change of plan to allow them to begin activating the workshop that evening, but flight planners saw no advantage in that. Carr agreed to wait until the next day.6

After Skylab went out of radio range, Carr and Gibson debated what they should say about Pogue's illness during the evening status report, due in just over an hour. Carr was inclined to keep mum for the time being. To account for the food Pogue had not eaten, Carr would say that Pogue was not hungry. As they prepared their second meal, Carr and Gibson mulled over the situation. It was ironic, because Pogue was noted for his resistance to motion sickness. He was known as "Iron Belly -the guy with "cement in his inner ear." Cement or no, Pogue was miserable. The others had helped him move to the docking tunnel, where air from a cabin fan might make him feel somewhat better, but he was not improving. When Houston came on the air again, Carr asked to postpone the status report, since they had not started eating. Houston agreed, and Carr had two more hours to decide what to do.7

Had they remembered that an onboard tape recorder was running all this time, Carr and Gibson would have reported Pogue's vomiting. But they did not remember; and, thinking that only the three of them would ever know what had happened, they decided to minimize the potential repercussions of the pilot's illness. Pogue had vomited very little; it was not a gut-wrenching attack. Surely he would recover before they moved into the workshop the next morning. Gibson feared that the doctors would overreact if they knew of the vomiting. Carr wavered. He considered reporting Pogue's illness but not the vomiting. "I'd just say he doesn't feel like eating." But a few minutes before the medical conference, he told Pogue, "I think we better tell the truth tonight.... Because we're going to have a fecal/vomitus bag to turn in, although I guess we could throw that down the trash airlock and forget the whole thing.... Gibson liked that idea: "I think all the managers would be happy." Vomiting was worse than nausea in the flight surgeons' view, and it would be simple to dispose of the bag and report only that Pogue was nauseated. The distinction was a fine one, hardly worth the uproar that would result if they reported what actually happened. So, as Gibson put it, they could keep the incident "between you, me, and the couch. You know darn well, the scientist-pilot incautiously added, "that every manager at NASA would probably, under his breath, want us to do just that." So, during the medical conference, Pogue's nausea was mentioned but not the vomiting. Before retiring, Carr read the evening status report to the ground, reporting that "the pilot had no strawberries for lunch and has not eaten meal C." 8

Saturday morning they all felt better after a good night's sleep. Pogue was recovering, but he still chose to take things easy for a white. The others fixed breakfast while enjoying a view of the Alps and south-[316] eastern Europe. At a quarter to nine they were ready to enter the workshop. It took half an hour to pressurize the multiple docking adapter remove its hatch, and stow both the hatch and the docking probe in the command module. At 9:16 Carr turned on the lights and the crew started to work, hooking up communications, starting up the environmental control system, and powering up the workshop.9

Meanwhile, the tapes from the onboard recorder were being routinely transcribed in Houston, revealing the candid discussions Carr and Gibson had held regarding Pogue's illness. Reaction was prompt. A medical conference was called in mid-afternoon. Toward the end of the day, Alan Shepard, chief of the Astronaut Office, took the microphone in Mission Control to give the crew a public and official, if mild, reprimand. I just wanted to tell you," he said, "that on the matter of your status reports, we think you made a fairly serious error in judgment here in the report of your condition." Carr accepted the rebuke: "Okay, Al. I agree with you. It was a dumb decision." And that was that. At that evening's change-of-shift press briefing, reporters wondered if the incident portended a break in frank and open communication between crew and flight controllers. Flight Director Neil Hutchinson thought not; but if there were any further signs of lack of candor, he said, flight controllers would immediately take steps to set matters right.10

How much this incident contributed to the crew's later problems is uncertain. Managers believed-and the tape-recorded evidence supports their view-that the astronauts meticulously reported on channel B every mistake they made thereafter. They were, however, unwilling to discuss their problems on the public air-to-ground channel. As Carr noted later, they could hardly enjoy having their shortcomings discussed on front pages across the country the next day. And since Pete Conrad's use of the private line for operational purposes (p. 281) had stirred up such a flap within the agency, that route was closed to them except in real emergencies. All they had was channel B, with its built-in time lag of nearly 24 hours before Mission Control could read transcripts of the tapes. Even there (since channel B transcripts were also made public) they hesitated to be completely frank; flight controllers would have had to be finely attuned to the personalities of the crewmen to detect specific problems That kind of rapport was unfortunately missing on the last Skylab mission; there had been little close interaction between the crew and their flight controllers during training. This helped to produce frustration for all concerned during the next six weeks.11

 

ACTIVATION

 

Flight control teams, happy to have men back in the workshop after several weeks of unmanned operation, swung back into their routine with [317] gusto. Activating the workshop was the first order of business. Although one flight controller characterized activation as "only a little more complicated than when you come back from vacation," Carr and his crew (like the two crews before them) found it considerably more than that. Every job took more time than anticipated. Inevitably mistakes slowed them down still more, as did communications from Houston; every few minutes an interruption required someone's attention. An hour was lost when Pogue, flushing the potable water system with iodine solution preparatory to tapping a new water tank, left a valve in the wrong position and dumped the disinfectant into the waste tank. By the end of the first day, they were about two hours behind. They did not reduce that deficit the next day. Nevertheless, planners set up a regular flight plan for Monday.12

The big job on Monday was to recharge the primary coolant loop that cooled the spacesuits and airlock batteries. Successful completion of this task would permit carrying out the first extravehicular activity as scheduled; without cooling, the outside activities would probably require two trips. Using equipment exactly like that used for recharging ground-based refrigerating systems, Pogue finished that job without trouble.13

This repair was only one of several extra chores the third crew had to accomplish during the first week of flight. A particularly time-consuming one was a new set of medical measurements. Girth measurements at more than 50 points on the astronauts' bodies, together with photographs on infrared-sensitive film, would show how blood and body fluids moved toward the head in zero g. The measurements took about four man-hours; the tapes were hard to handle and the crew had not used them at all before flight. The photography would have been easier had there been better provision for restraining the photographer. While the subject lay on the floor of the upper workshop compartment, the cameraman was supposed to float above him. Pogue, trying this for the first time on the fifth day, found himself drifting. Trying to steady his body, he wedged a shoe between two water tanks, accidentally turned a valve and then kicked it off. The resulting loss of pressure was discovered that night.14

Tuesday, their fourth day in the workshop, was another jam-packed day; they had no time to look out the wardroom window, although visual observations were on their list of optional activities. Later Carr told Houston, "If we're ever going to get caught up . . . we're going to have to whack something out [of the flight plan] tomorrow.... We haven t had time to . . . stow everything properly, and this place is really getting to be a mess." 15

The first week's big event was the extravehicular activity scheduled for 22 November, Thanksgiving day, when Pogue and Gibson would reload the ATM cameras and check out the inoperative antenna on the [318] microwave sensor. The latter job might be tricky, since there were no restraints on the under side of the multiple docking adapter where the antenna was mounted. But having worked out the procedures in Huntsville's big water tank, the astronauts were confident it could be done.

Just before noon on Thursday, Gibson and Pogue suited up in the workshop s forward dome and squeezed into the airlock. An hour later after meticulously checking over their gear-stepping out into a vacuum does not allow for careless preparation-they let the air out of the airlock and opened the hatch.16

Pogue's first task was to take some photographs to record the amount of contamination surrounding the workshop. He had taken only a few exposures when the camera failed. The shutter speed knob spun ineffectually in his gloved fingers. He then helped Gibson reload the ATM cameras. After finishing that task, they worked their way around the airlock to the inoperative antenna on the earth-facing side of the cluster. They quickly found that, although Pogue had to do the work on the electronics module, Gibson could better restrain himself. So the science-pilot held on to his colleague and moved him around, while Pogue called out directions and used both hands to work. 17

From telemetry, scientists suspected faults in one or both of the potentiometers that controlled the antenna's oscillations. Pogue opened the module and cleaned the potentiometers; but when Carr applied power to the antenna, it did not function. Some simple tests showed that the problem was in the pitch circuit (controlling fore-and-aft oscillations) and could not be corrected; so Pogue installed a pin to lock the pitch gimbal and a Jumper to bypass it. When Carr activated the unit again, it worked, though only side-to-side, scanning across the spacecraft's ground track. Restoring more than half of the instrument's function delighted the experimenters. 18

Pogue and Gibson returned to the airlock after a 6 1/2-hour, near-flawless exercise. EVA had come a long way since Gemini; Pogue and Gibson had hardly worked up a sweat. Still, it had been a long day, and that evening Carr saw no reason to stay up late to finish the post-EVA checklist. They were tired, and it could wait until Friday. 19

Next day the astronauts were still behind schedule. Neil Hutchinson told reporters that the crew might get Saturday off, instead of Monday. (Their first scheduled day off, 19 November, had been canceled before launch.) The mission could afford the time, and he thought the crew needed some breathing space. Hutchinson admitted that flight planners had erred in estimating the time needed to get things done and had given the crew too much work to do.20

The same problem had come up on the earlier missions, but evidently the hard-charging second crew had left a lasting impression on flight planners, who were trying to bring Carr, Pogue, and Gibson up to the [319] level that Bean, Lousma, and Garriott had achieved. On the first mission, Pete Conrad had been quick to let Mission Control know when he was pressed too hard (p. 288); but Jerry Carr was no Pete Conrad, and no doubt his misjudgment about reporting Pogue's illness had inhibited him still more. He did not want to tell Houston that his crew could not keep up with the flight plan-certainly not on the open communications loop.21

A free day on the 24th helped, especially since Mission Control studiously avoided saying anything that might sound like harassment. That evening the commander sat down and reviewed the first week for flight controllers. "The best word I can think of to describe it," he told the channel B tape recorder, "is frantic." Learning to move around "just takes a great deal of time. I think you could tell by our voices that we were very, very frustrated.... No matter how hard we tried, and how tired we got, we just couldn't catch up with the flight plan. And it was a very, very demoralizing thing to have happen to us." He was cautiously optimistic; they had finished all the work scheduled through that day, but could easily get behind again. He urged flight planners to give them schedules they could keep up with.22

 

GETTING TO WORK

 

Sunday it was back to the grind: running the cardiovascular assessment on Gibson, replacing a video display tube and installing a new automatic timer on the ATM console, and checking out the earth-resource sensors. That evening Flight Director Donald Puddy commented positively on the day's accomplishments. The crew's spirits had been lifted by their day off, and he offered the opinion that "within the next few days the comments that . . . we're following a little bit behind the flight plan will disappear from the agenda." Weather permitting, the first earth-resources pass would be made on Monday, and ATM observations were scheduled to start Tuesday.23

Flight controllers intended to start a normal work schedule on the 24th. But the day off had postponed that, and on the 23d the workshop sprang a surprise. That night, without warning, one of the control moment gyros heated up and slowed down alarmingly. All indications suggested that an inadequately lubricated bearing had seized up. Flight controllers turned off the sick gyro, switched the workshop computer to two-gyro operation, and began to wonder how they were going to complete the mission.24

In normal circumstances the loss of one control moment gyro would have been a minor disturbance; what made it serious was the depleted supply of gas for the attitude-control thrusters. The first few days after launch of the workshop, attitude-control fuel had been used up at an alarming rate (p. 257). When the third crew reached Skylab, the system [320] had only about one-third its original capability. Many earth-resource passes remained to be done, and the maneuvers to observe comet Kohoutek would be especially costly in fuel. If there was to be any hope of completing those assignments, flight controllers had to know exactly how much propellant every maneuver would require. Experts at Huntsville and Houston immediately set to work devising more accurate ways to assess the workshop's momentum state and working out new computer programs. All experiments that required maneuvering became much more complicated.25

Monday's scheduled earth-resources pass was canceled because clouds covered the site, so the day was given over to a cardiovascular experiment on Carr, stellar spectroscopy, and an observation of comet Kohoutek. Gibson checked out the solar instruments in preparation for the first observing period on Tuesday. It was another busy day, and Carr and Pogue complained of making errors and being rushed.26

Tuesday's schedule was typical of the way things would go for the next two weeks. By 6:30 a.m. the astronauts had started their early morning chores. At 8:22 Carr reported that he had begun ATM operations. Half an hour later, they learned that the observing schedule would be more crowded than planned, since scientists could see considerable solar activity and felt there was a good chance for a solar flare.27

While Carr was watching the sun-he had most of the day's ATM duty-Pogue and Gibson had several tasks to perform. Pogue set up a camera in the wardroom window to photograph a cloud of barium vapor released from a rocket, part of an experiment to study the earth's magnetic field. He and Gibson took turns monitoring each other as subjects of the vestibular-function experiment. For the news media, they made a 9-minute TV tape to illustrate in-orbit exercise. Carr explained the ergometer and the "Thornton treadmill" while performing on them. The treadmill was a sheet of slippery Teflon fixed to the floor, on which the astronaut walked in his stocking feet. A bungee-cord harness pressed him down, substituting for gravity. Scientist-astronaut William Thornton had conceived this simple device to stress the leg muscles that were not properly exercised by the bicycle, and it worked very well-so well, in fact, that no one could use it for more than a few minutes. It was a welcome addition to the exercise program.28

At intervals during the day, Carr and Pogue took photographs through the wardroom window, choosing sites from a list sent up by Mission Control. This was part of a program to systematize the heretofore informal observation of cloud patterns, ocean currents, and geologic features. Later they would supplement the photography with detailed visual observations and descriptions.29

Flight controllers and CMG experts, meanwhile, were learning the limits of their maneuvering capability with two control moment gyros.

 


[
321]

A symmetrical bow-wave cloud pattern downwind of small, mountainous Gough Island in the South Atlantic.

A symmetrical bow-wave cloud pattern downwind of small, mountainous Gough Island in the South Atlantic. The island itself, lower right, is clear. The photo was taken with a hand-held 70-mm Hasselblad camera. SL4-137-3632.

 

Positioning the workshop for Pogue's photography of the barium cloud saturated the CMGs, and considerable fuel was used in returning to solar inertial attitude. Around mid-afternoon the next day's maneuvers were canceled so that engineers could study the problem a bit more. At the evening press briefing, reporters urged Donald Puddy to estimate how much earth-resources data might be lost, but the flight director was unwilling to concede that any would be. He expected that in a few days the complexities of maneuvering with two gyros would be mastered, so that before the mission was over all mandatory sites could be covered.30

After a long day, Carr sat down at 9 p.m. to give the evening status report-sleep, exercise, changes in food and water intake, clothing used, [322] and so on. Ground and spacecraft exchanged several questions and answers about flight plans and the status of systems, and after briefly summarizing the day's news headlines, CapCom signed off shortly after 10'0 clock. 31

By 30 November the guidance and control experts felt confident that they understood their new constraints. They executed a complicated earth-resources pass that day; the astronauts carried out their part flawlessly and the amount of attitude-control fuel used was very close to what had been predicted. Two days later, however, an attempt to conduct two passes in sequence saturated the gyros and used much more thruster gas than expected. Back to the computers and simulators went the engineers; two more days were needed to devise new procedures.32

During the week of 26 November, as flight planners began to step up the pace of the work day, each astronaut responded to a questionnaire about the habitability of the workshop. A question calling for comments on unanticipated problems prompted Carr to reflect on the frantic first two weeks. Most of the unanticipated trouble arose because there was no way to train adequately for zero-g maneuvering. "When you get up here . ., it's a whole new world.... Everything we did took two or three times as much time as we thought it would take. We fooled ourselves." Then he touched on the root cause of their trouble:

We told the people on the ground before we left that we were going to take it slow and easy on activation, . . . that we were not going to allow ourselves to be rushed. We got up here, and we let ourselves just get driven right into the ground. We hollered a lot about we were being rushed too much, but we did not, ourselves, slow down and say "to heck with everything else"; and do things just one after the other, like we said we were going to do.

These reflections went unnoticed by flight planners; still trying to get the third crew up to the pace set by the second, they were in no frame of mind to read such comments for what they were.33 So they pressed on, shortening the time for tasks by degrees, decreasing the time between planned activities, following what they assumed was the crew's increasing proficiency. Flight directors noted several times that crew performance was not yet as high as they had hoped. On 5 December both the flight director and the crew physician professed to see signs that the astronauts were no longer as rushed as they had been, but next day, Carr complained about the schedule for seven minutes. We wouldn't "be expected to work a 16-hour day for 85 days on the ground," the commander told them, "so I really don't see why we should even try to do it up here." The flight director told reporters that night that 27 man-hours per day of experiment work were being planned-an "increase from the nominal," but less than Bean's crew had done.34

 

FIRST MONTH'S ACCOMPLISHMENTS

 

[323] Program officials reviewed the mission on its 28th day, 13 December 1973, assessing the performance of spacecraft systems and crew and weighing the prospects for completing 84 days. That afternoon at a press conference, Bill Schneider ticked off the mission's accomplishments: 84 hours of solar observations, 12 earth-resource passes, 80 photographic and visual earth observations, all of the scheduled medical experiments, plus numerous corollary experiments, student experiments, and science demonstrations. The astronauts had done three major repair jobs. The principal worries were the solar x-ray telescope, which had a jammed filter wheel, and an occasional sign of distress in one of the remaining control moment gyros-something everyone was watching very carefully. Unless something unforeseen happened, Schneider said, "we're GO for our 60-day mission, open-ended to 84." 35

Reporters immediately raised questions about the crew. Why were they so slow? Why were they making mistakes? How did they compare with the first two crews? Both Schneider and Kenneth Kleinknecht denied that there was any higher incidence of error on the third mission than on the first two and refused to compare the performance of crews. Hundreds of changes to the flight plan had made the third crew's job much harder. Kleinknecht put some of the blame on people on the ground who had approved so many changes and asserted that Carr, Pogue, and Gibson were doing "an outstanding job." One unidentified reporter then resurrected the vomiting incident and the crew's unguarded discussion, which he called "in effect . . . a coverup." Was Schneider suspicious, he asked, that other matters were being withheld from flight controllers or physicians? No, the program director replied; the channel B tapes were full of admissions of error and the doctors were satisfied that their medical conferences were frank and open. As for any coverup, the true gauge of that first day's discussion was that Carr and Gibson had finally decided that managers would have to know what had happened and had saved the physical evidence. Both Schneider and Kleinknecht warmly defended the crew, and reporters let the subject drop.36

No matter how much officials protested, there was a problem; angry comments from each crewman proved the point that very week. On 12 December Pogue complained bitterly to channel B about the tight scheduling of experiments. He had just lost a couple of photographs because he had to set up a camera in a hurry, and addressing the principal investigator he remarked, "this is going to happen again [and again] until the word gets through to the Flight Activities Officers that they're going to have to give us time to get from one point in the spacecraft to another.... I don't know how we're going to get this across to [them] unless you [principal investigators] put your foot down and stomp it hard." Two days later Carr complained-again to channel B-in the same vein. [324] Flight planners seemed to forget that it took time to enter all the changes to checklists that they sent up. "One little [teleprinter message] 3 or 4 inches long represents about 30 minutes of work." Gibson took his turn on the 20th, detailing exactly how his schedule had been knocked awry that morning by a series of small but time-consuming problems. "That's no way to do business," he complained, and went on: "I personally have found the time since we've been up here to be nothing but a 33-day fire drill.... I've been engulfed in building blocks rather than being concerned with the quality of the data." He then declared his personal independence from rigid scheduling, stating that he intended to take as much time as he needed to do each job right. If something got pushed off at the end of the day, too bad. "It's going to come down right, rather than on time."37

Gibson's comments explicitly expressed something that flight planners had sensed already: the crew could not handle the work load that flight planners were giving them. Program Scientist Robert Parker, an astronaut and astronomer, recalled later that every attempt to increase the daily work load came up against a brick wall at about 25 man-hours. Having indicated that about 30 man-hours would be available when he accepted requirements from the principal investigators, Parker was getting his plans all tangled up. Around the end of the first month he cut back by about 15%. 38

 

A COMET FOR CHRISTMAS

 

AS comet Kohoutek sped toward perihelion on 28 December, America's newspapers began a crescendo of coverage intended to climax with the brilliant display they expected around the end of the year (app. F). Scientists and engineers had spent the summer of 1973 working out plans to use Skylab's instruments for comet studies and had developed two new cameras to supplement the ATM telescopes and four corollary experiments already on board.39

Systematic comet observations began on 23 November, when Pogue used one of the new instruments, a photometric camera that measured the comet's intrinsic brightness. Observations to collect data on the composition of its coma and tail began two days later. Three corollary experiments and a new electronographic camera measured ultraviolet radiation emitted by hydrogen and oxygen atoms, from which scientists hoped to determine whether Kohoutek contained substantial amounts of ice. These instruments all operated through the antisolar scientific airlock and required maneuvering the workshop to bring them to bear on the comet. By 20 December the crew had made 17 observations with these cameras.40

As the comet drew closer to the sun, the solar telescopes became the primary means of gathering data. Because the pointing system was.....

 


[
325]

Comet Kohoutek as photographed through the white-light coronagraph, experiment S052.

Comet Kohoutek as photographed through the white-light coronagraph, experiment S052. A coronagraph creates an artificial eclipse so that relatively dim objects near the sun can be seen. Here the comet is passing behind the sun, 27 December 1973. High Altitude Observatory photo.

 

.....designed to keep the ATM centered on the sun, extra work was required to point it a few degrees away. Two crewmen were assigned to comet observation for the first few days. With only the coronagraph display to provide visual guidance, it was not easy to locate the comet, but after they had run through the new procedures a few times, the astronauts could carry out the complex maneuvers with confidence.41

An extravehicular excursion was scheduled for Christmas day, a second four days later. Besides reloading ATM film, the astronauts were to take out two cameras to photograph the comet. There were also two more repair jobs: pinning open a balky aperture door on the ultraviolet spectroheliograph and freeing a jammed filter wheel in the x-ray telescope.42

On Christmas morning, after a brief exchange of holiday greetings, Carr and Pogue made the lengthy preparations and stepped out. First, they took a series of exposures of the comet with the coronagraphic camera. Carr then reloaded the ATM cameras and pinned the malfunctioning experiment door open-staying an extra minute or two, at Gibson's insistence, to enjoy the spectacular view from the sun end of the telescope mount. Carr and Pogue then clamped the electronographic camera in place to get some photographs of the comet. Neither could see it, so they pointed the camera at the region where the comet was expected to be and began the prescribed sequence of exposures.43

Six hours into the EVA, Carr positioned himself at the center work station on the telescope mount to attempt repair of the filter wheel. It had jammed while his crew was in Skylab, so there had been no chance to train for this job on the ground. Using a flashlight and an oversized dentist's mirror, he located the barely accessible filter holder and verified that it was stuck between two positions. Carr then used a screwdriver to push the [326] wheel to an open position, with no filter in place. As he was working his hand into position, Carr momentarily slipped; the shutter snapped shut, and the screwdriver bent one of its thin metal blades. Carr feared he had disabled the instrument and did nothing until he could talk with Houston again-radio contact had faded just as he began to work. When he described the situation to Mission Control, the experiment managers quickly decided to bend the shutter blades out of the way, leaving the aperture fully open. Another 30-minute communications gap came up just as Carr was about to move the filter wheel, and when radio contact was reestablished, he verified the filter position with Houston's telemetry and then pushed the wheel to the open slot. That concluded their scheduled work. When they were back inside the airlock, 6 hours and 54 minutes had elapsed.44

On 28 December, Lubos Kohoutek himself came to Houston for a well publicized 11-minute talk with the Skylab crew. Neither the astronomer nor the astronauts learned anything from the conversation; it was simply taken for granted that some such gesture had to be made. For the American press, the Czech astronomer had become the important personage of the comet drama, though he was no expert on comets and had only an incidental connection with this one. Seemingly puzzled by the great interest in comet 1973f in the United States, Kohoutek nonetheless went through the public affairs routine, including the conversation with the astronauts, with poise and good humor.45

On 29 December, during the third EVA (provided specifically for comet observation), Gibson and Carr finally got a good look at the comet. Gibson gave Mission Control a brief description before the comet passed into the airglow just after orbital sunset. He and Carr then retrieved some samples of materials from outside the spacecraft, set up the cameras to photograph the comet, and made the exposures after they had gone around the earth again. Gibson then provided a more detailed description of the size, orientation, and color of the tail and of the prominent spike stretching out toward the sun. After three and a half hours, the two came back inside, trying to retain their mental impressions of the comet so they could make sketches later. During the next few days the crew spent considerable time observing Kohoutek, using the ATM instruments while it was still near the sun. From 5 January 1974 onward, most of the comet-watching was done with other instruments as the comet headed rapidly away from the sun, to return (perhaps) in 75 000 years.46

 

CARR CALLS FOR AN ASSESSMENT

 

Aside from one or two complaints from Jerry Carr, the crew said little about workloads and schedules during the last two weeks of December. It had been a busy month, with the extra activity involved in observing [327] comet Kohoutek, but the crew had no trouble keeping up with their work assignments. They even found time to build a crude Christmas tree out of packing material from the food storage cans and decorated it with makeshift ornaments. But crew and ground were not yet marching to the same drumbeat. Flight planners, having mastered the complex art of assembling a day's activity for three men without wasting a minute, were justifiably proud of their expertise and of the quantity of scientific data it could produce. The astronauts, however, did not share that philosophy; they felt their job was to turn out quality results, not merely some arbitrarily large quantity of data. And they chafed under the inflexible scheduling; every tiny housekeeping chore had its bit of time in the daily routine. All three felt that the flight plans were dragging them around by the nose and that the system was not responsive to their needs.47

Around Christmas, Carr, Gibson, and Pogue agreed that they had to have a better understanding with the flight planners as to the way things were done. On the evening of 28 December, after sending down the daily status report, Carr remarked to CapCom Richard Truly that he was preparing a special message for Mission Control; he would put it on channel B before he retired for the night. He then went to the onboard recorder and taped a six-minute plea for a frank discussion of the mission's status at the halfway point. "We'd all kind of hoped before the mission," he said, that "everybody had the message, that we did not plan to operate at the [previous crew's] pace." Now he was worried about how his crew was measuring up to expectations. He was puzzled by some of the questions being asked; he had begun to wonder, "Are we behind, and if so how far?" Were flight controllers worried because the crew wanted so much free time? Were they upset by the time the crew wanted for exercise? "If you guys think that's unreasonable, I'd like some straight words on that." Carr assured Houston that he would ask for a private communication if management wanted to talk privately; by now, however, he was ready to talk things out before the whole world. The big question was, "Where do we stand? What can we do if we're running behind and we need to get caught up? . . . we'd like to have some straight words on just what the situation is right now."48

Carr later regretted that he had waited so long. "We swallowed a lot of problems for a lot of days because we were reluctant to admit publicly that we were not getting things done right," he recalled. "That's ridiculous, [but] that's human behavior." With that summation both of his crewmates emphatically agreed.49

The astronauts were not the only ones who felt they needed a frank exchange of views. Robert Parker recalled that ground personnel too were inhibited by the open communications channel. No one who spoke directly to the crew ever suggested that they were doing less than a great job. "We just very seldom [found] ourselves capable of calling a spade a [328] spade," was the way Parker put it. It got worse when the newspapers began to suggest that the third crew was slower and more error-prone than the second. Everyone in Houston became defensive about the crew, feeling that they were being maligned.50 Not without reason did Carr call for some "straight words" from Mission Control.

Truly acknowledged Carr's message the following night, and the next day flight planners sent up a long teleprinter message outlining their views and scheduled an air-to-ground discussion for the evening of 30 December. If it took two hours to reach an understanding, everything else could wait.51

The importance of the discussion was that it took place at all, although substantive issues were settled as well. One of Truly's first comments was that Mission Control had not been aware of the commander's expressed intention to work at a more deliberate pace than the second crew. Flight planners had indeed tried to push the third crew up to the second crew's level, but when that proved impossible they had cut the load back. To their surprise, however, when flight planners compared the accomplishments of the two missions between the 1 5th and 30th mission days, they found no significant difference.52

Turning to specific scheduling problems, Truly spoke of physical exercise, which Carr felt strongly about. Truly pointed out that the 90 minutes set aside for exercise caused serious scheduling difficulty. The only solution the planners had found was to break it up into two 45-minute sessions. Carr interrupted to give his side of the question: he wanted time to cool down and clean up after a workout on the ergometer because he despised rushing off to some other job feeling grimy and hot. Doing that twice a day was more than he could take.53

Free time was another sensitive issue. All of the astronauts wanted some uninterrupted time after they got out of bed in the morning, and again at the end of the day so they could unwind; this was all the more important because they expected to stay in orbit for 12 weeks. Mission Control was willing to plan for an uninterrupted hour before bedtime, but reserved the option to break into it if a scientific opportunity arose that they could not pass up. "Yes, we appreciate that too, Dick," Carr said; the reason we started hollering is that there was just getting to be too much of that." "Okay," said Truly, "you asked what some of our flight plan problems are, and that has been one of them."54

After nearly half an hour, Truly summed up his end of the conversation with encouraging words. "I think it's important for you to know that we realize that these last couple of weeks, the work load that we've been putting on you is a level that you very obviously have handled with no problems.... We naturally would like to continue to get more science per invested hour as we go along"-a hint that Houston still wanted to increase the work load-so "any time you see a consistent gap in the flight [329] planning that provides you a little extra time, believe me, it will help us to know about it.... [And] when we go to talk about flight planning . . ., we think it's a lot better to talk about it on the air-to-ground than on the voice dump.... so you'll be talking to the team that did it to you, and you guys can have it out." "Okay," said Carr, "we'll sure do it that way from now on."55

During the 20-minute communications gap that followed, Carr consulted with Pogue and Gibson and put together his own summation. He still insisted on some quiet time at the end of the day, but said the crew would consider breaking up their exercise periods if that would help. He also suggested that activities that were not time-critical (such as some of the corollary experiments and most of the housekeeping tasks) the crew should do when they could best get around to them. This would allow some judgment and relieve the automaton-like existence they had been leading for six weeks.56

Closing the 55-minute discussion, Truly expressed Mission Control's satisfaction. "Jerry, let me say one thing, that [JSC Director] Dr. Kraft and Deke [Slayton, Flight Crew Operations chief] have been here and listened . . . and they're very happy with the way you're doing business, . . .and they think we've made about a million dollars tonight. " 57

Just how much they had actually made was not immediately obvious, but everyone was relieved to find that candid conversations could be held in public without serious consequences. With the assurance that difficulties could be quickly settled and that mission planners were responsive to their needs and preferences, crew morale went up. Why it took so long to reach this level of candor remained a mystery. Many of those involved agreed that ground personnel simply did not realize that the third crew could not be dealt with in the same way as the first two. Jerry Carr- unlike some other astronauts-was not easily prodded into expressing dissatisfaction. Though he vowed before launch that he would blow the whistle if Mission Control pushed his crew too far, his mishandling of Pogue's first-day illness put him on the defensive and made him feel he had to make up for it by producing results. Looking back on it at mission s end, Carr accepted some of the responsibility, but he also faulted flight planners for allowing the crew no time for adjustment. "Obviously [they] were not thinking," he said; "they were just coloring squares and filling in checklists. That is no way to operate a mission. 58

Afterward, members of the Mission Control team minimized the importance of this discussion-and of the circumstances that led up to it-in the overall success of the last mission. At the time, however, everyone was glad the air had been cleared. Two days later, Flight Director Neil Hutchinson remarked that the astronauts were more alert, that they were looking ahead in the day's flight plan and organizing activities to [330] optimize their work schedule, and that they had stayed ahead of the flight plan all day.59

 

AROUND THE WORLD FOR 84 DAYS

 

Early in January, Carr, Pogue, and Gibson were closing in on the existing records for duration of spaceflight. On the 4th they eclipsed Pete Conrad's mark-one that had taken four missions to accumulate. On 25 January the first all-rookie crew in eight years would become the worldrecord holders for time spent in space, but for the time being that title still belonged to the second Skylab crew. The members of the third crew were little concerned with setting new endurance records; that was incidental. Their main interest was in completing the mission planned for them, and, after settling their differences with Mission Control, they went about their work with new enthusiasm.60

The 10th of January, the astronauts had a day off-which meant that only about a third of their time was formally scheduled. Otherwise they did as they pleased. Gibson spent almost the entire day watching the sun; Pogue and Carr stayed by the wardroom window much of the time, making observations, taking photographs, or simply enjoying the view. Like the earlier crews, they were fascinated by the constantly changing panorama.61

Managers, meanwhile, were conducting the 56-day mission review, deciding whether men and machines should be cleared for an 84-day mission. Next day Bill Schneider announced that the word was "GO" for 84 days. Strictly speaking, approval was given only for a week at a time, but little doubt remained that the full 12-week flight could be completed. The only thing likely to curtail it was the ailing control moment gyroscope. Even if that failed, it would create no emergency; the crew would have plenty of time to retrieve the ATM film, pack up their command module, and leave the workshop in orderly fashion.62

The gyro, however, was becoming worrisome. Engineers suspected inadequate lubrication of its wheel bearings and conducted maneuvers carefully, trying to reduce stress on those bearings. Toward the end of December they began manually controlling the bearing heaters to keep temperatures in the upper part of the allowed range. This, the experts hoped, would thin the oil and allow it to flow more easily into the bearings. There was not much else they could do. Experiments that required maneuvering the spacecraft now had to be scheduled much more carefully; earth-resource passes had to look exactly right before they were finally put in the flight plan. Weather conditions in late December and early January were not favorable, and earth-resources photography suffered somewhat. Otherwise, at the 56-day milestone the crew was roughly two-thirds of the way through the experiment program.63

 


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Bags of trash were deposited in the trash airlock, which had been the liquid-oxygen tank on the S-IVB stage. Toward the end of the third mission, some encouragement was required-which Pogue is prepared, left, to apply.

Bags of trash were deposited in the trash airlock, which had been the liquid-oxygen tank on the S-IVB stage. Toward the end of the third mission, some encouragement was required-which Pogue is prepared, left, to apply. Holding onto the ceiling, he is about to jump on the hatch, so that Carr will be able to insert the remaining bags. S-74-17304. Below, an unusual view inside Skylab. The photographer is near the hatch into the airlock module looking the length of the workshop. The crewman in the center, seen through a passageway in the floor, is stashing trash bags. Two spacesuits and the third crewman are visible on the upper deck. SL4-1505061.

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Below, an unusual view inside Skylab. The photographer is near the hatch into the airlock module looking the length of the workshop.

 

The solar observations were closest to being on schedule-in terms of observing time and photographs-but the sun had been fairly quiet. The corona had been active, mostly while the crew was asleep, but general solar activity had been low. Around 10 January, solar scientists expected [332] some active regions to come back into view as the sun rotated. Ed Gibson was particularly anxious for the sun to cooperate. No one had yet photographed a flare from beginning to end, and with only four weeks left, his chances to get one "on the rise" were dropping daily. Early in January, Gibson expressed his desire to spend considerable time in the "flare wait" mode, ready to pounce on pre-flare activity. On 10 January the principal investigator for the coronagraph, Robert MacQueen, conferred with Gibson about strategy for the next couple of weeks. The experimenters wanted more solar activity as badly as the man on the control panel; MacQueen commented, "This is the last time around after more than a decade of this, and we certainly hope the sun cooperates." He gave Gibson permission to change the preplanned programs at his discretion.64

After the ATM conference the entire crew took part in a general science conference with experimenters' representatives in Houston. Such conferences were scheduled several times during the mission-usually on the crew's days off-so that experimenters could brief the astronauts on the different science programs, lay out strategy for the next few days, and get their insights into experiment planning.i Specific instructions were sent up daily by teleprinter; the conferences, supplemented by occasional discussions at other times, gave the astronauts an understanding of the scientific objectives and moderated any feeling of isolation between the astronauts and the experiment planners.65

For Skylab midsummer day came in mid-January, when the position of the earth in its orbit and the high inclination of the workshop's orbital plane combined to keep the spacecraft in sunlight for 46 revolutions. The crew made special efforts to reduce the load on the cooling systems. Mission Control recommended that they not shower during this period to avoid increasing the humidity, but did not insist on it. Workshop temperatures climbed slowly, reaching 28°C on the 18th. Ed Gibson's sleeping compartment was not completely covered by the improvised solar shields, so he moved his sleep restraint into the cooler airlock. This added a constraint to mission operations, since the teleprinter, located in the airlock, was noisy and Mission Control tried to avoid using it while the science-pilot was asleep.66

On 20 January, CapCom advised Gibson that observers had seen two subnormal solar flares in one active region in a six-hour period. Later in the day, however, Houston reported that there was little hope anything spectacular might occur. Nonetheless, Gibson thought the region looked promising and watched it for a while. From now on Gibson would be the man on the console most of the time; both Jerry Carr and the scientists [333] wanted to ensure that if anything interesting happened, Gibson would be there to run the instruments. Flight plans were occasionally shuffled and duties exchanged so that he could spend more time at the control and display panel. 67

As far as ground-based observers could see, the sun had changed little by the next morning, but Gibson remained optimistic. Nothing developed during his afternoon watch, but he was so sure a flare was imminent that he offered Carr a bribe to let him stay on the panel for another orbit. Around 5 o'clock, asking Houston for a report on x-ray activity, Gibson said he wanted to spend the next orbit in the "flare wait" mode: "I've already promised the commander some butter cookies when we get back if I could have the orbit." Gibson got the extra orbit-at price of a bottle of Scotch; the butter cookies were for the benefit of listening public-but an hour later he was still waiting. Bill Pogue was scheduled to take over the ATM on the next orbit, but when Houston sent up some instructions from the solar scientists, Pogue, tongue in cheek, pointed out a problem: "Ed has the MDA hatch barricaded up there." Gibson stayed at the panel and was at last rewarded. Just before communications broke off he said, "I think this time we finally got one on the rise." He went straight to the channel B recorder and dictated a 23-minute description of the event, repeating it over the air-to-ground when Houston came back. He went to bed that night a happy man. 68

 

For the remainder of the mission the ailing gyroscope periodically gave concern. At one point Program Director Schneider ordered the prime recovery ship to prepare for early recovery. But the gyro settled down and at the end was humming along at a reduced speed, still doing its job. The possibility of gyro failure brought Skylab back into news prominence briefly, but manned spaceflight was no longer the darling of television. On 23 January the major networks announced that there would be no live coverage of splashdown. It was the first time since live coverage started with Gemini 6 in 1965 that the networks had intentionally passed up the return of a crew from space.ii 69

The crew held the second televised press conference of the mission on 31 January, in which they confirmed their faith in the value of Skylab and the scientific data collected. As they saw it, the program had proved that man was indispensable to a productive and flexible program of orbital science. Gibson was willing to predict that space stations and manned planetary expeditions, though admittedly far in the future, were clearly possible "when the American people choose to make the effort." When [334] that time came, Carr said, designers were going to have to pay a lot more attention to habitability. Not only was it important to have pleasant quarters and properly designed work areas, but "you're going to have to have a place that you can call home [where you can] be by yourself and do just what you want to do." Asked for comment on the low level of public interest, Carr said, "Well, I think people just get used to things.... and take [them] for granted.... As long as things stay rather routine in the space program . . . public interest will stay pretty low." The press conference was too short to include four questions submitted by a sixth-grade science class in upstate New York, but since they had been cleared for use, during the next revolution CapCom Dick Truly worked them in one at a time. The student's questions were, if anything, more penetrating than the newsmen's. One that gave Bill Pogue pause was whether the astronaut felt more of a man now, as compared with before you left?" Pogue begged off the philosophical implications of that one, but did allow that he was a better crewman-that is, a more efficient astronaut-after 77 days. Several students wondered whether the three missed female companionship. Taken somewhat aback, Gibson asked, "What grade did you say that was, Dick?" (Nobody had put that question so directly before.) Then he answered, "Obviously, yes."70

The first of February was the last full day of experiment work: an earth-resources pass, a set of medical experiments, a final shot of Kohoutek. Next day Ed Gibson finished his last observations from the ATM console. On the morning of the 3d, Carr and Gibson went outside to recover the ATM film carriers and bring in some particle collection experiments. Gibson took a number of photographs, including some to document the condition of the twin-pole sail after its long exposure to space.71

 

COMING BACK

 

Closing down the workshop and packing the things that had to be returned were big jobs. On the evening of 31 January, Houston sent up a list of changes to the deactivation and reentry checklists; next morning Carr was overwhelmed by 15 meters of teleprinter paper. Entering the changes in the books by hand filled the crew's idle moments for quite a while and provided material for jokes for two days. That evening, Carr greeted Bruce McCandless coming on his shift with, "I understand you're going to teleprinter up the Old Testament tonight."72

The mayor medical experiments continued right on through deactivation, and there were a few experiments left to clean up on 4 February. Carr ran some zero-g flammability tests-put off until the end of the mission because exhausting the residues to space created contamination.

 


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The effect of gravity on flame.

The effect of gravity on flame. In a gravity field, the hot gaseous products of combustion rise by convection, allowing colder air with additional Oxygen to enter and mix with the fuel. Without convection, a flame's corona is spherical and the available oxygen is quickly used. The flame dies down until more oxygen becomes available. Experiment M479 studied this phenomenon.

 

Pogue sandwiched in some observations on light flashes while the workshop passed through the South Atlantic anomaly.iii 73

The crew had little trouble locating things to take back, but like tourists returning from a long trip, they found some space limitations. Trying to stuff five earth-resource tapes into a command-module locker, Carr could not close its cover, no matter how he rearranged the contents. Before Houston could offer any suggestions, he reported that the overburdened tourist's customary solution worked equally well in space: "It fits if you force it." Gibson had a similar problem with the trays that held the mission's urine and blood samples.74

While the crew packed up data and shut down systems, reporters wondered whether NASA planned any more visits to Skylab. Neil Hutchinson played down the possibility, pointing out that there would be no atmosphere, no power, and no food. Besides, the workshop systems could be expected to deteriorate beyond reliability. The abandoned Skylab would be a drifting hulk, presenting too much risk to make a revisit attractive. He conceded that it would be possible to dock with the workshop, but saw no profit in reactivating and reusing it. Still, just before leaving, the last crew would use the Apollo thrusters to give the workshop a boost, raising its orbit to extend its life by five to eight years. Planners wanted to keep it up until Shuttle missions began, in case someone thought of a good reason to go back-to retrieve some of its components for testing, for example. And the crew would leave specimens of food, [336] clothing, and other articles in the multiple docking adapter for possible recovery to determine the effect of long-term storage in space. The last two nights the astronauts went to bed earlier, shifting their circadian rhythms to suit the planned recovery time.75

On 8 February 1974, Carr, Gibson, and Pogue moved into the command module and prepared for separation. The subsequent return to earth was normal, with one exception.

At 9:36 Houston time Carr fired the big propulsion engine on the service module, putting the spacecraft on its reentry trajectory. Nine minutes later, when he tried to maneuver the spacecraft with his hand controller, Carr was stunned to find absolutely no response to yaw and pitch commands-the more so since he had checked out all the attitude-control thrusters only minutes before and found everything normal. After a second or two of slack-jawed astonishment, Carr switched to a backup system and gained control. It was later determined that the astronauts had mistakenly opened four circuit breakers, disabling the yaw and pitch thrusters. The incident illustrated the need for maintaining proficiency by repeated simulations during long missions.76

Once in the water, the crew had about half an hour to wait while the recovery crews brought them aboard ship. Nobody was seasick, thanks to....

 


Parting view. The third crew has undocked for the trip home, Skylab would circle the earth for five more years. 74-H-96.

Parting view. The third crew has undocked for the trip home, Skylab would circle the earth for five more years. 74-H-96.

 


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Two views of Skylab taken by the third crew on the final fly-around inspection. Left, a sun's-eye view of the telescope mount.

Two views of Skylab taken by the third crew on the final fly-around inspection. Left, a sun's-eye view of the telescope mount. The lines extending left and right from the hub of the mount are discone telemetry antennas. SL4-143-4676. Below, SL4-1434706. In both pictures, the corners of the original parasol are visible on both sides of the twin-pole sunshade.

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Below, SL4-1434706. In both pictures, the corners of the original parasol are visible on both sides of the twin-pole sunshade.

 

....the calm seas. What they noticed most was the return of normal gravity. Gibson was acutely aware of the weight of his head and of the effort it took just to move his arms; he felt like he was still in the early stages of reentry. Pogue had taken a camera out of its locker while they were on the chutes and almost dropped it because of its unexpected weight. It felt "like it weighed about thirty-five or forty pounds." After taking one picture of the....

 


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Welcome sight to tired astronauts: the three main ring-sail parachutes deployed at about 3000 meters to slow the command module as it approached the water. SL3-114-1760.

Welcome sight to tired astronauts: the three main ring-sail parachutes deployed at about 3000 meters to slow the command module as it approached the water. SL3-114-1760.

 

....parachutes, he had to hold the camera until splashdown because he thought he could not get the heavy thing back into the locker.77

While the astronauts went through the first of their postflight medical tests, officials at Houston held the customary press briefing Administrator James C. Fletcher stressed the importance of Skylab's accomplishments for the future of manned spaceflight: "It has moved the space program from the realm of the spectacular into a new phase that can be characterized possibly as almost businesslike if not yet quite routine." Program Director William Schneider summarized the statistics on the experiment programs; every one, he noted, exceeded premission plans some by more than 200%. But that was only the start: "Our portion of Skylab has been completed. The science phase has just begun." Skylab had proved that in space research, "the limit is only our resolve, not the ability of men to work, and not our technical knowledge."78

As soon as the crew had departed, engineers tested the batteries in the main power system, assessing how much they had deteriorated in orbit. They unloaded and reloaded the ATM's computer memory, something that had not been necessary during the missions, and found that the system worked perfectly. They tried unsuccessfully to start up the dead control moment gyro, then switched off the power to the other two, measuring bearing friction as the wheels ran down. As best the experts could tell, inadequate lubrication was responsible for the failure of number one and the near-failure of number two. On the afternoon of 9 February flight controllers maneuvered Skylab into an attitude stabilized by the gravity gradient, with the docking adapter pointed away from the earth, and shut off the power. 79 After the cigar ashes were swept out, Mission Control was quiet.


i During the second mission, Mission Control had relaxed a long-standing rule and allow someone other than CapCom to speak directly with the astronauts.

ii Gemini 8 brought back early because of technical problems, landed far from the primary recovery zone, where TV coverage had been planned.

iii Scientists hypothesized that intraocular light flashes observed on several Apollo flights were caused by cosmic rays expending their energy in the retina. Earlier observations on Skylab, however, suggested a correlation with the South Atlantic magnetic anomaly, and Pogue's experiment was done in the hope of confirming that. Strapped in his sleep restraint, he noted the time, direction' end shape of the flashes. He found an abundance of events occurring in the South Atlantic anomaly, and the cosmic-ray hypothesis had to be reexamined. E. A. Hoffman et al., "Visual Light Flash Observations on Skylab 4 " Proceedings of the Skylab Life Sciences Symposium, August 27-29, 1974, NASA TM X 58154, pp. 287-95. In contemporary terminology, the unmanned launch of the cluster was called Skylab 1, the manned missions Skylab 2, 3, and 4.


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