Skylab's experiments and spacecraft systems received the best engineering attention NASA and its contractors could give them, to make sure they were functional, efficient, reliable, and safe. But the workshop was not just a workshop; it was home as well, where crews would be confined for as long as three months. Making it a pleasant place to live might be important in making it efficient.
George Mueller became concerned about the amenities of living in space in 1967 but, recognizing the difficulties inherent in the wet workshop, did not press the point strongly. Once those difficulties disappeared, however, he and the Headquarters program office put steady pressure on the field centers to improve living conditions in the dry workshop. Not only was it important for Skylab crews to have something better than a boiler room to live in, there was also the chance to learn something about living conditions in orbit for the benefit of future programs. Nobody knew much about housekeeping in a space station. Mueller found willing allies in Houston, where man had always been the principal concern; but Huntsville had to be convinced. Constrained by schedule, budget, and resources, Marshall resisted the extensive changes that Headquarters and Houston proposed. Improvements in Skylab's living conditions were debated for a year before being accepted as essential to mission success.
The three cluster modules enclosed 347 cubic meters of space-more than 150 times as much as a Gemini spacecraft, nearly 60 times that inside the Apollo command module. Over two-thirds of this was in the liquid hydrogen tank, 6.6 meters in diameter and 8.9 meters high, which became the orbital workshop. Here the crews would eat and sleep and do much of their work.
Early spacecraft had been designed to be operated, not lived in. Weight and volume limitations in the Mercury and Gemini "capsules"-the epithet, though despised by crews, was apt-meant that only  the bare requirements for protecting and sustaining life could be provided. Michael Collins, pilot on Gemini 10, compared the two-man Gemini craft to the front seats of a Volkswagen. That tiny space was home for Frank Borman and James Lovell for 14 days on Gemini 7. Borman later admitted they had made it on sheer motivation; after accomplishing their prime purpose, the first orbital rendezvous of two spacecraft, the rest of the mission had been a test of endurance.1
The Apollo command module, though just over twice the volume of Gemini, was still primarily a functional spacecraft. Some improvements made it a bit more pleasant-hot water, for example-and its extra space gave the crew of three some freedom to move around and exercise stiff muscles; but few concessions were made to mere comfort. For the most part, astronauts accepted whatever discomforts were inherent in their spacecraft, unless they interfered with performance; what mattered was accomplishing the missions. Quite a lot of minor inconvenience could be tolerated by a man on his way to the moon.
When early planners looked ahead to orbiting space stations, their attention was devoted to problems much more pressing than crew comfort. Of 41 papers presented at a space station symposium in 1960, only one addressed the question of making the station a pleasant place to live. This paper noted that operating an orbiting station would be much like keeping a lighthouse ("a rather humdrum task") and discussed some of the factors that would have to be improved so that people could be induced to go into space "after the romance has worn off." Some of these factors were intangible, said the author, but they were no less important for that. Nine years later the situation had changed little. Spacecraft technology still occupied the engineers' attention, while the questions of everyday living were left for someone else to look after.2
Habitability, livability-or whatever name is given to the suitability of the environment for daily living-is, as one NASA designer remarked, "a nebulous term at best," one not usually found in the engineer's vocabulary. Besides factors within the engineer's usual responsibilities, such as the composition and temperature of the atmosphere and the levels of light and noise, habitability also encompasses the ease of keeping house, the convenience of attending to personal hygiene, and the provision for exercise and off-duty relaxation. Experience and intuition both suggested that these factors would become more important as missions grew longer. Looking ahead to space stations, NASA designers needed basic information on these problems of living in space, as George Mueller had told congressional committees more than once.3
The earliest spent-stage proposal had not called for using the S-IVB as round-the-clock living quarters, although it had provided for testing  some habitability features. As planning progressed through 1966, how ever, the idea of setting up housekeeping in the spent stage took hold. In September of that year the Manned Space Flight Experiments Board approved an MSC-sponsored experiment entitled "Habitability/Crew Quarters," having the objective of obtaining design criteria for advanced spacecraft and long-term space stations. Houston's presentation of this experiment included sketches showing the workshop divided into compartments by means of fabric panels, which were stowed at launch in canisters mounted on the airlock trusses.4
Marshall too had an experiment that included crew quarters: the workshop itself, on the books in the early days as "Experiment M402, Orbital Workshop." For a while the two overlapping experiments were a point of contention between the centers. Crew quarters were obviously a part of the workshop, which, as Marshall read the Lake Logan agreement of 1966, was a mission module belonging to Huntsville. Houston saw habitability as an experiment with a principal investigator at MSC; besides, it logically came under the jurisdiction of MSC's Crew Systems Division. For over a year the two program offices could not agree on what the habitability experiment was or who had charge of it. Finally Charles Mathews issued an order giving Marshall overall management and integration responsibility for "Experiment M487, Habitability/Crew Quarters," while dividing a list of specific hardware items between the centers. Houston kept the life-support systems, along with food management, waste management, personal hygiene, and sleep restraints; Marshall got the rest, which was mostly the structure, plumbing, and wiring of the crew quarters.5
Houston could do very little with its share of the workshop duties in 1967. It was not stated center policy, but everyone understood that Apollo Applications had low priority until Apollo was back on track. The fact was, as one MSC division chief said, "if we didn't get the Apollo program done, a lot of the discussion about AAP [would be] academic." It was well into 1968 before the center could spare any manpower to work on projects such as habitability.6
At Huntsville meanwhile, Belew's engineers went ahead, using their own ideas plus whatever help MSC could give. By early 1967 the plan to use fabric curtains to subdivide the workshop had been dropped in favor of metal partitions installed in the tank before launch. These were fabricated of aluminum, machined into a triangular grid pattern that did not obstruct fuel flow; folding sheet-metal partitions made it possible to close two of the compartments during occupancy. The workshop ventilation system, a set of fabric panels forming an annular space next to the wall, was also put in place before flight. During activation of the workshop the crew would install fans to circulate the air and rig a curtain under the floor to form a mixing chamber for the circulating atmosphere.7
 Houston's first look at Marshall's detailed plans came at the preliminary design review at Huntsville, 8-10 May 1967. Design details were necessarily tentative, but it was evident that Marshall had paid very little attention to habitability. Houston, however, was more concerned with fire hazards than anything else, and about the only comment concerning living conditions dealt with the temperature control system.8
During that summer and fall George Mueller took a strong interest in the workshop, especially the layout of the living quarters. After examining the mockup in July, he suggested adding a second floor (a ceiling on the crew quarters) to provide extra work space; but since that would have aggravated a serious weight problem, his suggestion was not adopted. Later he proposed installing two grids 2.6 meters above the liquid oxygen-tank dome, creating two compartments with floors back to back. This became the accepted configuration until July 1969.9
Looking at the mockup, Mueller was appalled by the barren, mechanical character of the workshop interior. "Nobody could have lived in that thing for more than two months," he said of it later; "they'd have gone stir-crazy." Expressing this concern to Lee Belew and Charles Mathews, he suggested that an industrial design expert be brought in to give the workshop "some reasonable degree of creature comfort. Late in August, Mathews wrote to Belew recommending action on Mueller's suggestion and offering the names of two commercial firms. Marshall arranged for Martin Marietta, the integration contractor, to engage an industrial design consultant on subcontract. His task would be to provide "comments and recommendations based on the latest industrial design concepts, relative to floor plan arrangements, color schemes, lighting, noise levels, and all other factors relating to human comfort in confined quarters." A two-month study beginning on 1 December 1967 would evaluate the wet workshop.10
For the habitability study, Martin Marietta chose one of the best known industrial design firms in the world-Raymond Loewy/William Snaith, Inc., of New York. Loewy, a pioneer of industrial design in the United States, had worked on functional styling for a variety of industrial products for forty years, besides designing stores, shopping centers, and office buildings. Approaching his 75th birthday in 1968, Loewy had reduced the scope of his own professional activity somewhat, but he took a personal interest in the workshop project. Early in December 1967 he and Fred Toerge, the firm's vice president, visited all the AAP contractors' plants, ending their tour at Huntsville with briefings on the program and an examination of what Marshall had done to that point. Loewy and Toerge then stopped off in Washington to discuss their impressions  (which were mostly bad) with Mueller, Mathews, and other AAP officials.11
Loewy/Snaith produced a formal report in February 1968, citing many faults in the existing layout and suggesting a number of improvements. The interior of the workshop was poorly planned; a working area should be simple, with enclosed and open areas "flow[ing] smoothly as integrated elements . . . against neutral backgrounds." While they found a certain "honesty in the straightforward treatment of interior space," the overall impression was nonetheless forbidding. The basic cylindrical structure clashed with rectangular elements and with the harsh pattern of triangular gridwork liberally spread throughout the workshop. The visual environment was badly cluttered. Lights were scattered apparently at random over the ceiling, and colors were much too dark. This depressing habitat could, however, be much improved simply by organized use of color and illumination. Loewy/Snaith recommended a neutral background of pale yellow, with brighter accents for variety and for identifying crew aids, experiment equipment, and personal kits. Lighting should be localized at work areas, and lights with a warmer spectral range substituted for the cold fluorescents used in the mockup.12
Martin Marietta presented these findings along with some of their own recommendations at Huntsville on 28 February, urging immediate attention to the consultant's recommendations. The color scheme was of first priority; it would not be easy to find a finish that could stand immersion in liquid hydrogen, and there was not much time to look. The floor plan should be revised as soon as possible. Loewy recommended creating a wardroom-a space for eating, relaxing, and handling routine office work-and Martin's engineers concurred. Better yet, the floor plan should be made flexible by the use of movable panels, so that different arrangements could be tested. Evaluating a single layout was not a good way to acquire information about the design of space stations.13
These suggestions were received at Marshall with a certain amount of perplexity. To the extent that they had considered styling and interior decor, Huntsville engineers had assumed that Douglas, an experienced builder of commercial aircraft, would tend to them. And since none of the astronauts who had examined the mockups had attached any importance to such things, Marshall had assumed that they were of small concern. Fairly soon, however, program officials recognized that there was something to the Loewy/Snaith study and began to work on the color scheme. Because of the liquid-hydrogen problem, this turned out to be a major headache for the duration of the wet-workshop plans.14
Mueller was pleased with Loewy/Snaith's work, and a new contract was drawn up engaging the firm through 1968. By now MSC was taking greater interest in the crew quarters, and the new Loewy/Snaith contract specifically provided that the consultants would work with the principal investigator for MSC's habitability experiment.15
 In June 1968 a new principal investigator was appointed for experiment M487 at MSC: Caldwell C. Johnson, chief of spacecraft design in the Advanced Spacecraft Technology Division.16 Caldwell (the first I is silent) Johnson was a tidewater Virginian who had joined NACA in 1939, two years after graduating from high school. He had been a member of Gilruth's design team since Mercury days and had worked on Apollo from 1961 to 1963, when he became assistant chief of the Advanced Spacecraft Technology Division. Johnson was an idea man, whose forte was producing novel design concepts for all kinds of systems; he took little interest in overseeing hardware development. His new assignment probably reflected Gilruth's desire to have an experienced designer do an end-to-end job on the workshop's crew quarters.17
His first look at the workshop convinced Johnson that habitability had been given no thought at all. In the course of their work, he and his colleagues had built up a store of information on design factors for all kinds of crew activity under circumstances of confinement and isolation; but their data might as well not have existed. Marshall, lacking experience in manned spacecraft, apparently had taken ideas from any available source-including the astronauts, whose talents as spacecraft designers, Johnson felt, were limited at best. But since Huntsville's engineers regarded crew quarters as part of their design responsibility, they were annoyed when Loewy/Snaith and Caldwell Johnson undertook to set them straight. Johnson understood their annoyance, but went ahead with his suggestions in spite of it.18
It took the rest of 1968 for Johnson to establish the boundaries of his habitability experiment and to define its content. The following May he summarized his approach.19 Habitability, he said, was not an experiment in the usual sense; it was simply not practical to test several different design concepts. Instead, MSC's best design judgment would go into the workshop, and the missions would evaluate that judgment. Johnson took his task to be the creation of an operational system that would reduce the chores of daily living to a level "entirely incidental" to spaceflight operations. He proposed to deal with nine major components of habitability: environment, architecture, mobility and restraint, food and water, clothing, personal hygiene, housekeeping, communication within the spacecraft' and off-duty activity. By systematizing the man-spacecraft relationship' Johnson hoped to bring some engineering rigor into an otherwise chaotic field.20
The limitations of the wet workshop cramped the habitability experiment, as they did almost everything else, and after the wet-to-dry change it seemed that much more could be done; but Marshall showed no inclination to improve the workshop. A month after the change, MSC  criticized the layout as "too austere"; far from providing the best that current technology could offer, "the present concept [looks like] a canvas tent city." The floor plan made no sense; the food management compartment was too small and the sleeping compartments too large. Later the same month, preparing for the preliminary design review of Marshall's habitability support system,i MSC found the workshop still "designed to the threshold of acceptability.... The dry workshop has none of [Apollo's] constraints, and yet an . . . austere design persists." Huntsville, however, had no plans to make substantial changes. Belew envisioned only minor impact [on habitability] as a result of the 'dry' workshop configuration," and intended to use most of the wet-workshop hardware in the dry workshop.21
Early that fall it became obvious that there were at least two schools of thought on habitability. In Mueller's view, the workshop should be a laboratory to test concepts and devices, with a view to establishing criteria for design of future space stations. Both he and Schneider put habitability high on the list of Skylab priorities. Houston did not believe this laboratory concept was practical, but agreed with the importance Headquarters attached to improved habitability. The beneficiaries of this concern-the astronauts-cared less about styling and appearance than efficiency; they wanted a spacecraft in which they could do their jobs without a lot of petty annoyances. They were, in fact, somewhat disdainful of the attention given to such amenities as interior color schemes.ii Since the astronauts were reviewing crew quarters concepts before anyone else at MSC was deeply involved, their advice was often (too often, some thought) followed at Marshall. Partly this was because Marshall engineers were a bit overawed by personal contact with astronauts; partly it was because the engineers hoped the astronauts would influence MSC's Skylab program office to accept Huntsville's decisions. Marshall was reluctant to make any but clearly necessary changes-which did not yet include habitability improvements.22
By September 1969 George Mueller was concerned that Huntsville was not acting on Loewy/Snaith's ideas, so he called a meeting on habitability for mid-October. Schneider spelled out the issues for the program offices on 30 September, noting that provisions for crew comfort left much to be desired. He did not intend to abrogate the minimum-change philosophy established in July, but "significant and necessary improvements [can be made] with relatively little cost or schedule impact."
 Crew comfort was not the only consideration. Marshall should keep in mind that "a public image will be formed by TV transmissions" from the workshop in orbit. The recommendations of both Raymond Loewy and Caldwell Johnson were to be given full consideration; ways could be found to keep costs down and still improve the workshop.23 Schneider had a way of emphasizing by understatement, and this memo indicated that Headquarters was more than a little impatient with the treatment habitability was getting.
The workshop principals (including Raymond Loewy, who came at Mueller's invitation) met in Washington on 14 October for a general review of the habitability support system. Mueller left the clear impression that he was not satisfied with the handling of crew quarters, remarking more than once that habitability was the most critical factor in future manned spaceflight-an attitude heartening to the MSC delegation, whose presentations focused on the shortcomings of current design in many areas.24 During the day all aspects of habitability were discussed, including some that had major impact on the workshop structure. Both Loewy and Johnson had suggested rearranging the floor plan to provide a wardroom; both had also endorsed adding a large window to allow the crew to enjoy the view from orbit, something that had been impossible in the wet workshop. The wardroom was easily agreed to, but the window created an impasse. While everyone agreed that it would be very nice to have, Belew pointed out that a window posed one of the toughest problems a spacecraft designer could face. It was too costly, it would weaken the structure, it would take too long to develop and test, and it was not essential to mission success. Counterarguments could not rebut his position. Finally, Mueller asked Loewy for an opinion. The response was unequivocal; it was unthinkable, Loewy said, not to have a window. Its recreational value alone would be worth its cost on a long mission. With that, Mueller turned to Belew and said, "Put in the window." Schneider formally authorized the window and the wardroom, along with several other changes,iii on 31 October.25
Not many habitability questions had to be settled at the associate administrator's level, but most of them did involve a great deal of two- and three sided argument-usually Caldwell Johnson on one side and Marshall engineers on another, with the crews sometimes on a third. Seemingly minor details often produced disagreement. Johnson had to persuade the crews that the test pilot's traditional one-piece flight coveralls were not suited to long-term living in the workshop. In this they acquiesced' but they would not give up the pockets on the lower trouser leg- ....
....ideal for a pilot strapped into an airplane cockpit, but (Johnson believed) a useless impediment to moving around freely in zero g. Johnson and Fred Toerge designed a basic two-piece uniform to which a matching jacket could be added. It was both practical and attractive; Johnson had one of his staff wear a prototype to conduct a briefing in May 1969, and it "brought down the house," as he told Toerge later. Subsequent versions retained the three-piece design, but Johnson was disappointed when the crews spoiled the effect by covering the shirt and jacket with name tags and badges.26
When it came to matters of purely personal preference, such as off-duty relaxation and entertainment, Johnson was content to let crewmen have their choice. He proposed an entertainment center in the wardroom, equipped to show movies or provide music, but it drew no enthusiastic response. Nor did card or board games; crew preferences  tended strongly toward reading and recorded music-provided everyone could have his own private tape player; musical tastes were quite disparate. As it turned out, this was about as much entertainment as anyone wanted, or had time for. Amusing themselves in off hours was no problem for any of the crews.27
Keeping clean was of more concern. Though Houston's medical experts were satisfied that sponge baths were enough to keep down serious dermatological problems, Mueller and Schneider wanted to provide some way to take a shower. In April 1969 Schneider told Belew to look into a lightweight, low-cost "whole-body bather" of some kind-not something on which the mission would depend, but which would permit the concept to be evaluated. Caldwell Johnson, although he thought it was not a good idea, provided a design concept and Belew dutifully sent it to McDonnell Douglas for a cost estimate. The contractor returned an estimate of over $3 million for a space bath and water reprocessor. Belew asked for and got permission to reject this proposal, but Schneider continued to press for an experimental device that could be tried a few times on the first mission. In the event, a simple shower went into the workshop and was used on all three flights, but it got mixed reviews from the crews.28
Many aspects of habitability were troublesome because there were no clear analogies for the workshop missions and little experience to draw on. Submarines seemed to be reasonably close parallels, but when astronaut Paul Weitz talked with knowledgeable Navy people early in the program, he learned little. Apart from some figures for optimum light levels and maximum noise limits, what the Navy had was mostly "anecdotal data"-sea stories. In 1969, however, when Grumman sponsored an oceanographic mission by the Swiss scientist and engineer Jacques Piccard, Marshall participated, hoping to gain some basic knowledge of habitability. Piccard's voyage, called the Gulf Stream Drift Mission, used a six-man submarine named Ben Franklin. It set out from Florida....
 ...on 16 July 1969 with a Marshall engineer in the crew, and 31 days later, having drifted 2700 kilometers submerged in the Gulf Stream, surfaced off Nova Scotia.29
Piccard visited MSC on 25 February 1970, and Caldwell Johnson took particular note of every complaint he made about living conditions aboard Ben Franklin. Reporting these comments to the Skylab office, Johnson passed along Piccard's statement that many of the faults had been pointed out before the mission, but Grumman engineers seemed unable to remedy them-or even to understand the complaints. Having had little success getting his own ideas into practice in 1969 and reflecting on Franklin's similarity to Skylab, Johnson told the MSC Skylab manager, "if I hadn't known better, I would have thought I was listening to a debriefing of the first Workshop mission in 1973."30
Nothing gave the workshop developers more trouble than the human digestive tract-and the experimenters whose main concerns were with what went into it and what came out of it. Food management and waste management would have been complicated enough as independent systems, but the imposition of stringent medical requirements made things much worse. The waste management system (see chap.8) produced major design problems down to a few months before launch; the food system was brought under control by the end of 1971.
Contemplating two-month missions, almost everyone agreed that space food had to be improved. In Mercury and Gemini, crews had not complained about food, even though it was designed to meet the engineering requirements of spaceflight rather than to appeal to the palate. Compressed, processed, and packaged, space food was an engineering triumph: it took up little space, it would survive launch without disintegrating, and it would last almost indefinitely. Furthermore, it provided balanced nutrition to sustain life up to 90 days-provided, as one official put it, a way could be found "to influence the crews to eat [it].''31
The first three manned Apollo flights in 1968 and 1969 brought complaints about the food. This was somewhat surprising, because the food was much the same as in Gemini, and some of the same astronauts had found it quite acceptable. Seeking an outside opinion, MSC nutritionists persuaded Donald D. Arabian, chief of MSC's Test Division, to evaluate Apollo rations. Although he admitted to being "something of a human garbage can," Arabian found the experience one he did not care to repeat. He had agreed to subsist on Apollo food for four days, but the prospect quickly became unappealing. The sausage patties in his first breakfast resembled "coarse granulated rubber with a sausage flavor," which left a sickening aftertaste that persisted for an hour. At the end of  the first day Arabian noted a marked loss of appetite; by the third day, eating was a real chore. Meal preparation offered no pleasant anticipation; there were no aromas to stimulate the appetite and no textural variety to provide satisfaction. Those items that most closely resembled off-the-shelf foods were excellent, but those prepared especially for spaceflight could only be called bad. Arabian could not understand why such common items as peanuts and chocolate had to be ground up and converted into bite-size cubes, which stuck to the teeth.32
Improving the food and solving the problems of long-term storage would have been challenge enough to food-system developers; superimposed on those were the rigorous requirements of the medical experiments. From the earliest days of AAP, medical scientists had planned to conduct a mineral balance study, measuring the astronauts' intake and output of calcium and nitrogen as part of the effort to understand the effects of long periods of weightlessness on man. Gemini had shown that astronauts lost calcium from bones and nitrogen from muscle-not enough to be operationally dangerous on a lunar landing mission but potentially serious for longer flights. Nothing was done in Apollo, however, and in 1969 the medics knew no more about the process than in 1966. Two Skylab experiments, M071 and M073, were designed to determine how long the losses continued, how serious they were, and whether anything could be done to arrest or reverse the changes.
Experiment M073 measured the urinary output of several substances of metabolic importance; its requirements affected mainly the urine and feces collection systems. M071, on the other hand, required accurate control of mineral intake as well as accurate measurement of output. Mineral-balance studies are common but exacting procedures. The subjects, usually hospital patients confined to bed, are given a constant, carefully measured supply of the constituents under study (calcium and nitrogen), and their total output of urine and feces is collected, accurately measured, and carefully analyzed. Even in a well equipped hospital such studies are difficult; on Skylab, experimenters proposed to conduct them on active astronauts engaged in a host of other activities at the same time.33
For medical purposes the best diet was made up of homogeneous items whose composition could be accurately determined and controlled-pureed vegetables, puddings, and compressed, bite-size solids. Dehydrated foods were acceptable, provided they were reasonably uniform, but heterogeneous items like spaghetti and meat balls or turkey with gravy posed serious problems for the experimenters. The diet that best suited the scientists, however, was the very kind that could be depended on to provoke strong crew resistance. For missions of four to eight weeks, management at Houston believed the crews should be pampered, and good food was one way to make long missions tolerable-or perhaps  more accurately, bad food was a sure way to make them intolerable. Mueller, Schneider, and Caldwell Johnson, probably reflecting the complaints passed on by the Apollo crews, began to campaign for more conventional and appealing meals that could be eaten in more or less normal fashion, rather than pastes to be squeezed from tubes or cubes to be eaten cold. It could be done; the Apollo 8 crew had enjoyed a hot meal of turkey and gravy, eaten with a spoon, and the effect on morale was remarkable. Johnson recognized a challenge in designing a food system that would remove many of the engineering restrictions that had limited space menus, and in the spring of 1969 he began formulating some ideas.34
By the time the dry workshop was baselined, the food system was not defined in detail, though its major constraints were understood. In April 1969, Paul C. Rambaut noted that medical requirements and habitability considerations sometimes conflicted. The latter, however, took precedence; if the experiments made the food intolerable, the experiments would have to yield. Rambaut, an MSC nutritionist who was principal coordinating scientist for the M070 series of experiments, expected Skylab to use a wider variety of foods, including hot and cold items; and the workshop's food management compartment would provide some of the amenities of conventional dining.35
At the April Management Council meeting, not long after the Apollo 9 mission and its crew's complaints about the food, George Mueller decided something should be done about it. On 22 April, Schneider offered some guidelines to the MSC program office. It was time to get away from complete reliance on Apollo-type food, he said, and provide something more like normal cuisine-perhaps frozen dinners, freeze-dried camping foods, possibly even fresh fruits and vegetables. He recognized that providing for stowage and preservation would affect workshop development, but suggested that if meals could be greatly improved, the weight and volume allowances for food could be raised by as much as 10%.36
Marshall had already held a preliminary requirements review in late March; at that time MSC's specifications had been rather broad: an estimate of total storage space, plus provision for heating and cooling certain items during preparation. On 16 April Johnson urged the Houston program office to add a food freezer; a Martin Marietta study had convinced him it was feasible, and it would permit a much greater variety of food to be taken along. In May, MSC's program office sent Huntsville a new set of requirements, including a freezer, an oven, and provision for protecting stored food from pressure changes. The new specifications called for five classes of food: dehydrated, intermediate moisture, wetpack (heat-sterilized items similar to the turkey dinner provided on Apollo 8), frozen, and perishable fresh foods. Marshall was uneasy about the escalation in size and complexity of the larder and galley at this late  date, but went along, since Headquarters urged the improvements. By the end of July, after several meetings involving both centers and McDonnell Douglas, the new requirements had been accepted and several concepts were under study.37
Houston was late with its definition of the food system for several reasons. During the wet-workshop phase of AAP, dieticians at MSC had depended on data from the Air Force Manned Orbiting Laboratory, expecting to modify systems and procedures to meet Skylab's medical requirements. When MOL was canceled in June 1969, full responsibility suddenly fell on the MSC group, already overloaded with Apollo duties. With Marshall clamoring for storage and preparation requirements, Caldwell Johnson designing a completely new system, and the development contract not yet firm, MSC's chief of food and nutrition pleaded for help. He wanted three more persons assigned to food-system integration at Martin Marietta. The request for proposals on the food system had to be out in two weeks, and Martin Marietta should be working on....
 ...eight other problem areas as soon as possible. It took another five months to get food-system management in hand.38
Marshall's uneasiness about the changing requirements turned into alarm in mid- 1969, as it became clear that Houston was just beginning to work over the food system. That fall, Caldwell Johnson proposed to simplify the development of the food system by taking the engineering problems off Marshall's hands. Another contractor should take charge of storage and preparation equipment, furnishing to the workshop contractor a complete system, ready to be installed. Backing up this proposal, he submitted a concept for a simplified storage and preparation system, packing individual servings of food in metal containers shaped to fit compactly within a pressure-proof canister. One protective canister held several days' supply of food, so the wardroom pantry could be replenished once a week. The food containers were designed to fit the compartments in a preparation and serving tray, where they could be heated as required. To prepare a meal, the crewman who had chef's duties would simply take out the items on the menu, add water to dehydrated foods, secure the containers in the tray, turn on the automatically timed heating elements, and let the tray do the rest. After the meal the containers could easily be weighed to account for leftover food (as required by the medical experiments) and then discarded, with very little mess.39 This proposal was not adopted in its entirety, but several of the basic concepts found their way into the final food system.
Lee Belew, Skylab program manager at Marshall, expressed reservations in July 1969 about his center's ability to meet a July 1972 launch date. By the fall of 1969, when Headquarters agreed that several major jobs should be farmed out to contractors, he felt he could make it- provided everyone followed the minimum-change directive that both Schneider and Mueller had affirmed. Instead, both Houston and Washington spent the rest of the year thinking up improvements-mostly in habitability-that cost time and money. In November Belew remonstrated to Schneider that changes were threatening his budget and schedule. The tradeoff studies that had to be done on proposed improvements siphoned off Marshall's manpower and delayed action. Either costs would go up or the schedule would slip unless Marshall got some relief.40
From Caldwell Johnson's point of view, nothing much was happening; so few of his suggestions were being acted on that by early 1970 he felt compelled to go outside normal channels to make his points. He got a chance the first week in April, when center directors, program managers, and key technical people set out on a four-day tour of Skylab contractors' plants for a first-hand assessment of the program's condition. At  every stop Johnson called Gilruth's attention to the sad state of habitability features, losing no opportunity, as he recalled later, "to put the needle in." Many of the faults he pointed out were minor, and some were only apparent because the mockups were not accurate, but the effect was what he intended. Habitability became an issue.41
Chris Kraft, MSC's deputy director, put the matter with characteristic bluntness as soon as the tour was over. "I think," he told his chief, "that everyone who has a feel for the problems of living in space came away from the Skylab tour with the same thought-that insufficient attention has been paid to how the astronauts are going to live during those very tedious missions." No matter that the contractors had all protested that the crews had reviewed their work; Kraft said the astronauts should not have the last word anyway. "They are too prone to accept a make-shift situation on the basis of 'that's the way things have been done in the past."' He suggested that Gilruth assign perhaps 10 people to review habitability and assure that proper attention be given to it.42
Gilruth sent Kraft's memo to Eberhard Rees, urging Houston's concern on Marshall's new director.iv Passing the letter along to Belew, Rees remarked that Kraft's points were well taken. Rees had spent enough time at an Antarctic base early in 1967 to appreciate some of the hardships of a less-than-ideal environment, and he felt that MSC's suggestions ought to be examined, "even if [implementing them] costs more money." He wanted Belew to appoint someone to examine the whole matter without considering cost. In response, Belew sketched out the history of the habitability problem, listing several major accommodations Marshall had already made. Evidently he brought the director around to the Skylab office's view of the matter, for Rees's answer to Gilruth emphasized Marshall's concern for costs and schedules. Habitability changes, Rees said, were on the point of changing the whole Skylab program concept. It was time either to reaffirm Skylab's fund-limited and experimental nature or to commit the program to a different objective.43
Others at Huntsville had just about reached the end of their tethers on habitability matters. The chief of the Man/Systems Integration Branch reacted impatiently to Caldwell Johnson's comments on the Ben Franklin mission. The source of the "hardships" that Franklin's crew had endured was no mystery; it was lack of money. Tradeoffs had been made with full consideration of habitability provisions, and the little  submarine had proved adequate to perform a successful mission. Skylab's habitability changes (most of which were trivial) were about to "send the program into convulsions." Certain amenities had to be provided, but unless program officials were careful they might be doing nothing more than "a job of interior decorating."44
Belew had asked Gaylord Huffman, technical assistant to Marshall's workshop project manager, to survey the habitability question Huffman reported his recommendations in June. He concluded that the purpose of the experiment should be changed; NASA could learn more by testing a variety of concepts. He also felt it would be best to move the principal investigator's responsibility to Huntsville. Current attempts to satisfy the crew and the principal investigator, who frequently disagreed, were the main reasons for the almost continual redesign of workshop systems. That problem, he implied, was best solved by getting a new principal investigator. Besides, the Ben Franklin mission, in which Marshall had participated, was a better analogy to Skylab than an Apollo mission-which, after all, was the only experience Houston had.45
After the tour of contractor facilities, Gilruth, wanting to be sure that Caldwell Johnson's criticisms had some foundation, appointed an ad hoc committee to examine them. Late in May the committee submitted 17 pages of detailed recommendations for correcting the deficiencies Johnson had been citing for months. Attached were 15 requests for engineering design changes, approved by MSC's Skylab office and classified as "mandatory for operational suitability." Gilruth forwarded the report and the change requests to Rees on 26 May 1970, characterizing them as "requirements." Acknowledging that Houston had acquiesced in Marshall's workshop design-probably longer than it should have-he nonetheless felt strongly that crew comfort had to be assured on missions as long as those proposed for Skylab. MSC's management had not approved all of the committee's findings, but those forwarded to Marshall were considered necessary.46
Rees's reply reflected surprise and dismay, the more so because the new requirements were produced by people who had been working with Marshall for more than three years. Without disputing that many of Houston's demands were desirable, Rees was alarmed at their cumulative effect-an assessment much like Gilruth's criticisms of the wet workshop at the "warning flags" review of November 1967. As Rees saw it, the Skylab program was in danger of running off in all directions unless Headquarters and the field centers were working to the same rules, and he had so advised Headquarters.47
One of the 15 mandatory changes was the new food system that Johnson and MSC's nutritionists had just got down on paper. Selling it to the Marshall program office was not easy, since the MSC proposals involved thoroughgoing changes to a design that McDonnell Douglas had already started to fabricate. May and June saw a series of meetings  between the center program offices and the contractor, with MSC doggedly insisting on change and Marshall tenaciously arguing that the cost and schedule impacts would wreck the program. Houston not only proposed a drastic increase in food storage space, but also lower freezer temperatures, a relocated wardroom table, and a new food tray requiring a special fixture in the galley. Coming as they did on top of serious problems that were developing in the urine collection system (chap. 8), MSC's proposals were just about the last straw for Marshall's Skylab office-and it looked as though Houston was not finished with the new design.48
Responding to Rees's pleas, OMSF chief Dale Myers scheduled a top-to-bottom program review for 7-8 July 1970 at Huntsville. Marshall's major worry was with fundamental program guidelines. Was Skylab an experimental, fund-limited program, or was it supposed to be the next Apollo? Houston, on the other hand, came to the meeting with yet another series of proposals requiring more changes. The medical experimenters, concerned about the humidity and carbon dioxide levels in the workshop, wanted the environmental control system changed. The major question raised about habitability was the high cost of MSC's new food system; but since no one could suggest a cheaper alternative, it came through practically untouched. Schneider was not sure that the new arrangement would simplify management and reduce costs, as Houston argued, but after detailed examination of the tradeoffs, he agreed to it. Headquarters representatives, pointing out that habitability factors were uncommonly difficult to reduce to numbers, pleaded with both field centers to make more effort to negotiate their differences, Marshall making more allowance for intangibles and Houston showing more cost consciousness.49
The program review approved significant changes while reaffirming both the July 1972 launch date and the existing cost ceilings. Rees conveyed his disappointment to Charles Mathews later in the month. The review had made Marshall's task nearly impossible; the approved changes took absolutely all the slack out of his center's schedule. Furthermore, he expected still more changes to come; everyone but Marshall seemed eager to upgrade Skylab far beyond its origins as an austere, experimental program. If that trend continued, NASA's ability to get on with other programs would suffer, because it would appear that Skylab's cost had been seriously underestimated. Rees then summarized his center's view of the past year's events:
We started with an open-ended astronomy mission where we were ready to take a number of risks . . . and where habitability accommodations were consistent with an early launch/lower cost approach.... we are proceeding to perform in orbit a very sophisticated and unprecedented medical experiment where the subjects must be handled delicately so as not to disturb the medical baseline.
 The trouble was that the desirable changes often had serious impact on other systems-the medical experiments being horrible examples-and Rees wondered where it would all end. Marshall would go along with the decisions reached at the review, but Rees did not believe that the schedule could be met within the budget.50
Mathews's response indicated his sympathy with Rees's problems but he again stipulated that the July 1972 launch would be met-and within budget. Some compromises would no doubt have to be made in order to reconcile resources with requirements; but the basic Skylab philosophy, "economical application of existing hardware with minimum new developments . . . consistent with basic objectives," still held As for the exceptions made in the past year, each had powerful justification, and their approval did not signal departure from the policy He reminded Rees that "Skylab may be the only manned mission flown for an uncomfortable number of years [and] it is critical that we make the most of this opportunity." It would take the best management that NASA could muster, but Mathews was confident that Schneider and the center program managers could do it.51
In mid-August Rees wrote to Gilruth summarizing the status of MSC's engineering change requirements of 26 May. After a good deal of horse-trading, in which MSC withdrew some requests and others were disapproved because of excessive cost or delay, the major changes in the food system had been adopted. Rees urged his MSC counterpart to help him hold the line against further changes, because Marshall had neither the funds nor the time to accommodate them.52
In fact, the workshop suffered no more spasms from habitability requirements. The next big headache came from the waste collection and measurement systems (chap. 8). Later in 1970 the astronauts would raise some issues with the medical experimenters about the food, but the impact on the major food systems was unimportant. Caldwell Johnson's office kept an eye on the development of habitability systems, while he turned his attention to design problems in Shuttle and in the embryonic Apollo-Soyuz Test Project.
i The habitability support system included all of the hardware required to carry out the habitability experiment: lights, fans, floor and walls, food storage and preparation equipment, water supply, and so on.
ii An astronaut-office joke recalled an early suggestion that the interior of the Apollo command module should be painted blue above and brown below, so that pilots disoriented by zero g would have an up/down visual reference. Michael Collins tells the story in Carrying the Fire, it was repeated to the present authors by some of the Skylab crewmen, with the implication that this was typical of the absurd things some people will worry about if they are encouraged.
iii One of these was a door cut into the S-IVB wall to provide access to the cluster during Checkout at KSC. Besides making checkout easier, the door speeded up assembly of the workshop at McDonnell Douglas. W. K. Simmons, Jr., "Saturn I Workshop Weekly Notes," I Aug. 1969; R M. Machell to mar., AAP Off., "Weekly Activity Report," 29 Aug. 1969.
iv Von Braun had been promoted to Deputy Associate Administrator for Planning 13 Mar. 1970. Rees was born in Wurttemberg, Germany, in 1908; he received an M.S. in mechanical engineering from Dresden Institute of Technology in 1934. During World War 11 he was technical plant manager at Peenemunde. He came to the U.S. with von Braun in 1945, working first at Fort Bliss and later at the Redstone Arsenal. He became a deputy director of Marshall in 1960.