[2] Chapter 1: Skylab.

[3] Shortly after noon on May 14, 1973, America launched Skylab, its first space station, from Kennedy Space Center. For the first time in the dozen years that had elapsed since Astronaut Alan Shepard had briefly arched through the lower fringes of space and 12 men had walked upon the Moon, the nation launched a space station that was designed solely as a laboratory, workshop, and home in the space relatively near Earth.

Skylab was no small spacecraft in which one or two men could perform limited scientific and engineering experiments in cramped quarters as they orbited Earth or journeyed to and from the Moon. It was big enough for three men to live and work in for months on end. Indeed, man and his unique capabilities were uppermost in the minds of Skylab's designers. The crew could move freely within it to undertake complicated experiments. Each of the three astronauts had his own bedroom, but they all had to share a kitchen and bath. Still, Skylab, a three-bedroom home and workshop in orbit 270 miles above Earth, was one of the greatest achievements in manned spaceflight during the decade of the 1970's.

The Genesis of Skylab

The original idea for Skylab was as novel at its inception as it was later to prove complex in execution. The concept, at first, was to have a Saturn IB rocket place its burned-out second stage into orbit about Earth. Once there, it would be visited by crews of astronauts in Apollo spacecraft launched by other Saturn IB rockets. They would dock their Apollo with the orbiting rocket stage, move in, and furnish the spent rocket with equipment and supplies brought with them. Since the rocket stage would have contained liquid oxygen and liquid hydrogen propellants during the flight into orbit, this version of the Skylab was known as the "wet workshop."

Where did the idea originate? Like the appearance of so many concepts in science and technology, tracing the origin of Skylab is impractical and fruitless. Sometimes the same idea appears to various individuals around the world at almost the same time. Calculus, for example, was developed....

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[4] ...independently and almost simultaneously by Newton in England and Leibnitz in Germany in the 17th century. The earliest written ideas for the "wet workshop" appeared in a November 1962 technical report of the Douglas Aircraft Co., which manufactured the second stage (or S-IVB stage) of the Saturn IB rocket booster. However, such a thought had probably occurred much earlier to a number of individuals, even in those early days of manned spaceflight.

Throughout the mid-1960's, the idea was pursued with increasing detail and planning. However, by 1969, the concept was altered; a Saturn V rocket booster, left over from the Apollo program, would launch its third stage into orbit. That stage was the same (S-IVB) as the second stage of the Saturn IB. Thus was born the idea of a "dry workshop." Such a space station would be launched from Earth with all supplies and equipment aboard. Once in orbit, it would be visited by teams of astronauts launched in Apollo spacecraft by Saturn IB rockets to perform scientific and technical experiments. The final concept for Skylab had arrived, and detailed planning and design for America's first space station got under way at the Marshall Space Flight Center in Huntsville, Ala.

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The Astronauts of Skylab

While nine astronauts lived and worked in Skylab during the 171 days of its manned occupancy, an additional six were also involved as backup crewmen to the primary flight crews. Each primary crew had a commander and pilot who were technically educated and qualified jet pilots. Additionally, each crew had a scientist pilot who was also a jet pilot.

The first crew consisted of Commander Charles Conrad, Jr., Pilot Paul J. Weitz, and Scientist Pilot Joseph P. Kerwin. Conrad was a U.S. Navy captain who had become an astronaut in 1962. He had been in space before on the Gemini 5 mission in 1965 and the Gemini 11 flight in 1966. In 1969, he became the third man to walk on the Moon as commander of the Apollo 12 mission. Weitz was a commander in the U.S. Navy, and he became an astronaut in 1966. Kerwin, also a commander in the U.S. Navy, was a doctor of medicine who had been selected as an astronaut in 1965.

The men of the second Skylab mission were Commander Alan L. Bean, Pilot Jack R. Lousma, and Scientist Pilot Owen K. Garriott. Bean, like his close friend Conrad, was also a captain in the U.S. Navy. He became an astronaut in 1963 and flew in Apollo 12 as the lunar module pilot in 1969. Lousma, a major in the U.S. Marine Corps, joined the astronaut ranks in 1966. Garriott was a civilian with a Ph.D. in electrical engineering who became an astronaut in 1965.

Skylab's third mission was headed by Commander Gerald P. Carr, a lieutenant colonel in the U.S. Marine Corps, who had been appointed an astronaut in 1966. Pilot William R. Pogue, a lieutenant colonel in the U.S. Air Force, had joined the astronauts in 1966. Scientist Pilot Edward G. Gibson, a civilian with a Ph.D. in engineering and physics, had been named as an astronaut in 1965.

Assisting these nine astronauts during their training, and capable of taking over for them in case of emergency, were six other astronauts who formed backup crews. For the first mission, the backup men included Russell L. Schweickart, a civilian, who had joined the astronauts in 1963. "Rusty" had been the lunar module pilot for Apollo 9 in 1969. He was assisted by Bruce McCandless II, a lieutenant commander in the U.S. Navy who had been appointed an astronaut in 1966. The third member of the crew was Story Musgrave, a civilian and a doctor of medicine (with [7] three other college degrees) who had been selected as an astronaut in 1967.

Backup crews for the second and third missions were the same. Vance D. Brand, a civilian, was named as an astronaut in 1966. Don L. Lind, a civilian with a Ph.D. in physics, joined the astronaut corps in 1966. He also had a scientific experiment aboard Skylab. William B. Lenoir, also a civilian, with a Ph.D. in electrical engineering, became an astronaut in 1967.

With the exception of Conrad, Bean, and Schweickart, none of the crewmen had flown in space before Skylab.

Getting Skylab Together

Skylab was much more than merely an empty third stage of a Saturn V rocket that had launched the first men to the Moon. The 117-foot-long space station consisted of five major components.

The empty stage itself was called the orbital workshop and housed most of the scientific, engineering, and biological experiments for the mission. Also, the former S-IVB stage provided the astronauts with their three bedrooms, kitchen, and bath. The orbital workshop was the hydrogen propellant tank portion of the rocket stage, which was divided into an upstairs and downstairs. Most of the astronauts' activities took place downstairs. The upstairs consisted largely of storage bins for various supplies and tanks for water as well as freezers for food, packaged somewhat like TV dinners. Spacesuits for the crew were also stowed there when not needed. With their boots anchored to the floor, the spacesuits stood like headless and handless crucifixes in the zero gravity of Skylab.

[9] Additionally, two important engineering experiments for the future of manned spaceflight were located upstairs. These were astronaut maneuvering units, rocket-propelled devices designed to permit an astronaut to move about freely outside his spaceship. The upstairs also had two airlocks in the wall through which scientific instruments could be placed into space. The oxygen tank of the S-IVB stage, much smaller than the hydrogen tank and suitably fitted with a special airlock, served as a garbage can for the astronauts.

The workshop also had two huge solar panels to supply electric power. These were folded against the outside of the workshop during launch and were designed to spring outward once Skylab was in orbit.

Attached to the forward end of the workshop was the airlock module. As the name implies, this cylindrical compartment permitted the astronauts to leave and reenter the workshop without having to depressurize it. This compartment had a circular hatch, or door, at either end and a rectangular hatch on the side. All could be sealed airtightly against the almost complete vacuum of space. The forward hatch gave entrance and exit to the compartment, while the aft hatch gave entrance and exit to the workshop. The rectangular hatch in the side of the airlock module permitted the astronauts to enter and reenter Skylab. This hatch was the same as that used on the Gemini spacecraft. In 1965, Astronaut Edward White had exited through one like it on Gemini 4 to become the first American to walk in space. The hatch had been well tested and proven in space. It was selected because of the predominant design philosophy of Skylab, which was to use, as much as possible, equipment that had proven itself in the environment of space.

The airlock module had other functions, too. In it were located the controls for the temperature of the Skylab and the purification system of its air. In addition to the space station's electrical control and hazard warning systems, the module also had a Teletype printer, like that used by newspaper wire services and telegraph companies, over which Skylab astronauts received messages from Earth. Much more information could be sent over it than by voice.

Attached to the forward end of the airlock module was the multiple docking module, a cylindrical compartment that permitted the Apollo....

.....spacecraft to dock with the Skylab at either of two ports. One of these was on the end, and the other was on the side. The latter was to be used for emergency rescues, which were not required during the mission. While the primary purpose of this module was to allow the astronauts to dock with the Skylab, it had other purposes as well. The major components located in it were the solar observatory control and display console and the electric furnace and vacuum chamber for materials processing experiments. It also provided space for various Earth resources experiments and had a window through which the astronauts could view and photograph Earth.

Attached by a trusswork to the shroud around....

....the upper end of the airlock module was the Apollo Telescope Mount or solar observatory. The mount was fixed to the trusswork in a manner that permitted it to pivot. During flight to orbit, it was stowed over the multiple docking adapter and covered by a large shroud to provide a streamlined cover for it. Once in orbit, the observatory swung 90 degrees to the side so that it could face the Sun.

Basically, the observatory consisted of a canister fitted within a rack that was free to rotate and also to be pointed up and down and from side to side. Attached rigidly to a spar that ran lengthwise through the canister were eight instruments to measure various radiations of the Sun. Film for these instruments was changed by the astronauts, who exited Skylab through the airlock module.

This canister could also be held stationary by an extremely accurate gyroscopic control system. The instruments in the canister could be pointed out at a spot on the Sun and held there for 15 minutes with an error of only 2.5 seconds of arc, which is....

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[11] ...equivalent to pointing a 7-foot-long rod at a certain spot and not having it move in any direction more than 1/1 000th of an inch.

Also an important part of the solar observatory were four large panels containing solar cells. These were folded against the sides of the Mount during launching and unfolded after the Skylab reached orbit. They provided electric power for the instruments in the observatory as well as for other systems of the space station.

Science and Engineering in the Space Environment

Skylab was designed primarily as a laboratory and workshop to study various aspects of science and engineering technology in the space environment near Earth. Included, too, were important studies of man himself in such an environment.

These experiments fell into seven categories: the life sciences, solar physics, Earth observations, astrophysics, materials science and manufacturing.

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[13] ....engineering and technology, and student experiments.

The life sciences experiments included studies of man and other forms of life from the cellular level to the functional being. Among them were experiments to determine the effect of weightlessness on the inner ear, the loss of minerals from bones, the loss of body weight, and the degradation of the cardiovascular system. Others included studies of sleep patterns and the bioassay of body fluids.

Physics of the Sun were investigated by eight special instruments located within the solar observatory that measured solar radiation in the visible light as well as ultraviolet and X-ray regions of the electromagnetic spectrum.

Earth was observed by six especially designed systems of instruments to help scientists better understand the natural and cultural features that impact its ecology. These cameras and other....

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[14] ...devices gathered data of tremendous importance to agriculture, forestry, oceanography, geology, geography, meteorology, and hydrology.

The astrophysical experiments included three instruments for probing into the workings of the atmosphere of Earth and the nature of the interplanetary medium. An additional six others investigated celestial objects beyond the solar system, including Comet Kohoutek.

Eighteen experiments were involved in materials processing and manufacturing. They included such techniques as welding in zero gravity, forming almost perfect spheres of metals, and growing extremely pure crystals for electronic components such as transistors.

The engineering and technological experiments numbered a dozen. Several studied the interaction between man and his space station in the zerogravity environment, while others investigated the environment of Skylab itself, both natural and....

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A special instrument called the spectroheliometer scanned the Sun and recorded its ultraviolet radiation.		Among many images of the Sun made by Skylab's solar observatory was this one showing its X-ray corona.
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Taken during the last manned mission, this view from Skylab shows smoke from oil well fires along the coast of Louisiana, near Bayou Teche.

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Comet Kohoutek was photographed by Skylab's far-ultraviolet camera. Its hydrogen halo had a diameter of some 1 600 000 miles.		Many photographs of Earth's surface were made with a special camera, seen here being operated by Astronaut Kerwin.
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Astronaut Bean became astronomer Bean during his mission. Here he operates a special camera for photographing star fields in their ultraviolet light.

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....induced. Included in these experiments were two types of rocket-propelled, gyroscope-stabilized astronaut maneuvering units, which were to be tested to see if future astronauts could use them to move about freely, and safely, outside their spacecraft. For experimental purposes the units were flown only in the roomy upstairs of the orbital workshop to demonstrate their fundamental practicality.

Finally, there were the student experiments and science demonstrations. From thousands of experiments proposed by high school students, 25 were selected for use aboard Skylab. Some of them required especially designed equipment to be operated or monitored by the astronauts, while others used data supplied by the experimental instruments already aboard the space station. In addition, the astronauts also performed science demon....

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Astronaut Carr tested a special astronaut maneuvering unit by flying it around in the orbital workshop.		One of the engineering and technology experiments aboard Skylab was a special suit instrumented to measure body motions as the wearer went through typical tasks aboard the space station. Astronaut Lousma inspects such a suit during a training session on Earth.

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[20] .....strations on television that could not have been done in the earthly laboratory because of gravity.

Mission in Space-Skylab in Trouble

As originally planned, Skylab was to be launched from Kennedy Space Center. The first crew would stay aboard for 28 days; the second and third would remain for 56 days each.

The space station's orbit would trace a wavelike line on Earth's surface from 50 degrees above the equator to 50 degrees below it. Thus, Skylab would sweep over 75 percent of Earth's surface, consisting of some 147 705 000 square miles. Within this area resides 90 percent of the world's food-producing regions. In such an orbit, Skylab would circle Earth every hour and a half.

Skylab was to be launched from Cape Canaveral on May 14, 1973. Once it was smoothly in orbit....

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....and everything functioning on schedule, Commander Conrad and his crew then would be launched a day later.

To the hundreds of thousands of observers at Launch Complex 39 at Kennedy Space Center and nearby, the liftoff of Saturn V with Skylab aboard seemed to be a perfect one. The 334-foot-tall rocket roared off the launching pad and climbed slowly at first. Gathering speed, it passed through a low-hanging cloud and then reappeared briefly, its white contrail twisting behind it.

Within little more than a minute, Skylab was in trouble. Flight controllers of the Saturn V reported "a strange lateral acceleration at approximately 63 seconds after liftoff on the S-II second stage." It happened only 13 seconds before the huge rocket was to pass "Max Q," the point in flight when maximum aerodynamic pressure builds up on the vehicle.

It became apparent from the endless stream of telemetry feeding into Mission Control at the Johnson Space Center that a metal shield only 0.025 inch thick around the orbital workshop had torn loose. This shield performed two critical functions. While it was there primarily to protect the workshop from possible puncture by very small meteoroids, it also protected the workshop from the searing heat of the Sun.

[23] To compound the misfortune, radars in Australia also reported that the two solar cell panels of the workshop had not swung out into the open position. There was practically no electric power in the space station.

Temperatures within Skylab began climbing above 120°F and reached as high as 190°F in places. If this were not bad news enough, telemetry finally confirmed that one of the solar cell panels had been torn away with the meteoroid shield and was tumbling along in orbit behind the space station.

Clearly something had to be done immediately to lower the temperature within the workshop. Flight controllers sent commands for Skylab to go into a "barbeque roll" or to turn slowly as it moved along its orbit. The temperature stabilized between a very uncomfortable 105°F and 110°F.

Engineers at the Marshall Space Flight Center and the Johnson Space Center went to work immediately. Their problem was to provide a means of keeping the Sun off the sensitive skin of the nude workshop. A parasol like a giant beach umbrella was developed by the Johnson Space Center. It fitted into a package that could be deployed through the Sunfacing airlock in the wall of the orbital workshop.

With the arrival of the first crew at the stricken Skylab on May 25, the parasol was installed, and the space station's temperature came down quickly. Climbing outside Skylab, Conrad and Kerwin freed the stuck solar panel, and electricity began to flow into it immediately.

Skylab had been saved by its astronauts, and its salvation proved that man is an indispensable part of a complex space venture such as the operation....

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Of a large space station in orbit about Earth. In the two remaining missions, which left Earth on July 28 and November 16, the Skylab astronauts were called upon time and again to repair failing or malfunctioning equipment or to provide services that simply could not have been programed into an unmanned automated station.

Skylab-The Ultimate Triumph

Skylab provided a unique learning environment. Men had been in space prior to it, but of necessity they had existed in cramped quarters, largely preoccupied with short-term survival and the operational testing of their spacecraft. As in the [25] evolutionary progress of all pioneering efforts in science and technology, the early steps into space had been relatively ill-equipped for making meticulous scientific experiments. Room and time simply did not permit sophisticated scientific or technical investigations by harried astronauts, most of whom were not scientists. However, those brief, early, manned space missions did whet the appetite of Earth-bound scientists and engineers, and such spaceflights provided the impetus for Skylab, America's first laboratory in space.

Experience may be the best teacher, but experience on Earth does not necessarily provide the best learning environment for all forms of scientific study. Earth's gravitational effects sometimes obscure basic physical laws or impede physical or chemical processes. Atmospheric effects limit the astronomer's capability to observe certain celestial phenomena. Agricultural engineers and scientists often (and literally) cannot see the forest for the trees. Above the atmosphere, freed from gravitational forces, and with a broader view of Earth than possible from any point on it, new horizons of learning open to the scientist and engineer.

In Skylab, men adjusted to the space station environment in a freer manner than before. They demonstrated that man cannot only survive for long periods of time in reduced gravity, but that he can also carry out important and useful tasks not otherwise possible.

As an educational experience, Skylab exposed on television the living conditions of its crew and....

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...the way in which its astronauts worked within the huge space station. The viewing of their activities helped illustrate the importance and value of the space program to a wide variety of the peoples of the world. In addition, Skylab generated enough scientific and technological data to keep scientists and engineers on Earth busy for a long time to come. Based on their findings, educators will be faced with the job of revising current textbooks and perhaps writing new ones.

Of great value to the teacher of science were the demonstrations by the astronauts of the fundamental principles of physics that simply cannot be done on Earth because of its gravity. Such demonstrations of laws that previously had appeared only

in print and mathematical equations for the first time became understandable for many students. In short, the knowledge acquired as a result of Skylab has had and will continue to have significant effect on the lives not only of scientists, engineers, and astronauts, but also of teachers and their students.

The ultimate success of Skylab as a practical and functional scientific laboratory in space was not a unanimous conviction of American scientists prior to its launch. But following its successful conclusion, Leo Goldberg, director of Kitt Peak National Observatory, said in retrospect: "Many of us had serious doubts about the scientific usefulness of men in space, especially in a mission such as the ATM [solar observatory], which was not designed [27] to take advantage of man's capability to repair and maintain equipment in space. But these men performed near-miracles in transforming the mission from near-ruin to total perfection. By their rigorous preparation and training and enthusiastic devotion to the scientific goals of the mission, they have proven the value of men in space as true scientific partners in space science research."

In so saying, Goldberg was unknowingly echoing a sentiment expressed a decade earlier by Wernher von Braun, then director of the Marshall Space Flight Center. He spoke of an earlier, much less complex, manned space program in terms that would apply equally well to Skylab: "I am often asked what reason there is for man's going into space. It seems the notion is popular in this age of electronic and mechanical miracles that man is rapidly becoming obsolete. Computers, for example, are much faster; and other instruments are much more sensitive to physical phenomena about us. Man, in space, some people say, is a liability and a nuisance. Well, men like Glenn, Carpenter, Cooper, Grissom, and Young proved that this simply isn't true. When equipment in the spacecraft malfunctioned, it was man in the loop, the astronaut, who saved the day. Equipment can be designed to react to many known and few unanticipated situations or events; but man can observe and correlate facts and respond to the unexpected. He is not merely going along for the ride. Man is the necessary element."

Thus, in the end, Skylab bore out von Braun's earlier view of the role of man in space. It was men like Conrad, Kerwin, Weitz, and their fellow astronauts of Skylab who saved the mission. Yet, they demonstrated more than man's ability to run a very good repair shop in space. They showed that he can adapt to the space environment, living and working there. As a scientific observer, he can reprogram automated instruments and equipment to take advantage of events which could not have been detected by such machines. Also, he can see, think, exercise judgment, and report things unobservable to unprogramable instruments. In short, the men of Skylab proved that in space man is the necessary element.

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