Three bedrooms, kitchen, and
dinette, with bath.
The orbital workshop of Skylab was home, office, and laboratory for its
was America's first experimental space station. Designed as a precursor to
what many hoped would be a larger, more extensive space station, Skylab
set out to prove that humans could live and work in space for extended
periods of time and also to expand knowledge of solar astronomy well
beyond that available from Earth-based observations. Successful in all
respects despite early mechanical difficulties, three crews of three
persons each occupied the Skylab workshop for a total of 171 days, 13
hours. The orbiting laboratory was the site of nearly 300 scientific and
technical experiments: medical experiments on humans' adaptability to zero
gravity, solar observations, and detailed Earth resources experiments.
National Aeronautics and Space Administration (NASA) had studied concepts
for space stations, including an inflatable donut-shaped station, since
the earliest days of the space program. However, it was not until the
Saturn rocket was developed in the mid-1960s that the Skylab program was
born. Initially called the Apollo Applications Program, Skylab planned to
use leftover Apollo lunar hardware on its missions.
there were two competing concepts. The first was called a “wet” workshop,
in which the smaller Saturn 1B rocket would be launched, fuelled, and its
S-IVB upper stage vented and refurbished in orbit. The second was the
“dry” workshop, whereby an empty S-IVB stage was outfitted on the ground
before launch, then launched on the massive Saturn V rocket. In July 1969,
NASA selected the “dry” workshop concept. The crews visiting the orbiting
S-IVB, given the name Skylab, would travel to and from the orbiting
laboratory in modified Apollo command and service modules launched by
Saturn 1B rockets.
100-ton (91-metric ton) structure was 118 feet (36 meters) high, 22 feet
(6.7 meters) in diameter, and flew at an altitude of 270 miles (435
kilometres). It had a habitable volume of about 10,000 cubic feet (283
cubic meters) and was divided into two levels separated by a metal
floor—actually an open grid into which the astronauts' cleated shoes could
be locked. The upper floor had storage lockers and a large empty space for
conducting experiments, plus two scientific airlocks, one pointing toward
the Earth and the other toward the Sun. The lower floor had compartmented
“rooms” with a dining room table, three bedrooms, a work area, a shower,
and a bathroom.
Astronaut Charles Conrad Jr.,
Skylab 2 commander, poses after a hot bath
in the shower facility in the crew quarters of the Orbital Workshop.
largest piece of scientific equipment, attached to one end of the
cylindrical workshop, was the Apollo Telescope Mount (ATM), used to study
the Sun in different wavelengths with no atmospheric interference. The ATM
served as the platform for eight experiments: two X-ray telescopes; an
X-ray and extreme ultraviolet camera; an ultraviolet spectroheliometer; an
extreme ultraviolet spectroheliograph and an ultraviolet spectroheliograph;
a white light coronagraph; and two hydrogen-alpha telescopes. The unit had
its own electricity-generating solar panels.
also had an airlock module for spacewalks (required for repairs,
experiment deployments, and routine changing of film in the ATM). The
Apollo command/service module remained attached to the station's docking
adapter while the astronauts were on board.
Skylab space station was launched May 14, 1973, from the NASA Kennedy
Space Centre by a huge Saturn V launch vehicle. It was planned that a crew
would be launched from Earth the next day to inhabit the space station.
Sixty-three seconds after lift-off, however, a critical meteoroid shield
ripped off, taking one of the craft's two solar panels with it and
preventing the other from deploying properly. Ground command manoeuvred
Skylab so its solar panels faced the Sun to provide as much electricity as
possible. But because the meteoroid shield was gone (which also operated
as a sun shield), temperatures inside the workshop rose to 126˚F (52˚C).
The launch of Skylab 2 (the first crew to inhabit the space station) was
postponed for 10 days while scientists, engineers, astronauts, and
management personnel at NASA's Marshall Space Flight Centre in Huntsville,
Alabama, and elsewhere developed procedures and trained the crew to make
the workshop habitable. At the same time, engineers "rolled" Skylab to
lower the temperature of the workshop.
Parking places for two Apollo
spacecraft were provided by the docking module of Skylab.
The circular port on the right end was used as the primary one.
The port on the bottom would have been used had a rescue become necessary.
25, 1973, the crew of Skylab 2, Charles Conrad, Jr., Paul Weitz, and
Joseph Kerwin, finally began their 28 days aboard Skylab. Their first task
was to make substantial repairs. These included positioning of a parasol
sunshade that cooled the inside temperatures to a more comfortable 75˚F
(23.8˚C). By June 4, 10 days after launch, the workshop was fully
operational, and the crew began to conduct solar astronomy and Earth
resources experiments, medical studies, and student experiments. In the
period up to June 22, when the crew left for home, they circled the Earth
404 times, completed 392 experiment hours, and carried out three
“spacewalks” (extravehicular activities—EVAs) totalling six hours, 20
Spacelab 3 crew, consisting of Alan Bean, Jack Lousma, and Owen Garriott,
arrived on July 28 for a 59-day stay. After an early bout of motion
sickness, they continued the work of the previous crew. Garriott and
Lousma deployed a second sun shield during a spacewalk that lasted
six-and-a-half hours. This crew completed 858 Earth orbits and 1,081 hours
of solar and Earth experiments. Their three EVAs totalled 13 hours, 43
Astronaut Jack R. Lousma, Skylab 3 pilot, is seen outside the Skylab space
Earth orbit during the August 5, 1973, Skylab 3 extravehicular activity
(EVA) in this photographic reproduction
taken from a television transmission made by a colour TV camera aboard the
days and 1 hour, Skylab 4 remains the longest U.S. spaceflight to date.
Its crew members—Gerald Carr, William Pogue, and Edward Gibson-used a
treadmill in addition to the on-board bicycle-like ergometer to help stay
in shape. The last of the Skylab missions, its experiments included
observations of the Comet Kohoutek. The crew completed 1,214 Earth orbits
and four EVAs totalling 22 hours, 13 minutes.
all crew activities had been completed and the crews had returned to
Earth, Skylab was positioned into a stable attitude and systems were shut
down. It was expected that Skylab would remain in orbit for eight to ten
years. However, in the fall of 1977, Skylab was no longer flying in a
stable attitude as a result of greater than predicted solar activity. On
July 11, 1979, the empty Skylab spacecraft returned to Earth, scattering
debris from the south-eastern Indian Ocean across a sparsely settled region
of western Australia. NASA and the U.S. space program were criticized for
allowing this to happen-ranging from the sale of hardhats as "Skylab
Survival Kits" to serious questions about the propriety of space flight
altogether if people were likely to be killed by falling debris. It was an
inauspicious ending to the first American space station, not one that its
originators had envisioned. Nevertheless, the experiment had whetted the
appetite of NASA leaders for a permanent presence in space.
Skylab, both the hours spent in orbit and those spent performing EVA
exceeded the combined totals of all of the world's previous space flights.
And the good health and physical condition of the astronauts after
returning from their extended stay in the weightlessness of space
conclusively demonstrated the feasibility of longer human spaceflight