Lyceum & Book Club - Week 42 - Article: Skylab

Skylab was the first United States space station, launched by NASA, occupied for about 24 weeks between May 1973 and February 1974.

It was operated by three separate three-astronaut crews: Skylab 2, Skylab 3 and Skylab 4.

Major operations included an orbital workshop, a solar observatory, Earth observation, and hundreds of experiments.

Unable to be re-boosted by the Space Shuttle, which was not ready until 1981, Skylab's orbit decayed and it disintegrated in the atmosphere on July 11, 1979, scattering debris across the Indian Ocean and Western Australia.

As of 2021, Skylab was the only space station operated exclusively by the United States. A permanent station was planned starting in 1988, but funding for this was canceled and replaced with United States participation in an International Space Station in 1993.

It was launched uncrewed into low Earth orbit by a Saturn V rocket modified to be similar to the Saturn INT-21, with the S-IVB third stage not available for propulsion because the orbital workshop was built out of it.

This was the final flight for the rocket more commonly known for carrying the crewed Apollo Moon landing missions.

Three subsequent missions delivered three-astronaut crews in the Apollo CSM launched by the smaller Saturn IB rocket.

For the final two crewed missions to Skylab, NASA assembled a backup Apollo CSM/Saturn IB in case an in-orbit rescue mission was needed, but this vehicle was never flown. The station was damaged during launch when the micrometeoroid shield tore away from the workshop, taking one of the main solar panel arrays with it and jamming the other main array. This deprived Skylab of most of its electrical power and also removed protection from intense solar heating, threatening to make it unusable.

The first crew deployed a replacement heat shade and freed the jammed solar panels to save Skylab. This was the first time that a repair of this magnitude was performed in space.

Skylab included the Apollo Telescope Mount (a multi-spectral solar observatory), a multiple docking adapter with two docking ports, an airlock module with extravehicular activity (EVA) hatches, and the orbital workshop, the main habitable space inside Skylab. Electrical power came from solar arrays and fuel cells in the docked Apollo CSM. The rear of the station included a large waste tank, propellant tanks for maneuvering jets, and a heat radiator. Astronauts conducted numerous experiments aboard Skylab during its operational life. The telescope significantly advanced solar science, and observation of the Sun was unprecedented. Astronauts took thousands of photographs of Earth, and the Earth Resources Experiment Package (EREP) viewed Earth with sensors that recorded data in the visible, infrared, and microwave spectral regions. The record for human time spent in orbit was extended beyond the 23 days set by the Soyuz 11 crew aboard Salyut 1 to 84 days by the Skylab 4 crew.

Later plans to reuse Skylab were stymied by delays in the development of the Space Shuttle, and Skylab's decaying orbit could not be stopped.

As the Skylab program drew to a close, NASA's focus had shifted to the development of the Space Shuttle. NASA space station and laboratory projects included Spacelab, Shuttle-Mir, and Space Station Freedom, which was merged into the International Space Station.

A dry workshop simplified plans for the interior of the station. Industrial design firm Raymond Loewy/William Snaith recommended emphasizing habitability and comfort for the astronauts by providing a wardroom for meals and relaxation and a window to view Earth and space, although astronauts were dubious about the designers' focus on details such as color schemes. Habitability had not previously been an area of concern when building spacecraft due to their small size and brief mission durations, but the Skylab missions would last for months. NASA sent a scientist on Jacques Piccard's Ben Franklin submarine in the Gulf Stream in July and August 1969 to learn how six people would live in an enclosed space for four weeks.

Astronauts were uninterested in watching movies on a proposed entertainment center or in playing games, but they did want books and individual music choices. Food was also important; early Apollo crews complained about its quality, and a NASA volunteer found it intolerable to live on the Apollo food for four days on Earth. Its taste and composition were unpleasant, in the form of cubes and squeeze tubes. Skylab food significantly improved on its predecessors by prioritizing palatability over scientific needs.

Each astronaut had a private sleeping area the size of a small walk-in closet, with a curtain, sleeping bag, and locker. Designers also added a shower and a toilet for comfort and to obtain precise urine and feces samples for examination on Earth.The waste samples were so important that they would have been priorities in any rescue mission.

Skylab did not have recycling systems such as the conversion of urine to drinking water; it also did not dispose of waste by dumping it into space. The S-IVB's 73,280 litres (16,120 imp gal; 19,360 US gal) liquid oxygen tank below the Orbital Work Shop was used to store trash and wastewater, passed through an airlock.

• Skylab 2: launched May 25, 1973 - 28 days

• Skylab 3: launched July 28, 1973 - 59 days

• Skylab 4: launched November 16, 1973 - 84 days - returned to Earth on Feb.8,1974

Shower

Skylab had a zero-gravity shower system in the work and experiment section of the Orbital Workshop designed and built at the Manned Spaceflight Center. It had a cylindrical curtain that went from floor to ceiling and a vacuum system to suck away water. The floor of the shower had foot restraints.

To bathe, the user coupled a pressurized bottle of warmed water to the shower's plumbing, then stepped inside and secured the curtain. A push-button shower nozzle was connected by a stiff hose to the top of the shower. The system was designed for about 6 pints (2.8 liters) of water per shower, the water being drawn from the personal hygiene water tank. The use of both the liquid soap and water was carefully planned out, with enough soap and warm water for one shower per week per person. The first astronaut to use the space shower was Paul J. Weitz on Skylab 2, the first crewed mission.He said, "It took a fair amount longer to use than you might expect, but you come out smelling good".A Skylab shower took about two and a half hours, including the time to set up the shower and dissipate used water. The procedure for operating the shower was as follows:

1. Fill up the pressurized water bottle with hot water and attach it to the ceiling

2. Connect the hose and pull up the shower curtain

3. Spray down with water

4. Apply liquid soap and spray more water to rinse

5. Vacuum up all the fluids and stow items.

One of the big concerns with bathing in space was control of droplets of water so that they did not cause an electrical short by floating into the wrong area. The vacuum water system was thus integral to the shower. The vacuum fed to a centrifugal separator, filter, and collection bag to allow the system to vacuum up the fluids. Waste water was injected into a disposal bag which was in turn put in the waste tank. The material for the shower enclosure was fire-proof beta cloth wrapped around hoops of 43 inches (1,100 mm) diameter; the top hoop was connected to the ceiling. The shower could be collapsed to the floor when not in use. Skylab also supplied astronauts with rayon terrycloth towels which had a color-coded stitching for each crew-member.There were 420 towels on board Skylab initially.

A simulated Skylab shower was also used during the 56-day SMEAT simulation; the crew used the shower after exercise and found it a positive experience.

Conrad in the Skylab shower in 1973

Skylab had a zero-gravity shower system in the work and experiment section of the Orbital Workshop designed and built at the Manned Spaceflight Center. It had a cylindrical curtain that went from floor to ceiling and a vacuum system to suck away water. The floor of the shower had foot restraints.

To bathe, the user coupled a pressurized bottle of warmed water to the shower's plumbing, then stepped inside and secured the curtain. A push-button shower nozzle was connected by a stiff hose to the top of the shower. The system was designed for about 6 pints (2.8 liters) of water per shower, the water being drawn from the personal hygiene water tank. The use of both the liquid soap and water was carefully planned out, with enough soap and warm water for one shower per week per person. The first astronaut to use the space shower was Paul J. Weitz on Skylab 2, the first crewed mission.He said, "It took a fair amount longer to use than you might expect, but you come out smelling good".A Skylab shower took about two and a half hours, including the time to set up the shower and dissipate used water. The procedure for operating the shower was as follows:

1. Fill up the pressurized water bottle with hot water and attach it to the ceiling

2. Connect the hose and pull up the shower curtain

3. Spray down with water

4. Apply liquid soap and spray more water to rinse

5. Vacuum up all the fluids and stow items.

One of the big concerns with bathing in space was control of droplets of water so that they did not cause an electrical short by floating into the wrong area. The vacuum water system was thus integral to the shower. The vacuum fed to a centrifugal separator, filter, and collection bag to allow the system to vacuum up the fluids. Waste water was injected into a disposal bag which was in turn put in the waste tank.[55] The material for the shower enclosure was fire-proof beta cloth wrapped around hoops of 43 inches (1,100 mm) diameter; the top hoop was connected to the ceiling. The shower could be collapsed to the floor when not in use. Skylab also supplied astronauts with rayon terrycloth towels which had a color-coded stitching for each crew-member.There were 420 towels on board Skylab initially.

A simulated Skylab shower was also used during the 56-day SMEAT simulation; the crew used the shower after exercise and found it a positive experience.