Skylab program

Skylab

Skylab as photographed by its departing final crew (Skylab 4)
Skylab program insignia
Station statistics
COSPAR ID	1973-027A
Call sign	Skylab
Crew	3 per mission (9 total)
Launch	May 14, 1973 17:30:00 UTC
Launch pad	Kennedy Space Center LC-39A
Reentry	July 11, 1979 16:37:00 UTC near Perth, Australia
Mission status	Complete
Mass	170,000 lb (77,000 kg) w/o Apollo CSM
Length	82.4 feet (25.1 m) w/o Apollo CSM
Width	55.8 feet (17.0 m) w/ one solar panel
Height	36.3 feet (11.1 m) w/ telescope mount
Diameter	21.67 feet (6.6 m)
Pressurised volume	12,417 cu ft (351.6 m3)
Perigee	269.7 mi (434.0 km)
Apogee	274.6 mi (441.9 km)
Orbital inclination	50°
Orbital period	93.4 min
Orbits per day	15.4
Days in orbit	2,249 days
Days occupied	171 days
No. of orbits	34,981
Distance travelled	~890,000,000 mi (1,400,000,000 km)
Statistics as of Re-entry July 11, 1979
Configuration
Skylab configuration as planned

Skylab was the United States' space station that orbited the Earth from 1973 to 1979, when it fell back to Earth amid huge worldwide media attention. Launched and operated by NASA, Skylab included a workshop, a solar observatory, and other systems necessary for crew survival and scientific experiments. It was launched unmanned by a modified Saturn V rocket, with a weight of 170,000 pounds (77,000 kg). Lifting Skylab into low earth orbit was the final mission and launch of a Saturn V rocket (famous for carrying the manned Moon landing missions). There were a total of three manned expeditions to the station, conducted between May 1973 and February 1974. Each mission delivered a three-astronaut crew in the Apollo Command/Service Module (Apollo CSM) launched by the smaller Saturn IB rocket. For the final two manned missions to Skylab, a backup Apollo CSM/Saturn IB was assembled and made ready in case an in-orbit rescue mission was needed, but this backup 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 was able to save Skylab by deploying a replacement heat shade and freeing the jammed solar panels. This was the first time a repair of this magnitude had been performed in space.

Skylab included the Apollo Telescope Mount (a multi-spectral solar observatory), Multiple Docking Adapter (with two docking ports), Airlock Module with extravehicular activity (EVA) hatches, and the Orbital Workshop (the main habitable space inside Skylab). Electrical power came from solar arrays, as well as 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. Numerous experiments were conducted aboard Skylab during its operational life. Solar science was significantly advanced by the telescope, and observation of the Sun was unprecedented. Thousands of photographs of Earth were taken, 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.