The International Space Station - The American Skylab

Long before an Apollo spacecraft landed on the moon, NASA planners were looking ahead to their next great project. The Apollo Applications Program (AAP) began in 1963 with a plan to use leftover Apollo hardware in some kind of orbiting station including a laboratory, workshop, and space telescope. When the Apollo 20 mission was cancelled in 1970, the AAP inherited a Saturn V rocket. They used the rocket as the launch vehicle for a newly developed station called Skylab.

The Skylab program had two primary goals:

• Prove that humans could live and work in space for extended periods of time
• Expand knowledge of solar astronomy using a space-based telescope

The program was composed of four flights, as shown in Table 5.1.

The station was designed with two solar panels that were folded flat against the rocket during launch. Once in TABLE 5.1 Skylab statistics Adapted from "Skylab Statistics," in Skylab Program Overview, National Aeronautics and Space Administration, Kennedy Space Center, December 12, 2000, http://www-pao.ksc.nasa.gov/kscpao/history/skylab/skylab-stats.htm (accessed January 31, 2006)orbit, they were to open up like wings and harness the sun's energy to provide electricity for the station. On May 14, 1973, the unmanned Skylab station was launched into orbit. It was damaged during liftoff when a protective shield came loose and smashed against the solar panels, ripping one of them off and damaging the other.

TABLE 5.1
Skylab statistics
	Skylab 1	Skylab 2	Skylab 3	Skylab 4
SOURCE: Adapted from "Skylab Statistics," in Skylab Program Overview, National Aeronautics and Space Administration, Kennedy Space Center, December 12, 2000, http://www-pao.ksc.nasa.gov/kscpao/history/skylab/skylab-stats.htm (accessed January 31, 2006)
Launch date	5/14/1973	5/25/1973	7/28/1973	11/16/1973
Launch vehicles	Saturn V	Saturn 1B	Saturn 1B	Saturn 1B
Orbital parameters	268.1 × 269.5 miles	268.1 × 269.5 miles	268.1 × 269.5 miles	268.1 × 69.5 miles
Orbital inclination	50 degrees	50 degrees	50 degrees	50 degrees
Orbital period (approximate)	93 minutes	93 minutes	93 minutes	93 minutes
Distance orbit	26,575 miles	26,575 miles	26,575 miles	26,575 miles
Crew's mission distance		11.5 million miles	24.5 million miles	34.5 million miles
Crew's number of revolutions		404	585	1,214
Crews mission duration		28 days 49 min	59 days 11 hrs 9 min	84 days 1 hr 16 min
Crew's experiment time		392 hr	1,081 hr	1,563 hr
Crew's EVA time		6 hr 20 min	13 hr 43 min	22 hr 13 min

A team of three Skylab astronauts was to have launched the next day. However, their flight was delayed for ten days as engineers assessed the damage to the station. The astronauts, called the Skylab 2 crew, finally launched on May 25, 1973. They successfully docked with the station and began repairing its damaged components. Crewmembers deployed a temporary sail-like shield to replace the torn-off solar panel. Their mission lasted just over twenty-eight days, a new record for Americans in space. This record was bested by the astronauts of Skylab 3 and Skylab 4.

The Skylab station weighed nearly 100 tons and was about the size of a small three-bedroom house. It included a two-level workshop.

The Skylab 3 mission included two spiders named Anita and Arabella. The spiders were part of an experiment suggested by a high school student named Judith Miles from Lexington, Massachusetts. She wondered if spiders would be able to spin their webs in microgravity. NASA scientists seized upon the idea and sent the spiders into space in cages equipped with still cameras and television cameras. The public became enthralled in hearing about the two spiders.

Neither spider adjusted well to their new environment. Arabella's initial webs were sloppy and lopsided. After a few days the spider seemed to get her space legs and began spinning webs of Earth-like patterns. Both spiders died during the mission, apparently of dehydration. Their bodies were turned over to the Smithsonian Institution and are still kept there in 2006.

Skylab was not designed for long-term use. It had no method of independent reboost to keep it from falling out of orbit. On July 11, 1979, the station reentered Earth's atmosphere and broke apart over the Pacific Ocean.

Despite its early mechanical problems, the Skylab program was considered a great success. The total number of hours spent in space by Skylab astronauts was greater than the combined totals of all space flights made up to that time. NASA gained valuable knowledge about human performance under microgravity conditions.