Science Fair Project Encyclopedia
|Mission Name:||Skylab IV|
|Call Sign:||Skylab 4|
|Launch:||November 16, 1973|
Kennedy Space Center
|83 d 4 h 38 min 12 s|
|22 h 21 min|
|Landing:||February 8, 1974|
|Duration:||84 d 1 h 15 min 31 s|
|Mass:||CSM ~20,000 kg|
|Skylab 4 Crew|
The fourth Skylab mission, Skylab 4 or SL-4, started November 16, 1973, with the launch of three astronauts on a Saturn IB rocket, and lasted 84 days, 1 hours and 16 minutes. A total of 6,051 astronaut-utilization hours were tallied by Skylab 4 astronauts performing scientific experiments in the areas of medical activities, solar observations, Earth resources, observation of the Comet Kohoutek and other experiments.
(1) number of spaceflights each crew member has completed, including this mission.
- Mass: about 20,000 kg
- Maximum Altitude: 440 km
- Distance: 34.5 million miles (55,500,000 km)
- Launch Vehicle: Saturn IB
- Docked: November 16, 1973 - 21:55:00 UTC
- Undocked: February 8, 1974 - 02:33:12 UTC
- Time Docked: 83 days, 4 hours, 38 minutes, 12 seconds
- Gibson and Pogue - EVA 1
- EVA 1 Start: November 22, 1973, 17:42 UTC
- EVA 1 End: November 23, 00:15 UTC
- Duration: 6 hours, 33 minutes
- Carr and Pogue - EVA 2
- EVA 2 Start: December 25, 1973, 16:00 UTC
- EVA 2 End: December 25, 23:01 UTC
- Duration: 1 hours, 01 minute
- Carr and Gibson - EVA 3
- EVA 3 Start: December 29, 1973, 17:00 UTC
- EVA 3 End: December 29, 20:29 UTC
- Duration: 3 hours, 29 minutes
- Carr and Gibson - EVA 4
- EVA 4 Start: February 3, 1974, 15:19 UTC
- EVA 4 End: February 3, 20:38 UTC
- Duration: 5 hours, 19 minutes
Last of the Skylab missions. The crew had problems during activation of the workshop that earlier crews had not faced. One of its first tasks was to unload and stow within Skylab thousands of items needed for their lengthy mission. The schedule for the activation sequence dictated lengthy work periods with a large variety of tasks to be performed. The crew soon found themselves tired and behind schedule.
As the activation progressed, the astronauts complained of being pushed too hard. Ground crews disagreed; they felt that the flight crew was not working long enough or hard enough. During the course of the mission, these disagreements continued, eventually leading to the crew going on strike until their workload was reduced.
By the end of their mission, the third crew had completed even more work than had been planned before launch.
Thanksgiving Day, Gibson and Pogue accomplished a 6 1/2 hour spacewalk. The first part of their spacewalk was spent replacing film in the solar observatory. The remainder of the time was used to repair a malfunctioning antenna.
The crew reported that the food was good, but slightly bland. The crew would have preferred to use more condiments to enhance the taste of the food. The amount of salt they could use was restricted for medical purposes. The quantity and type of food consumed was rigidly controlled because of their strict diet.
Seven days into their mission, a problem developed in the Skylab attitude control gyroscope system, which threatened to bring an early end to the mission.
Skylab depended upon three large gyroscopes, sized so that any two of them could provide sufficient control and maneuver Skylab as desired. The third acted as a backup in the event of failure of one of the others.
The gyroscope failure was attributed to insufficient lubrication. Later in the mission, a second gyroscope showed similar problems, but special temperature control and load reduction procedures kept the second one operating, and no further problems occurred.
The crew spent many hours looking at the Earth. Carr and Pogue alternately manned controls, operating the sensing devices which measured and photographed selected features on the Earth's surface. When not otherwise occupied, they watched through the workshop window as the Earth rolled steadily beneath them.
Solar observations were made, with about 75 000 new telescopic images of the Sun recorded. Images were taken in the X-ray, ultraviolet, and visible portions of the spectrum.
As the end of their mission drew closer, Gibson continued his watch of the solar surface. On January 21, 1974, an active region on the Sun's surface formed a bright spot which intensified and grew. Gibson quickly began filming the sequence, as the bright spot erupted, he had filmed the birth of a solar flare from space, the first recording in history.
On December 13, the crew sighted Comet Kohoutek and trained the solar observatory and hand-held cameras on it. They continued to photograph it as it approached the Sun. On December 30, as it swept out from behind the Sun, Carr and Gibson spotted it as they were performing a spacewalk.
Skylab 4 completed 1,214 Earth orbits and four EVAs totalling 22 hours, 13 minutes. They traveled 34.5 million miles (55,500,000 km) in 84 days, 1 hour and 16 minutes in space.
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