astronautix.com | Skylab 2 |
Epic repair mission which brought Skylab into working order. Included such great moments as Conrad being flung through space by the whiplash after heaving on the solar wing just as the debris constraining it gave way; deployment of a lightweight solar shield, developed in Houston in one week, which brought the temperatures down to tolerable levels. With this flight US again took manned spaceflight duration record.
Skylab 2 , consisting of a modified Apollo CSM payload and a Saturn IB launch vehicle, was inserted into Earth orbit approximately 10 minutes after liftoff. The orbit achieved was 357 by 156 km and, during a six-hour period following insertion, four maneuvers placed the CSM into a 424 by 415 km orbit for rendezvous with the Orbital Workshop. Normal rendezvous sequencing led to stationkeeping during the fifth revolution followed by a flyaround inspection of the damage to the OWS. The crew provided a verbal description of the damage in conjunction with 15 minutes of television coverage. The solar array system wing (beam) 2 was completely missing. The solar array system wing (beam) 1 was slightly deployed and was restrained by a fragment of the meteoroid shield. Large sections of the meteoroid shield were missing. Following the flyaround inspection, the CSM soft-docked with the OWS at 5:56 p.m. EDT to plan the next activities. At 6:45 p.m. EDT the CSM undocked and extravehicular activity was initiated to deploy the beam 1 solar array. The attempt failed. Frustration of the crew was compounded when eight attempts were required to achieve hard docking with the OWS. The hard dock was made at 11:50 p.m. EDT, terminating a Skylab 2 first-day crew work period of 22 hours.
The Skylab space station was launched May 14, 1973, from the NASA Kennedy Space Center by a huge Saturn V launch vehicle, the moon rocket of the Apollo Space Program. Sixty-three seconds after liftoff, the meteoroid shield--designed also to shade Skylab's workshop--deployed inadvertently. It was torn from the space station by atmospheric drag. This event and its effects started a ten-day period in which Skylab was beset with problems that had to be conquered before the space station would be safe and habitable for the three manned periods of its planned eight-month mission.
When the meteoroid shield ripped loose, it disturbed the mounting of workshop solar array "wing" two and caused it to partially deploy. The exhaust plume of the second stage retro-rockets impacted the partially deployed solar array and literally blew it into space. Also, a strap of debris from the meteoroid shield overlapped solar array "wing" number one such that when the programmed deployment signal occurred, wing number one was held in a slightly opened position where it was able to generate virtually no power.
In the meantime, the space station had achieved a near-circular orbit at the desired altitude of 435 kilometers (270 miles). All other major functions including payload shroud jettison, deployment of the Apollo Telescope Mount (Skylab's solar observatory) and its solar arrays, and pressurization of the space station occurred as planned.
Scientists, engineers, astronauts, and management personnel at the NASA Marshall Space Flight Center and elsewhere worked throughout the first ten-day period of Skylab's flight to devise the means for its rescue. Simultaneously, Skylab--seriously overheating--was maneuvered through varying nose-up attitudes that would best maintain an acceptable "holding" condition. Because of the loss of the meteoroid shield, however, this positioning caused workshop temperatures to rise to 52 degrees Celsius (126 degrees F). During that ten-day period and for some time thereafter, the space station operated on less than half of its designed electrical system, in the partially nose-up attitudes, was generating power at reduced efficiency. The optimum condition that maintained the most favorable balance between Skylab temperatures and its power generation capability occurred at approximately 50 degrees nose-up.
The crew rendezvoused with Skylab on the fifth orbit. After making substantial repairs, including deployment of a parasol sunshade which cooled the inside temperatures to 23.8 degrees C (75 degrees F), by June 4 the workshop was in full operation. In orbit the crew conducted solar astronomy and Earth resources experiments, medical studies, and five student experiments; 404 orbits and 392 experiment hours were completed; three EVAs totalled six hours, 20 minutes.
Skylab-2 MANHOUR UTILIZATION MEDICAL ACTIVITIES 145.3 HOURS 7.5 PERCENT SOLAR OBSERVATIONS 117.2 " 6.0 " EARTH RESOURCES 71.4 " 3.7 " OTHER EXPERIMENTS 65.4 " 3.4 " SLEEP, REST & OFF DUTY 675.6 " 34.7 " PRE/POST SLEEP & EATING 477.1 " 24.5 " HOUSEKEEPING 103.6 " 5.3 " PHYSICAL TRAINING & PERSONAL HYGIENE 56.2 " 2.9 " OTHER (EVA) ETC 232.5 " 12.0 " TOTAL: 1944.3 " 100 "References: 1 , 2 , 5 , 6 , 33 , 60 .