Pegasus (satellite)

Pegasus Satellite

File:Pegasus deployment.png

Deployment of an Pegasus Satellite

The Pegasus satellite program was a series of three satellites, which were launched in 1965 to study the frequency of micrometeorite impacts. All three Pegasus satellites were launched by Saturn I rockets, and remained connected with the upper stage.

It was named for the winged horse of Greek mythology and was first lofted into space by a NASA Saturn I rocket on Feb. 16, 1965. Like their namesake, the Pegasus satellites were notable for their wings; however, these 96-foot (29 m)-long, 14-foot (4.3 m)-wide wings were not for flying. They carried 208 panels to report punctures by potentially hazardous micrometeoroids at high altitudes where the manned Project Apollo missions would orbit. Spacecraft designers were keenly interested in the information because the Apollo spacecraft and crew were in jeopardy if tiny particles could puncture a spacecraft skin.

Micrometeoroid detectors and sample protective shields were mounted on the satellite's wing-like solar cell arrays. The sensors successfully measured the frequency, size, direction and penetration of scores of micrometeoroid impacts.

The NASA Marshall Space Flight Center was responsible for the design, production and operation of Pegasus I and two additional Pegasus satellites which were also launched by Saturn I rocket test flights in 1965. At launch, an Apollo command and service module boilerplate and launch escape system tower were atop the Saturn I, with the Pegasus experiment folded inside the service module. After first stage separation and second-stage ignition, the launch escape system was jettisoned. When the second stage attained orbit, the 10,000-pound Apollo boilerplate command and service modules were jettisoned into a separate orbit. Then a motor driven device extended the winglike panels on the Pegasus to a span of 96 feet (29 m). The Pegasus wings remained attached to the Saturn I's second stage as planned.

A television camera, mounted on the interior of the service module adapter, provided pictures of the satellite deploying in space and as one historian has written, "captured a vision of the eerie silent wings of Pegasus I as they haltingly deployed." The satellite exposed more than 2,300 square feet (210 m²) of instrumented surface, with thickness varying up to 16/1000 of an inch.

Ernst Stuhlinger, then director of the MSFC Research Projects Laboratory, noted that all three Pegasus missions provided more than data on micrometeoroid penetration. Scientists also were able to gather data regarding gyroscopic motion and orbital characteristics of rigid bodies in space, lifetimes of electronic components in the space environment, and thermal control systems and the degrading effects of space on thermal control coatings. Space historian Roger Bilstein reported that for physicists the Pegasus missions provided additional knowledge about the radiation environments of space, the Van Allen radiation belts and other phenomena.

Orbits

• Pegasus 1
  • Launched: 16 February 1965
  • Launch vehicle: A-103
  • Orbital inclination: 31.7 degrees.
  • Perigee: 510 km
  • Apogee: 726 km
  • Launch weight: 10.5 tons.
  • Dry weight: 1451.5 kg
  • Decayed: 17 September 1978
  • International Designator: 1965-009A

• Pegasus 2
  • Launched: 25 May 1965
  • Launch vehicle: A-104
  • Orbital inclination: 31.7 degrees.
  • Perigee: 502 km
  • Apogee: 740 km
  • Launch weight: 10.46 tons.
  • Dry weight: 1451.5 kg
  • Decayed: 03 November 1979
  • International Designator: 1965-039A

• Pegasus 3
  • Launched: 30 July 1965
  • Launch vehicle: A-105
  • Orbital inclination: 28.9 degrees.
  • Perigee: 441 km
  • Apogee: 449 km
  • Launch weight: 10.5 tons.
  • Dry weight: 1451.5 kg
  • Decayed: 4 August 1969
  • International Designator: 1965-060A

External links

• Encyclopedia Astronautica entry