Pegasus Satellite was Lofted into Space in 1965
Marshall Space Flight Center Historian
The history of the Marshall Space Flight Center
in the 1960s is clearly associated with building the Saturn V
moon rocket. Less well-known, however, is the Center's early work
in designing scientific payloads.
The Pegasus satellite was named for the winged
horse of Greek mythology and was lofted into space by a Marshall-built
Saturn I rocket on Feb.16, 1965. Like its namesake, the Pegasus
I satellite was notable for its wings; however, the 96-foot-long,
14-foot-wide wings were not for flying. They carried 208 panels
to report punctures by potentially hazardous micrometeoroids at
high altitudes where the manned 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 Marshall Center was responsible for the design, production
and operation of Pegasus I and two additional Pegasus satellites
which were also launched by Saturn I rockets in 1965. At launch,
an Apollo command and service module boilerplate and launch escape
system tower were atop the Saturn 1, with Pegasus I 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. Pegasus I 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 of instrumented
surface, with thickness varying up to 16/1000 of an inch.
Ernst Stuhlinger, then director of the Center's 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 belts and other phenomena.