Pegasus satellite program
Encyclopedia
Satellite
In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....
s launched in 1965 to study the frequency of micrometeorite impacts on spacecraft. All three Pegasus satellites were launched by Saturn I
Saturn I
The Saturn I was the United States' first heavy-lift dedicated space launcher, a rocket designed specifically to launch large payloads into low Earth orbit. Most of the rocket's power came from a clustered lower stage consisting of tanks taken from older rocket designs and strapped together to make...
rocket
Rocket
A rocket is a missile, spacecraft, aircraft or other vehicle which obtains thrust from a rocket engine. In all rockets, the exhaust is formed entirely from propellants carried within the rocket before use. Rocket engines work by action and reaction...
s, and remained connected with their upper stages.
The Pegasus satellite was named for the winged horse of Greek mythology
Pegasus
Pegasus is one of the best known fantastical as well as mythological creatures in Greek mythology. He is a winged divine horse, usually white in color. He was sired by Poseidon, in his role as horse-god, and foaled by the Gorgon Medusa. He was the brother of Chrysaor, born at a single birthing...
and was first lofted into space by a NASA Saturn I
Saturn I
The Saturn I was the United States' first heavy-lift dedicated space launcher, a rocket designed specifically to launch large payloads into low Earth orbit. Most of the rocket's power came from a clustered lower stage consisting of tanks taken from older rocket designs and strapped together to make...
rocket on February 16, 1965. Like its namesake, the Pegasus satellite was notable for its "wings", a pair of 96 feet (29.3 m)-long, 14 feet (4.3 m)-wide arrays of 104 panels fitted with sensors to detect punctures by micrometeoroids at high altitudes, in support of the Apollo Program to send manned lunar landing missions starting by 1970. Micrometeroids were believed to be potentially hazardous to the Apollo crew if they could puncture the spacecraft skin. The sensors successfully measured the frequency, size, direction and penetration of scores of micrometeoroid impacts. The satellite also carried sample protective shields mounted on the arrays.
The NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
Marshall Space Flight Center
Marshall Space Flight Center
The George C. Marshall Space Flight Center is the U.S. government's civilian rocketry and spacecraft propulsion research center. The largest center of NASA, MSFC's first mission was developing the Saturn launch vehicles for the Apollo moon program...
was responsible for the design, production and operation of the three Pegasus satellites which were launched by Saturn I rocket test flights in 1965. At launch, a boilerplate Apollo Command/Service Module
Apollo Command/Service Module
The Command/Service Module was one of two spacecraft, along with the Lunar Module, used for the United States Apollo program which landed astronauts on the Moon. It was built for NASA by North American Aviation...
and launch escape system
Launch escape system
A Launch Escape System is a top-mounted rocket connected to the crew module of a crewed spacecraft and used to quickly separate the crew module from the rest of the rocket in case of emergency. Since the escape rockets are above the crew module, an LES typically uses separate nozzles which are...
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 (29.3 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 2300 square feet (213.7 m²) of instrumented surface, with thickness varying up to 0.016 inch (0.4064 mm).
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 belt
Van Allen radiation belt
The Van Allen radiation belt is a torus of energetic charged particles around Earth, which is held in place by Earth's magnetic field. It is believed that most of the particles that form the belts come from solar wind, and other particles by cosmic rays. It is named after its discoverer, James...
s and other phenomena.
Orbits
- Pegasus 1Pegasus 1Pegasus 1 or I, known before launch as Pegasus A, was an American satellite which was launched in 1965 to study micrometeoroid impacts in Low Earth orbit. It was the first of three Pegasus satellites to be launched...
- Launched: 16 February 1965
- Launch vehicle: A-103
- Orbital inclination: 31.7 degrees.
- PerigeePerigeePerigee is the point at which an object makes its closest approach to the Earth.. Often the term is used in a broader sense to define the point in an orbit where the orbiting body is closest to the body it orbits. The opposite is the apogee, the farthest or highest point.The Greek prefix "peri"...
: 510 km - Apogee: 726 km
- Launch weight: 10.5 tons.
- Dry weight: 1451.5 kg
- Decayed: 17 September 1978
- International DesignatorInternational DesignatorThe International Designator, also known as COSPAR designation, and in the United States as NSSDC ID, is an international naming convention for satellites...
: 1965-009A
- Pegasus 2Pegasus 2Pegasus 2 or Pegasus II, known before launch as Pegasus B was an American satellite which was launched in 1965 to study micrometeoroid impacts in Low Earth orbit. It was the second of three Pegasus satellites to be launched, following the launch of Pegasus 1 three months earlier...
- Launched: 25 May 1965
- Launch vehicle: A-104
- Orbital inclination: 31.7 degrees.
- PerigeePerigeePerigee is the point at which an object makes its closest approach to the Earth.. Often the term is used in a broader sense to define the point in an orbit where the orbiting body is closest to the body it orbits. The opposite is the apogee, the farthest or highest point.The Greek prefix "peri"...
: 502 km - Apogee: 740 km
- Launch weight: 10.46 tons.
- Dry weight: 1451.5 kg
- Decayed: 3 November 1979
- International Designator: 1965-039A
- Pegasus 3Pegasus 3Pegasus 3 or III, also known as Pegasus C before launch, was an American satellite which was launched in 1965 to study micrometeoroid impacts in Low Earth orbit. It was the last of three Pegasus satellites to be launched, the previous two having been launched earlier the same year...
- Launched: 30 July 1965
- Launch vehicle: A-105
- Orbital inclination: 28.9 degrees.
- PerigeePerigeePerigee is the point at which an object makes its closest approach to the Earth.. Often the term is used in a broader sense to define the point in an orbit where the orbiting body is closest to the body it orbits. The opposite is the apogee, the farthest or highest point.The Greek prefix "peri"...
: 441 km - Apogee: 449 km
- Launch weight: 10.5 tons.
- Dry weight: 1451.5 kg
- Decayed: 4 August 1969
- International Designator: 1965-060A