Pegasus is an air-launched launch vehicle developed by Orbital Sciences Corporation (OSC) and now built and launched by Northrop Grumman. Pegasus is the world's first privately developed orbital launch vehicle. Capable of carrying small payloads of up to 443 kg (977 lb) into low Earth orbit, Pegasus first flew in 1990 and remains active as of 2021. The vehicle consists of three solid propellant stages and an optional monopropellant fourth stage. Pegasus is released from its carrier aircraft at approximately 12,000 m (39,000 ft), and its first stage has a wing and a tail to provide lift and altitude control while in the atmosphere. Notably, the first stage does not have a thrust vector control (TVC) system.
Vanguard 3 is a scientific satellite that was launched into Earth orbit by the Vanguard SLV-7 on 18 September 1959, the third successful Vanguard launch out of eleven attempts. Vanguard rocket: Vanguard Satellite Launch Vehicle-7 (SLV-7) was an unused Vanguard TV-4BU rocket, updated to the final production Satellite Launch Vehicle (SLV).
Explorer 6, or S-2, was a NASA satellite, launched on 7 August 1959, at 14:24:20 GMT. It was a small, spheroidal satellite designed to study trapped radiation of various energies, galactic cosmic rays, geomagnetism, radio propagation in the upper atmosphere, and the flux of micrometeorites. It also tested a scanning device designed for photographing the Earth's cloud cover. On 14 August 1959, Explorer 6 took the first photos of Earth from a satellite.
Explorer 7 was a NASA satellite launched on 13 October 1959, at 15:30:04 GMT, by a Juno II launch vehicle from Cape Canaveral Air Force Station (CCAFS) to an orbit of 573 × 1,073 km (356 × 667 mi) and inclination of 50.27°. It was designed to measure solar X-ray and Lyman-alpha flux, trapped energetic particles, and heavy primary cosmic rays. Secondary objectives included collecting data on micrometeoroid penetration, molecular sputtering and studying the Earth-atmosphere heat balance.
Explorer 32, also known as Atmosphere Explorer-B (AE-B), was a NASA satellite launched by the United States to study the Earth's upper atmosphere. It was launched from Cape Canaveral on a Delta C1 launch vehicle, on 25 May 1966. It was the second of five "Atmosphere Explorer", the first being Explorer 17. Though it was placed in a higher-than-expected orbit by a malfunctioning second stage on its launch vehicle, Explorer 32 returned data for ten months before failing due to a sudden depressurization. The satellite reentered the Earth's atmosphere on 22 February 1985.
Orbiting Vehicle or OV, originally designated SATAR, comprised five disparate series of standardized American satellites operated by the US Air Force, launched between 1965 and 1971. Forty seven satellites were built, of which forty three were launched and thirty seven reached orbit. With the exception of the OV3 series and OV4-3, they were launched as secondary payloads, using excess space on other missions. This resulted in extremely low launch costs and short proposal-to-orbit times. Typically, OV satellites carried scientific and/or technological experiments, 184 being successfully orbited through the lifespan of the program.
Explorer 9, known as S-56A before launch, was a NASA satellite which was launched in February 1961 to study the density and composition of the upper thermosphere and lower exosphere. It was a reflight of the failed Explorer S-56 mission, and consisted of a 7 kg (15 lb), 3.66 m (12.0 ft) balloon which was deployed into a medium Earth orbit. The mission was conducted by NASA's Langley Research Center.
Vanguard SLV-5, also called Vanguard Satellite Launch Vehicle-Five hoped to be the third successful flight of the American Vanguard rocket following the successful Vanguard 2 satellite on rocket Vanguard SLV-4.
Explorer S-56 was a NASA satellite launched on 4 December 1960, at 21:14 GMT as part of the Explorer program. The satellite was composed of a 3.66 m (12.0 ft) diameter inflatable sphere, and was intended to study the density of the upper atmosphere. The Scout X-1 rocket used to launch Explorer S-56 failed in flight, and the satellite never reached orbit.
Explorer 19,, was a NASA satellite launched on 19 December 1963, as part of the Explorer program. It was the third of six identical Explorer satellites launched to study air density and composition, and the second to reach orbit. It was identical to Explorer 9.
Explorer 27 was a small NASA satellite, launched in 1965, designed to conduct scientific research in the ionosphere. It was powered by 4 solar panels. One goal of the mission was to study in detail the shape of the Earth by way of investigating variations in its gravitational field. It was the third and last of the Beacons in the Explorers program. The satellite was shut off in July 1973 so that its transmission band could be used by higher-priority spacecraft.
Explorer S-1, also known as NASA S-1 or Explorer 7X, was a NASA Earth science satellite equipped with a suite of scientific instruments to study the environment around the Earth. The spacecraft and its Juno II launch vehicle were destroyed five seconds after launch on 16 July 1959, in a spectacular launch failure caused by complications with the launch vehicle's power supply. A relaunch of the mission in October 1959, Explorer 7 (S-1A), was successful.
Explorer 20, also known Ionosphere Explorer-A, IE-A, S-48, TOPSI and Topside Explorer, was a NASA satellite launched as part of Explorer program. Its purpose was two-fold: long-term investigation of the ionosphere from above, and in situ investigation of ion concentrations and temperatures.
Explorer 22 was a small NASA ionospheric research satellite launched 9 October 1964, part of NASA's Explorer Program. It was instrumented with an electrostatic probe, four radio beacons for ionospheric research, a passive laser tracking reflector, and two radio beacons for Doppler navigation experiments. Its objective was to provide enhanced geodetic measurements of the Earth as well as data on the total electron content in the Earth's atmosphere and in the satellite's immediate vicinity.
Explorer 29, also called GEOS 1 or GEOS A, acronym to Geodetic Earth Orbiting Satellite, was a NASA satellite launched as part of the Explorer program, being the first of the two satellites GEOS. Explorer 29 was launched on 6 November 1965 from Cape Canaveral, Florida, with a Thor-Delta E launch vehicle.
Explorer 31, also called DME-A, was a NASA satellite launched as part of the Explorer program. Explorer 31 was launched on 29 November 1965 from Vandenberg Air Force Base, California, with a Thor-Agena launch vehicle. Explorer 31 was released along with the Canadian satellite Alouette 2.
Explorer 36 was a NASA satellite launched as part of the Explorer program, being the second of the two satellites GEOS. Explorer 36 was launched on 11 January 1968 from Vandenberg Air Force Base, with Thor-Delta E1 launch vehicle.
Orbiting Vehicle 2-5, the third and last satellite of the second series of the United States Air Force's Orbiting Vehicle program, was an American particle science and ionosphere research satellite. Launched 26 September 1968 along with three other satellites, OV2-5 became the first scientific satellite to operate at geosynchronous altitude.
Orbiting Vehicle 3-2, launched 28 October 1966, was the fourth satellite to be launched in the OV3 series of the United States Air Force's Orbiting Vehicle program. The satellite measured charged particles in orbit, mapping irregularities in the ionosphere, particularly the auroral zone. OV3-2 reentered the Earth's atmosphere on 29 September 1971.
Dynamics Explorer 2 was a NASA low-altitude mission, launched on 3 August 1981. It consisted of two satellites, DE-1 and DE-2, whose purpose was to investigate the interactions between plasmas in the magnetosphere and those in the ionosphere. The two satellites were launched together into polar coplanar orbits, which allowed them to simultaneously observe the upper and lower parts of the atmosphere.
