The Injun program was a series of six satellites designed and built by researchers at the University of Iowa to observe various radiation and magnetic phenomena in the ionosphere and beyond.
The design specifics of the satellites had little in common, though all were solar-powered and the first five used magnetic stabilization to control spacecraft attitude. (The last in the series was spin-stabilized.) Instruments included particle detectors of varying types, magnetometers, and photometers for observing auroras. [1] The last three satellites were launched as part of the Explorer program of the NASA.
In spite of various hardware difficulties and the loss of Injun 2 due to an upper stage failure, the program was generally successful. In particular, they produced data on the Van Allen radiation belts including electrical convection in the magnetosphere, [2] and the radiation after effects of the Starfish Prime high-altitude nuclear test. [3]
Name | Also known as | Launched | Vehicle | Ceased operation | Notes | |
---|---|---|---|---|---|---|
Injun 1 | 29 June 1961 | Thor-Able | 6 March 1963 | Failed to separate from Solrad 3; still in orbit. [4] | ||
Injun 2 | 24 January 1962 | Thor-Able | Failed to orbit | Upper stage produced insufficient thrust. | ||
Injun 3 | 12 December 1962 | Thor-Agena | 25 August 1968 | Deorbited on 25 August 1968. | ||
Injun 4 | IE-B, Explorer 25 | 21 November 1964 | Scout X-4 | December 1966 | Still in orbit. [5] | |
Injun 5 | IE-C, Explorer 40 | 8 August 1968 | Scout X-4 | June 1971 | Still in orbit. [6] | |
Injun 6 | IE-D, Hawkeye, Neutral Point Explorer, Explorer 52 | 3 June 1974 | Scout X-4 | 28 April 1978 | Main article: Explorer 52 | |
Explorer 4 was an American satellite launched on 26 July 1958. It was instrumented by Dr. James van Allen's group. The Department of Defense's Advanced Research Projects Agency (ARPA) had initially planned two satellites for the purposes of studying the Van Allen radiation belts and the effects of nuclear explosions upon these belts, however Explorer 4 was the only such satellite launched as the other, Explorer 5, suffered launch failure.
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).
IMAGE was a NASA Medium Explorer mission that studied the global response of the Earth's magnetosphere to changes in the solar wind. It was believed lost but as of August 2018 might be recoverable. It was launched 25 March 2000, at 20:34:43.929 UTC, by a Delta II launch vehicle from Vandenberg Air Force Base on a two-year mission. Almost six years later, it unexpectedly ceased operations in December 2005 during its extended mission and was declared lost. The spacecraft was part of NASA's Sun-Earth Connections Program, and its data has been used in over 400 research articles published in peer-reviewed journals. It had special cameras that provided various breakthroughs in understanding the dynamics of plasma around the Earth. The principal investigator was Jim Burch of the Southwest Research Institute.
The Scout family of rockets were American launch vehicles designed to place small satellites into orbit around the Earth. The Scout multistage rocket was the first orbital launch vehicle to be entirely composed of solid fuel stages. It was also the only vehicle of that type until the successful launch of the Japanese Lambda 4S in 1970.
Explorer 52, also known as Hawkeye-1, Injun-F, Neutral Point Explorer, IE-D, Ionospheric Explorer-D, was a NASA satellite launched on June 3, 1974, from Vandenberg Air Force Base on a Scout E-1 launch vehicle.
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Dynamics Explorer was a NASA mission, launched on 3 August 1981, and terminated on 28 February 1991. It consisted of two unmanned 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.
The Magnetospheric Multiscale (MMS) Mission is a NASA robotic space mission to study the Earth's magnetosphere, using four identical spacecraft flying in a tetrahedral formation. The spacecraft were launched on 13 March 2015 at 02:44 UTC. The mission is designed to gather information about the microphysics of magnetic reconnection, energetic particle acceleration, and turbulence — processes that occur in many astrophysical plasmas. As of March 2020, the MMS spacecraft has enough fuel to remain operational until 2040.
Explorer 10 was a NASA satellite that investigated Earth's magnetic field and nearby plasma. Launched on 25 March 1961, it was an early mission in the Explorer program and was the first satellite to measure the "shock wave" generated by a solar flare.
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The ISEE-2 was an Explorer-class daughter spacecraft, International Sun-Earth Explorer-2, was part of the mother/daughter/heliocentric mission. ISEE-2 was a 165.78 kg (365.5 lb) space probe used to study magnetic fields near the Earth. ISEE-2 was a spin-stabilized spacecraft and based on the design of the prior IMP series of spacecraft. ISEE-1 and ISEE-2 were launched on 22 October 1977, and they re-entered on 26 September 1987.
ArgoMoon is a CubeSat that was launched into a heliocentric orbit on Artemis 1, the maiden flight of the Space Launch System, on 16 November 2022 at 06:47:44 UTC. The objective of the ArgoMoon spacecraft is to take detailed images of the Interim Cryogenic Propulsion Stage following Orion separation, an operation that will demonstrate the ability of a cubesat to conduct precise proximity maneuvers in deep space. ASI has not confirmed nor denied whether this took place, but several images of the Earth and the Moon were taken.
Explorer 12, also called EPE-A or Energetic Particles Explorer-A and as S3), was a NASA satellite built to measure the solar wind, cosmic rays, and the Earth's magnetic field. It was the first of the S-3 series of spacecraft, which also included Explorer 12, 14, 15, and 26. It was launched on 16 August 1961, aboard a Thor-Delta launch vehicle. It ceased transmitting on 6 December 1961 due to power failure.
Explorer 25, was a NASA magnetically aligned satellite launched simultaneously with Explorer 24 (AD-B) using a Scout X-4 launch vehicle. This was NASA's first dual-satellite launch. The satellite's primary mission was to make measurements of the influx of energetic particles into the atmosphere of Earth and to study atmospheric heating and the increase in scale height which have been correlated with geomagnetic activity. Studies of the natural and artificial trapped Van Allen radiation belts were also conducted. A biaxial fluxgate magnetometer was used to monitor the orientation of the spacecraft with respect to the local magnetic field.
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SOLRAD 3 was a solar X-ray satellite, the third in the SOLRAD program. Developed by the United States Navy's Naval Research Laboratory (USNRL), it shared satellite space with and provided cover for the Navy's GRAB 2, a secret electronic surveillance program.
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