International Sun-Earth Explorer 1
NamesExplorer 56, ISEE-1
Mission typestudy Earth's magnetic field and the solar wind
COSPAR ID1977-102A
SATCAT no.10422
Spacecraft properties
Launch mass340 kg (750 lb)
Start of mission
Launch date13:53, October 22, 1977 (UTC) (1977-10-22T13:53Z)
Launch siteCape Canaveral LC-17B
End of mission
Decay dateSeptember 26, 1987 (1987-09-26)
Orbital parameters
Reference systemGeocentric
Perigee altitude763 kilometers (474 mi)
Apogee altitude137,531 kilometers (85,458 mi)
Period3556.8 min
EpochOctober 22, 1977

The International Sun-Earth Explorer 1 (ISEE-1, or Explorer 56) was a 340-kg space probe used to study magnetic fields near the Earth.[1] ISEE-1 was a spin-stabilized spacecraft and based on the design of the prior IMP (Interplanetary Monitoring Platform) series of spacecraft.[1] ISEE-1 and ISEE-2 were launched on October 22, 1977, and they re-entered on September 26, 1987.[2]


International Sun Earth Explorers Orbits

The space probe was part of a program consisting of three spacecraft: a mother/daughter pair (ISEE-1 and ISEE-2) and the ISEE-3 spacecraft (later renamed to International Cometary Explorer). The program was a cooperative mission between NASA and ESRO (later ESA) designed to study the interaction between the Earth's magnetic field and the solar wind. At least 32 institutions were involved, and the focus was on understanding magnetic fields.[1] ISEE-1 (a.k.a. Explorer 56) and ISEE-3 were built by NASA, while ISEE-2 was built by ESA. All three had complementary instruments supported by the same group of over 100 scientists.[1]


ISEE-1 and ISEE-2 remained near the Earth. ISEE-3 was the first spacecraft to be placed in a halo orbit at the Earth-Sun Lagrangian points L1 and it was later launched into a heliocentric orbit.[1]

See also


  1. ^ a b c d e "ISEE - eoPortal Directory - Satellite Missions". Retrieved 2014-03-12.
  2. ^ "NASA - NSSDC - Spacecraft - Details". Retrieved 2014-03-12.