Explorer 28

Explorer 28
Explorer 28 satellite
NamesIMP-C
IMP-3
Interplanetary Monitoring Platform-3
Mission typeSpace physics
OperatorNASA
COSPAR ID1965-042A Edit this at Wikidata
SATCAT no.01388
Mission duration2 years (achieved)
Spacecraft properties
SpacecraftExplorer XXVIII
Spacecraft typeInterplanetary Monitoring Platform
BusIMP
ManufacturerGoddard Space Flight Center
Launch mass128 kg (282 lb)
Dimensions71 × 20.3 cm (28.0 × 8.0 in)
Power4 deployable solar arrays and batteries
Start of mission
Launch date29 May 1965, 12:00:00 GMT
RocketThor-Delta C (Thor 441 / Delta 031)
Launch siteCape Canaveral, LC-17B
ContractorDouglas Aircraft Company
Entered service29 May 1965
End of mission
Last contact12 May 1967
Decay date4 July 1968 [1]
Orbital parameters
Reference systemGeocentric orbit[2]
RegimeLow Earth orbit
Perigee altitude32,290 km (20,060 mi)
Apogee altitude227,456 km (141,335 mi)
Inclination53.60°
Period8341.90 minutes
Instruments
Cosmic-Ray Range versus Energy Loss
Cosmic Rays
Fluxgate Magnetometer
Ion Chamber and Geiger–Müller Counters
Langmuir probe
Plasma and Faraday Cup
Retarding Potential Analyzer
← IMP-B
IMP-D →

Explorer 28, also called IMP-C, IMP-3 and Interplanetary Monitoring Platform-3, was a NASA satellite launched on 29 May 1965 to study space physics, and was the third spacecraft launched in the Interplanetary Monitoring Platform program. It was powered by chemical batteries and solar panels. There were 7 experiments on board, all devoted to particle studies. Performance was normal until late April 1967, when intermittent problems began. It stayed in contact until 12 May 1967, when contact was lost. The orbit decayed until it re-entered the atmosphere on 4 July 1968.[1] The spacecraft design was similar to its predecessors Explorer 18 (IMP-A), launched in November 1963, and Explorer 21 (IMP-B), launched in October 1964, though this satellite was a few kilograms lighter. The successor Explorer 33 (IMP-D) began the use of a new design.[3]

  1. ^ a b "Display: Explorer 28 (IMP 3) 1965-042A". NASA. 28 October 2021. Retrieved 8 November 2021. Public Domain This article incorporates text from this source, which is in the public domain.
  2. ^ "Trajectory: Explorer 28 (IMP 3) 1965-042A". NASA. 28 October 2021. Retrieved 8 November 2021. Public Domain This article incorporates text from this source, which is in the public domain.
  3. ^ "Explorer-series reference images". Retrieved 4 July 2021.