Explorer 25

Explorer 25
Explorer 25 (Injun 4) satellite
NamesInjun 4
IE-B
Ionospheric Explorer-B
Explorer XXV
Mission typeIonospheric research
OperatorNASA
COSPAR ID1964-076B Edit this at Wikidata
SATCAT no.00932
Mission duration20 months (planned)
60 years
(in orbit)
Spacecraft properties
SpacecraftExplorer XXV
Spacecraft typeExplorer
BusInjun
ManufacturerUniversity of Iowa
Launch mass40 kg (88 lb)
PowerSolar cells and
rechargeable batteries
Start of mission
Launch date21 November 1964,
17:09:39 GMT
RocketScout X-4 (S-135R)
Launch siteVandenberg, PALC-D
ContractorVought
Entered service21 November 1964
End of mission
Last contactDecember 1966
Orbital parameters
Reference systemGeocentric orbit[1]
RegimeLow Earth orbit
Perigee altitude522 km (324 mi)
Apogee altitude2,494 km (1,550 mi)
Inclination81.40°
Period116.30 minutes
Instruments
Cadmium Sulfide Detectors
Geiger–Müller Counter
Plastic Scintillator Particle Detectors
Solid-State Detector
Spherical Retarding Potential Analyzer
Explorer program

Explorer 25 (or Injun 4), was a NASA magnetically aligned satellite launched simultaneously with Explorer 24 (AD-B) (Air Density experiment) 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.[2]

  1. ^ "Trajectory: Explorer 25 (Injun 4) 1964-076B". NASA. 28 October 2021. Retrieved 8 November 2021. Public Domain This article incorporates text from this source, which is in the public domain.
  2. ^ "Display: Explorer 25 (Injun 4) 1964-076B". NASA. 28 October 2021. Retrieved 8 November 2021. Public Domain This article incorporates text from this source, which is in the public domain.