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Explorer 33 (also known as AIMP-D, IMP-D, AIMP 1, Anchored IMP 1, Interplanetary Monitoring Platform-D) was a spacecraft in the Explorer program launched by NASA on July 1, 1966 on a mission of scientific exploration.

Explorer 33
IMP-D.jpg
Mission typeMagnetospheric research
OperatorNASA
COSPAR ID1966-058A
SATCAT no.2258
Mission duration1,876 days (5 years, 1 month and 21 days)
Spacecraft properties
ManufacturerGoddard Space Flight Center
Launch mass212.0 kilograms (467.4 lb)
Start of mission
Launch dateJuly 1, 1966, 16:02:25 (1966-07-01UTC16:02:25Z) UTC
RocketDelta E1
Launch siteCape Canaveral LC-17A
End of mission
Last contactSeptember 21, 1971 (1971-09-22)
Orbital parameters
Reference systemGeocentric
RegimeHigh Earth
Eccentricity0.2832989990711212
Perigee altitude265,689 kilometers (165,091 mi)
Apogee altitude480,762 kilometers (298,732 mi)
Inclination24.399999618530273°
Period38792.0 minutes
RAAN173.5399 degrees
Argument of perigee119.2000 degrees
Mean anomaly21.7899 degrees
Mean motion0.03712071
Epoch12 May 1971, 12:00:00 UTC
Revolution no.142
 

OrbitEdit

Originally intended for a lunar orbit, mission controllers worried that the spacecraft's trajectory was too fast to guarantee lunar capture.[1] Consequently, mission managers opted for a backup plan of placing the craft into an eccentric Earth orbit with a perigee of 265,679 km and an apogee of 480,762 km — still reaching distances beyond the Moon's orbit.[2]

Despite not attaining the intended lunar orbit, the mission met many of its original goals in exploring solar wind, interplanetary plasma, and solar X-rays.[3] Principal investigator James Van Allen used electron and proton detectors aboard the spacecraft to investigate charged particle and X-ray activity.[4] Astrophysicists N. U. Crooker, Joan Feynman, and J. T. Gosling used data from Explorer 33 to establish relationships between the Earth's magnetic field and the solar wind speed near Earth.[5]

See alsoEdit

ReferencesEdit

  1. ^ J. J. Madden (December 1966). "Interim Flight Report, Anchored Interplanetary Monitoring Platform, AIMP I - Explorer XXXIII" (PDF). NASA Goddard Space Flight Center.
  2. ^ "IMP Chronology". Encyclopedia Astronautica. Archived from the original on January 16, 2010.
  3. ^ "Explorer 33 (NSSDC ID: 1966-058A)". NASA / National Space Science Data Center. April 2, 2008. Retrieved July 4, 2008.
  4. ^ "Explorer 33 – Electron and Proton Detectors". NASA / National Space Science Data Center. April 2, 2008. Retrieved July 4, 2008.
  5. ^ Crooker, N. U.; Feynman, J.; Gosling, J. T. (May 1, 1977). "On the high correlation between long-term averages of solar wind speed and geomagnetic activity". NASA. Retrieved July 4, 2008.

External linksEdit