Explorer-1 Prime

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Explorer-1 Prime
Mission type Radiation research
Operator Space Science and Engineering Laboratory, Montana State University - Bozeman
Mission duration Failed to orbit
Spacecraft properties
Bus 1U CubeSat
Start of mission
Launch date 4 March 2011, 10:06 (2011-03-04UTC10:06Z) UTC
Rocket Taurus-XL
Launch site Vandenberg LC-576E
Orbital parameters
Reference system Geocentric
Regime Low Earth
Epoch Planned

Explorer-1 [Prime], also known as E1P and Electra,[1] was a CubeSat-class picosatellite built by the Space Science and Engineering Laboratory (SSEL)[2] at Montana State University. It was launched aboard a Taurus-XL rocket from Vandenberg Air Force Base, California on 4 March 2011,[3] but failed to achieve orbit after the rocket malfunctioned.

As part of NASA's ELaNA[4] program, E1P was to be launched along with NASA's Glory satellite,[5] Kentucky Space's KySat-1 and the University of Colorado-Boulder's Hermes CubeSats.[6]

E1P was a reflight mission of Explorer 1, the first American satellite, using modern technology including a geiger tube donated by James Van Allen. The name of the satellite was also adopted from Van Allen, who referred to the satellite as Explorer-1 Prime prior to his death in 2006.

It was originally intended to be launched in 2008 to commemorate the 50th anniversary of the launch of Explorer 1. If it had been successful, E1P would have been Montana's first successful launch of a satellite after the loss of SSEL's MEROPE[7] in 2006.[1]

There was a spare, Explorer-1 Prime Unit 2,[8] that was launched with NPP.[9]

The Michigan Exploration Laboratory (MXL) suspects that the M-Cubed CubeSat, a joint project run by MXL and JPL, became magnetically conjoined to Explorer-1 Prime, a second CubeSat released at the same time, via strong onboard magnets used for passive attitude control (see: Magnetorquer), after deploying on October 28, 2011. This is the first non-destructive latching of two satellites.

See also[edit]


  1. ^ a b Byers, Celena. "Explorer-1 [Prime]: A Re-flight of the Explorer-1 Science Mission" (PDF). Montana State University. Archived from the original (PDF) on 2009-02-24. Retrieved 2008-11-16. 
  2. ^ SSEL. "Explorer-1 PRIME". Archived from the original on 2010-07-07. Retrieved 2010-07-07. 
  3. ^ Schwartz, Patrick C. "Launches". Mission Set Database. NASA GSFC. Archived from the original on 2009-03-20. Retrieved 2010-07-07. 
  4. ^ Trinidad, Katherine (2010-01-26). "NASA Cues Up University CubeSats for Glory Launch This Fall". NASA. Retrieved 2010-07-07. 
  5. ^ "Glory". Gunter's Space Page. Retrieved 2009-08-08. 
  6. ^ Jacobs, Danny (2008-09-26). "We get press-release". Montana State University. Archived from the original on 2010-04-05. Retrieved 2008-11-16. 
  7. ^ Hiscock, Bill (2006-07-27). "Crash of Russian rocket destroys Montana's first satellite". Montana State University. Retrieved 2010-07-07. 
  8. ^ "Archived copy". Archived from the original on 2014-01-10. Retrieved 2012-08-27. 
  9. ^ "Archived copy". Archived from the original on 2011-11-09. Retrieved 2011-11-26.