M-CUBED and EXPLORER-1 PRIME are two university CubeSats that became stuck to each other after deployment from their Delta II launch vehicle in October, 2011. It is believed that the strong permanent magnets used to stabilize M-CUBED caused it to become magnetically attached to EXPLORER-1 PRIME as the satellites drifted away from their launch vehicle.
M-Cubed
M-Cubed is a 1U CubeSat developed by the University of Michigan's Student Space Systems Fabrication Lab (S3FL). Development began in 2007. The name 'M-Cubed' is a shortening of Michigan Multipurpose Minisat.
It was launched from Vandenberg Air Force Base on the NASA's third Educational Launch of Nanosatellites (ELaNa) in October 2011 atop a Delta II rocket. This was a multi-payload mission with five other CubeSats, AubieSat-1, DICE-1, DICE-2, Explorer-1 Prime, and RAX-2.
The objective of MCubed was to obtain a mid resolution image to date of Earth with at least 60% land mass and a maximum of 20% cloud coverage from a single cubesat platform. S3FL is also developing the MCubed bus with the intention of making it a heritage design, thus allowing for future missions to be flown on the same bus.
Also on board is JPL's COVE (CubeSat On-board processing Validation Experiment) to demonstrate an on-board processing system to optimize the data processing and instrument design of a multi-angle SpectroPolarimetric Imager (MSPI) for the ACE Decadal Survey mission which will achieve a two-orders of magnitude reduction in data rate.
M-Cubed uses a passive Attitude control system consisting of a large permanent magnet that aligns the satellite with the Earth's magnetic field. On-board control is provided by a Taskit Stamp9G20 microcontroller running Real time Linux.
Explorer-1 Prime
EXPLORER-1 PRIME (E1P) is a Montana Space Grant Consortium Cubesat-class satellite in development by the Space Science and Engineering Laboratory (SSEL) at Montana State University.
Its mission was to detect the Van Allen radiation belts in honor of the 50th anniversary of Explorer-1, America's first satellite, that discovered the cloud of highly energetic electrons trapped in the Earth's magnetic field. 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 in 2006.
E1P carried a miniature Geiger tube donated by Dr. Van Allen, and intended to use it to measure the intensity and variability of these electrons in low earth orbit.
E1P also intended to demonstrate software technology developed at SSEL that used a popular chip radio to close a digital data link with standard ham radio hardware, allowing people around the world to contact the satellite and download science and housekeeping data.
As part of NASA's ELaNA program, E1P was to be launched along with NASA's Glory satellite, Kentucky Space's KySat-1, and the University of Colorado-Boulder's Hermes CubeSats. It was launched aboard a Taurus-XL rocket from Vandenberg Air Force Base, California on 4 March 2011 but failed to achieve orbit after the rocket malfunctioned (the payload fairing did not separate.)
There was a spare, Explorer-1 Prime Unit 2. This second flight model, E1P U2, was launched with NPP through the NASA Educational Launch of Nanosatellites (ELaNa) program in October 2011. After reaching successfully orbit, it was renamed HRBE (William A. Hiscock Radiation Belt Explorer).
However, shortly after its deployment from the launch vehicle, it became magnetically stuck to M-Cubed, as described previously.
Facts in Brief
Launch Date: 2011-10-28
Launch Vehicle: Delta II 7920
Launch Site: Vandenberg AFB, United States