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MEPSI was a pair of picosatellites connected by a tether which was deployed by the STS-113 shuttle flight. The purpose of MEPSI was to demonstrate the integration of Microelectromechanical Systems (MEMS) subsystems as a means of enabling new technology, low-power, autonomous on-board systems for critical satellites operations. Such a system is anticipated to incoporate imaging and other sensor capabilities that will allow for "ride-along" spacecraft that can be released on command to inspect parent spacecraft. The principal components aboard this flight were inertial measurement units comprised of MEMS angular rate sensors and accelerometers.

The satellites were released on 12 December 2002 at 22:05 UT.

MEPSI was comprised of a launcher, or garage, which housed the two small deployable satellites. Each picosatellite was identical in mass and were attached by a 15.2-m tether. The satellites were roughly cubic in shape, measuring roughly 10 cm x 10 cm x 12.5 cm. Each carried a cold gas propulsion system consisting of 5 thrusters of 0.1 N thrust. After release, the satellites operated on battery power for three days conducting a variety of tests of their systems.

The satellites were manufactured for DARPA by the Aerospace Corporation at a cost of $152k.

Alternate Names

  • 27562
  • Microelectromechanical System Based Picosatellite Inspector

Facts in Brief

Launch Date: 2002-11-24
Launch Vehicle: Shuttle
Launch Site: Cape Canaveral, United States
Mass: 2 kg

Funding Agency

  • Defense Advanced Research Projects Agency (United States)


  • Engineering

Additional Information

Questions and comments about this spacecraft can be directed to: Coordinated Request and User Support Office


Related Information/Data at NSSDCA

STS 113

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