The Synchronized Position Hold, Engage, Reorient Experimental
Satellites ) experiment is a testbed consisting of three 8-inch
diameter miniaturized satellites that can operate in a variety
of environments, including inside the International Space
Station (ISS). The MIT Space Systems Laboratory developed the
experiment to provide the Air Force with a long term,
replenishable, and upgradable testbed for formation flight. It
will be used to validate high risk control, metrology , and
autonomy technologies. The technologies are critical to the
operation of distributed satellite and docking missions such as
TechSat21, Starlight , Terrestrial Planet Finder , and Orbital
Express . The SPHERES concept was inspired by the Training
Remotes from Star Wars To approximate the dynamics presented by
these missions, the testbed consists of three miniaturized
satellites, microsatellites or "spheres," which can control
their relative positions and orientations, and is operable on a
2-D laboratory platform, NASA's KC-135, and t