The Orbital Sciences' PegaStar platform, which was originally developed for the APEX mission, is a Pegasus or Taurus class low earth orbit satellite platform designed to accommodate payloads up to 570 kg and 60 W.  The APEX spacecraft operated for 28 months, far in excess of its 12 month mission requirement.  Since then the PegaStar has been adapted to host the SeaWiFS/Orbview-2 mission, which was launched in August 1997.

The PegaStar is a flexible platform designed for a 3 to 5 year on-orbit lifetime.   The satellite bus uses an aluminum honeycomb hexagonal satellite structure that is mated to a separate payload module located on top of the bus, offering the payload an unrestricted field of view and a simple interface to improve integration.  According to Orbital, the attitude control system can be reconfigured to support inertial sun-pointed (APEX satellite), nadir ground track (Orbview-2 satellite) or target tracking missions.  Orbital Sciences offers the PegaStar spacecraft by itself, as an integrated satellite, or as a complete "turn-key service".