Ball Aerospace's RS-300 was a small, low-cost spacecraft aimed at cost-capped principle investigator led missions for Earth or space science.

The low-risk spacecraft bus offered high performance in Earth or stellar pointing knowledge and control; data storage and transmission rates; available power; and payload mass fraction and volume. It was intended to fit on a Pegasus launch vehicle. The RS-300 design included Advanced Spacecraft Electronics (ASPEN) flight avionics developed for the Deep Impact comet impactor for the Jet Propulsion Laboratory (JPL).

The spacecraft also featured National Aeronautics and Space Administration (NASA) standard radio, and command and control data formats and interfaces to simplify operations and ground segment interfaces. The RS-300 provided 3-axis fine control and large, clear instrument fields of view. Its industry standard, single-board computer and non-volatile memory were complemented by custom electronics for communications interfaces, thermal control, sensor and actuator interfaces, and power control - all on a standard high speed backplane.

RS-300 avionics and software formed the core of the Orbital Express Advanced Technology Demonstration program, and the Widefield Infrared Survey Explorer (WISE).

Mass: 150 kg (330 lb).

• 2007 March 9 - NextSat - Launch Site: Cape Canaveral. Launch Vehicle: Atlas V. Mass: 250 kg (550 lb). Perigee: 491 km (305 mi). Apogee: 498 km (309 mi). Inclination: 46.00 deg. Period: 94.50 min.

  The passive satellite portion of DARPA's Orbital Express satellite servicing experiment. NextSat carried hydrazine for fluid transfer experiments, but no propulsion system. Attitude was controlled by momentum wheels supplemented by magnetic torquer rods.

• 2007 April 25 - AIM - Launch Site: Point Arguello WADZ. Launch Vehicle: Pegasus. Mass: 150 kg (330 lb). Perigee: 584 km (362 mi). Apogee: 602 km (374 mi). Inclination: 97.80 deg. Period: 96.50 min.

  NASA Small Explorer mission, for Aeronomy of Ice in the Mesosphere. AIM carried three scientific instruments to study polar mesospheric clouds: a solar occultation camera, an ultraviolet imager, and a cosmic dust experiment.