FAST was designed to observe and measure rapidly varying electric and magnetic fields and the flow of electrons and ions above the aurora.

FAST would correlate measurements of electrical and magnetic fields from other sensors and simultaneously correlate these forces with their effects on electrons and ions at altitudes of 350 to 4200 km. These observations would be complemented by data from other spacecraft at higher altitudes, which would be observing fields and particles and photographing the aurora from above, thus placing FAST observations in global context. At the same time, auroral observatories and geomagnetic stations on the ground would provide measurements on how the energetic processes FAST observes affect the Earth. Although prepared for mid-1994 launch date, FAST was placed into storage until a series of problems with the Pegasus launch vehicle could be corrected. The vehicle was finally placed into orbit on 21 August 1996.

The spacecraft was spin stabilized (12 rpm), keeping the spin axis aligned with orbit-normal, and powered by body mounted GaAs solar cells. It has an aluminum structure and the control computer used dual 80C85 rad hard processors. An S-Band transponder was used for command and telemetry. Passive thermal control.

Payloads included:

• Electric Field Experiment, used 3 orthogonal boom pairs to measure plasma density and electron temperature.
• Magnetic Field Experiment, had 2 magnetometers 180 deg apart deployed on graphite booms.
• Time-of-Flight Energy Angle Mass Spectrograph (TEAMS), a mass-resolving spectrometer designed to measure 3-dimension distribution functions of major ion species.
• Sixteen Electrostatic Analyzers (ESA) were used for electron and ion measurements from 3 eV to 30 KeV.

Total mission cost was $ 60 million mission: $ 27 million for the satellite + $ 18 million for the instruments + $ 15 million for the launch.

Design Life: 1 year. Typical orbit: 350 x 4200 km, 83 deg inclination. Length: 1.80 m (5.90 ft). Maximum Diameter: 1.20 m (3.90 ft). Associated Launch Vehicle: Pegasus XL.

• 1996 August 21 - FAST - Program: Small Explorer. Launch Site: Point Arguello WADZ. Launch Vehicle: Pegasus. Perigee: 353 km (219 mi). Apogee: 4,163 km (2,586 mi). Inclination: 83.00 deg. Period: 132.70 min.

  Second Small Explorer mission.