FAST
type: Concept
in scheme: platforms
definition: The Fast Auroral SnapshoT Explorer (FAST), the second mission in NASA's Small Explorer Satellite Program (SMEX), is a satellite designed to study Earth's aurora. This highly successful spacecraft has helped scientists answer fundamental questions about the causes and makeup of the aurora. FAST was launched on August 21, 1996 from a Pegasus rocket into a highly elliptical orbit. It crosses Earth's auroral zones (donut shaped regions centered on the poles) four times each orbit, and only collects high-resolution data ("snapshots") while in those zones. It ventures high into the charged particle environment of the aurora to measure the electric and magnetic fields, plasma waves, energetic electrons and ions, ion mass composition, and thermal plasma density and temperature. The FAST instrument set consists of sixteen electrostatic analyzers, four electric field langmuir probes suspended on 30 m wire booms, two electric field langmuir probes on 3 m extendible booms, searchcoil and fluxgate magnetometers and a time-of-flight mass spectrometer. The science investigation makes extremely temporal and spatial resolution measurements of the auroral plasma at apogee altitude. The instrument hardware consists of the sensor assemblies and an instrument data processor. The instrument electronics include a 32-bit data processing unit that performs the science data processing and recording in a one gigabit, solid-state memory. The stored data are transferred to the ground at one of three selectable high data rates of 900 Kbps, 1.5 Mbps or 2.25 Mbps. The instruments weigh 51 kg; the total observatory mass is 191 kg. The FAST mission is in a 351 x 4175 km orbit with an 83? inclination. The FAST observatory is a 12 rpm, spin-stabilized spacecraft with its spin axis oriented parallel to the orbit axis. Spin rate and spin-axis orientation are maintained by two magnetic torquer coils, one spinning Sun sensor, one horizon crossing indicator and a spacecraft magnetometer. The Attitude Contr…

Solar/Space Observation Satellites
type: Concept