Fast Auroral SnapshoT Explorer
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Launch and Orbit

On August 21, 1996, FAST was launched by a Pegasus-XL rocket into a highly elliptical, 4175 km by 350 km orbit. Its orbital period is 133 minutes, and it crosses the auroral zones four times per orbit. FAST's launch date was selected so that it would be positioned best for the northern hemisphere winter, to coordinate with ground-based observations and the Polar satellite.

FAST's orbit takes it high into the atmosphere to study a region of critical importance to understanding the aurora. The light from the visible aurora is generated in the lower part of the upper atmosphere (100-200 km), but the particles that create this effect are accelerated much higher (2000 - 10,000 km). FAST reached an apogee of 4175 km.

FAST stores its data in solid-state memory until it is appropriately positioned over a ground station, at which point it telemeters the data down to earth. Downlinks can range from 0.9 to 2.25 Mbps, for an average volume of 4-5 Gbytes per day (during campaigns) to 1-3 Gbytes per day.

"Campaigns" are a key part of the FAST mission. During these investigations, FAST observations are coordinated with those from ground-based equipment, other spacecraft, or airplanes. (Please see Conjunctive Studies.) While participating in campaigns, FAST telemeters its high resolution data to the ground on every orbit.

FAST operations are carried out at UC Berkeley's Mission & Science Operations Center. The MSOC archives FAST data online and provides software for its analysis. (For more information, please see Science Operations.) Data is also sent to National Space Science Data Center.