The FAST (Fast Auroral Snapshot Explorer) was successfully launched on
1996-08-21 into its intended orbit. FAST investigates the plasma physics of auroral
phenomena at extremely high time and spatial resolution using the full complement of
particle and fields instruments. FAST is the second spacecraft in the Small Explorer
(SMEX) program at NASA-GSFC.
In order to capture the auroral phenomena over small time (microseconds) and spatial
scales, FAST utilizes high speed data sampling, a large, fast-loading ("burst")
memory, and a smart, on-board software to trigger on the appearance of various key
phenomena. Using a 1 Gb solid-state memory and a data acquisition rate of 8 Mbs (almost
two orders of magnitude faster than previous satellites), FAST produces high-resolution
"snapshots" of auroral arcs and other interesting auroral events.
FAST flies in a highly eccentric, near-polar orbit. The orbit processes nominally one
degree per day throughout the planned mission duration of one year. Scientific
investigations will operate in a campaign mode (about 60 days long) as apogee transitions
through the northern auroral zone and in less intense survey mode during the rest of the
orbit.
The FAST mission uses a unique, lightweight, orbit-normal spinner spacecraft developed
by the SMEX project. The spacecraft has body-mounted solar arrays, and is spin-stabilized,
rotating at 12 rpm with the spin axis normal to the orbit plane ("cartwheel").
FAST (Fast Auroral Snapshot Explorer) features four experiments to analyze the changing
electric and magnetic fields, and the flow of electrons and ions above the aurora:
- Electric Field Experiment (Langmuir probes),
- Magnetic Field Experiment (searchcoil and fluxgate magnetometers),
- Time-of-Flight Energy Angle Mass Spectrograph (TEAMS),
- 16 Electrostatic Analyzers [ESA].
