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FAST mission graphic

Fast Auroral Snapshot Explorer

Phase: Past

Launch Date: August 21, 1996

Program(s):Explorers, Heliophysics Explorers, Heliophysics Research

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Fast Auroral Snapshot Explorer (FAST) is the second of the Small-Class Explorer (SMEX) missions. It will investigate the plasma physics of the auroral phenomena which occur around both poles of the Earth. This will be accomplished by taking high data rate snapshots with electric and magnetic fields sensors, and plasma particle instruments, while traversing through the auroral regions.


The FAST satellite is a highly sophisticated scientific satellite designed to carry out in situ measurements of acceleration physics and related plasma processes associated with the Earth's aurora.  Initiated and conceptualized by scientists at the University of California at Berkeley, is designed to carry out small, highly focused, scientific investigations. FAST's primary objective is to study the microphysics of space plasma and the accelerated particles that cause the aurora.


FAST was launched on August 21, 1996 into a high inclination (83o) elliptical orbit with apogee and perigee altitudes of 4175 km and 350 km, respectively.  The spacecraft design was tailored to take high-resolution data samples (or "snapshots") only while it crosses the auroral zones, which are latitudinally narrow sectors that encircle the polar regions of the Earth.  


The scientific instruments include energetic electron and ion electrostatic analyzers, an energetic ion instrument that distinguishes ion mass, and vector DC and wave electric and magnetic field instruments.  A state-of-the-art flight computer (or instrument data processing unit) includes programmable processors that trigger the burst data collection when interesting physical phenomena are encountered and stores these data in a 1 Gbit solid-state memory for telemetry to the Earth at later times.  


The spacecraft incorporates a light, efficient, and highly innovative design, which blends proven sub-system concepts with the overall scientific instrument and mission requirements.  The result is a new breed of space physics mission that gathers unprecedented fields and particles observations that are continuous and uninterrupted by spin effects.  In this and other ways, the FAST mission represents a dramatic advance over previous auroral satellites.  


The measurements made by FAST will address a broad range of scientific objectives in such areas as:


•    Electron and ion acceleration by parallel E-fields

•    Wave heating of ions-ion conics

•    Electrostatic double layers

•    Field-aligned currents

•    Kilometric radiation

•    General wave/particle interactions


The NASA/Goddard supplied FAST spacecraft is a 12 rpm classical spinner that will keep its spin axis continually aligned with the orbit-normal vector. Orbit altitude will be approximately 350 km x 4200 km at an inclination of 83 degrees.