TERRIERS
Tomographic Experiment using Radiative Recombinative Ionospheric EUV and Radio Sources
Part of the STEDI program

Using a combination of ground based and space instruments, TERRIERS surveys the upper asmosphere using a technique called tomography, measuring ultraviolet light emissions, to construct an image of Earth's ionosphere. While the ionosphere has been studied in detail in the past, there is currently no other means to obtain these types of global three dimensional maps of electron density. Such measurements are of crucial importance in understanding many upper atmosphere phenomena. As secondary goals, TERRIERS examines related upper atmospheric phenomena, and tests the utility of long term solar irradiance measurements.

Spacecraft
Spins at 3 rpm in "Thompson Spinner" configuration. Attitude and spin rate control with 3 magnetic torque coils. Attitude determination with sun sensors, magnetometers and horizon crossing indicators. Satellite uses 16W of orbit-averaged power and can downlink telemetry at 250 kbit/s in S-band. Spacecraft Bus is based on, though not an exact copy of AeroAstro's HETE design.

Payload
Primary payload is 5 imaging spectrometers, 4 of which operate in the night portion of the orbit. TERRIERS also carries 2 photomoters, and a Gas Ionization Solar Spectral MOnitor (GISSMO) which is an optics-free solar EUV spectrometer. Riding piggyback at the base of the spacecraft bus is a small payload built by Cleveland Heights High School.

Country of Origin	United States
Customer/User	Boston University Center for Space Physics
Manufacturer(s)	AeroAstro, LLC
Launch	Early 1998 on Pegasus XL
Orbit	550 km circular, sun synchronous (9am/9pm)
Design Life	1 year
Related Sites	Terriers Home Page