Miniature Sensor Technology Integration-3

Spacecraft

The MSTI-3 spacecraft was 56 inches tall and 32 inches in diameter, weighing 466 pounds with its propellant. Power came from a single three-sided gallium arsenide solar panel attached to one side, which delivered an average of 291 watts at launch and 225 watts by the end of its mission. Three reaction wheels controlled the satellite's orientation, and hydrazine thrusters handled larger maneuvers and momentum adjustments. A GPS receiver improved its orbital tracking.

The satellite carried three instruments sharing one telescope: a Short Wavelength Infrared Camera, a Medium Wavelength Infrared Camera, and a Visible Imaging Spectrometer. Each infrared camera used a seven-position filter wheel and a 256-by-256-pixel indium antimonide detector array, with the SWIR covering 2.5 to 3.3 micrometers and the MWIR covering 3.5 to 4.5 micrometers. The VIS employed a 499-by-768-pixel CCD sensor for wavelengths between 0.5 and 0.8 micrometers.

Data was saved to an experimental 8.64-gigabit (1.08-gigabyte) hard drive called Erasable Disk Mass Memory, then transmitted via the Air Force Satellite Control Network.

Overview

The Miniature Sensor Technology Integration program began in December 1991 under the Ballistic Missile Defense Organization, and was transferred to the United States Air Force by congressional direction in 1994. MSTI-3 was initiated by Phillips Laboratory at Kirtland Air Force Base. Its bus was designed and built by Phillips Laboratory, Spectrum Astro, and Wyle Laboratories, based on Spectrum Astro's SA-200S bus. Science Applications International Corporation built the instrumentation.

Mission management came from the Space and Missile Systems Center at Los Angeles Air Force Base, while spacecraft control was handled by SMC Detachment 2 out of Onizuka Air Force Station and later Kirtland AFB through the USAF Satellite Control Network. Operations and data processing took place at the MSTI Payload Operations Center, a component of the Naval Research Laboratory managed by Analytical Services. MSTI-3 used lessons from the two earlier spacecraft: MSTI-1, launched 21 November 1992, carried a single MWIR camera and validated the SA-200S bus during six months in orbit; MSTI-2, launched 9 May 1994, carried a PtSi SWIR camera and an InSb MWIR camera, successfully observed a Minuteman-III missile, but failed after four months of its six-month mission.

MSTI-3's primary mission was to survey Earth's surface and atmospheric features in SWIR and MWIR to characterize variation across observational angles, times of day, and seasons, building statistical data to assess feasibility of space-based surveillance tracking ballistic missiles in coast phase against Earth's warm background. The VIS instrument verified infrared observation integrity and performed secondary environmental monitoring at the same spatial resolution as Landsat 5 and 6 but with improved spectral resolution.

MIRACL Experiment

On October 17, the test of a chemical laser against an MSTI-3 satellite’s sensors failed. The Army reported the satellite malfunctioned, preventing a full evaluation. Though the Pentagon called it research, critics saw it as a step toward a blinding weapon.