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MACSAT 1 & 2 [DSI]

The two MACSAT (Multiple Access Communications satellite) spacecraft are third generation DSI digital communications satellites designed to demonstrate tactical UHF voice, data, fax and video store and forward capabilities for the U.S. military. The gravity gradient boom on one spacecraft appears to have failed to deploy. The other spacecraft was used during Operation Desert Storm for message relay to and from military troops in the Gulf region.

Spacecraft are gravity gradient stabilized (approx. 5 degrees control) using a 9+ meter boom and 2.3 kg tip mass. Damping achieved via hysteresis rods. Z-coil used to invert the spacecraft should it stabilize upside down. Dual digital processors provide redundancy and 2.4 to 16 megabytes of data storage. 16-sided cylindrical structure. Body mounted solar cells provide 10 to 17 Watts of orbit average power. Redundant NiCd batteries provide 150 Whr capacity.

Each satellite contains two digitally tunable 10 Watt transmitters, a 65 Watt high power auxiliary receiver for spacecraft command and hardware reconfiguration, and two antenna systems. This equipment was used to conduct store and forward communications demonstrations.

The MACSATs served as prototypes for the Navy's Arcticsat planned and later cancelled constellation of six similar satellites.

Nation: USA
Type / Application: Experimental communication (store and forward)
Operator: DARPA
Contractors: DSI
Equipment: 2 UHF transponders
Configuration: MAESTRO Bus
Propulsion: None
Power: Solar cells, batteries
Mass: 68 kg
Orbit: 613 km × 739 km, 90
Satellite COSPAR Date LS Launch Vehicle Remarks
MACSAT 1 1990-043A 09.05.1990 Va SLC-5 Scout-G1 with MACSAT 2
MACSAT 2 1990-043B 09.05.1990 Va SLC-5 Scout-G1 with MACSAT 1