ORBCOMM FM1 and ORBCOMM FM2 are American minisatellites that were launched by the same Pegasus rocket which launched the MICROLAB 1. The main payload is a transponder to relay the GPS-determined locations of cargo trucks, and data from oil pipeline monitors. Both Orbcomm-FM 1 and Orbcomm-FM 2 experienced transmission or reception problems, but were recovered and placed into operational status. The initial orbital parameters were period 99.6 min, apogee 747 km, perigee 734 km, and inclination 69.9 deg.
These satellites were part of a commercial venture to provide global messaging services using a constellation of 26 low-Earth orbiting satellites. The planned system was designed to handle up to 5 million messages from users utilizing small, portable terminals to transmit and receive messages directly to the satellites. The first 2 satellites of the constellation (95-017A + B) experienced communication problems after launch, but were recovered and placed into operational status. The nominal 26 satellite constellation was to be deployed by 1997, with the potential for an additional 8 satellite plane and 2 more polar orbiters depending on demands for increased coverage. The vehicles were controlled from a single control center located in Dulles, VA.
The spacecraft was a circular shaped disk. Circular panels hinged from each side after launch to expose solar cells. These panels articulated in 1-axis to track the sun and provide 160W. Deployed spacecraft measured 3.6 m from end to end with 2.3 m span across the circular disks. VHF telemetry was at 57.6 kbps. The spacecraft contained an on-board GPS navigation and timing system, and 14 volt power system. Gravity gradient stabilization provided 4 degs control with magnetic torques for damping cold gas (nitrogen) propulsion system.
The spacecraft carried 17 data processors and 7 antennas and was designed to handle 50,000 messages per hour. The long boom was a 2.6 meter VHF/UHF gateway antenna. Receive: 2400 bps at 148 - 149.9 MHz. Transmit: 4800 bps at 137 - 138 MHz and 400.05 to 400.15 MHz. The system used X.400 (CCITT 1988) addressing. Message size was 6 to 250 bytes typical (no maximum).
Facts in Brief
Launch Date: 1995-04-03
Launch Vehicle: Pegasus
Launch Site: Vandenberg AFB, United States
Mass: 41.0 kg
Nominal Power: 160.0 W