About ACTS
History
Program Beginnings
ACTS was developed as an experimental on-orbit, advanced
communications satellite test bed, bringing together industry,
government, and academia to conduct a wide range of technology,
propagation, and user application investigations. NASA Glenn
Research Center awarded in August 1984 the ACTS contract to
an industry team consisting of:
- Lockheed Martin, East Windsor, NJ for system integration
and the spacecraft bus;
- TRW, Redondo Beach, CA for the spacecraft communications
payload;
- COMSAT Laboratories, Clarksburg, MD for the network control
and master ground station;
- Motorola, Chandler, AZ for the baseband processor; and
- Electromagnetic Sciences, Norcross, GA for the spot-beam
forming networks.
The contract was awarded to RCA Astro Space of East Windsor,
NJ, which was subsequently acquired by General Electric, and
then by Martin Marietta (itself acquired by Lockheed Aircraft
Corporation in 1995 to become Lockheed Martin). In 1988, as
a result of a congressionally mandated program funding cap,
Lockheed Martin assumed responsibility for completing the
development of the communications payload. Subsequently, Lockheed
Martin (then General Electric Astro Space) subcontracted with
Composite Optics, Inc. San Diego, CA for the manufacture of
the antenna reflectors and part of the bus structure.
Launch
 ACTS
was launched as the primary payload aboard the Space Shuttle
Discovery (OV-103) from the Kennedy Space Center, Pad 39B,
as part of the STS-51 mission on September 12, 1993. At launch
and for insertion into its geosynchronous orbit, ACTS was
mated to the transfer orbit stage component (TOS) for a total
weight of 6108 lbs. View
the launch movie (.mov, 1.3 MB
) Alternative Movie Text.
Separation
 On
separation from the shuttle orbiter, the TOS was ignited to
inject ACTS into geotransfer orbit. The TOS then separated
from ACTS. At approximately 50.5 hours into the mission, the
apogee kick motor injected ACTS into drift orbit. After seven
days, ACTS, guided by the firing of spacecraft thrusters,
moved into its operations orbit and transitioned to a stabilized
spacecraft configuration. Before the payload was actuated,
the solar arrays were deployed, earth-sun attitude control
was established, and the main communication antennas were
deployed. View
the deployment movie (.mov, 370 KB) Alternative Movie Text
Orbit
 ACTS
was stationed at its designated geosynchronous orbit location
at 100 degrees west longitude. In July 1998 the spacecraft's
north/south stationkeeping was stopped to extend operations
in an inclined
orbit. In August 2000, the satellite was moved to 105.2
W longitude to be permanently located.
The weight of ACTS at the beginning of its on-orbit life
was 3250 lbs. At full deployment, it measures 47.1 feet from
tips to tip of its solar arrays and 29.9 feet across from
its main receiving and transmitting antenna reflectors.
Experiments
Experimental studies began twelve weeks after ACTS was deployed.
The communications payload has continued to operate flawlessly
24 hours per day, seven days per week, year round. The only
periods of "down time" occur during parts of the
spring and fall equinox periods when the ACTS’ solar
panels are eclipsed. Experimentation supported by ACTS
continued until June 2000. In May 2001, the Ohio Consortium
for Advanced Communications Technology began using ACTS for
educational research.
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