The Boeing 376 (sometimes referred to as the BSS-376, and previously as the HS-376) is a

communications satellite A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth. C ...

bus introduced in 1978 by

Hughes Space and Communications Company Hughes may refer to: People * Hughes (surname) * Hughes (given name) Places Antarctica * Hughes Range (Antarctica), Ross Dependency * Mount Hughes, Oates Land * Hughes Basin, Oates Land * Hughes Bay, Graham Land * Hughes Bluff, Victoria La ...

. It was a

spin-stabilized Spin stabilization is the method of stabilizing a satellite or launch vehicle by means of spin, i.e. rotation along the longitudinal axis. The concept originates from ballistics, where the spin is commonly obtain by means of rifling. For most sate ...

bus that the manufacturer claims was the first standardized platform.

Design

The satellite bus was designed and manufactured by

Hughes Hughes may refer to: People * Hughes (surname) * Hughes (given name) Places Antarctica * Hughes Range (Antarctica), Ross Dependency * Mount Hughes, Oates Land * Hughes Basin, Oates Land * Hughes Bay, Graham Land * Hughes Bluff, Victoria La ...

. This

platform had two main sections. The spinning section was kept rotating at 50 rpm to maintain attitude, and a despun section was used by the payload to maintain radio coverage. The spinning section included the apogee kick motor, most of the attitude control, the power subsystem and the command and telemetry subsystems. The despun section contained the communications payload, including the antennas and transponders. The stock version had a launch mass of , a mass of after reaching

geostationary orbit A geostationary orbit, also referred to as a geosynchronous equatorial orbit''Geostationary orbit'' and ''Geosynchronous (equatorial) orbit'' are used somewhat interchangeably in sources. (GEO), is a circular geosynchronous orbit in altitud ...

and an 8 to 10-year design life. When stowed for launch, its dimensions were in height and in diameter. With its solar panels fully extended its height was . Its power system generated approximately 1,100 to 1,200

watts Watts is plural for ''watt'', the unit of power. Watts may also refer to: People *Watts (surname), list of people with the surname Watts Fictional characters *Watts, main character in the film '' Some Kind of Wonderful'' *Watts family, six chara ...

of power at beginning of life, thanks to two cylindrical solar panels. The bottom panel was retracted around the body and top panel for launch, and extended downwards for operation. It also had two NiCd batteries for solar eclipses.

Versions

There were four variations of this platform: * HS-376: The original version of the platform was launched in 1977. It had a mass between . * HS-376L: The Longer life version of the platform was launched in 1991. It had reduced power of 700 Watts and reduced electronics weight, which allowed for increased station keeping propellant supply. This lengthened the design life to 13.5 years. * HS-376HP: A Higher Power version of the platform was launched in 1995. It had a mass between . * HS-376W: The Wide version of the platform was launched in 1990. It was wider, more powerful and modernized electronics. It was a joint development with INPE. It had a diameter of and more power.

Satellites

The HS-376 was a very successful satellite platform with 58 satellites ordered, built and launched. It was also the first satellite to launch from the

Space Shuttle The Space Shuttle is a retired, partially reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. Its official program na ...

References

{{Hughes satellites Satellite buses

Design

Versions

Satellites

See also

References