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 (satellite communications), transponder; it creates a communication channel between a source transmitter and a Rad ...

bus A bus (contracted from omnibus, with variants multibus, motorbus, autobus, etc.) is a motor vehicle that carries significantly more passengers than an average car or van, but fewer than the average rail transport. It is most commonly used ...

introduced in 1978 by

Hughes Space and Communications Company Hughes may refer to: People * Hughes (given name), including a list of people with the given name * Hughes (surname), including a list of people with the surname Places Antarctica * Hughes Range (Antarctica), Ross Dependency * Mount Hugh ...

. It was a

spin-stabilized In aerospace engineering, spin stabilization is a method of stabilizing a satellite or launch vehicle by means of spin, i.e. rotation along the longitudinal axis. The concept originates from conservation of angular momentum as applied to ballistic ...

bus, a successor to Hughes

HS-333 In 1970, Hughes Aircraft Company (HAC) Space and Communications Group offered the first standardized satellite: the HS 333 design. A spinning satellite, it was based on previous one-design satellites like Intelsat I. HAC built eight of these 300 ...

Design

The satellite bus was designed and manufactured by Hughes. 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 An apogee kick motor (AKM) is a rocket motor that is regularly employed on artificial satellites to provide the final impulse to change the trajectory from the transfer orbit into its final orbit (most commonly circular). For a satellite laun ...

, 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 orbit, circular geosynchronous or ...

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), a list of people with the surname Watts Fictional characters *Albie Watts, a fictional character in the British soap opera ''EastEnders'' *Angie ...

of power at

beginning of life Abiogenesis is the natural process by which life arises from non-living matter, such as simple organic compounds. The prevailing scientific hypothesis is that the transition from non-living to living entities on Earth was not a single even ...

, 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 launch system, 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. ...

References

{{Hughes satellites Satellite buses

Design

Versions

Satellites

See also

References