A satellite bus or spacecraft bus is the general model on which multiple-production satellite spacecraft

Spacecraft

A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....

 are often based. The bus is the infrastructure of a spacecraft, usually providing locations for the payload (typically space experiments or instruments).

They are most commonly used for geosynchronous

Geosynchronous orbit

A geosynchronous orbit is an orbit around the Earth with an orbital period that matches the Earth's sidereal rotation period...

 satellites, particularly communications satellites, but are also used in spacecraft which occupy lower orbits, occasionally including low earth orbit

Low Earth orbit

A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...

 missions.

A bus-derived satellite would be used as opposed to a one-off, or specially produced satellite, such as Prospero X-3

Prospero X-3

-External links:* from "Woomera on the Web"* from Encyclopedia Astronautica* in the Global Frequency Database...

. Bus-derived satellites are usually customised to customer requirements, for example with specialised sensors or transponders

Transponder (Satellite communications)

A communications satellite’s transponder, is the series of interconnected units which form a communications channel between the receiving and the transmitting antennas .A transponder is typically composed of:...

, in order to achieve a specific mission.

Examples

Some more notable satellite bus examples include:

• Astrium's Eurostar
  Eurostar (spacecraft)
  Eurostar is the brand name for a satellite bus made by Astrium which has been used for a series of spacecraft providing telecommunications services in geosynchronous orbit . More than 60 Eurostar satellites have been ordered to date, of which 45 have been successfully launched since October 1990...
  
  
• Spacebus
  Spacebus
  Spacebus is a satellite bus produced at the Cannes Mandelieu Space Center in France by Thales Alenia Space. Spacebuses are typically used for geostationary communications satellites, and fifty-two have been launched since development started in the 1980s. Spacebus was originally produced by...
  
  
• Boeing 702
  Boeing 702
  Boeing 702 is a communications satellite design. The Boeing Satellite Development Center tailors the payload of each Boeing 702 to meet customer specifications based on a modular design but with usually more than seventy transponders....
  
  
• STAR Bus
  STAR Bus
  STAR Bus is a satellite platform manufactured by Orbital Sciences Corporation with an apogee kick motor to place a communications satellite into geostationary orbit, a thruster to provide the satellite with orbital station-keeping for a 15 year mission, and solar arrays to provide the satellite...
  
  
• Loral 1300
• Lockheed Martin Space Systems
  Lockheed Martin Space Systems
  Lockheed Martin Space Systems Company is one of the four major business divisions of Lockheed Martin. It is headquartered in Denver, Colorado with additional sites in Sunnyvale, California; Newtown, Pennsylvania; Huntsville, Alabama; and elsewhere in the US and UK...
  
   A2100
  A2100
  The A2100 is a communications satellite spacecraft made by Lockheed Martin Space Systems for telecommunications in geosynchronous orbit.The Lockheed Martin A2100 geosynchronous spacecraft series is designed for a variety of telecommunications needs including Ka band broadband and broadcast...
  
  

Components

A bus typically consists of the following subsystems:

• Command and Data Handling
  On-Board Data Handling
  The On-Board Data Handling subsystem of a spacecraft is the subsystem which carries and stores data between the various electronics units and the ground segment, via the Telemetry, Tracking and Command subsystem....
  
   (C&DH) System
• Communications system and antenna
  Antenna (radio)
  An antenna is an electrical device which converts electric currents into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver...
  
  s
• Electrical Power System (EPS)
• Propulsion
• Thermal control
• Attitude Control System
  Attitude control system
  In spaceflight, the attitude control system or attitude determination and control system of a spacecraft consists of equipment to measure, report and change the orientation of the vehicle.- Components :...
  
   (ACS)
• Guidance, Navigation and Control
  Guidance, Navigation and Control
  Guidance, navigation and control is a branch of engineering dealing with the design of systems to control the movement of vehicles, especially, automobiles, ships, aircraft, and spacecraft. In many cases these functions can be performed by trained humans...
  
   (GNC) System
• Structures and trusses
• Life support (for crewed missions
  Human spaceflight
  Human spaceflight is spaceflight with humans on the spacecraft. When a spacecraft is manned, it can be piloted directly, as opposed to machine or robotic space probes and remotely-controlled satellites....
  
  ).