A satellite bus (or spacecraft bus) is the main body and structural component of a satellite or spacecraft, in which the payload and all scientific instruments are held.
Bus-derived satellites are less customized than specially-produced satellites, but have specific equipment added to meet customer requirements, for example with specialized sensors or transponders, in order to achieve a specific mission.
A satellite or an artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation (GPS), broadcasting, scientific research, and Earth observation. Additional military uses are reconnaissance, early warning, signals intelligence and, potentially, weapon delivery. Other satellites include the final rocket stages that place satellites in orbit and formerly useful satellites that later become defunct.
Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope thermoelectric generators (RTGs). Most satellites also have a method of communication to ground stations, called transponders. Many satellites use a standardized bus to save cost and work, the most popular of which are small CubeSats. Similar satellites can work together as groups, forming constellations. Because of the high launch cost to space, most satellites are designed to be as lightweight and robust as possible. Most communication satellites are radio relay stations in orbit and carry dozens of transponders, each with a bandwidth of tens of megahertz.
Pioneer 10 (originally designated Pioneer F) is a NASA space probe launched in 1972 that completed the first mission to the planet Jupiter. Pioneer 10 became the first of five artificial objects to achieve the escape velocity needed to leave the Solar System. This space exploration project was conducted by the NASA Ames Research Center in California. The space probe was manufactured by TRW Inc.
Pioneer 10 was assembled around a hexagonal bus with a 2.74-meter (9 ft 0 in) diameter parabolic dish high-gain antenna, and the spacecraft was spin stabilized around the axis of the antenna. Its electric power was supplied by four radioisotope thermoelectric generators that provided a combined 155 watts at launch.
Cygnus is an expendable American uncrewed cargo spacecraft developed for International Space Station (ISS) resupply missions. It was originally built by Orbital Sciences Corporation with financial support from NASA under the Commercial Orbital Transportation Services (COTS) program. The spacecraft consists of a pressurized cargo module—based largely on the Multi-Purpose Logistics Module and built by Thales Alenia Space—paired with a service module derived from Orbital's GEOStar, a satellite bus. Following a successful demonstration flight in 2013, Orbital was awarded a Commercial Resupply Services (CRS) contract.
Over time, Cygnus has been upgraded to increase its size and capabilities. The Enhanced Cygnus variant debuted in 2015, and the further enlarged Cygnus XL entered service in 2025. Features added over time include reboost capability to raise the ISS orbit, the ability to support late cargo loading shortly before launch, and the option to conduct secondary missions after undocking. Each mission ends with a controlled destructive reentry, which also provides a means of disposing of waste generated aboard the station. Alongside Cygnus, other ISS resupply spacecraft have included the Russian Progress, the European Automated Transfer Vehicle, the Japanese H-II Transfer Vehicle, and the American SpaceX Dragon.