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. Communications satellites are used for television, telephone, radio, internet, and military applications. Many communications satellites are in geostationary orbit 22,300 miles (35,900 km) above the equator, so that the satellite appears stationary at the same point in the sky; therefore the satellite dish antennas of ground stations can be aimed permanently at that spot and do not have to move to track the satellite. Others form satellite constellations in low Earth orbit, where antennas on the ground have to follow the position of the satellites and switch between satellites frequently.
Pioneer 5 was a spin-stabilized space probe in the NASA Pioneer program used to investigate interplanetary space between the orbits of Earth and Venus. It was launched on 11 March 1960 from Cape Canaveral Air Force Station Launch Complex 17A at 13:00:00 UTC with an on-orbit dry mass of 43 kilograms (95 lb). It was a 0.66 metres diameter sphere with 1.4 metres span across its four solar panels and achieved a solar orbit of 0.806 × 0.995 AU.
The Relay program consisted of Relay 1 and Relay 2, two early American satellites in elliptical medium Earth orbit. Both were primarily experimental communications satellites funded by NASA and developed by RCA. As of December 2, 2016, both satellites were still in orbit. Relay 1 provided the first American television transmissions across the Pacific Ocean.
Mercury-Scout 1, or MS-1, was a United States spacecraft intended to test tracking stations for Project Mercury flights. It grew out of a May 5, 1961 NASA proposal to use Scout rockets to launch small satellites to evaluate the worldwide Mercury Tracking Network in preparation for crewed orbital missions. The launch of Mercury-Scout 1 on November 1, 1961, was unsuccessful, and the satellite failed to reach orbit.
Explorer 2 was an American unmanned space mission within the Explorer program. Intended to be a repetition of the previous Explorer 1 mission, which placed a satellite into medium Earth orbit, the spacecraft was unable to reach orbit due to a failure in the launch vehicle during launch.
Project Echo was the first passive communications satellite experiment. Each of the two American spacecraft, launched in 1960 and 1964, were metalized balloon satellites acting as passive reflectors of microwave signals. Communication signals were transmitted from one location on Earth and bounced off the surface of the satellite to another Earth location.
Explorer 6, or S-2, was a NASA satellite, launched on 7 August 1959, at 14:24:20 GMT. It was a small, spheroidal satellite designed to study trapped radiation of various energies, galactic cosmic rays, geomagnetism, radio propagation in the upper atmosphere, and the flux of micrometeorites. It also tested a scanning device designed for photographing the Earth's cloud cover. On 14 August 1959, Explorer 6 took the first photos of Earth from a satellite.
The Lincoln Experimental Satellite series was designed and built by Lincoln Laboratory at Massachusetts Institute of Technology between 1965 and 1976, under USAF sponsorship, for testing devices and techniques for satellite communication.
The Manned Space Flight Network was a set of tracking stations built to support the American Mercury, Gemini, Apollo, and Skylab space programs.
The Intelsat VI series of satellites were the 8th generation of geostationary communications satellites for the Intelsat Corporation. Designed and built by Hughes Aircraft Company (HAC) in 1983-1991, there were five VI-series satellites built: 601, 602, 603, 604, and 605.
SSETI Express was the first spacecraft to be designed and built by European students and was launched by the European Space Agency. SSETI Express is a small spacecraft, similar in size and shape to a washing machine. On board the student-built spacecraft were three CubeSat picosatellites, extremely small satellites weighing around one kg each. These were deployed one hour and forty minutes after launch. Twenty-one university groups, working from locations spread across Europe and with very different cultural backgrounds, worked together via the internet to jointly create the satellite. The expected lifetime of the mission was planned to be 2 months. SSETI Express encountered an unusually fast mission development: less than 18 months from kick-off in January 2004 to flight-readiness.
The Unified S-band (USB) system is a tracking and communication system developed for the Apollo program by NASA and the Jet Propulsion Laboratory (JPL). It operated in the S band portion of the microwave spectrum, unifying voice communications, television, telemetry, command, tracking and ranging into a single system to save size and weight and simplify operations. The USB ground network was managed by the Goddard Space Flight Center (GSFC). Commercial contractors included Collins Radio, Blaw-Knox, Motorola and Energy Systems.
Cooby Creek Tracking Station, an Earth station in Australia, was located 22.5 kilometres (14 mi) north of Toowoomba, Queensland. Built near the Cooby Dam, the station was located in a radio quiet zone, where there were no powerlines and other sources of potential interference.
Telstar is the name of various communications satellites. The first two Telstar satellites were experimental and nearly identical. Telstar 1 launched on top of a Thor-Delta rocket on July 10, 1962. It successfully relayed through space the first television pictures, telephone calls, and telegraph images, and provided the first live transatlantic television feed. Telstar 2 was launched May 7, 1963. Telstar 1 and 2—though no longer functional—still orbit the Earth.
TIROS 5 was a spin-stabilized meteorological satellite. It was the fifth in a series of Television Infrared Observation Satellites.
TIROS 6 was a spin-stabilized meteorological satellite. It was the sixth in a series of Television Infrared Observation Satellites.
TIROS-10 was a spin-stabilized meteorological satellite. It was the tenth and last in a series of Television Infrared Observation Satellites.
Lincoln Experimental Satellite 1, also known as LES-1, was a communications satellite, the first of nine in the Lincoln Experimental Satellite program. Launched by the United States Air Force (USAF) on February 11, 1965, it pioneered many then-advanced technologies including active use of the military's SHF band to service hundreds of users. LES-1 did not have a successful operational life due to being placed in a suboptimal orbit, and it ceased transmissions in 1967. After 45 years of inactivity, LES-1 spontaneously resumed transmissions in 2012 making it one of the oldest zombie satellites.
Lincoln Experimental Satellite 4, also known as LES-4, was a communications satellite, the fourth of nine in the Lincoln Experimental Satellite, and the first of the series designed for operations at geosynchronous altitudes. Launched by the United States Air Force (USAF) on 21 December 1965, it demonstrated many then-advanced technologies including active use of the military's SHF band to service hundreds of users.
The Environmental Research Satellite program was a series of small satellites initially operated by the United States Air Force Office of Aerospace Research. Designed to be launched "piggyback" to other satellites during launch, detaching once in orbit, they were the smallest satellites launched to date—what would today be classified as microsatellites. 33 ERS satellites in six different series were launched between 1962 and 1971, conducting scientific research and serving as test beds to investigate the reliability of new spacecraft components.
