ATS-6 (Applications Technology Satellite-6) was a NASA experimental satellite, built by Fairchild Space and Electronics Division It has been called the world's first educational satellite as well as world's first experimental Direct Broadcast Satellite as part of the Satellite Instructional Television Experiment between NASA and Indian Space Research Organisation (ISRO). It was launched May 30, 1974, and decommissioned July 1979. At the time of launch, it was the most powerful telecommunication satellite in orbit. ATS-6 carried no fewer than 23 different experiments, and introduced several breakthroughs. It was the first 3-axis stabilized spacecraft in geostationary orbit. It was also the first to use experimentally with some success electric propulsion in geostationary orbit. It also carried several particle physics experiments, including the first heavy ion detector in geostationary orbit. During its five-year life, ATS-6 transmitted connection programming to various countries, including India, the United States and other regions. The vehicle also conducted air traffic control tests, was used to practice satellite-assisted search and rescue techniques, carried an experimental radiometer subsequently carried as a standard instrument aboard weather satellites, and pioneered direct broadcast TV. ATS-6 was a precursor to many technologies still in use today on geostationary spacecraft: large deployable antenna, 3-axis attitude control with slewing capabilities, antenna pointing through RF sensing, electric propulsion, meteorological radiometer in geostationary orbit, and direct to home broadcasting. It is also possible that ATS-6 was a forerunner of the large ELINT satellites such as Mentor. Launch ATS-6 was launched on May 30, 1974, by a Titan III-C launch vehicle. The spacecraft was inserted directly in the geosynchronous orbit. This reduced the on-board fuel requirements to less than (for a total mass at launch of nearly ). The highly accurate orbit insertion further lowered the amount of fuel required for final positioning to . This enabled a life extension from the original 2 year to 5 years, even accounting for the premature failure of the electric propulsion subsystem (the station-keeping fuel requirement being around ). Structure, power subsystem and antenna One of the major innovations of ATS-6 was an in-flight deployable antenna of more than in diameter. The antenna reflector was furled during launch under the launch vehicle fairing, and was deployed in orbit much like an umbrella. The antenna reflector was built from 48 aluminum ribs, supporting a metallized Dacron mesh. The antenna feeds (in C, S, L, UHF and VHF bands) were placed on the