Vela satellites

Vela was the name of a group of satellites developed as the Vela Hotel element of Project Vela by the United States to monitor compliance with the 1963 Partial Test Ban Treaty by the Soviet Union.

Vela started out as a small budget research program in 1959. It ended 26 years later as a successful, cost-effective military space system, which also provided scientific data on natural sources of space radiation. In the 1970s, the nuclear detection mission was taken over by the Defense Support Program (DSP) satellites. In the late 1980s, it was augmented by the Navstar Global Positioning System (GPS) satellites. The program is now called the Integrated Operational Nuclear Detection System (IONDS).

The total number of satellites built was 12, six of the Vela Hotel design and six of the Advanced Vela design. The Vela Hotel series was to detect nuclear tests in space, while the Advanced Vela series was to detect not only nuclear explosions in space but also in the atmosphere.

All spacecraft were manufactured by TRW and launched in pairs, either on an Atlas–Agena or Titan III-C boosters. They were placed in orbits of 118,000 km (73,000 miles), well above the Van Allen radiation belts. Their apogee was about one-third of the distance to the Moon. The first Vela Hotel pair was launched on October 17, 1963, one week after the Partial Test Ban Treaty went into effect, and the last in 1965. They had a design life of six months, but were actually shut down after five years. Advanced Vela pairs were launched in 1967, 1969 and 1970. They had a nominal design life of 18 months, later changed to 7 years. However, the last satellite to be shut down was Vehicle 9 in 1984, which had been launched in 1969 and had lasted nearly 15 years.

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