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Chalet / Vortex / Mercury 8, 9, 10, 11, 12, 13

The Chalet / Vortex / Mercury ELINT satellites were the successors to the Canyon series of near GEO ELINT/SIGINT satellites of NRO's Program A. They were focussed on communications intelligence (COMINT), but had the capability added to intercept also missile telemetry. These satellites were launched under the designation Program 7500.

Reportedly they consist of a large (ca. 38 m diameter) antenna and are three axis stabilized. They were deployed into a 24 h orbit, which was not geostationary, so that triangulations of emitter sources can be made from different points. The satellites of this series were injected directly into the final orbit by the launch vehicle's upper stage, so they did not feature an apogee propulsion system.

The numbering sequence continued the earlier Canyon sequence. The name was changed from Chalet to Vortex, when the former name was disclosed in a New York Times report in 1979. They are also known as AFP-366 series. When the name Vortex was revealed in 1987, the satellites were renamed Mercury.

These satellites proved to be extraordinary long lived. Vortex 10 operated for more than 25 years.

The successor of these satellites were the Mercury 14 - 16 geostationary ELINT satellites.

Nation: USA
Type / Application: SIGINT, COMINT, ELINT
Operator: NRO, NSA
Contractors: E-Systems ?
Equipment: ?
Configuration: ~ 38 m Dish Antenna, 3-Axis-Stabilization
Propulsion: ?
Power: Solar arrays, batteries
Lifetime: +25 years (reached #10)
Mass: 932 kg ?
Orbit: 30200 km × 40800 km, 7.00 (typical)
Satellite COSPAR Date LS Launch Vehicle Remarks
Chalet 8 → Vortex 8 (Mission 7508, OPS 9454) 1978-058A 10.06.1978 CC LC-40 Titan-3(23)C
Vortex 9 (Mission 7509, OPS 1948) (ex Chalet 9) 1979-086A 01.10.1979 CC LC-40 Titan-3(23)C
Vortex 10 → Mercury 10 (Mission 7510, OPS 4029) (ex Chalet 10) 1981-107A 31.10.1981 CC LC-40 Titan-3(23)C
Vortex 11 → Mercury 11 (Mission 7511, OPS 0441) (ex Chalet 11) 1984-009A 31.01.1984 CC LC-40 Titan-34D Transtage
Mercury 12 (Mission 7512, USA 31) (ex Vortex 12 ex Chalet 12) 1988-077A 02.09.1988 CC LC-40 f Titan-34D Transtage
Mercury 13 (Mission 7513, USA 37) (ex Vortex 13 ex Chalet 13) 1989-035A 10.05.1989 CC LC-40 Titan-34D Transtage


Further high orbit SIGINT missions:

Geostationary orbit COMINT (Canyon-Chalet-Vortex-Mercury series) Geostationary orbit SIGINT (Rhyolite-Aquacade-Magnum-Orion series) High elliptical orbit SIGINT (Jumpseat-Trumpet series) Other high orbit SIGINT

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