Chalet/Vortex was even larger than Rhyolite, weighing around 1800 kg and having a 38-m diameter antenna. Its primary mission was to intercept communications carried on UHF radio links which used antennae directed towards stationary orbit, or antennae with wide main lobes. There were six launches in total: Chalet-1 (June 10, 1978) and Vortex 1-5 (October 1, 1979 – May 10, 1989). The second batch of three Vortex satellites, launched from 1984 to 1989, probably had enhanced sensors. One was stranded in the wrong orbit when its Titan Transstage (transfer stage) malfunctioned. Each Chalet/Vortex satellite had a nominal lifetime of 5 to 7 years.
|launch vehicle||Titan-3C and -34D|
32,940 × 38,330 km × 5.5°
|size||38.4 × 36.6 m|