Aquacade, previously designated Rhyolite, was a class of SIGINT spy satellites operated by the National Reconnaissance Office for the United States Central Intelligence Agency.

The Rhyolite/Aquacade satellites, made by TRW, are rumored to have an umbrella-like reflecting dish 20 meters in diameter.

The satellites had a mass of approximately 700 kg and operated in near-geosynchronous orbits over the Middle East.

Signals were relayed to a remote NSA Earth station in Australia, Pine Gap, out of range of Soviet detection.

Secrecy around the program was tight and the initial Rhyolite mission in 1970 was the first space launch at Cape Canaveral in seven years that reporters were not invited to cover.