Mercury

Country of origin	United States
Operator	National Reconnaissance Office United States Air Force
Applications	Espionage
Specifications
Launch mass	4,000–5,000 kilograms (8,800–11,000 lb)
Regime	Geostationary
Production
Built	3
Launched	3
Failed	1
Maiden launch	27 August 1994, 8:56:58UTC
Last launch	12 August 1998, 11:30:01UTC
← Vortex

Mercury, also known asAdvanced Vortex, was a series of three United Statesspy satellites launched in the 1990s. These satellites were launched and operated by theNational Reconnaissance Office with the participation of theUnited States Air Force. The satellites collectSIGINT from near-geosynchronous orbits. Their precise mission and capabilities are highlyclassified, but they are widely believed to be successors to theVortex/Chalet satellites.

Two of the three launches fromCCAFSLC-41 were successful, with the third failing to achieve orbit. All launches used aTitan IV(401)A rocket.

The last launch attempt, on 12 August 1998 failed, with the US$700–800 million satellite and the $344 millionTitan IV(401)A launch vehicle exploding over the Atlantic Ocean. The failure was caused by ashort circuit in the guidance system, which lost power and reset, causing the vehicle to pitch over. This in turn led to premature separation of one of theSRBs, which automatically self-destructed. The resulting explosion also destroyed the core vehicle, and the second SRB then initiated its own self-destruction.^[1] Roughly 4 seconds later theRange Safety Officer also issued a self-destruct signal to the rocket.^[2] Observers estimate each spacecraft has a mass of 4,000–5,000 kg.^[3]

• Mercury ELINT atEncyclopedia Astronautica
• Mercury/Advanced VORTEX fromFederation of American Scientists
• Video of the launch and destruction

• Reconnaissance satellites of the United States
• Signals intelligence satellites
• Military equipment introduced in the 1990s

• Articles with short description
• Short description is different from Wikidata