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USA 181, also named Demosat is a dummy/mockup of an American military satellite that was launched by a Delta 4-Heavy (720 tonne, 23-story high) rocket on a maiden flight at 21:50 UT on 21 December 2004. With a mass of 6.1 tonnes, and a cylindrical size of 2 m height and 1.4 m diameter, it has an outer aluminum skin enclosing sixty 13.7 cm diameter brass rods, both designed to ensure complete burn-out of the craft during reentry. The dummy carried two 15 kg, nano-satellites named 3CSAT 1 (also known as SPARKY) and 3CSAT 2 (also known as RALPHIE) built by Universities in Arizona and Colorado states, but their releases from DEMOSAT have not been ascertained so far. The cryogenic upper stage failed to inject the satellite into a geostationary orbit.

Alternate Names

  • 28500

Facts in Brief

Launch Date: 2004-12-21
Launch Vehicle: Delta IV
Launch Site: Cape Canaveral, United States
Mass: 6100 kg

Funding Agency

  • Unknown (United States)


  • Technology Applications

Additional Information

Questions and comments about this spacecraft can be directed to: Coordinated Request and User Support Office

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