USA 205 launch.jpg
Launch of a Delta II rocket carrying an experimental satellite (STSS-ATRR) for the Missile Defense Agency.
Block 2010 Spacecraft Risk Reduction
Mission typeU.S. military technology demonstration
OperatorMissile Defense Agency / U.S. Air Force
COSPAR ID2009-023A Edit this at Wikidata
SATCAT no.34903
Start of mission
Launch date5 May 2009, 20:24:25 UTC
RocketDelta II 7920-10C
(Delta D341)
Launch siteVandenberg, SLC-2W
ContractorUnited Launch Alliance
Orbital parameters
Reference systemGeocentric orbit
RegimeSun-synchronous orbit

USA-205,[1] also known as Space Tracking and Surveillance System-Advanced Technology Risk Reduction (STSS-ATRR), and previously as Block 2010 Spacecraft Risk Reduction is a satellite formerly operated by the United States Missile Defense Agency. It was launched to demonstrate new technology for missile detection early warning systems (MDEWS).[1] The technology demonstrated on STSS-ATRR was used in the development of the Space Tracking and Surveillance System (STSS) part of the Space-Based Infrared System (SBIRS).[2]

It was launched on a Delta II 7920-10C launch vehicle from Space Launch Complex 2W (SLC-2W) at the Vandenberg Air Force Base (VAFB) in California, at 20:24:25 UTC on 5 May 2009 into a Sun-synchronous orbit (SSO). The launch was conducted by United Launch Alliance.[3]

Operational and administrative control of the Space Tracking and Surveillance System-Advanced Technology Risk Reduction (STSS-ATRR) satellite was transferred to Air Force Space Command (AFSPC), effective 31 January 2011. In addition to successfully demonstrating required on orbit system performance parameters for a prototype sensor technology, STSS-ATRR conducted Space Situational Awareness and related operations on an as-capable basis.[4]


  1. ^ a b Krebs, Gunter. "STSS-ATRR". Retrieved 18 April 2009.
  2. ^ "STSS Risk Reduction Flight Eyes Launch". Aviation Week & Space Technology. 28 April 2009.
  3. ^ "United Launch Alliance Mission Overview".
  4. ^ "Missile Defense Agency Space Tracking and Surveillance System Advanced Technology Risk Reduction Satellite transfers to Air Force Space Command". Missile Defense Agency. 26 February 2011. Archived from the original on 2 December 2011. Retrieved 26 December 2020. Public Domain This article incorporates text from this source, which is in the public domain.