| USA-205 | |
| Names List: | STSS-ATRR Block 2010 Spacecraft Risk Reduction |
| Mission Type: | U.S. military technology demonstration |
| Operator: | Missile Defense Agency / U.S. Air Force |
| Cospar Id: | 2009-023A |
| Satcat: | 34903 |
| Launch Date: | 5 May 2009, 20:24:25 UTC |
| Launch Rocket: | Delta II 7920-10C (Delta D341) |
| Launch Site: | Vandenberg, SLC-2W |
| Launch Contractor: | United Launch Alliance |
| Orbit Reference: | Geocentric orbit |
| Orbit Regime: | Sun-synchronous orbit |
| Orbit Inclination: | 97.8° |
| Apsis: | gee |
USA-205, 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]