The Space Tracking and Surveillance System Advanced Technology Risk Reduction (STSS ATRR) satellite has successfully demonstrated required on-orbit system performance parameters for a prototype sensor technology. Additionally, STSS ATRR has been conducting Space Situational Awareness (SSA) and related operations on an as-capable basis. The Missile Defense Agency (MDA) is coordinating the transfer of STSS ATRR operational control to Air Force Space Command to continue support for the SSA mission area.

STSS ATRR was launched May 5, 2009, from Vandenberg Air Force Base. STSS ATRR is a small experimental satellite that serves as a pathfinder for prototype sensor technology and future MDA space missions.