The U.S. Air Force plans to award a contract for a follow-on Space Based Space Surveillance (SBSS) satellite on a competitive basis in fiscal year 2015 and anticipates launch availability in 2020, according to a fact sheet on the service’s 2013 budget request.

The SBSS Block 10 satellite was launched in September 2010 and is scheduled to begin operations in May 2012, according to the fact sheet. The Air Force at one time intended to award a contract for the follow-on satellite in 2011, but those plans were deferred due to budgetary pressures.

The Air Force’s 2013 budget request includes just $2 million for SBSS, but documents show funding ramping up to $60 million by 2015 and about $152 million in 2017. The service’s 2012 budget request did not allot any money for the program from 2014 to 2016.

The Air Force “accepts the risk” of a gap in its ability to keep tabs on objects in geosynchronous orbit, the fact sheet said. That scenario would become a reality if the SBSS Block 10 satellite fails before the follow-on satellite is launched.

The SBSS system is part of an emerging space situational awareness program that includes ground- and space-based gear to track in-orbit satellites and orbital debris. A Boeing-led team that includes Ball Aerospace & Technologies Corp. built the SBSS Block 10 satellite.