Senior Airman Joseph Fletcher and Airman 1st Class Christopher Kelly inspect a TPS-75 radar on March 13, 2012, in Southwest Asia. Officials from the Three-Dimensional Long-Range Radar office, headquartered at Hanscom Air Force Base, Mass., expect to announce a contract to replace the radar with a production-ready, commercially available system in early 2021. (U.S. Air Force photo by Staff Sgt. Nathanael Callon)