Four examples of DARPA’s space programs are Responsive Access, Small Cargo, Affordable Launch (RASCAL); Space Surveillance Telescope; Orbital Express; and Innovative Space- Based Antenna Technology.
RASCAL is designed to place small payloads in orbit on a moment’s notice by launching them from a high-speed, high-altitude, reusable aircraft that eliminates a large and expensive first stage booster. RASCAL is aimed toward a system to place 50- to 130-kilogram satellites and commodity payloads into low earth orbit at any time, at any inclination, and with a launch cost that is less than a third of current capabilities for the dedicated micropayload size.
The Space Surveillance Telescope program is developing a ground-based, wide-aperture, deep field-of-view optical telescope to search for very faint objects in geosynchronous orbit. It will enable us to identify and assess unidentified objects that suddenly appear in orbit with unknown purpose.
The above passage appears on Page 5 of an unclassified March 27, 2003 DARPA document. "Unidentified objects that suddenly appear in orbit with unknown purpose" could only mean two things: either an object that was launched into orbit from Earth, or an object that entered Earth orbit from space. It certainly wouldn't apply to a meteor or an asteroid, as neither one of those has a "purpose," nor will either one enter into an orbit. To read the DARPA document, click here.