As you all know, I am a big fan/advocate of space based weapons. It's teh high ground that's not so easy for most countries to get involved in. The USAF wants to deploy a space based AWACS system: the so-called Space Based RADAR. DARPA has been working on a demonstration of technologies needed: the Innovative Space Based Radar Antenna Technology (ISAT) program. Read about the recent downselect here.