This improvement builds a complex of hypersonic missile sites capable of attacking enemy ships in orbit. Each site can fire an unlimited number of missiles during a conflict. They require tech level X to build. The seem to replace GDMs ... but sometimes they don't.

Screen Shot 2012-12-08 at 13.10.31

screen shot of hypersonic missile site

damage 20

range 40

armor 50

build time: 15 watches

minimum tech level: 6