More than 1,200 active satellites circle the globe; the lifeblood of modern military operations flows through many of them. In May, the U.S. Air Force announced a $5 billion budget to develop space-based offensive and defensive weapons. Other countries too are building capabilities on high. To win the next war, any great power will need to hold the ultimate in commanding heights.

A Good Offense

In a chapter from the Cold War, the U.S. and Russia are both reportedly developing anti-satellite systems. Last fall, Russia tested what's believed to be the beginnings of a killer satellite. The Pentagon also admitted, in a 2014 report, that it was investing in offensive space weapons.