They have nine months to perfect a strategy to reach a U.S. space capsule in time to retrieve the astronauts aboard.
Weapons capable of jamming or destroying U.S. satellites will reach initial operational capability in the next few years.
SpaceX's new rocket blasted off on its first test flight, carrying a sports car aiming for an endless road trip past Mars.
Officials remained tight-lipped about a satellite that could be somewhere in orbit -- or crashed into the sea.
While the launch was deemed successful, the payload failed to reach orbit.
A highly classified spy satellite appears to have been lost after its launch aboard a SpaceX rocket Sunday.
SpaceX will launch a secret military payload, code-name Zuma, this weekend on a Falcon 9 rocket.
Fischer was selected in 2009 as part of NASA's 20th astronaut class, and completed astronaut candidate training in July 2011.
The first astronaut to take an untethered "spacewalk" died last week at age 80.
DoD had never before acknowledged the program's existence, but officials say it was shut down in 2012.