The report said "the least mature" technologies were three radar systems meant to track incoming warheads.

The monthslong experiment, experts say, was vital to discovering if similar systems could track enemy missiles and warheads so space-based weapons could attack them.

And officials are planning interceptor flight tests meant to track and destroy mock tumbling warheads, but only years from now.

Officials are planning the first interceptor flight tests meant to track and destroy mock tumbling warheads - though the move lies years in the future.

The least contentious element of the new program may be advanced, space-based sensors that could track warheads in space but also perform other surveillance duties as well.

Experts from that office have reportedly said that the satellites may not initially incorporate a sensor to track warheads in space.

Large radars, if deployed inland, could serve as powerful eyes meant to track warheads and to guide Star Wars interceptors to destroy them.

They contend that this type of transmitter is unsuitable for use in Star Wars antimissile battles, which usually have higher-frequency radars to track warheads.

The Boeing 767 aircraft has a 5.5-ton sensor, packed with 38,400 detectors, meant to track warheads in space.

On a shakedown cruise, it succeeded in tracking stars and is now preparing to track mock warheads.