The Pentagon will wait to take the shot until the shuttle Atlantis, currently docked at the International Space Station, returns to Earth, a flight scheduled for Monday.
The Navy ships will be modified so the missiles can be used to shoot down the satellite, but Cartwright said those changes will consist of minor software modifications, meaning the shoot-down will be similar to missile defense tests regularly performed in the Pacific.
"What we're trying to do is match up that period in which the satellite looks most like a reentering missile," Cartwright said.
The most high-profile parts of the Bush administration's missile defense system -- ground-based interceptors in Alaska and Central California -- have had a spotty track record in testing. However, the Navy's Aegis system, designed to shoot down short- and mid-range missiles, has had more success in missile defense tests in recent years.
Several Aegis-equipped cruisers and destroyers were deployed to the waters off the coast of North Korea in July 2006 when Pyongyang tested several medium- and long-range missiles, including the Taepo-Dong II, suspected to be capable of reaching U.S. bases in the Pacific. None of the ships fired on the missiles, however, but used their radars to track and monitor the test.
The satellite shoot-down will give the Navy its first real-life, uncontrolled test of the Aegis-based system.
"It's basically taking technology designed for missile defense and using it to knock out a satellite," said James Lewis, an expert on military technology at the Center for Strategic and International Studies. "This is interesting because it's new technology. The first time they tested it was a year ago."