Speaking on the condition of anonymity, a Defense Department official said that a U.S. Navy vessel, modified for ballistic missile defense, will fire several interceptor missiles at the satellite before it re-enters the earth's atmosphere.
A date for the intercept was not revealed. Details of the plan are expected to be released later, at a Pentagon briefing. The intercept is expected to occur before the missile plunges back to earth next month.
Blasting the satellite before it reenters the atmosphere will decrease the dangers from hazardous materials carried on the space vehicle, and lessen chances that sensitive technology could fall into the wrong hands.
The disabled spy platform has a large fuel tank filled with hydrazine, used to power the satellite's thrusters. Experts are concerned that the tank could survive re-entry and break apart upon reaching the earth, spreading the toxic fuel across populated areas. The satellite also has smaller quantities of hazardous materials in its sensors, which pose a lesser hazard.
The missile intercept is also aimed at destroying or damaging sensitive equipment on the satellite--technology that could help adversaires determine our surveillance capabilities, or imrove their own overhead systems.
While DoD hasn't revealed the ship that will carry out the intercept, that assignment will almost certainly fall on an AEGIS cruiser, equipped with SM-3 interceptor missiles. The SM-3 is designed specifically for ballistic missile defense, with the ability to hit targets at extremely high altitudes. U.S. alllies are also participating in the SM-3 program. The most recent (and successful) test of the missile was conducted in December, from a Japanese AEGIS destroyer.
While intercepting any high-velocity target is difficult, the returning spy satellite should be (slightly) easier to hit than a missile reentry vehicle. The satellite will present a much larger target, and the SM-3's discrimination algorithims allow it to compare objects within the target scene. Obviously, there's no guarantee of a successful intercept, but the SM-3/AEGIS combination is more than capable of identifying and engaging the satellite, creating smaller pieces of debris that pose less of a threat.
Needless to say, a successful engagement will also provide a big boost for ballistic missile defense, and (in particular) the Navy leg of that program. The mobility of sea-based BMD systems make them particularly attractive, and it's a given that the Navy will make hay of the event--assuming that the AEGIS system and SM-3 perform as advertised.