The U.S. Navy is specially modifying three advanced SM3 anti-ballistic missile interceptors to shoot down an electronically dead, intelligence-gathering satellite that was launched into space for the National Reconnaissance Organization (NRO). Communications with the satellite were lost almost immediately, which means there’s no way of guiding the spacecraft to a predictable crash site as it returns from orbit, says Marine Corps Gen. James Cartwright, vice chairman of the Joint Chiefs of Staff.
The extraordinary decision to shoot it down was the result of analyses that show the satellite’s 40-in.-dia. hydrazine tank—now holding a 1,000-lb. frozen sphere of maneuvering propellant—will survive the descent. It will pose a lethal danger when it strikes the Earth, cracks open, and the frozen slush turns into a toxic gas, says James Jeffrey, White House deputy national security adviser. The effect on human lungs would be similar to ammonia or chlorine gas.
The three Aegis ships involved in the intercept, from a launch site in the northern Pacific, will be “reconfigured on a one-time, reversible basis,” says Jeffrey. Even if the space defense missiles miss or misfire, the threat will be no greater, says NASA Administrator Michael Griffin. However, even if the missile only grazes the errant satellite, it will fall out of orbit faster, analysts contend. If they make a direct hit, the spacecraft is expected to fall into an unpopulated area, Cartwright says.
If the SM3 missile hits the satellite as it nears the atmosphere, more than 50% of the debris will reenter within two orbits, about 10-15 hr. Most of the remaining pieces would fall within a month, Cartwright says. It will be critical to hit the satellite before it enters the atmosphere, where its nonaerodynamic shape will cause it to tumble and be almost impossible to engage, he says. If the first SM3 misses, operators will reassess and try again with the backup missiles.
It is officially denied that debris from the payload could reveal secret new U.S. national security capabilities if satellite wreckage were recovered by another nation. (more) (follow the whole story)
