EE Times February 14, 2008
DoD may use modified Navy missle to shoot down wayward satellite
By Loring Wirbel
COLORADO SPRINGS, Colo. — The Associated Press reported prior to a Pentagon briefing Thursday (Feb. 14) that the U.S. Navy will attempt to shoot down a wayward National Reconnaissance Office (NRO) satellite.
National security analysts Globalsecurity.org suggested the Navy would likely use a modified SM-3 missile from an Aegis cruiser, which is considered a key element of a U.S. theatre missile defense at sea.
According to sources, discussions are underway with NRO, the National Security Agency and Department of Homeland Security over whether the shoot-down could be planned in a way to reduce possible space debris, a problem that arose following the January 2007 anti-satellite test conducted by the Chinese military.
According to the satellite-tracking service Jonathan's Space Report, the USA 193 is an experimental intelligence satellite designed to test several multispectral sensors, including radar. It failed soon after its December 2006 launch from a Delta II rocket, and its orbit has been decaying since then.
As of Jan. 22, it was in a 275 by 279 km by 58-degree orbit and is dropping a kilometer a day. The Pentagon was expecting orbit decay to accelerate catastrophically by early March.
In a statement, DoD said: "Based on modeling and analysis, our officials have high confidence that the engagement will be successful. As for when this engagement will occur, we will determine the optimal time, location and geometry for a successful engagement based on a number of factors.
"As the satellite's path continues to decay, there will be a window of opportunity between late February and early March to conduct this engagement. The decision to engage the satellite has to be made before a precise prediction of impact location is available."
Jonathan McDowell, author of the report, said that the 5000-pound payload was larger than many de-orbited satellites but was far smaller than the failed Skylab, contrary to some media reports.
The Pentagon has cited the risk of "dangerous material" on the spacecraft, possibly referring to the hydrazine propellant used to adjust orbits. John Pike, chief analyst of Globalsecurity.org, said DoD's concern with hydrazine seems genuine.
Sources close to another space institute, however, privately suggested that the impetus for shooting down the satellite may have more to do with the experimental nature of the sensor payloads -- and the concurrent risk that they could fall where another nation could retrieve the payload.
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