Feb 14, 2008 11:22 AM

Pentagon to Shoot Down Rogue Satellite (Updated)

We predicted it earlier in the week. Now it’s confirmed: Despite cautionary notes from space security veterans, "the Pentagon is planning to shoot down a broken spy satellite expected to hit the Earth in early March," according to the AP. (Details of the plan, up here.) The good news, space experts tell DANGER ROOM, is […]

We predicted it earlier in the week. Now it's confirmed: Despite cautionary notes from space security veterans, "the Pentagon is planning to shoot down a broken spy satellite expected to hit the Earth in early March," according to the AP. (Details of the plan, up here.) The good news, space experts tell DANGER ROOM, is that the orbital debris won't be all that bad. The problem is, the shoot-down might legitimize China's provocative moves, above the sky.

U.S. officials said Thursday that the option preferred by the Bush administration will be to fire a missile from a U.S. Navy cruiser, and shoot down the satellite before it enters Earth's atmosphere...
The disabled satellite is expected to hit the Earth the first week of March. Officials said the Navy would likely shoot it down before then, using a special missile modified for the task...
Shooting down a satellite is particularly sensitive because of the controversy surrounding China's anti-satellite test last year, when Beijing shot down one of its defunct weather satellites, drawing immediate criticism from the U.S. and other countries.
A key concern at that time was the debris created by Chinese satellite's destruction—and that will also be a focus now, as the U.S. determines exactly when and under what circumstances to shoot down its errant satellite.
The military will have to choose a time and a location that will avoid to the greatest degree any damage to other satellites in the sky. Also, there is the possibility that large pieces could remain, and either stay in orbit where they can collide with other satellites or possibly fall to Earth.
It is not known where the satellite will hit. But officials familiar with the situation say about half of the 5,000-pound spacecraft is expected to survive its blazing descent through the atmosphere and will scatter debris—some of it potentially hazardous—over several hundred miles. The officials spoke on condition of anonymity because of the sensitivity of the matter.
*The satellite is outfitted with thrusters—small engines used to position it in space. They contain the toxic rocket fuel hydrazine, which can cause harm to anyone who contacts it. *

There's a briefing at the Pentagon later this afternoon with deputy national security advisor James Jeffrey, Joint Chiefs of Staff vice chairman Gen. James Cartwright and NASA chief Michael Griffin. We'll get you word as soon as we're able.

In the meantime, veteran military space specialist Theresa Hitchens, with the Center for Defense Information, tells DANGER ROOM while she's not "all that concerned about orbital debris," she is "concerned about the political ramifications."

Under ordinary circumstances, The Aegis SM-3 interceptor missile -- the Navy's most likely weapon against the satellite -- can only reach 160,000 feet meters, so the debris won't stay up long, Hitchens notes. However...

Other folks (say China!) may see this as an ASAT [anti-satellite weapon]
test, and as a response to the Chinese test last January. My own thoughts is that the Navy simply wants a chance to show off its Aegis anti-missile capabilities. Free test!!! But what do we say when the
Indian satellite goes belly up, and they want to shoot it down. Then the Iranian "satellite?" Sigh. I guess the other question would be whether you make a bigger mess on the ground. If you are accurate and it falls in the ocean, fine. But it would be uncool to rain hydrozine down on the Japanese or the Haiwaians. (If the sat hit in one place at least you could get a warning in and hopefully get it cleaned up quickly; a bunch of pieces would be harder to deal with.) They must be pretty sure they can kill it over the water.

UPDATE: MIT space security expert Geoffrey Forden tells DANGER ROOM:

1) It would be very feasible to use a standard missile to shoot down the satellite. There is really very little difference between a satellite and a warhead except that a satellite has no counter-measures. In fact, I would claim that our hit-to-kill missile defense technology started with our 1985
ASAT test. You save a lot of money on targets if you get to re-use them if you miss (or intentionally fly-by the target) which both we and the Chinese did a number of times before our respective hits. (So we have come full circle!)
2) It would create a debris field but no where near the sort of debris catastrophe that China created last year. China created well over 2,600
large pieces of debris and hundreds of thousands of smaller pieces. It is likely that shooting down the spy sat would create a similar amount but they would all have much lower perigees. (roughly at most 250 km as opposed to
850 km for the China's test) That means that they would decay much, much faster. For instance, all the pieces of debris from the US ASAT test in
1985 decayed within roughly 20 years (they have all decayed by now. The only reason it took so long was because the target satellite was at 650 km, so you see how quickly the lifetimes change with altitude.) China's debris will be in orbit for thousands of years (and I mean that literally). Of course, some pieces could end up in orbits with very high apogees because of rare momentum transfers but they would still decay very quickly since their perigee would still be at 250 km.
3) It would not violate any treaty that I know of. In fact, the only thing
China violated was that it did not warn people that it was going to do that.
However, do we really want to legitimate China's ASAT test by doing this?
Because if we did, China would automatically claim that this was the capability it was developing. (Which I don't believe for a minute.) Is the danger for the hydrazine really that great?

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