Satellite smash was fine-tuned in flight
Posted: Friday, February 29, 2008 4:56 PM by Alan Boyle
This week we exploded five of the myths surrounding last week's spy satellite smash-up, in a report from NBC News space analyst James Oberg. The first myth-buster was that the missile intercept really wasn't a "shootdown," in the sense of a rifle shot that brought down a bird, but was a messier breakup of both the target satellite and the missile interceptor.
Oberg's No. 4 myth was that the Pentagon was actually aiming directly at the biggest potential hazard on the satellite, a tank filled with half a ton of frozen hydrazine fuel. He said it was "hard to imagine" how the warhead's guidance system could have spotted the target on its blobby view of the satellite.
Now Oberg says he'd like to expand upon that remark, based on feedback he's just received from the Pentagon's Missile Defense Agency. It turns out that the SM-3 missile changed its flight path to get as close as it could to the tank. The feedback came from a high-level official, who provided information on a not-for-attribution basis because the official was not authorized to respond publicly. Here's how Oberg summarized the response:
"Actually, while they did not 'aim at the tank' in their gunsight, the Navy space sharpshooters really did target for the tank's known location within the satellite's structure. According to a Missile Defense Agency response to questions from msnbc.com, 'The [warhead] seeker computes an aimpoint on the target’s image that it sees as they come together (quickly), and moves to maximize hit effectiveness. The kinetic warhead (kill vehicle) then sharpened the aim at end game as noted above to move to a sweeter spot on the target.'
"This implies an amazing degree of real-time pattern recognition by the warhead's guidance system. This is a BIG WOW to me. ... I stand corrected, and impressed."
On another point, there had been reports that only 17 pieces of debris from the satellite were still being tracked - but today, veteran satellite tracker Ted Molczan reports on the SeeSat-L discussion board that 42 pieces are on the list. Oberg also notes that the Federal Aviation Administration's warning about falling satellite debris is effective through March 9.
Ironically, the smash-up of one spy satellite has forced a delay in the launch of another spy satellite. So there's no question that the orbital debris is having an effect on the space environment. To claim otherwise would give rise to Myth No. 6.
