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This shows the first 14 pieces of debris associated with Cosmos 2251 to be cataloged
As I said before, it takes a while for NORAD to accumulate enough observations on separated debris before they can uniquely identify the same object over and over. Today, exactly when I expected it (based on the week it took NASA to catalog the first debris from the 2007 Chinese ASAT test), the first 14 pieces of debris have been cataloged and listed on the web. Note that there are three out of the 14 with either very high or very low apogees. What I’m surprised about is that these should have been the first to separate from the swarm and I was expecting them to have the lowest ID numbers. They do not, however. As time goes by, I expect to see many more pieces show up from both satellites. An analysis of their velocity and direction distributions will be very informative about hypervelocity collisions. Oh boy, I’m looking forward to that!
Update: Eight pieces of the Iridium 33 have also been cataloged. We can expect more of these too.
I suppose we have no idea what the impact parameter was? Is it likely we’ll be able to figure it out?
I think lots of things will be able to be examined by the debris pattern but perhaps not the “impact parameter,” at least in a quantitative sense. But the total number of pieces of debris, which will continue to be cataloged over the next year and more, should give us a qualitative feeling for it. However, I put no stock in the very low numbers currently being talked about (several dozen). Lets wait a month and see. After all, we still haven’t even seen any debris formally associated with the Iridium satellite yet.
Some interesting results have just showed up on SeeSat-L. Apparently the dV of the catalogued debris objects are all fairly low, but the Iridium ones are considerably lower than for C2251. I’d suppose this, if it holds up, might result from the details of the collision, what parts of the satellites were involved.
http://www.satobs.org/seesat/Feb-2009/0375.html
The reason I mention it is that a KE impactor is likely to target and hit the center of mass, while a random collision is (more likely than not) rather off-center. So the qualitative behavior might be substantially different.
I’m trying (and failing) to figure out what my intuition says about the physics of such collisions. Can’t decide whether I expect a substantial torque in an off-center collision or not (because it happens too fast, and the portion that is gone vaporizes before imparting any significant mechanical force).
Certainly the energy is deposited much faster than the speed of sound in metal, so I’d think it’d be similar to a detonation of the material in question. For a small impactor on the center of mass, this likely blows the object to bits. For an off-center collision, it might just provide an large impulse and torque. Though likely large enough to cause portions to fragment.
Any idea if any of this speculation is in any way realistic? I’m far from an expert in the field.
Greg Laden posts that the National Weather Service has reported falling satllite debris
for an area of Texas.
From the NWS:
THE FEDERAL AVIATION ADMINISTRATION HAS REPORTED TO LOCAL LAW ENFORCEMENT THAT THESE EVENTS ARE BEING CAUSED BY FALLING SATELLITE DEBRIS. …THE CLOUD OF DEBRIS IS LIKELY THE RESULT OF THE RECENT IN ORBIT COLLISION OF TWO SATELLITES ON TUESDAY…FEBRUARY 10TH WHEN KOSMOS 2251 CRASHED INTO IRIDIUM 33.
Is this even remotely plausible?
Andrew, No, its not plausible. The Texas object was a meteor approximately 1 meter in diameter and had nothing to do with the satellite collision.