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Collided Satellite Debris Coming Down?
Jamie found this Bad Astronomy blog on the many reports beginning about 7 hours ago of one or more fireballs in the sky across Texas. That blog's proprietor first doubted that the phenomena could be due to the satellites that collided in orbit last week, but later left the possibility open. The National Weather Service for Jackson, KY put out an announcement about possible explosions and earthquakes across the area and blamed the defunct satellites. "These pieces of debris have been causing sonic booms...resulting in the vibrations being felt by some residents...as well as flashes of light across the sky. 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."
An Austin TV station has more reports.
now this would be a cool sight to see, i'm hoping nobody gets hurt from all of this
From a few tons of colliding satellite? Seriously?
Oh dear, someone doesn't have a well tuned sense of scale methinks.
A learning experience is one of those things that say, 'You know that thing you just did? Don't do that.' - D. Adams
"I can now state unequivocally that this is not the result of the satellite collision. The meteor is moving far too quickly for that; satellite collision debris would fall at perhaps 10 km/sec max, while incoming meteoroids are moving at 11km/sec at a minimum, and this thing is screaming across the sky at several dozen km/sec (assuming itâ(TM)s at a typical meteor height of 50 or more km). So I was probably right in the first place, and what we have here is almost certainly a single object, perhaps a meter or two across, and it came from deep space"
My understanding was that the satellites were in an orbit high enough that the debris would float around for several thousand years before being caught by the atmosphere. I suppose a few bits might have had the energy to move closer in, but all in all it sounds more like the Martians have arrived. Might be a good idea to go make some bacteria bombs before they finish building those tripedal walkers.
As someone noted above, I'm now very sure this was a natural piece of cosmic debris, a chunk of asteroid or something similar. I posted a wrapup with my thoughts.
*** Phil Plait, aka The Bad Astronomer http://www.badastronomy.com
Staying in orbit requires a the right velocity. The results of a collision will have different velocities and some of that will de-orbit.
Engineering is the art of compromise.
The FAA issued a Notice To Airmen yesterday predicting debris and asking pilots to report.
I think there may be some conflict between the FAA's safety concerns and NORAD's secrecy. NORAD will weigh in eventually (when they're sure what they can and can't say), but there no reason to throw away the FAA's opinion, even though they are not the "go to" agency.
call it spacebook
rewriting history since 2109
(Also posted to Bad Astronomy.)
A simple orbital analysis using the ground tracks from, e.g. Heavens-Above.com shows that this was not debris form the collision.
The debris from a collision keeps more or less the same orbit as before, but is spread out along the orbit. (Orbital plane changes require a lot more delta-v than changing the along-track position or altitude, since drift along the orbit accumulates, but displacements across the orbit swing back and forth with each cycle.)
Looking at the ground tracks of
Iridium 33 and
Cosmos 2251
Just eyeballing the tracks, the North-going leg of the orbit of Iridium 33 crosses the latitude of Texas at around 10 PM local time. For Cosmos 2251, it crosses about 4 PM local.
An 11 AM fireball could be Iridium debris, but only if it were heading to the south-south-east. The fireball was heading NNE. So this was NOT debris from either satellite.
Except that none of the pieces would be anywhere NEAR that size. The iridium satellite was about half a ton, and the Russian satellite weighed in at just under a ton. Even if they had fused into one solid mass on impact, you still wouldn't have enough material to make up "a couple of tons".