Posted on 02/17/2009 10:24:42 AM PST by Freeport
Space weapons are dangerous – but out-of-control, defunct satellites can do just as much damage, if not more.
So says a leading space scientist who has calculated that Tuesday's collision between an Iridium communications satellite and the defunct Soviet-era Cosmos 2251 spacecraft expended a great deal more destructive energy than China's infamous anti-satellite missile test did in January 2007.
In 2003, space debris expert Hugh Lewis and colleagues at the University of Southampton in the UK ran predictions on the debris field that would be created in a hypothetical Iridium satellite break-up owing to a collision with just 1 kilogram of space junk (Acta Astronautica, doi:10.1016/S0094-5765(02)00290-4).
Now, based on initial analysis of Cosmos 2251's orbital data, mass and velocity, he has estimated some of the dynamics involved in last week's much more energetic collision event.
To be completely obliterated, a spacecraft must suffer a direct hit with an energy of 40 joules for every gram of its mass.
In China's anti-satellite (ASAT) test, a defunct weather satellite called Fengyun-1C was destroyed by a missile that imparted an estimated 350 joules per gram of its mass. (The figure is an estimate because the missile's mass is not known for certain.)
But the Iridium and Cosmos satellites collided at 42,120 kilometres per hour, Lewis calculates, imparting 50,000 joules per gram of their mass.
(Excerpt) Read more at newscientist.com ...
From the articles I've read, I had assumed that this was an overtake collision where the cosmos and the iridium were in essentially the same orbit and therefore a much likelier chance of a collision.
This was more like two cars meeting at an intersection... Except both were going in excess of 17,000 MPH!
a couple of good solar flares (the big ones, the kind that can screw up a power grid) can knock a lot of the smaller debris out of orbit.
Damn, iff’n I had a space garbage truck I’d sho nuff clean up on the disposal..... (believe it or not, there was a short lived SciFi programs about this)
Any chance this was not an accident, or that we are not being told “the whole truth” about this incident?
Iridium is now a U.S. military communication system, correct?
I assume we have the technology to know whether or not the Russian trajectory was coincidental or intentional and I trust the grownups not to reveal that (just please don’t tell Feinstein). Unfortunately, I do not trust the current set of grownups to process that info and draw the correct conclusions.
What's the aircraft collision probability over Denver?
The mere fact that this was not predicted blows my mind. All US space vehicles are monitored for collisions. There is an entire AF unit designated to do just that. Are they grossly incompetent? Maybe, their ranks are filled with as many PC idiots as any corporation. It is possible.
How would they do that?
If it wasn’t an accident then who was driving the dead cosmos? The cosmos has been dead at for at lease 20 years now.
No. It’s a case of all probabilities eventually do happen...
Could this be a semi-deniable Russian test, or warning? A demo that they can take out our Iridiums? (I think there are 66 up, each the size of a mini-van.)
If they can get an Iridium, then the bigger lower spysats would be easier, I’m thinking.
Can't ever say "never," but it's almost certainly an accident. It would be almost impossible to target such a collision with the sort of hardware involved. At most, a person seeking to cause a collision could adjust an orbit so as to increase the likelihood of one -- but the odds would still be tiny.
When a tree falls in the woods and no one is around does it make any noise??
Seems everyone did know they would come close to each other, but it never occurred to anyone that they’d actually collide.
I think the probabilities were so outrageous (Bugg’s Bunny actually jumping off your TV and stealing your soda ridiculous.) that no one bothered to do anything about it.
Solar flares have the effect of heating the upper atmosphere, which makes it extend higher above the earth.
An orbiting object that encounters air molecules experiences drag, the effect of which is to cause the orbital altitude to decrease.
For objects with a high area/mass ratio, the increased atmospheric density will cause them to drop relatively quickly into thicker air, and they'll decay relatively rapidly.
For objects with a smaller area/mass ratio, the effect of drag is correspondingly less.
“At most, a person seeking to cause a collision could adjust an orbit so as to increase the likelihood of one — but the odds would still be tiny”
Yeah, you’d basically need a camera on board & manually aim the thing
But how do we know it was “a dead cosomos?”
Because our govt said so?
Would they tell us if the Russians had just one-upped us, firing a shot across our bow?
Or would they go along with a bogus cover story, to save face?
The name Iridium wasn’t an accident. A marketer at Motorola noticed the number of satellites that were going to be in the constellation matched with element 77, Iridium, hence the name. Everyone though it was cool... :-)
Manually aiming something at a closing velocity of about 17,000 MPH (for 90 degree hit) isn’t going to be possible.
By the time you saw it and you reacted... Well... Think about that a minute.
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