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USA 193 Shootdown Set For Feb 21, 03:30 UTC
An anonymous reader writes "Amateur satellite watcher Ted Molczan notes that a "Notice to Airmen" (NOTAM) has been issued announcing restricted airspace for February 21, between 02:30 and 05:00 UTC, in a region near Hawaii. Stricken satellite USA 193, which the US has announced plans to shoot down, will pass over this area at about 03:30. Interestingly, this is during the totality of Wednesday's lunar eclipse, which may or may not make debris easier to observe."
if they chose the eclipse date on purpose. We'll wait and see what they say AFTER it all happens.
... they're going to use a pop bottle to do the deed.
Bruce is a fellow satellite spotter also with some degree of background and in the subject matter and has good coverage here.
Visit Jonesblog and say hello.
A super secret sat is not responding for unknown reasons. This requires a shootdown which just happens to occur during a lunar eclipse.
Wow, who gets the movie rights for this one?
Yep, I never spell check.
More incorrect spellings can be found he
They're shooting it down not because it might hit and blow up, but because it might hit and not blow up, and yield a lot of classified hardware/software for some enterprising person(s) to pick up.
Since that time interval occurs during daylight hours near Hawaii, with the eclipsed moon (necessarily) below the horizon, I doubt the eclipse will have much effect on visibility. :)
When all you have is a hammer, everything looks like a skull.
50's called. They want their missiles back.
Disappointing. We need to LASER it.
The ill-tempered sea bass have a limited range, sorry.
This post may or may not be a way to tell you that may or may not is a totally ambigious statement. Some people may or may not notice this. I may or may not be modded Offtopic but I can also be modded +1 Funny or +1 Insightfull. However, this may or may not be the case.
Knowledge is power. Knowledge shared is power lost.
:(){
I find your post a little hard to follow, however with regard to space debris, the satellite is sufficiently low that all the debris is expected to deorbit relatively quickly (days or weeks).
Grr! Arg!
While perhaps a bit unconventional, there's a lot to be said for our government's decisive action here that could prevent a small-scale disaster if the satellite were to hit the ground. It seems like the prudent thing to do.
*cough*THEL*cough*
An airplane needs an engine to fly, and when that engine is destroyed and crashes somewhere near where you shot it down. A satellite needs no engine to fly, and when you shoot at it, it becomes thousands of little satellites, all of which continue to "fly" at 25,000 miles per hour.
I hope the people shooting at (not "down") this satellite have seen "Fantasia." In _The Sorceror's Apprentice,_ Mickey Mouse decides that the best way to deal with an out-of-control magic broom is to chop it into thousands of pieces... all of which just keep right on going, making the problem worse instead of better.
"How to Do Nothing," kids activities, back in print!
That this is just a response to China's ASAT test of January last year?
China: you see, we can blow up your satellites!!
USA: aha! We can blow up your satellites too!!
General public: Why are they blowing up satellites?
How we know is more important than what we know.
I doubt the lunar eclipse has anything to do with it. The timing is almost certainly based on the need to get the SBX to sea and in position (it's not exactly a speedboat), and the best orbital conditions for the shot. The location was almost certainly based on the SBX being in Hawaii and having nice long empty stretches of ocean downrange for the SM-3 missile. (Both for the booster and for the payload to fall if it misses.)
No doubt goats will be slaughtered, wiccans consulted, and pentagrams drawn all in the hope that our missile intercept technology will actually work in a non-staged event.
Have gnu, will travel.
Are there any Slashdotters here in Hawaii?? Surely a missile zooming up to shoot down a satellite would be visible, would it not?
Fixed
I'm surprised we didn't outsource this to China.
I really hope the weapons officer who gets to push the missile-firing button says: "ASSIMILATE THIS!!!"
- They don't want a repeat of Skylab where parts landed in Australia and made us look bad.
- If it comes down in Russia (Russia spans 11 time zones so that's not too unlikely) they don't want the Russians to be able to figure out much from the debris.
- They want a chance to test their anti-satellite weaponry on a real target that isn't saying "Over here! I'm over here! Here I am! Yoo Hoo!"
There's actually a 4th reason - blowing stuff up is fun but they would never cop to it.Actually, it doesn't. Orbital mechanics guarantee that the debris will pass through the same altitude one orbit later.
That's certainly believable if you can take Deputy National Security Advisor James Jeffrey at his word:Apparently man-made objects containing hydrazine propellant frequently rain down from the sky without incident, according to rocket scientists and space security experts who "scoff" at this rationale. And Joint Chiefs of Staff Vice Chairman Gen. James Cartwright doesn't seem too impressed either. But surely our Deputy National Security Advisor knows something about hydrazine that we don't.
Now who is this man James Jeffrey, you may ask?Source: Wall Street Journal, July 19, 2007, four months before the information in the Iran NIE would be exposed, having been known to the White House since 2006.
This guy sounds totally not full of shit at all!
Along the lines of the self-destruct, I agree that a satellite which absolutely could not be allowed to return to Earth intact would be built with the proper destructive methods.
However, a self-destruct would also be useful in cases just like this, where the danger is not classified information, but hazardous materials. I am assuming that satellites are usually launched with the anticipation of decaying orbits, so why not build satellites with standard self-destruct for cases like this?
It seems like a relatively common occurrence (Skylab, anyone?) and seems like it would be a lot less expensive and require less logistical planning than having to time a missile interception.
I had a chat with my grandfather who works on attitude control systems for commercial satellites about hydrazine. Hydrazine is used for attitude control and orbit stabilization. Since contact was never made with this USA 193, the hydrazine tank should be full. The ignition for hydrazine is heat, so all they do to fire it is have a little toaster that ignites a little bit of fuel at a time. Because the ignition source is heat, the hydrazine tank has to be incredibly well insulated to maintain a constant temperature. If the tank were to survive reentry, by being shielded by other components melting off, it would most likely rupture when it hit the ground at terminal velocity. Hydrazine is a pretty serious hazmat, and even a small concentration of that into your system will do serious, potentially permanent or even fatal damage to your lungs. Even worse, the hydrazine could ignite upon hitting the Earth and cause a small explosion, though the gas leak is more likely. If you took the surface of the earth and divided it into 1 acre chunks, I doubt more than 5% of those acres would have people in them( figure 10% of the Earth is inhabited, and large portions of that are farm) Nevertheless, a 1/20 chance of killing/permanently damaging anywhere from 1(hits near Bear Grylls in the desert) to 10,000 people(hits Rio), it certainly seems like a politically influenced decision to get rid of a potential disaster.
Okay, forget for a minute that the orbit is decaying. Whether or not a decaying orbit is "in orbit" is kind of a philosophical question.
So imagine the satellite in a stable orbit. Then you blow it up. So some pieces go flying in all directions. If you work out the orbital mechanics, every one of those pieces will be in a different orbit, but all of those orbits will pass through the point of the explosion. Caveats: this isn't true of orbits that intersect the ground first, or bits that, as you noted, get flung out of orbit altogether - that is, they achieve escape velocity. Escape velocity is awfully fast though, so that's probably not an issue here, and if something does hit escape velocity then it's not going to be a problem for us because that chunk of satellite will be GONE.
That's the reason you can't fire things into orbit with a gun (railgun, whatever), by the way. Any "orbit" you can put it into will have a point intersecting your gun. In order to put something in orbit that way you'd have to fire it out of the gun, then have a rocket on board to fire later and put it into an orbit that doesn't intersect the ground.
You can't actually escape the gravitation of anything, much less a planet. Technically, Earth, the sun, your toothbrush, will all pull on you (very weakly) no matter how far away you get. What you're thinking of is escape velocity, the speed at which you will never fall back, but continue on (slower and slower) outward forever.
Things we send into space can go a few different ways. If it's above escape velocity (Voyager, say) then it will never come back. If it's in a nice high orbit, way above the atmosphere (like geosynchronous satellites) then it will stay up for a LONG time. It will probably eventually come down, because there are always a few stray particles and things, but not for a long, long time. Things on a suborbital trajectory will come back down without circling the planet. Like SpaceShip One. Or you can have a low orbit, like spy satellites and the space shuttle. The atmosphere at that altitude is really thin, but not non-existent, so without thrusters to boost the orbit those sats will come back down, often on a fairly short time scale. The space station is fairly high (and massive) but if I recall correctly, it's orbit will decay in something less than a year without periodic boosting.
The problem with the satellite is that they've lost control. It isn't responding to commands. So it has lots of fuel (hydrazine) but the controllers have no way to fire the thrusters.
As someone else pointed out, orbital mechanics is kind of a counterintuitive thing. You'd think you could shoot things into orbit with a big enough gun, or that blowing up a satellite could boost some bits of it into stable orbits, but it turns out not to work that way. Something else weird: when you thrust in the same direction as you're traveling you slow down. You gain altitude, but you slow down - the opposite of what we normally expect. These satellite bits are speeding up (and losing altitude) due to atmospheric friction.