AP is reporting that the Pentagon is planning to "shoot down" the errant NRO bird.
You can't "shoot down" a satellite. In order to do so, you have to remove its momentum, so it falls out of orbit. All you can really do (at least with something as crude as a missile) is break it up into smaller pieces. If that's what they plan to do, they certainly can.
Won't it make a mess? Yes, for a while. Some of the pieces will enter immediately, others will be given a higher apogee (but lower perigee, so they'll enter half an orbit later). The orbits of those that aren't given much of an energy change will continue to decay as the satellite's original orbit was, except at a higher rate, because they'll have a lower mass/drag ratio. So in theory, if they do this, all of the pieces will have entered within a month or so (i.e., none of them will survive longer than the satellite itself is expected to).
This just points up the fact, once again, how nice it would be to actually have a robust in-space infrastructure of tugs and servicing facilities that would allow us to take care of things like this in a more elegant fashion. In fact, it would allow us to even go get the thing and put it in the right orbit, so we wouldn't have to dispose of it, and replace it. Unfortunately, it's not a capability that either NASA or the Air Force evidence any interest in developing.
[Late afternoon update]
Daniel Fischer is live blogging the Pentagon briefing on NASA TV, here and here.
No! I want a chance at a free taco!
>This just points up the fact, once again, how >nice it would be to actually have a robust in->space infrastructure of tugs and servicing >facilities that would allow us to take care of >things like this in a more elegant fashion.
Unfortunately, space just isn't important enough to justify a robust in-space infrastructure. You might as well complain about the lack of airship hangers.
Would breaking it up decrease the amount of debris
that reaches the ground or just spread it out over
a larger area?
If they decide to "shoot it down", it will be solely for geopolitical reasons, not for sanitary reasons.
The excuse given is to rupture the fuel tanks and release the hydrazine, which is mostly unburned.
I think this real reason is to demonstrate ASAT technology, maybe a response to the Russian/Chinese proposal of an ASAT ban ("Look! We need ASAT to shoot down broken satellites! Just being tidy!")
Breaking it up would decrease the size of the debris, which would reduce the amount that would make it to the ground. The “burn up” by reentry is a factor of exposed surface area and blowing the sat up will increase that.
So there’s some logic to it.
Unfortunately, space just isn't important enough to justify a robust in-space infrastructure. You might as well complain about the lack of airship hangers.
I must have missed something. Does NASA spend $17 billion a year on airships?
Does DoD spend a similar amount?
I think you simply underestimate the explosives required to shoot it down without debris. Perhaps they are planning to use nukes like in the game missile command (best to use two just in case it slips by).
Yeah there would be political, financial and EMP effects but anyone over 30 (with the proper rolling ball controller) could probably target the missiles and ensure it was effectively taken out.
Not saying there isn't a geopoltical reason to do it. There's also the PR and the "sexy" factor too.
But at least this ASAT test could be tidy.
If the satellite is close to the point of orbital decay and you hit it against the velocity vector, you'll remove momentum from it. That'll lower the perigee and cause quite a bit of it to decay more rapidly, in effect, shooting it down.
The Chinese ASAT test last year hit a satellite that was over 500 miles high. Some of the debris from that test will still be up there 100 years from now. This will be a much lower target so there shouldn't be nearly so much long term debris.
This will be a much lower target so there shouldn't be nearly so much long term debris.
There will be none at all.
>I must have missed something.
It would hardly be the first time, Ed. :-)
>Does NASA spend $17 billion a year on airships?
>Does DoD spend a similar amount?
Leave it to a socialist such as yourself to judge the importance of something by how much the government spends on it. :-)
But, yes, there once *was* a time when the government spent considerable sums of money (and quite a few lives) on the research, development, and operation of rigid airships with dissapointing results. And there were those that insisted on major investments in airship infrastructure on the premise that future results were *certain* to justify them.
It all seems quaint now.
I hope space avoids that fate.
Jim Davis
I think this is a reasonable thing.
It's a no downside demonstration.
They need to wait until the sat is really low and about to decay then they should set up a series of tests...
first shot near japan targets sat.
2nd shot neat Hawaii targets largest two pieces etc...
That way we get to practice shooting down incoming mirvs.
how nice it would be to actually have a robust in-space infrastructure of tugs...
I would think that a tele-robotic tug would be economically viable now assuming it used a fuel that didn't just boil off, could be refueled in orbit and just hung around in orbit until needed. The single launch of such a tug could be amortized over all it's lifetime usage which I would presume to be decades.
A manned version would be preferable but require more support that isn't so economically viable.
Tards talking to tards.
This article doesn't tell the whole story. They're going to wait until it is entering the atmosphere to shoot it, so there won't be anything running around in erratic orbits.
The official reason is that there are sensitive, confidential components on board. What is so senseless about that?
me
me wrote:
"Tards talking to tards.
This article doesn't tell the whole story. They're going to wait until it is entering the atmosphere to shoot it, so there won't be anything running around in erratic orbits.
The official reason is that there are sensitive, confidential components on board. What is so senseless about that?"
Tards to tards?
At the press conference they said that they would shoot at it above the atmosphere.
They also said that they were not shooting it down because of sensitive, confidential components.
So, you're wrong on both counts. Who's the tard?
How about a remotely operated fuel release valve that's independent from other systems? If a satellite goes wonky, you push a button and it empties itself.
Armchair rocket science is so much easier than the real thing!
yes, there once *was* a time when the government spent considerable sums of money (and quite a few lives) on the research, development, and operation of rigid airships with dissapointing results.
Yes, and there was a time when the government spent a "considerable sum" on messenger pigeons -- a few million dollars isn't anywhere close to $17 billion but it is "considerable."
What does that have to do with your curious belief that the lack of airship hangars proves "space just isn't important enough to justify a robust in-space infrastructure"?
Next, I suppose, you'll tell us space is not important because Mickey Mouse doesn't wear an overcoat?
A different era, Ed. We didn't spend $17 billion on anything then. Surely you're not suggesting as a result that nothing was important back then?
No, Jim, I'm suggesting (in fact, stating) that the space economy today is much larger than the airship economy. Hence, your inane comment about the lack of airship hangars has no relevance.
It's like saying NASA deserves more money because Americans spend more on Coca Cola. To determine whether space infrastructure is justified, you need to look at the space economy -- not the Coca Cola economy or the airship economy.
I'm sorry if that point was too subtle for you.
That "space just isn't important enough to justify a robust in-space infrastructure" is an observation not a conclusion.
No, Jim, an observation is a fact. Your statement is not a fact, it's an opinion -- a conclusion -- your conclusion.
An obervation would be something like, "Jim Davis says that space isn't important enough to justify a robust in-space infrastructure."
Or, "Jim Davis says that space isn't important enough to justify a robust in-space infrastructure but isn't able to provide any logical argument to support his conclusion."
Unfortunately, space just isn't important enough to justify a robust in-space infrastructure. You might as well complain about the lack of airship hangers.
Jim, while I don't necessarily disagree with your initial statement, politically speaking, the second sentence seems like a bizarre non sequitur.
We have no airships, to first order. We have many satellites, and they play a vital role in our national defense.
Since Hydrazine is also a monopropellant, one might expect that under the high energies of impact, the Hydrazine will detonate. That will get rid of most or all of the Hydrazine. What it does in giving delta-v to the *rest* of the structure is uncertain. Some of it would be even more decisively slowed, while other portions will get a boost forwards. This might prolong the orbital lifetime of a *small* percentage of the debris, no?
Regards,
Tom Billings
Some of it would be even more decisively slowed, while other portions will get a boost forwards. This might prolong the orbital lifetime of a *small* percentage of the debris, no?
No. Regardless of how much energy is put into any piece of debris, while it might dramatically increase the apogee, it would correspondingly decrease the perigee, bringing it in within half an orbit. The orbit's period might be increased quite a bit, but unless it is increased to something beyond that of the moon, it will still come in within a week or two. If it is increased beyond that of the moon, most likely it will escape completely and never return. I'm assuming that this is the logic that Aerospace was working on.
Jim,
I advise you to "let it go". I got the metaphor, and I understand it as a metaphor. Perhaps not a perfect one, but few metaphors and analogies are. You could try to explain it again, but if you haven't noticed, it is a pointless act.
Certainly the importance of Space isn't measured in terms of dollars. And if one does want to measure it that way, then the way the US spends its dollars is hardly to develop new and innovative infrastructure, such as suggested by Rand. Indeed, not only on the space infrastructure, but on a terrestrial infrastructure necessary to build the space assets.
A standby Space Tug might make sense at GEO as the amount of energy necessary to move around the GEO cluster of sats is not huge.
A standby Space Tug at LEO makes no sense, as it would have to be in the same plane as the sat it wants to tug. plane changes are very expensive from a delta V standpoint. The DV to go from an the ISS orbit to an equatorial orbit is about the same as that needed to go from LEO to GEO.
A Space tug that goes from LEO to GEO and back to LEO
would need performance on par with a SSTO 9km.sec delta V. The possible big win would be to use some kind of low thrust high ISP ION thruster.
A Space Tug that takes a sat from LEO to GEO would add complexity and risk to the mission, where there are a lot of low risk off the shelf solutions for this problem. For the TUG to work effectively the sat its towing would need to bring enough propellant with it to give the tug such that the tug can refuel.
Why didn't they put a laser on the shuttle than we could just fire away the way Bond did in Moonraker, followed of course by zero g sex and bad jokes from Q.