UPDATE: A DoD press release states that "Nearly all of the debris will burn up on reentry within 24-48 hours and the remaining debris should re-enter within 40 days." They also say that confirmation that the fuel tank carrying the hydrazine was disrupted will come within 24 hours. Stay Tuned.
UPDATE II: CNN video of a press conference by the Pentagon has some footage of the missile very clearly hitting the satellite. Very cool… and at the very end of the few seconds of the footage, I’d swear a bow wave forms as the expanding cloud slams into the very thin atmosphere at that height. Also, they appear to have seen indications of hydrazine in a spectrum of the explosion they took, which means it looks like they hit the tank.
CNN is reporting that the Navy successfully blew up the spy satellite USA 193 that was in danger of an uncontrolled re-entry:
At approximately 10:26 p.m. EST today, a U.S. Navy AEGIS warship, the USS Lake Erie, fired a single modified tactical Standard Missile-3, hitting the satellite approximately 247 kilometers (133 nautical miles) over the Pacific Ocean as it traveled in space at more than 17,000 mph.
Well then. This was reported to have been postponed, but I guess the seas calmed down enough for them to take the shot.
Interestingly, the CNN story says the missile had no warhead. A simple impact is enough to do the deed; at relative velocities of several miles per second a small pebble can do serious damage.
I’ll note that in their video, CNN shows Hubble when talking about the satellite. Geez.
I don’t know what more there will be to this story until the pieces come down, which may take a few more weeks. As usual, when I learn more, I’ll post!
February 20th, 2008 at 9:57 pm
Have any of the sat watchers had a chance to observe a change in track/ brightness/ existence? If they had, where would they post that?
February 20th, 2008 at 9:57 pm
Im in ur skyz …
February 20th, 2008 at 9:58 pm
I’ll note that in their video, CNN shows Hubble when talking about the satellite. Geez.
Either that or someone on the ship made a *serious* targeting error.
February 20th, 2008 at 9:59 pm
Nice shot, BTW. Go Navy!
February 20th, 2008 at 9:59 pm
scattering debris?
February 20th, 2008 at 9:59 pm
I just checked the ground track at heavens-above.com and it’s swinging way north; I was hoping maybe to get a pass at it tonight. Oh well.
February 20th, 2008 at 9:59 pm
Haha, I like how they relate the satellite to Armageddon and Deep Impact. Good job CNN.
February 20th, 2008 at 10:10 pm
No news report had yet reported on the details of the expected result of the impact, other than the inaccurate “blowing it up.” Presumably the major intended effect was to rupture the hydrazine tank.
Neither did they mention the expected speed of collision, which could be anywhere from 0 to 34,000 mph (matching velocity versus headon collision).
But if it was a significant velocity, wouldn’t the impact slow the satellite (or the center of mass of the remaining pieces of the satellite) and precipitate reentry even sooner? Will it really take several weeks for reentry since the original reports were claiming an unassisted reentry of early March?
Can an impact as high as this be used to slow the spacecraft enough to increase the predictability of the reentry swath?
February 20th, 2008 at 10:18 pm
Cant recall the source but I read that the the warhead was a ~40kg inert mass. Of course with a closure of about 30,000mph K=mv2, thats quite a punch.
February 20th, 2008 at 10:27 pm
From Prince George, British Columbia we were treated to a great show – as our crowd at the Observatory were just getting the first healthy glimpse of the eclipsed moon the sky above broke out into six near-bolide streaks across the sky (Auriga –> Ursa Maj) with tails lasting up to a minute. Satellite, we presume? They were wonderful, accompanied by a crowd of “ooooh’s” in the background! It stole the show from the moon…
February 20th, 2008 at 10:27 pm
What Timothy said.. simple physics. I think the impact will have a significant effect on the speed of the satellite. Seeing the the navy is going for a “kinetic” kill, just take the mass of the projectile and do some math or something. I’m sure they cooked up lots of models of debri fields
February 20th, 2008 at 10:29 pm
Ever considered that a decent optical recce satellite is “just” a telescope (Hubble) pointed in the “wrong” direction” (more or less give some details about relative speeds of satellite and target and angles of view and such)
February 20th, 2008 at 10:47 pm
Phil;
You should be ashamed of yourself for not understanding simple orbital dynamics and atmospheric drag. Remember the MIR space station?
This was so simple, that even the U.S. Navy could do it!
Since the orbit was well known, all anyone had to do was place something else at the right place and time. The rest is simple F=MV^2 and the total distruction of the orbiting object.
Why was it done? Once it got news coverage, the military realized that they had a golden opportunity to show their stuff.
Personally, I would have been more impressed if it had been destroyed by a Laser, but that can wait until another day.
However, when the Navy decided to use a SM-3 missile, they were thumbing thier noses. This is like using a BB gun to destroy the Keck telescope. Simplist possible technology to get the job done.
February 20th, 2008 at 10:51 pm
Obviously this is a government cover story to disguise the fact that that asteroid made a U-turn and came back to get us when we weren’t looking because it’s piloted by Aliens from Zeti Rediculus. Or they might have been on bicycles.
Either way, they had to shoot it down with their frickin’ shark lasers.
Also, Oprah is one of them, (you can tell because she weighs the same as a duck) and she told me not to tell anyone (by telepathy, of course) or else she would aaaaarrrrrrggghhh…
February 20th, 2008 at 10:54 pm
When my local news station reported on it, they had a computer-generated image of Hubble up in the corner. It made me laugh.
February 20th, 2008 at 10:55 pm
This is good news, Phil! W00T!
I’m glad something worked as advertized for once!
Rich
February 20th, 2008 at 11:01 pm
“Debris will begin to re-enter the Earth’s atmosphere immediately,” the department said. “Nearly all of the debris will burn up on re-entry within 24-48 hours and the remaining debris should re-enter within 40 days.”
From the CNN article:
http://www.cnn.com/2008/TECH/space/02/20/satellite.shootdown/index.html
February 20th, 2008 at 11:44 pm
minor point to steven H its kinetic energy that is mv2 not force.
February 20th, 2008 at 11:54 pm
Has anyone checked that Hubble is still there? Maybe that *was* their real target!
February 20th, 2008 at 11:56 pm
Um, will any of the toxic material from the satellite make it to the ground?
February 20th, 2008 at 11:58 pm
I stated the equation of F=MV^2 correctly.
For the mathematical proof, as it applies to a satellite, this website will explain it better than anything that I can type.
http://www.practicalphysics.org/go/Guidance_156.html;jsessionid=alZLdQlAHb1?topic_id=3&collection_id=117
February 21st, 2008 at 12:25 am
Lately, AP reports “unofficials” saying the tank was probably hit.
http://ap.google.com/article/ALeqM5h7aoM2ii3QVBCAV8m2HtJSuPxPNwD8UUGJC04
“[...] two defense officials close to the situation said later that it appeared the fuel tank was hit. One said observers saw what appeared to be an explosion, indicating that the tank was hit.”
February 21st, 2008 at 12:29 am
David; Steve’s right. Kinetic energy is 1/2 m.v^2
February 21st, 2008 at 12:30 am
Although he probably meant (m.v^2)/r
February 21st, 2008 at 12:42 am
Steve, you forgot to divide by R … if you don’t, the units don’t work out in your equation (which is quoted correctly in the link, but not in your post)
Force(newtons) ~ m(kg) v^2(meters^2 / sec^2) / meters OR
Energy(joules = newtons/meter) ~ m(kg) v^2(meters^2 / sec^2).
Remember, dimensional analysis is your friend!
February 21st, 2008 at 1:01 am
I would think that a spy satellite “the size of a bus” was probably a big honkin’ telescope, so why wouldn’t it look like the Hubble? IIRC, Hubble is a modified KH series spy sat.
February 21st, 2008 at 1:55 am
I agree. Why wouldn’t the sat look like hubble? Also, a factor of 1/r is a HUGE deal.
February 21st, 2008 at 2:14 am
Acoording to some graphics at agi.com, the intercept speed in their sims was about 9.8 km/s (7.8 for the sat, 3 for the SM3, coming in from below and front).
http://www.agi.com/corporate/mediaCenter/news/spySatellite.cfm
That is a lot of energy.
February 21st, 2008 at 2:51 am
Here’s the same AGI video on YouTube. Not quite as clear, but loads much faster and is embeddable.
http://www.youtube.com/watch?v=zSd5j8xEaKM
February 21st, 2008 at 4:03 am
Impact energies are interesting in those sort of collisions. For the most part, the impactor should punch strait through, it’s not easy to get them to fragment reliably at those speeds.
Heh, an explosive warhead wouldn’t be finished exploding by the time it passed through at those speeds.
They’ll be relying on fragmentation off wherever it enters that’ll punch through the rest of the body at a slightly wider angle. Can’t say it’d reliably disintegrate the structure, but it’d leave a bigger mess in the back than the front, and you could get reasonable disintegration depending on the internal structure (there needs to be much more internal shrapnel created by the initial spread, effectively using up more of the energy on it’s quick trip through).
The thing would burn up in the atmosphere either way. It’s not shielded, and a full fuel tank would have *much* more momentum to (literally) burn off than an empty one.
It’s still a good test of a an anti-sat weapon, assuming their “success” is somewhat more literal than the old patriot test results turned out to be.
February 21st, 2008 at 4:16 am
Observers in BC, Canada have reported seeing debris:
http://forum.nasaspaceflight.com/forums/thread-view.asp?tid=11627&mid=247539#M247539
More:
http://satobs.org/seesat/Feb-2008/index.html
February 21st, 2008 at 4:47 am
Yesterday on (I think) Reuters’ web site that the combined speed was about 22,000 mph.
As for showing an image of the Hubble… wasn’t one of the Keyholes (KH-11) thought to have resembled Hubble? I had heard talk back when Hubble was launched that it was somewhat based on one of these spy sats.
February 21st, 2008 at 4:54 am
“China expressed concern over “possible harm.”
“China is continuing to closely follow the possible harm caused by the U.S. action to outer space security and relevant countries,” Foreign Ministry spokesman Liu Jianchao said Thursday.”
…Oh you slimy littles… YOU made harm, THEY actually waited for enough decay!
February 21st, 2008 at 5:02 am
[...] if you want a lovely summary of the spy satellite story – check out Phil Plait’s [...]
February 21st, 2008 at 5:05 am
http://podblack.wordpress.com/2008/02/21/were-on-space-debris-alert/
Breaking news! It’s going to hit Australia!!
Near my town! Whoo hoo! 
February 21st, 2008 at 5:26 am
Yeah, China should shut up and lay low. Bunch of hipocrites.
February 21st, 2008 at 5:38 am
I hope whoever got to push the launch button quoted a Bond villain.
February 21st, 2008 at 6:18 am
Key points from a DoD briefing one hour ago and links to some (unconfirmed) independent reports – and impressive DoD pictures of the operation – are here.
February 21st, 2008 at 6:50 am
“Interestingly, the CNN story says the missile had no warhead. A simple impact is enough to do the deed; at relative velocities of several miles per second a small pebble can do serious damage.”
BA, you sound as if you’re surprised by this fact. Others have chided you in earlier posts on your use of the phrase “blow up” when referring to this shot. Yet you used it again in this article? What’s up with that?
February 21st, 2008 at 7:00 am
fly writes:
[[Of course with a closure of about 30,000mph K=mv2]]
And Steve H writes:
[[The rest is simple F=MV^2 ]]
Guys, kinetic energy is
Ek = (1/2) m v^2
and force is
f = m a
Here Ek is kinetic energy (in joules in the SI), m is mass (kg), and v velocity (m s^-1). F is force (newtons), m mass again (kg), and a acceleration (m s^-2).
Check an introductory physics textbook.
February 21st, 2008 at 7:07 am
[...] as Bad Astronomy has already noticed, “this one” was in fact the Hubble Space Telescope. Not a very bright idea, if you ask [...]
February 21st, 2008 at 7:33 am
Here is some footage from the briefing on CNN
http://www.cnn.com/video/#/video/tech/2008/02/21/pentagon.sat.shoot7a.cnn
February 21st, 2008 at 7:41 am
Northern BC – saw everything. Right infront of the ecliped moon passed the pieces of exploded satellite. For once living in the frigid pulp-mill city paid its divdends.
It was an awsome show. Awsome.
February 21st, 2008 at 7:43 am
http://gizmodo.com/359031/video-of-spy-satellite-getting-shot-down
Gizmodo has the footage too.
I prefer them myself, their videos load quicker.
February 21st, 2008 at 8:01 am
Have you seen *this* little bit of craziness?
http://news.bbc.co.uk/1/hi/world/middle_east/7255657.stm
February 21st, 2008 at 9:14 am
Yeah, I noticed CNN put up stock satellite footage rather than a meaningful visual.
Enjoy your blog a lot (a write a vaguely science-themed blog). Thank you, thank you, thank you for the Heavens Above link!
February 21st, 2008 at 9:14 am
Yeah, I noticed CNN put up stock satellite footage rather than a meaningful visual.
Enjoy your blog a lot (I write a vaguely science-themed blog). Thank you, thank you, thank you for the Heavens Above link!
February 21st, 2008 at 9:17 am
“Boom! Headshot”.
I told you so, the odds of missing were nearly nil.
February 21st, 2008 at 10:49 am
“the CNN story says the missile had no warhead.”
Umm, ain’t a kinetic kill vehicle a warhead?
On second thought, maybe not. A bullet is a kinetic kill vehicle, and it isn’t considered a warhead.
February 21st, 2008 at 8:13 pm
I’ve got mixed feelings about this & don’t really know whether to congratulate the folks involved for achieving an impressive technological feat with such good execution and accuracy? Or condemn them for the further militarisation of space and the negative implications this has – diplomatically and for space usage & exploration generally?
Aren’t there some serious issues here with the international (UN?) law on space -in terms if not militarizing space or using it for aggressive military purposes?
Now ok, it was rationalised – not overly convincingly – as a possible threat to people with hydrazine fuel but c’mon, there’s a lot of understandable cynicism about that!
Wasn’t there a lot of hydrazine or suchlike dangerous chemicals spilt when ‘Columbia’ broke up on re-entry? Seem to recall NASA using that as a warning-off from morbid ghouls picking up pieces of the shuttle debris and seling them on e-bay or whatever ..
The real reasons being showing off to China and preventing it falling into non-US military hands strikes me as being much more credible. & just because China does something bad doesn’t mean the USA has to copy them .. “Great Powers” politics is so stupidly & dangerously childish on occassion.
(I blow up a satelite! Hah Hah! Hey! I can blow one up too! Ner,ner! Grow up please “Uncle Sam” and “Chinese Lil’ Emperors”!
In fairness, I ’spose all three reasons could be combined to justify destroying Sat. USA-193 but … hmmn… as I said, mixed feelings & mixed messages there.
I am glad of one thing though – at least unlike in ‘Futurama’ they didn’t miss the real target and blow up Hubble by mistake!
February 21st, 2008 at 8:16 pm
D’oh! Frakkin’ typos!
“Aren’t there some serious issues here with the international (UN?) law on space -in terms if not militarizing space or using it for aggressive military purposes? ”
Should be :
Aren’t there some serious issues here with the international (UN?) law on space – in terms *of* not militarizing space or using it for aggressive military purposes?
Obviously!
—————
‘Needless to say’,
It need not be said
But so many needlessly say it.
Is this because its not ‘needless to say‘
And that’s why we so often say it?
For if its not needless
Then needs must we say
But if not we needn’t e’er say it!
February 21st, 2008 at 9:21 pm
I thought this sort of thing was hard to do and they weren’t having much luck developing antiballistic missiles to intercept ICBMs. Are the computers and tracking better, or are satellites just easy to hit?
February 22nd, 2008 at 11:51 am
Satellites are easier to hit. You know the path well ahead of time, and there’s plenty of time to prepare. ICBM’s give little notice and you have to observe them to project where they will be when you want to hit them.
StevoR said:
> Now ok, it was rationalised – not overly convincingly – as a possible threat to people with hydrazine fuel but c’mon, there’s a lot of understandable cynicism about that!
Understandable cynicism. Maybe multiple reasons for the takedown. Doesn’t negate the hydrazine risk.
> Wasn’t there a lot of hydrazine or suchlike dangerous chemicals spilt when ‘Columbia’ broke up on re-entry? Seem to recall NASA using that as a warning-off from morbid ghouls picking up pieces of the shuttle debris and seling them on e-bay or whatever ..
Yes, there was some hydrazine on Columbia, and there was concern over contaminated parts. Not sure, but it sounds like you’re trying to belittle the hydrazine risk by saying Columbia had hydrazine, too. Couple differences. 1) Columbia had used up most of the hydrazine on board, vs this satellite having full tank. 2) Columbia broke up, dispersing most of the remaining hydrazine, while the satellite was predicted to have tanks survive reentry intact and thus have a large amount concentrated in the strike zone. Also, and this is significant, Columbia was intended to return intact, so breaking up and spilling hydrazine was not intentional, nor was scattering potentially contaminated parts across Texas.
April 27th, 2008 at 11:50 pm
The hydrazine was a red herring. Virtually every spacecraft and rocket ever launched carries some form of it in some amount. A ton seems like a lot, but is it really? The Apollo lunar module had 10+ tonnes of the hypergolic fuels hydrazine (actually Aerozine-50) and nitrogen tetroxide. The Delta II second stage, based on the LM ascent engine, carries about 6 tonnes of the same propellants. The real hypergolic guzzlers were the Titans (a Titan-IVB launched Cassini): 155 tonnes for the first stage and 35 tonnes for the second stage.
These are serious amounts of nasty chemicals for those who work with or near them. Sometimes these rockets do blow up shortly after launch and create a hazard. But the USA-193 tank simply wasn’t a credible threat to anyone on the ground. Spacecraft fuel tanks are thin to save weight, and break apart quickly on re-entry. Hydrazine is flammable (it is a rocket fuel after all) so at most it would have briefly brightened the USA-193 re-entry fireball. BFD.
April 27th, 2008 at 11:58 pm
A comment about “kinetic kill” satellite weapons. At these velocities relatively little momentum is exchanged. It’s as if each object independently explodes and their debris clouds pass through each other with their centers of mass moving more or less unchanged.
August 14th, 2008 at 12:30 am
Lovely post. Please add my email address to your list and email me the updates if possible. I always like to read your blog and comment on it.