ASATs typically come in two flavors - direct ascent and co-orbital. They can also use either kinetic energy (direct impact), exploding warhead, or a nuclear detonation to take out the target. The direct ascent variety never needs to achieve orbit. They simply have to be able to climb high enough to intercept the target satellite and hit it with enough kinetic energy to destroy it or to detonate a weapon. Truth be told, any IRBM with a nuclear warhead could be used as a type of direct ascent ASAT if it is accurate enough, but the EMP effects could well do massive damage to the launching country's infrastructure.

I haven't been keeping up on my space history, so please forgive me, but has the US developed any space weapons yet that can blow up satellites? I heard somewhere that the US did develop the same thing China tested last week in the 1970s, but I have been unable to verify that claim.

As other posters have noted, the US has at times tested ASAT weapons. However, none are currently operational. Our last ASAT test was in 1985 when a direct ascent ASAT that used direct impact was launched against an old satellite that was successfully destroyed.

The old Soviet Union had an operational co-orbital ASAT for many years but, to the best of my knowledge, it has been abandoned. The last test for it was back in the 1980s. Their ASAT used an exploding warhead and shrapnel to destroy the target.

The bottom line is most exoatmospheric anti-missile systems inherently have some anti-satellite capability, even if that's not their main design purpose.

The new ABM weapons being developed can potentially have some ASAT capability. I don't know if the Navy missiles launched from an Aegis cruiser can get high enough to destroy most satellites of interest but I'm reasonably sure the ground based missiles being fielded in Alaska and California can. To be an effective ASAT, you have to be able to reach the target's altitude. The most militarily interesting satellites are typically in orbits over 400 kilometers high.

Surely much of the debris will have lost orbital velocity?

According to my just retired work partner (who had a Ph.D in astroengineering), satellites are fragile enough that the impact would cause the target to break into hundreds, even thousands of pieces. Some of the pieces would lose enough energy to reenter but many will be up there for 10 years or more. It depends on many factors, such as the altitude, the mass and surface area of the pieces, and the relative mass and impact angle between the intercepter and the target.

As for my earlier remark about treaties being little more than pieces of paper, I cite the examples of the Munich Pact and the non-aggression treaty between the Soviet Union and Nazi Germany. Both were used to buy time until they could be ignored. Personally, I put very little faith in diplomatic agreements.

Note that although the US Ground-Based Midcourse Defense isn't a purpose-built ASAT system, it is now operational and could probably intercept satellites if so ordered. The booster achieves about 19,000 ft/sec (5.9 km/sec). Not sure what the altitude limit is, but it would be pretty high.

http://www.missilethreat.com/missile...tem_detail.asp

Sorry about that. I don't often get to say things within my area of expertise on BAUT, so I jumped at the chance.

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Quaeso quousque humi defixa tua mens erit? Nonne aspicis, quae in templa veneris?

I wonder what is First Image viewpoint.

Do not hold horses. Call me idealistic idiot. Go ahead.

Force, mutual benefit, anything that works will be fine for me.

They say no word about this test, only general BS about non-militarizing space. I imagine that if these accusations about ASAT test was false, then China would protests, screams and demand blood and Pokemons from liars.

Yeah, because laws of physics are not applicable to Great Chinese Nation...

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Sanity is overrated.
Butterfly.

All this takes me back 40 years to when I had
a heavyweight Sunday paper delivered so I had
some alternative to the family tabloid. The
first one had an article about anti ballistic
missiles. First I heard about Sprint missiles
although a small book I had described Nike Zeus.
Fascinating! Five years passed and a colour
suppliment showed the first operational base
for the system. Thirty nuclear tipped missiles
ready to go! Another few years and a treaty
comes between the Soviet Union and the USA. And
the Pentagon cannot decommision the base fast
enougth! I remember a documentary describing how
Khrushchev confided with Eisenhower how his
military kept proposing very expensive systems
and they had to accept most or appear reckless
with security! And Eisenhower went on to warn
against the Military/Industrial complex.

Well... the First Image describes individuals rather than states or the international system as the most important actors.

Not my intention. I just saw that the debate was getting heated and stepped in to calm the waters since the topic was rather political. Sorry if it came off as patronizing.

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Quaeso quousque humi defixa tua mens erit? Nonne aspicis, quae in templa veneris?

Very interesting:

http://www.tcsdaily.com/article.aspx?id=012207E

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Sanity is overrated.
Butterfly.

Speaking for myself, I wasn't looking for a fisticuffs, just standing by the belief that this didn't seem to be something that could be won through a simple courtesy treaty. Not to say those don't work, but there's usually some level of trust between the component parties of such agreements.

Call me blind, but I just don't see it here.

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The last time I felt a warm fuzzy feeling, I was informed by my doctor that it was just gas.

Given the stated intention of the US to establish a monopoly of force in space, this is hardly a shocking development. If I were running China, I wouldn't have done anything different. The Chinese are just trying to make sure they won't have their access to space restricted by the Americans. I don't consider this move threatening at all.

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"I worry that, especially as the Millennium edges nearer, pseudo-science and superstition will seem year by year more tempting, the siren song of unreason more sonorous and attractive." - Carl Sagan, 1995

Apparently a lot of the debris has gained velocity and gone into higher orbits. Not sure if this was due to an explosive warhead or a kinetic intercept from behind.

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"The truth may be out there, but lies are inside your head" Terry Pratchett

Given the stated intention of the US to establish a monopoly of force in space, this is hardly a shocking development.

That's a gross mischaracterization of US policy. We're heavily dependent on space for our military and intend to protect our access to space. That doesn't mean we're trying to achieve a monopoly. If an opponent tries to use their space assets against US or allied forces, our policy is to do what we can to disrupt their operations. In essense, that's no different than stopping resupply ships or truck convoys. Would you make the claim that the US is trying to monopolize the oceans or roads?

Some people put a lot of faith in arms agreements and treaties. From my perspective and that of history, that's naive. Arms agreements only have meaning if all sides actually stick to them. In the past, this has hardly been the case.


Here's a famous quote from someone who put too much faith in a signed piece of paper.

My good friends, for the second time in our history, a British Prime Minister has returned from Germany bringing peace with honour. I believe it is peace for our time.

Neville Chamberlain

Eleven months later, Hitler invaded Poland and World War II began. Oh, if Stalin were still around, you could ask him about the value of treaties, too.

Interesting. I remember that policy statement a while back, I don't recall the concept of a sole monopoly being mentioned, simply the ability to prevent our access from being restricted.

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The last time I felt a warm fuzzy feeling, I was informed by my doctor that it was just gas.

Got a question for those of you aiming the blame cannon with the US in their sights.

Have any of you thought your knee jerks through enough to consider that space weapon systems don't just pop up overnight, or over the course of a year or so? If anyone thinks this test is a specific response to that policy statement a few months back, get some perspective. The necessary support technology to deploy this system, if its reached even a testable level of operational capability now, has been cooking for a while in ground tests, simulation and development. This thing is easily pre-dating the Bush memo, probably more closely related to the relative successes the US has had with the development of its ABM defense system, trying to get one up on the US from that perspective, than anything to do with stated ambitions for space weaponry of our own.

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The last time I felt a warm fuzzy feeling, I was informed by my doctor that it was just gas.

Here is the washington post on the subject:

http://www.washingtonpost.com/wp-dyn...701484_pf.html

This is pretty much outright saying that the US wants to control China's access to space. Aggressive statements don't sound so aggressive when its your nation issuing them.

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"I worry that, especially as the Millennium edges nearer, pseudo-science and superstition will seem year by year more tempting, the siren song of unreason more sonorous and attractive." - Carl Sagan, 1995

There´s no doubt about the nature of the impact. The use of a warhead in space would have set a dangerous precedent. And btw, the Chinese didn´t test a 'anti-satellite weapon'. They´ve tested a method to take out a satellite using a rocket.

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What brings us together is stronger than what pulls us apart

Apparently a lot of the debris has gained velocity and gone into higher orbits. Not sure if this was due to an explosive warhead or a kinetic intercept from behind.

There´s no doubt about the nature of the impact. The use of a warhead in space would have set a dangerous precedent. And btw, the Chinese didn´t test a 'anti-satellite weapon'. They´ve tested a method to take out a satellite using a rocket.

If the reports of debris pieces ending up in higher orbits than the target are accurate (and I think they are), then that indicates the interceptor must have struct the target somewhat from below as opposed to a direct head-on impact.

Warheads on an ASAT are nothing new. The Soviet Union's co-orbital ASAT program of the 1970s and 80s used a warhead. They tested it many times.

The Chinese test was most definitely an ASAT weapon. Killing a satellite is a non-trivial task. It was a deliberate operation to destroy the target with equipment made for the purpose, not merely "take out a satellite using a rocket".

Hum
it was just an impactor.

Latitude=28.27162 Longitude=102.00292

Here is an image of the Xichang Space Centre, and another which strangely has been censored by google...

Attached Images

	236771562_ab8da0418c_o.jpg (123.7 KB, 12 views)
	367122969_d5d559b426_o.jpg (76.2 KB, 14 views)

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`Irony` actually does mean `metal like`...

http://www.msnbc.msn.com/id/16757285/

Heads up, China's confirmed the test. It happened.

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The last time I felt a warm fuzzy feeling, I was informed by my doctor that it was just gas.

Asked about the danger posed by satellite fragments, Liu said he was not in a position to give an immediate response. “This is a highly technical question,” he said.

Or more likely: "If we told you anything about size and trajectories, it would reveal more about what we did."
I see a lot of double talk being made at this time... But; I won't get into it because it could get too political.

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Numbers are not case sensitive. (me)

Naturally.

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The last time I felt a warm fuzzy feeling, I was informed by my doctor that it was just gas.

Hum,
the size, orbit and trajectories can `easily` be guessed/worked out.

If i have some spare time from playing Quake, i`ll see if any large fragments are due to re-enter the Earths atmosphere.

__________________
`Irony` actually does mean `metal like`...

Hum,
simpler than i thought...

Debris (1999-025E) from the Chinese Feng Yun (Wind and Cloud) 1C polar orbit weather satellite that was launched in May, 1999, is predicted to re-enter the Earth atmosphere around noon on the 4th February 2007, ± 12 hours.

(Recap: The satellite was destroyed by an anti-satellite system launched from the Xichang Space Centre on 11 January, when it was passing 865km overhead.)

This piece of debris has currently the lowest orbit (orbit inclined at 99.443 degrees); other pieces (at least 33) have been scattered into an orbit as high as 3499 x 845 km, with orbits inclined as much as 100.158 degrees.

The polar satellite had originally an orbital height and inclination of 860 x 882 km, 98.6degrees.

TLE Data

Code:

FENGYUN 1C DEB
1 29716U 99025E 07024.49494127 .01363722 33951-5 74796-3 0 192
2 29716 099.4426 017.3279 0364082 273.4912 082.4608 15.51951446 1719
1 29716U 99025E 07023.91433350 .01390212 33879-5 85396-3 0 178
2 29716 099.4450 016.5605 0366117 274.6917 081.2592 15.50458593 1622
1 29716U 99025E 07023.91433388 .01388963 33879-5 85566-3 0 189
2 29716 099.4451 016.5607 0366017 274.6927 081.2501 15.50454943 1620
1 29716U 99025E 07023.52695506 .01394895 33843-5 84444-3 0 162
2 29716 099.4442 016.0514 0371283 275.8180 080.0741 15.49414372 1563
1 29716U 99025E 07022.94540536 .01412604 33792-5 87485-3 0 158
2 29716 099.4442 015.2907 0377187 278.0657 077.7892 15.47858472 1474

Attached Images

AAAH Feng Yun.jpg (83.8 KB, 9 views)

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`Irony` actually does mean `metal like`...

Here's a nice visualisation of the orbital data. The pictures are a stereo pair, if you have a dual lens viewer handy or can manage the cross-eyed trick without a viewer. The orbit/blob labelled Fengyun 1C is where the original satellite would be without the impact.

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"The truth may be out there, but lies are inside your head" Terry Pratchett

Hum,
nice image,

Yes, according to my calculations, at around noon the original satellite position would have been over Antarctica (142° west 73° south); the first piece of Fengyun 1C debris due to renter has a very similar orbit.

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`Irony` actually does mean `metal like`...

From ABC News, 02/01/07

Blowing up satellites is bad, m'kay?

When that junk starts deorbiting, its going to be fun.

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The last time I felt a warm fuzzy feeling, I was informed by my doctor that it was just gas.

US Debates Response To Chinese Anti-Satellite Test
http://www.spacewar.com/reports/US_D..._Test_999.html

From AviationNow: China Asat Test Called Worst Single Debris Event Ever

Chinese delegates will have some explaining to do in Vienna later this month, when they sit down with representatives of other spacefaring nations to adopt international guidelines designed to mitigate the growing problem of man-made space debris in Earth orbit.

The document drafted by a technical subcommittee of the U.N. Committee on the Peaceful Uses of Outer Space is aimed at preventing the sort of accidental events that have gradually engulfed Earth in a cloud of potentially destructive high-speed debris since the flight of Sputnik 1 kicked off orbital spaceflight a half-century ago. Chinese experts helped draft the document.

But China's Jan. 11 test of a primitive anti-satellite weapon against an aging weather satellite boosted the population of trackable debris by more than 900 objects--an instantaneous 10% increase in the 50-year figure--that threaten all spacecraft flying below about 2,000 km. (1,243 mi.).

"We still await a complete explanation from China as to how this ASAT test squares with its professed desire to seek only peaceful uses of space," says a U.S. State Dept. official, presenting the official U.S. government position on the test.

The test impact over the Chinese launch site at Xichang came with the target--the Feng Yun 1C weather satellite--in polar orbit at an altitude of 537 mi. (AW&ST Jan. 22, p. 24). The satellite and the missile-launched Asat weapon shattered into thousands of pieces that were thrown into a wide range of orbits ranging in altitude from 3,800 km. on the high end down to about 200 km. at the lowest, according to Nicholas Johnson, NASA's chief scientist for orbital debris and a longtime expert in the field.

"This is by far the worst satellite fragmentation in the history of the space age, in the past 50 years," he says.

As of last week, the U.S. Space Surveillance Network (SSN) in Colorado Springs had cataloged 647 of the 900+ items its sensors were tracking. On average, those objects must be at least 10 cm. (3.9 in.) in diameter to be tracked from the ground, although smaller objects can be pinpointed with the two radars at the Haystack Observatory in Tyngsboro, Mass., operated by MIT Lincoln Laboratory for the Defense Dept., and with other systems in the SSN.

One of the reasons why they have not been able to catalog all of the pieces yet is that you have to be sure each of your element sets consistently define the orbit of the same piece each time. Many of the pieces are too small to reliabily track with more space surveillance sensors, meaning it's hard to define good element sets because of too few dispersed observations.

Poetic justice would be some of that debris striking a future Shenzhou flight.

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The last time I felt a warm fuzzy feeling, I was informed by my doctor that it was just gas.

I'd never want that to happen, as much as you disagree with this military ASAT test astronauts or taikonauts have little say in a nations foreign policy and nobody really wished to see people like Yuri, Glenn or Valentina killed even during the height of the cold war.

On a related note
http://www.radioaustralia.net.au/new...s/s1853654.htm
US vice president, Dick Cheney, and Japanese prime minister, Shinzo Abe, have agreed on the need to closely monitor China's military capacity in space