Anti-satellite weapon test?, Is this true? Options

[djellison]

You don't need fusing - this was a kinetic impact...it just what WHACK not BOOM.

Doug

[climber]

(Just looking for the bright side since this is my 1000'th post. )

My 900 was yesterday
I was wondering if it was their first try of if we have infos that they've missed previously!

[Bob Shaw]

You don't need fusing - this was a kinetic impact...it just what WHACK not BOOM.

Doug

Doug:

They probably broke the kill vehicle up just before impact to increase their ability to whack the target, so a proximity fuse (or some other method of breaking the thing up) would have been needed.

The bottom line remains the same: this is an impressive bit of engineering. Perhaps less so in terms of the political repercussions (eg Sino/US space collaboration will now be more difficult), but that's another matter.


Bob Shaw

[Bob Shaw]

(Just looking for the bright side since this is my 1000'th post. )

1,000? Pah! Amateurs, don't know what things are coming to, mumble, why in my day, I remember back in '05...

Keep up the good work!


Bob Shaw

[Bob Shaw]

My 900 was yesterday
I was wondering if it was their first try of if we have infos that they've missed previously!

Interesting point. The ASAT engine plume would be highly visible in IR, so the US would almost certainly have seen the whole thing. Whether or not they'd have told anyone about previous attempts is a moot point, as the NRO (or whoever is running staring IR sensors in GEO) is notoriously shy and they'd rather not release any information which can be reverse-engineered to reveal their actual capabilities to any potential opponent. So the internal hierarchy of the US may well have known, and they may have told some of their regional allies, but that'd be about it - there's no international requirement for a nation to tell anyone else about sub-orbital activity if they don't want to, and the Chinese wanted a success rather than anything which might be seen as a failure. Personally, I'd be surprised if the Chinese managed an ASAT demonstration first time out, though the US appears to have done exactly that when they tried it. As an example of just how difficult it can be to launch big(ish) missiles from an aeroplane, see the whole NOTSNIK story!


Bob Shaw

[mchan]

There was an article quoting unamed sources that there were three previous unsuccessful attempts.

Regarding detecting / tracking the ASAT engine plume, the ASAT would only need course correction maneuvers in the end game. These burns are relatively low energy. Early warning sats are required to detect rocket plumes during boost phase which are much larger. Whether their sensors are sensitive enough to detect small ASAT course correction burns is unknown outside the classified realm, but my guess is not likely.

Regarding staring sensors, the operational US early warning sats in geosynchronous orbit still use a scanning sensor. There have been tests of staring senors in add-on payloads to other military sats in high elliptical orbits. I don't recall reading that these are in operational use.

[Bob Shaw]

There was an article quoting unamed sources that there were three previous unsuccessful attempts.

Regarding detecting / tracking the ASAT engine plume, the ASAT would only need course correction maneuvers in the end game. These burns are relatively low energy.

I'm not surprised to hear that, three sounds sorta sensible for a demo programme.

As for the rocket plume, I'll grant that control inputs will lessen as 'rendezvous' (haha) approaches, but you still need a reasonable belt to get up there in the first place, and that's the signature which would be detected. I'd also wager that the test took place over some appropriate part of China and that the USAF had a good idea of which might be a target satellite well in advance, thus making detection almost a numbers game. And that numbers game would serve to obfuscate the exact capabilities of US space intelligence assets, too... ...staring IR or not!


Bob Shaw

[climber]

Interesting article on this topic on Aviation Week.
US intelligence were ready to monitor the trial, so they knew about it ahead of time.

[tty]

As for the rocket plume, I'll grant that control inputs will lessen as 'rendezvous' (haha) approaches

Nix - that is true for a slow "friendly" rendezvous like ISS/STS. For a high speed interception it's the other way around. The need for control inputs increases dramatically at the end when the relative angular velocity goes up and the inevitable minor initial errors must be corrected.

tty

[Bob Shaw]

The need for control inputs increases dramatically at the end when the relative angular velocity goes up and the inevitable minor initial errors must be corrected.

tty

I'll buy that - however, with (presumably) burnout of the main stage the vehicle mass will be way down so smaller burps will do the job. One of the 1980s-era US kill vehicles had a (IIRC) *five* terminal engine setup, and these could actually support the thing (though briefly) in a 1G static environment. They did some testing with the thing flying free over a big a net, into which it dropped at the end. Something I just noticed is that some (early) reports spoke of an air-launch, while the latest are talking about the thing being on top of an IRBM. Somehow, I think the IRBM carrier version, knocking out a satellite in a well-known orbit is rather less of an achievement than the air-launched scenario.

I don't think the whole affair has made Sino/US space co-operation more likely, but international diplomacy is a funny old game.


Bob Shaw

[Thu]

Finally, we have an official announcement from China http://www.spacewar.com/reports/China_Offi...essful_999.html

[CosmicRocker]

I rarely stray into this section of the Forum, and I don't appreciate all of the important intricacies that some of you apparently do, but this really is a "funny game" as Bob pointed out. It is especially so when all you have to go on are published reports.

A comment I noticed in an IRC discussion on this topic kind of put it into perspective for me. Didn't China use remaining fuel to move the target into an orbital position that would be easy to hit? Will China declare it a success? Heck yes, it was a success. Will other nations complain? Yes, again. Can one dispute Chinese Foreign Ministry spokesman Liu Jianchao's response claiming that his country had displayed a "responsible attitude" and that it had "upheld the peaceful use of outer space? It gets kind of dicey at this point for me. If it wasn't gong to be a threat to people on the ground, or other satellites, was this a responsible action? It seems to me that the important question here is, was there a threat that needed to be minimized, or not?

[tty]

I think the IRBM carrier version, knocking out a satellite in a well-known orbit is rather less of an achievement than the air-launched scenario.

That is definitely true. It also makes the chinese system much less capable since it can only be used when the satellite track passes close to the launch site. An aircraft carried ASAT allows much more flexible targeting.

tty

[nprev]

Just to put a bit of (hopefully) UMSF-related spin on this: The guidance & control technologies used for ASAT ops probably will mature at a rapid rate because of this event and be available for other applications such as asteroid/comet interdiction, or even adaptive autonomous terminal guidance for risky outer-planet missions such as landing on Triton.

Admittedly, Deep Impact had a nice big target...but wouldn't it be nice if we could hit a potentially threatening comet in a very precise fashion in order to deflect its orbit just enough (like by exposing a deposit of volatiles near perihelion) to miss us?

Just makin' lemonade here, don't mind me...