11 December 2008

More Alternative Views of the Missile "Test"

From Arms Control Wonk

MDA Test Oddities

I am close to posting on the most recent Missile Defense Agency flight test (FTG-05).

In case you wonder why this is taking me literally days to work through (with lots of help from David Wright), read these statements by new MDA Director General Patrick O’Reilly.

Good afternoon, or as Mr. Whitman said, almost good evening. What I would like to do is go over exactly what happened this afternoon. At 1504 Eastern time, a little after 3:00, we launched a target out of Kodiak, Alaska and it did end up, 29 minutes later, with an intercept off of California using a ground-based mid-course defense system, the Aegis system, some of our satellite systems and our early warning radar system in Sacramento and also using a forward-based radar that we had located in Juneau, Alaska for today’s test only.


All right — and we showed the footage of today’s launch out of Vandenberg. As I said, the target was launched at 1504 and at 1523 Eastern Time, the target was in view and — of the Beale radar and the other sensors, and we launched a ground-based interceptor. That’s the first stage, and then it will show a separation. We’ll have other data that will come over the next 24 hours — the intercept occurred over 200 kilometers in altitude and 1,300 kilometers downrange from the launch point.


Q: Why is it hard for the target to — why is it hard to deploy countermeasures, why did that fail?

GEN. O’REILLY: Well, I can’t get into the great detail, but I can say simply, countermeasures, you try to build them to be very lightweight so that they don’t affect the original flight, but at the same time, you’re traveling at about 10 kilometers a second, somewhere around there, around 15,000 miles an hour. So at that, at that and you’re leaving the earth’s atmosphere, and you’re typically doing a lot of maneuvers at that point and at the same time you have to try to deploy two or three or four, whatever it is, lightweight objects. And that has been problematic on this particular target. The target itself is 40 years old, and it was one of some of our older missiles. Again, this was the last test using this particular target configuration, and we have a new target that is being assembled at this time by Lockheed Martin, that’ll be tested in the spring with Aegis and then follow up with a GMD later on this summer in another test. And that will be a different countermeasure system, again, a newer one.

The numbers in these passages are complete goobledygook.

— The entire scenario took 29 minutes? It is hard to believe that the interceptor was launched nineteen minutes into flight (15:23 EST) and took a full ten minutes to travel just 1,315 kilometers.

1,315 km in ten minutes works out to about 2.2 km/s. (The hypotenuse of triangle with 200 km and 1,300 km legs.) The GMD interceptor is supposed to have a burnout of like 7-8 km/s.

What, did MDA strap the interceptor to a flock of geese? That’s got to be a mistake. It probably should have taken four or five minutes for flyout. I am honestly very, very confused here.

— The countermeasures failed because the missile was traveling 10 km/s?

First, this is a 3,000 km range missile with a burnout velocity of probably around 4.5 km/s. It wasn’t traveling anywhere near 10 clicks a second. (Not that speed would explain why the countermeasures didn’t work, but he’s clearly trying to make something up on the spot and just gets confused.)

Second, ICBMs don’t travel 10 km/s. The speed is more like 7 or 8 km/s. Of course, O’Reilly also gave the measure in miles per hour — 15,000 mph, which in metric that is about 7 km/s.

So, here you what appears to be a simple error (the timeline doesn’t jibe), an apples-to-oranges comparison (talking about ICBM speeds in a test against a much slower moving MRBM) and a basic inability to convert to metric.

Other than that, everything is clear as a bell.


I’d looked at similar puzzlements in an earlier test. I don’t have an explanation for the apparently slow fly-out time of the interceptor, but do have a thought about the target speeds and, possibly, some constraints on decoy deployment.

If you look at the locations of the second and third stage range safety areas (http://www.kodiakdailymirror.com/?pid=19&id=7035), you see that they’re much closer together than would be expected. I suspect that means the third stage was used as an accelerator to give the target RV an ICBM-like trajectory. I.e., the second stage delivers the third stage to a point at or after the apogee of a simulated ICBM trajectory, then the third stage pitches down to impart the proper velocity vector. After which the decoys would have to deploy. Something like was done at White Sands way back when: http://www.designation-systems.net/dusrm/app4/athena.html

Might be worth running some simulations using such a scenario.

— Allen Thomson · Dec 11, 02:02 PM ·

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