MDA's New Test Vehicle


TTV in all its infrared nerdporn glory …

On 17 November 2005 the Missile Defense Agency conducted Flight Test Maritime 04-2 (FTM-2)—a test of its Aegis based missile defense system. A SM-3 interceptor did what its name implies and hit a dummy warhead jettisoned from a Medium Range Target (MRT) vehicle.

This test is considered a first because the interceptor was tasked with hitting a separated payload target, as opposed to just a missile.

Much is known about the MRT’s predecessor, the Target Test Vehicle (TTV)—also known as the Aries (right). Information on its flight path and main characteristics (it is based on a Minotaur booster motor) are publicly available.

David Wright, from UCS, analyzed a 2002 test of the Aegis which involved a SM-3 missile intercepting an Aries target. David’s main criticism of the test was that the target was very large, since the warhead did not separate from the booster:

A key finding is that the target used in the test was considerably larger than important targets that [the system] is presumably being developed to engage, such as a warhead from a North Korean Nodong missile.

Using a larger target increases the range at which the Aegis SPY-1 radar can detect and track the target, and provides a larger target for the kill vehicle to impact. In the test, the kill vehicle apparently collided with the booster of the target missile, and would not have destroyed a warhead on the missile.

All this is supposed to change with the new separating MRT vehicle. The warhead will separate and the target will be more “realistic” than a large missile. However, unlike the Aries/TTV, details on the MRT are not as well known.

One interesting tidbit is that the MRT is designed to be launchable from the ground, from the sea, and from the back of a C-17 Globemaster III (see the enormous plane at right).

This is all part of Lockheed Martin’s Flexible Targets Family approach for MDA. Sort of like Gumby’s family …

MDA tested the MRT in April (from a C-17) and Orbital, the manufacturer of the MRT, happily let us know that the test was a success and something about the MRT rocket motor:

The MRT integrates a Castor IVB rocket motor produced by Alliant TechSystems (ATK), which Orbital has integrated and launched on several recent and past missions for MDA.

The Castor IV family of motors are probably best known as the booster rockets seen on the side of some Delta and Atlas launch vehicles. Unfortunetly Thiokol’s Castor website disappeared when they were bought by ATK, however the specs of the Castor IVB continue to float around.

What’s missing from these specs however are the burnout speed of the rocket and therefore the speed of the separated warhead. This however can be computed using the rocket equation. We get a burnout velocity of around 5.5 km/s…almost twice that of the Minotaur based Aries TTV. In the actual test this velocity depended on a number of things including the mass of the payload and whether or not the maximum amount of fuel was used.

Also new for the MRT is a sensor package on the rocket including cameras, built by Johns Hopkins Applied Physics Lab that are able to view the intercept of the dummy warhead (right).

The APL press release describes the sensor package in some detail:

The payload consists of three fundamental parts – forward- and aft-looking sensors, and an electronics box.

The forward-looking sensor package consists of a radiometer, spectrometer, debris impact sensor and a visible-light camera to collect, for the first time, in situ measurements of an Aegis BMD intercept viewed from the target’s separated booster section. The target-based sensors provide closer, clearer observations acquired at a different angle than those obtained by airborne- and ground-based platforms, which are often subject to transmission losses.

In case you are interested, MDA was kind enough to record both the launch of the interceptor from the USS Lake Erie and the launch of the target (left) from the Pacific Missile Range Facility, located on the Hawaiian island of Kauaʻi.


Zooooooooom! A video of the intercept can be found here

Comments

  1. John Field (History)

    yes, but…

    there are a number of factors which all act to bring down the speed – gravity – atmospheric drag – rocket efficiency varies with backpressure – payload?

    Using the numbers on the Castor provided on the website, I get burnout speed as follows :

    nominal 5300 m/s
    w/gravity 4770 m/s
    +w/drag 4680 m/s
    +w/rkteff 4580 m/s
    +w/1ton 3450 m/s

    ( I allowed for the rocket to tip over to about 45 degrees during the flight )
    I figured on a Cp of about 0.15 for the nose cone. There is an atmospheric scale height of about 8 km included.

    Rocket efficiency is trickier to estimate, but the problem is that the rocket exhaust is doing work on the atmosphere until the rocket rises significantly. I had to make some assumptions and guesses that might not be true – figuring on about 9% thrust loss at sea level.

    So, I think this booster vehicle is probably comparable to or maybe a little bit better than the other one. It’s still a lot slower than a true ICBM vehicle.

    Anyway, for honesty’s sake, I posted the program and data output on my website :
    http://www.dorringtoninstruments.com/rocket.out
    http://www.dorringtoninstruments.com/rocket.cpp

  2. MKH

    I agree. Just the Minotaur rocket motor of the Aries has a burnout of 2.4 km/s (according to the LEAP study)..so I assume the actual TTV has a smaller burnout.

    The burnout of a Nodong is 3 km/s so in that sense, if we are actually developing the system to defend against North Korea, it may be a good model.

    Thanks for posting your code.

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