Orbital Sciences has been awarded a $400 million contract by US missile defence lead integrator Boeing to develop and test a boost vehicle for the ground-based midcourse defence (GMD) system. Follow-on production, if approved, would be worth another $535 million, and a total of 70 vehicles could be built over seven years.

The so-called alternate boost vehicle is required because of delays with the "off-the-shelf" booster under development by Boeing for the GMD interceptor. A new booster is required to provide a faster ground-based interceptor with a significantly increased engagement envelope compared with the boost vehicle now being used for flight tests.

Orbital's vehicle is a silo-launched three-stage rocket derived from its Pegasus and Taurus small satellite launchers. The booster will carry a Raytheon-developed exo-atmospheric kill vehicle (EKV) into orbit for a hit-to-kill interception of the ballistic-missile re-entry vehicle. Booster development and testing will continue to 2006, while production could begin in 2003 or 2004, and continue to 2010.

Following successful interceptions in July and December, further GMD tests are planned this year and next to demonstrate target discrimination and hit-to-kill capability in increasingly realistic scenarios, says Lt Gen Ronald Kadish, director of the newly created Missile Defense Agency (MDA). The agency is developing the so-called 2004 ballistic missile defence system testbed, which will include an upgraded Cobra Dane early warning radar in Alaska, five booster silos and other elements of the eventual GMD system.

The agency is seeking fiscal year 2003 funding for five ground-based interceptors using prototypes of the production booster and operationally representative kill vehicles. These will be flight tested in 2004, at which time the MDA hopes to be able to provide an early contingency capability using prototypes and test assets. Work on the kill vehicle could result in a common EKV for the ground-based and sea-based midcourse defence systems, and Kadish says the MDA's goal is to provide a ship-based capability for ascent and midcourse hit-to-kill interception in 2008-10.

Source: Flight International