SATELLITE WEEK October 29, 2001
SATELLITES TO AID IN MISSILE DISCRIMINATION AND EARLY WARNING
New satellite constellation set for orbit by 2012 will help discriminate between nuclear warheads and decoys for National Missile Defense (NMD) program. Another smaller satellite constellation by 2005 will replace Defense Support Program (DSP) satellites that now serve as early warning system against missile attack on U.S. Inability to discriminate has been focus of criticism of NMD program, debate that has returned to forefront since negotiations between President Bush and Russian leader Vladimir Putin over 1972 Anti-Ballistic Missile Treaty have heated up.
Space-Based InfraRed Satellites-Low (SBIRS-Low), 23- or 24-satellite constellation, will be part of "3-edged sword," with ground based radar and Exoatmospheric Kill Vehicle (EKV) that will "greatly increase confidence" that NMD program can discriminate, Lt. Col. Rick Lehner, spokesman for missile defense said: "SBIRS-Low will provide information on target characteristics in the midcourse phase [of missile's] flight... The primary discrimination capabilities will come from ground-based X-band radar and the EKV." SBIRS-Low provides first opportunity to discriminate real thing from decoy, Lehner said: "It will give us a good idea of what is up there." EKV has combined optical and infrared sensor through which it acquires, tracks and discriminates target. Five ultra-high frequency ground-based early warning radars receive initial tracking data from DSP through systems command and control network. SBIRS-Low attempts to use long wave infrared that tracks warm objects such as decoys, while SBIRS-High, future replacement for early warning DSP satellites, uses midwave and short-wave infrared to track hot objects such as missile plumes, said John Pike, one of nation's leading experts on defense and head of Globalsecurity.org. Still, some type of decoys are very difficult to discriminate, he said: "[SBIRS are] not something you would trust." There are many doubters in the program's ability, but they aren't privy to all information, Lehner said: "There are a few people who think we can't do it... They're not really a part of the program and don't know what we can and can't do. No doubt about it - - we will develop what is necessary to discriminate warheads from decoys."
Most critics are confused because they incorrectly think missile defense system is being tested, Lehner said: "We are designing the technology for a future system... Everything we test now is simply prototypical, but it will lead us to a final design down the road. We're still a long way from production design." Two of first 4 missile intercept tests have been failures. First and most recent tests were successful. Second failed when EKV had problem with sensor cooling apparatus. Third test failed when interceptor booster didn't separate from EKV. There will be one more test this year and at least 15 more after that, Lehner said.
SBIRS-High, constellation of 5 or 6 satellites, is scheduled by 2005 to replace DSP satellites that currently are employed for early warning system that has been in place for 4 decades. Early warning satellites are used for "birth- to-death tracking," that detect launch when it takes place and continuously track missile, presumably until impact, Pike said. Until SBIRS-High takes its place, DSP still is one part of now 6-part National Missile Defense program, with SBIRS-Low expected to be seventh part. U.S. govt. will turn to SBIRS-High because its tracking capability is superior to DSP. SBIRS-High generates higher refresh rate for target track data, Pike said: "SBIRS-High see several track data points per second... DSP is like a rotating radar beam. It sees one track data point every 20 seconds. SBIRS "stare" rather than "scan," Pike said. SBIRS also has a smaller focal plane array, making possible more precise target tracking, as well as trajectory and impact prediction, he said: "With DSP you could tell whether [a missile] was aimed at Baltimore or Washington... SBIRS-High can tell you what part of Washington [the missile] is aimed at."
Copyright 2001 Warren Publishing, Inc.
