本帖最后由 choi 于 4-30-2013 11:40 编辑
(2) Amy Butler, PTSS Kill Leaves Hole In Missile Defense Sensor Plan. Aviation Week, Apr 29, 2013.
http://www.aviationweek.com/Arti ... 2013_p33-572875.xml
Quote:
"Advances with two Space Tracking and Surveillance System (STSS) demonstration satellites have proved that midcourse, space-based infrared tracking can alert Navy ships to launch interceptors accurately before their radars can see the incoming missiles. A test in February was an eye-opener for the Navy, which now hopes that improved sensors outside of the ship's radar—combined with responsive communications links—can reduce the number of Aegis assets needed to patrol for the anti-ballistic missile mission. * * * By launching on remote—as was done in February—operators have more time to engage a target because the satellites are able from the vantage of space to see the ballistic missile before it can be detected by the Aegis ship's SPY-1 radar. 'Launch-on-remote' depends on disparate systems to work in concert as one weapon using communications infrastructures.
"But, only months after the seminal test, the Pentagon announced in its fiscal 2014 budget request it was terminating the Precision Tracking Space System (PTSS), a follow-on to STSS. Through PTSS, the U.S. Missile Defense Agency was pursuing a more simple satellite under the leadership of the Johns Hopkins University Applied Physics Laboratory (APL).
"MDA [Missile Defense Agency, of US Department of Defense] had planned to launch two PTSS demonstration satellites in 2017, which is now off the table. They were to be a follow-on demonstration to Northrop Grumman's STSS spacecraft that placed two satellites in orbit in 2009.
"The STSS satellites were designed for a two-year in-orbit life, which has already been exceeded. And the spacecraft, which carry gimbaled infrared sensors, still have redundant systems.
"Radars, however, require a protected area from which to operate, which can be tricky when dealing with some host nations. * * * At issue in these studies is striking a balance between the infrared and radar phenomonologies. 'Radar does its job by reflecting off of objects and IR does its job by detecting differences in temperature' between a missile and the cold backdrop of space, the industry source says. 'Having two phenomonologies look at something makes it easier to do * * * discrimination' of a warhead and countermeasures.
"The STSS satellites were crafted from parts fabricated during the defunct Air Force Sbirs-Low program and later put in storage once that project was terminated. Sbirs Low was intended to be a low-Earth-orbiting complement to the service's Sbirs-High infrared missile-detection satellites. Once resurrected as STSS, the program was transferred to MDA for management, and the Air Force focused on Sbirs High, but dropped the “high” portion of the moniker.
Note:
(a) gimbal
http://en.wikipedia.org/wiki/Gimbal
(b) phenomenology (n; phenomenon + logy)
http://www.merriam-webster.com/dictionary/phenomenology
(c) SBIRS stands for Space-Based_InfraRed_System. |