History
The Defense Support Program replaced the 1960s space-based infrared Missile Defense Alarm System (MiDAS). The first successful launch of MiDAS was May 24, 1960 and there were twelve launches before the DSP program replaced it in 1966.
The first launch of a DSP satellite was on 6 November 1970 and since then it has become the mainstay of the United States ballistic missile early warning system. For the last 40 years they have provided an uninterrupted space-based early warning capability. The original DSP satellite weighed 2,000 pounds (900 kg) and had 400 watts of power, 2,000 detectors and a design life of 1.25 years.
Throughout the life of the program, the satellite design has undergone numerous improvements to enhance reliability and capability. The weight grew to 5,250 pounds (2,380 kg), the power to 1,275 watts, the number of detectors increased threefold to 6,000 and the design life has been increased to a goal of five years.
The numerous improvement projects have enabled DSP to provide accurate, reliable data in the face of evolving missile threats. On-station sensor reliability has provided uninterrupted service well past their design lifetime. Recent technological improvements in sensor design include above-the-horizon capability and improved resolution. Increased on-board signal-processing capability improves clutter rejection. Enhanced reliability and survivability improvements were also incorporated.
The 23rd, and last DSP satellite was scheduled to be launched on April 1, 2007, aboard a Delta IV Heavy rocket, but the launch was postponed until mid-August 2007 after two structural cracks were found in the metal launch table at pad 37B, caused by a fuel leak during testing.
Further delays forced the launch back to November 11, 2007, when the satellite launched at 01:50:00 GMT (20:50 EST on 10 November). This satellite died in space sometime during 2008, for reasons unknown. It is now adrift in geosynchronous orbit and remains a potential hazard to other craft. The Department Of Defense sent a MiTEx spacecraft to inspect DSP 23 sometime in 2008.
Another DSP satellite was lost in 1999, after its Inertial Upper Stage failed following launch from a Titan 4 booster.
DSP satellites will be replaced by the Space-Based Infrared System (SBIRS) satellites. The project was originally to have had a life of 25 satellites, but the last two have been canceled, mainly due to SBIRS.
There were five major improvement programs prior to the current block:
- Block 1: Phase I, 1970–1973, four satellites
- Block 2: Phase II, 1975–1977, three satellites
- Block 3: Multi-Orbit Satellite Performance Improvement Modification (MOS/PIM), 1979–1984, four satellites
- Block 4: Phase II Upgrade, 1984–1987, two satellites
- Block 5: DSP-I (DSP-Improved), 1989
More recently, there has been some effort put into using DSPs' infrared sensors as part of an early warning system for natural disasters like volcanic eruptions and forest fires.
Read more about this topic: Defense Support Program
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