June 14, 2007: A not-so-secret top secret contract has been issued by the U.S. Air Force for work on a replacement for the SR-71 high-altitude, supersonic reconnaissance aircraft. The new aircraft, informally referred to as the SR-72, will apparently be unmanned, and use new high-altitude jet engines that the air force has been working on for some time. The original SR-71 was developed in the 1960s, and served until 1998. The 77 ton aircraft could hit a top speed of 3,500 kilometers an hour, and could operate at 85,000 feet. Typical mission range was 2,900 kilometers, and payload was about 1.6 tons of sensors. The last of the 32 aircraft were retired in 1998 because they were too expensive to maintain, and there were enough spy satellites, U-2 aircraft and UAVs to do what needed to be done. The SR-71 was actually retired in 1988, but was brought back in the early 1990s for a few more years service because of political pressure. The SR-71 was a complex piece of work, and required skilled pilots. Over 80 percent of the missions flown were training missions, and there were fewer than 4,000 actual recon missions flown.

The SR-72 is supposed to be capable of twice the range, and greater speed than the SR-71, and at an altitude of 100,000 feet or higher. A high-speed, high-altitude UAV like that would be a good replacement for spy satellites lost to anti-satellite weapons. Actually, the SR-71 could carry missiles (which the U.S. has already developed) than can knock down satellites in low earth orbit (as are most spy satellites.)