Though Sen. Hillary Clinton has balked so far at releasing a full list of her requested earmarks, the Seattle Times has published a partial list of the ones she secured in the 2007 Defense Authorization Bill, and they include $3.5 million for Minnesota-based ATK (formerly Alliant Tech Systems) for development of the X-51 robust scramjet. This particular earmark was secured by Clinton along with Defense Committee Chairman Sen. Charles Schumer, D-N.Y.

The two senators described the earmark in a press release after the bill was passed by the Senate in September 2006:

The bill appropriates $3.9 million in funding to continue development of scramjet technology needed to integrate and demonstrate hypersonic strike platforms, such as the United States Air Force’s X-51B vehicle. In a continuing effort to push technology forward, this Air Force program seeks to bring the HyTech engine to a flight test and provide a flight test platform for future technology development. Air Force Research Laboratory (AFRL) advocates working to integrate an alternate engine concept into the X-51A program, thus broadening the program’s technology base. Additionally, this program is coordinated with continuing NASA research to ensure broad potential applicability.

Continued: Click “Read more” As previously reported, ATK has a successful munitions business that produces everything from bullets for commercial and military use to highly controversial cluster bombs and land mines. But it has been rapidly developing its space systems operations through multiple acquisitions of firms in that sector.

Video: The X-51 in action

According to Global Security, scramjets “compress air as it moves through the engine at supersonic speeds — without the need for moving parts.” The X-51 is a continuation of work done by ATK on the X-41, a “High-Speed Strike Weapon.” The X-41 was successfully tested in 2005, “marking the first-ever free flight of a scramjet-powered vehicle using a conventional liquid hydrocarbon jet fuel and a major step forward in  advanced hypersonic weaponry.“

Hypersonic weapons traveling at Mach 8 deliver 64 times the force of a similar weapon traveling at Mach 1, making them attractive for rapid delivery and the ability to penetrate 12 meters below the surface at Mach 4.