Castor 30 engine test
A Castor 30 rocket motor was ground-tested Dec. 9, 2009, at the Arnold Engineering Development Center at Arnold Air Force Base, Tenn., in a specialized vacuum chamber that simulates the altitude at which the upper-stage motor will operate. This was the longest rocket-motor test ever in AEDC's J-6 Large Rocket Motor Test Facility, which became operational in 1994. (U.S. Air Force photo/Rick Goodfriend)