NASA's experimental X-43A hypersonic research vehicle, securely mounted to the B-52 mother ship that will launch it, took off from Edwards Air Force Base at 3:21 p.m. Pacific Standard Time Monday, Jan. 26, 2004 for a captive-carry test scheduled for two and a half hours during which the experimental craft remained attached to the B-52.
Monday's captive carry flight was conducted to allow X-43 engineers and technicians to test the X-43's systems at speeds and altitudes it will encounter on launch day. Analysis of data recorded during this dress rehearsal will enable the X-43 team to make the decision to launch the X-43 as early as February 21.
The B-52 rolls down the runway with the X-43A mounted and ready for captive carry testing.
The upcoming X-43 launch is planned to attain Mach 7 - seven times the speed of sound - by using a Pegasus booster rocket to accelerate the X-43, which then relies on its own supersonic combustion ramjet, or scramjet engine to combine fuel with ambient air for combustion at that speed. Central to the X-43 program is its scramjet engine, blended to the vehicle's flattened airframe. The promise of scramjet propulsion technology is the ability to save weight and valuable onboard space by scooping oxygen from the atmosphere at high altitudes instead of carrying oxygen in tanks as conventional rocket motors must. The X-43 is considered hypersonic, using the term for flight at or above five times the speed of sound.
The second X-43A begins its flight testing as the B-52 nose gear lifts off the runway.
The first X-43 vehicle and its Pegasus booster were lost shortly after release from the B-52 over a restricted Navy Pacific Ocean range on June 2, 2001, when the combined vehicles deviated from the flight path and were deliberately destroyed. Since that time, the X-43 team has made a number of changes intended to reduce the possibility of loss of another X-43, although by its very nature, the launch of the experimental X-43 is risky.
NASA's Langley Research Center, Hampton, Va., leads the X-43 project, with NASA's Dryden Flight Research Center, located on Edwards Air Force Base in California's Mojave Desert, conducting the flight research.
Frederick A. Johnsen
NASA Dryden Flight Research Center