The board investigating the failed launch of NASA's Hyper-X X-43A scramjet technology demonstrator aboard an Orbital Sciences (OSC) single stage HXLV Pegasus booster in June has attributed the failure to multiple causes, particularly related to the vehicle's control system and aerodynamics functions.

The hybrid Pegasus booster was built to withstand the higher aerodynamic loads within the Earth's atmosphere, as it was flying a lower profile for the Hyper-X test. The air-launched HXLV veered off course about 7s after ignition and was destroyed by the range safety officer at T+51s.

The Pegasus first stage is powered by an Alliant Techsystems Orion 50S solid propellant booster which also serves as the second stage of OSC's Taurus ground-launched satellite launcher. This Orion stage also veered off trajectory during its Taurus launch on 21 September, resulting in the eventual loss of the two satellite payloads, OrbView 4 and QuickTOMS.

Meanwhile, NASA has started looking for a prime contractor for a follow-on X-43 to test a Mach 5 hydrocarbon-fuelled scramjet engine developed by the US Air Force Research Laboratory.

The USAF and NASA plan to initiate a major spaceplane project in 2004, to replace the Boeing X-37 space manoeuvre vehicle. The X-37 is also part of NASA's Space Launch Initiative, but is unlikely to be able to meet military space transportation needs. USAF funding for the X-37 will cease in late 2002.

Source: Flight International