The flight of NASA’s X-43A has been postponed, due to an
incident with the rudder actuator on the booster. On Feb 11,
during setup at Orbital Sciences Corporation for testing of the
rudder and its actuator, an anomaly caused the actuator to go
hard over and hit its mechanical stop, exceeding the torque to
which the units were qualified.
Although the actuator may still function nominally, it will
have to be replaced. A joint government/contractor incident
investigation is under way to determine the cause and
corrective actions.
Prior to this incident, the program was considering a delay of
the flight to late March to retune the booster autopilot, to
optimize its performance based on the latest test data. With
the requirement for a replacement actuator, the two activities
will now be done in parallel. Planning is now focused on a
late-March to early-April flight.
The X-43A is a high-risk, high-payoff flight research program.
Designed to fly at seven and ten times the speed of sound, and
use scramjet engines instead of traditional rocket power, the
small, 12-foot-long X-43A could represent a major leap forward
toward the goal of providing faster, more reliable and less
expensive access to space.
The stack, consisting of the X-43A and its modified Pegasus
booster, will be air-launched by NASA’s B-52 carrier aircraft
at 40,000 feet altitude. The booster will accelerate the
experimental vehicle to Mach 7 at approximately 95,000 feet
altitude. At booster burnout, the X-43 will separate and fly
under its own power on a preprogrammed path. The flight will
take place over a restricted Navy Pacific Ocean range.
