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 The National Transportation Safety Board was expected this week to
complete its initial field investigation into Friday's ill-fated
test flight of SpaceShipTwo, a rocket-powered vehicle built to take
paying passengers for rides into space.
The ship broke apart at an altitude of about 50,000 feet (15,000
meters) and crashed in the Mojave Desert, 95 miles (150 km) north of
Los Angeles, moments after its separation from the special jet
aircraft that carries the spacecraft aloft for its high-altitude
launches.
The pilot, Pete Siebold, 43, survived the crash, parachuting to the
ground with a shoulder injury. The co-pilot, Mike Alsbury, 39, was
killed.
NTSB officials have said it was Alsbury, flying for the ninth time
aboard SpaceShipTwo, who unlocked the tail section, designed to
pivot upward during atmospheric re-entry to ease descent of the
craft.
 Alsbury was supposed to have waited until the ship was traveling at
1.4 times the speed of sound, fast enough for aerodynamic forces to
hold the tail in place until time to actually move it into descent
position, sources familiar with the spacecraft's operation told
Reuters.
Instead, for reasons unknown, he released the locking mechanism
roughly 9 seconds into a planned 20-second firing of the space
plane's rocket engine, while the ship was moving at about Mach 1,
the speed of sound, the sources said.
The result was disastrous. About 4 seconds after the tail was
unlocked, it began to swivel out, and the vehicle was ripped apart,
scattering debris over a 5-mile (8-km) swath of desert northeast of
the Mojave Air and Space Port.
A second command to deliberately move the tail upward after
unlocking it was never given.
The tail's so-called “feathering” system, developed and patented by
aircraft designer Burt Rutan, is designed to increase the vehicle’s
surface area and slow down the ship so it can fly like a badminton
shuttlecock as it safely re-enters Earth’s atmosphere from space.
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SpaceShipTwo’s feather mechanism had been operated extensively in
previous atmospheric test flights, including two rocket-powered
runs, officials said.
The NTSB expects it will take up to a year to piece together exactly
what triggered the accident and recommend changes to equipment,
procedures, operations and other factors that may have caused or
contributed to the crash, safety board Chairman Christopher Hart
said.
Initial interviews, collection of debris from the crash site and
preliminary examination of evidence were expected to be wrapped up
by the end of the week.
A human-factors expert joined the investigation team on Monday to
look at cockpit displays, checklist design, training and other pilot
operational issues. Siebold, the surviving pilot, had not yet been
interviewed due to medical concerns, Hart said on Monday.
NTSB’s preliminary accident investigation report was expected in
about 10 days.
(Reporting and writing by Irene Klotz; Editing by Steve Gorman and
Mohammad Zargham)
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