Dream Chaser nears piloted tests
By Mike Killian
On Oct. 26, 2013, Sierra Nevada
Corporation put their Dream Chaser
engineering test article through
its first free flight Approach and
Landing Test, or ALT-1, at NASA’s
Dryden Flight Research Center in
southern California.
The important flight test, a first
since the late 1970s with NASA’s
space shuttle test article Enterprise,
performed flawlessly up until the
command was given to deploy
the landing gear. An anomaly
was encountered, causing the left
landing gear to snag, and although
Dream Chaser touched down
on the runway 22L centerline at
Edwards Air Force Base, the vehicle
did sustain some minor structural
damage.
That incident, however, may
actually speed up Dream Chaser’s
development, rather than delay it.
“We believe we had a very
successful first day. The issue that
we had is certainly one that I
would like not to have had, but
at the end of the day – on the list
of things that could have gone
wrong for us – it was one that is very
minor in the future of the vehicle,”
said Mark Sirangelo, Vice President
of Sierra Nevada Corporation’s
Space Systems at a teleconference
held days after the test flight. “We
don’t think its actually going to set
us back, in some interesting way
it may actually accelerate our
progress. If we got all the flight data
we needed to get we may actually
be able to get the vehicle back to
Colorado earlier to get it ready for
its next flight, which may actually
accelerate the program.”
The Dream Chaser was carried
aloft in the skies over Edwards Air
Force Base and dropped from an
altitude of 12,500 feet by an Erickson
Air-Crane helicopter. The release
itself was accomplished perfectly,
sending the vehicle into a steep
50-degree nose dive to exactly
replicate the orbital re-entry flight
path and prove Dream Chaser’s
design is truly air-worthy.
“About 10 seconds into the dive
the commands were given by the
vehicle, as predicted, to begin the
pullout of the dive and enter into its
glide into Edwards,” said Sirangelo.
The Dream Chaser engineering test article (main photo) comes in for an autonomous landing
at Edwards Air Force Base, Calif. The view from inside the crew compartment view is shown
Photos: Sierra Nevada Corp.
in the inset photo.
“All commands given during the
flight were successful, and after
a period of 30-35 seconds the
vehicle began finding the runway,
associating itself, getting itself ready
for landing, and conducting what
was almost a perfectly stable flight.
In the final 20 seconds of the flight
the vehicle acquired the runway
and lowered its rate of descent to
1.58 feet per second, exactly as
predicted, and landed at 160 knots,
almost precisely on the runway
where we wanted to land.”
The 60-second flight itself was
fairly uneventful, as the vehicle’s
automated flight control system
did its job of steering the test
article to its intended glide slope
automatically based on data
collected by the vehicle’s sensors
and flight computer. However,
when the vehicle’s Ground Radar
Altimeter initiated the sequence to
open the landing gear, an anomaly
occurred—the left landing gear
was snagged.
“As the vehicle began its roll down
the runway the automatic software
noticed that the vehicle was having
some difficulty and commanded
the controls to compensate for
that, which was something that
we had predicted but we had
not known was going to happen,”
said Sirangelo. “Unfortunately the
anomaly with the gear, which we
are still investigating, caused the
vehicle to eventually land down on
its left side and skid off the left side of
the runway. There was no damage
to the runway and there were no
personnel injuries of any type. The
vehicle was damaged as it skidded
off the runway but we believe it to
be repairable and flyable again.”
“The 99% of the flight that we
really wanted to get - which was
does this vehicle fly, is it able to
be controlled, does the software
work, can we autonomously fly the
vehicle in to approach and land
on a runway – all that was 100%
successful,” added Sirangelo. “In
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