A private
space firm with orbital aspirations has revamped its plans for a crew-carrying
spacecraft.
Poway,
California-based aerospace firm SpaceDev has a new design for its Dream Chaser
vehicle and hopes to offer suborbital rides within two years, with orbital
flights to follow.
Instead of
deriving a spacecraft from NASA's X-34
space plane concept, the firm has opted for a blunt-nosed lifting body
approach to cut down on reentry heating stresses, SpaceDev chief Jim Benson
said in a telephone interview. The plans stem from work SpaceDev performed
with NASA's Ames Research Center to study the use of hybrid rocket propulsion
for spaceflight testbeds.
"Because of
the X-34's pointed nature and sharp edges, the high temperatures would meet the
limits of our vehicle right at the ragged edge," Benson said, adding that the
new Dream Chaser design more closely resembles the Horizontal Landing-20
(HL-20) model studied by NASA's Langley Research Center. "The HL-20 was a great
little vehicle and it's already designed."
Small
enough to fit inside the payload bay of a NASA shuttle with folded wings, the
HL-20 Personnel Launch System was slated to carry 10 astronauts (two pilots and
eight passengers) or small payloads into orbit, though funding for the program
dried up in 1990.
SpaceDev's
take on the small spacecraft would be lighter, seat four people for a
suborbital flight and up to six for an orbital trek. The space plane is
envisioned to launch atop a launch stack of hybrid
rocket engines - like those developed by SpaceDev as part of the SpaceShipOne
Ansari
X Prize entry - and make a runway landing back on Earth, according to its
designed flight profile.
"We don't
use cryogenic liquids, so there's no ice or foam to worry about, and it's
non-explosive," Benson said of the current design.
Benson said
that with $20 million or less and about two years, SpaceDev could have a
four-person suborbital Dream Chaser vehicle ready for flight. Given three more
years, as well as $100 million, and the firm could develop an orbital variant,
he added.
SpaceDev
hopes its design will enable the firm to participate in commercial cargo and
other services to support the International Space Station (ISS), and could aid
future Moon
expeditions as well. Last week, NASA chief Michael Griffin said private supply
ships with their own launch services will be vital to deliver future cargo
to the ISS.
"We're
keenly interested in that," Benson said, adding that an orbital Dream Chaser could
haul one ton of cargo - with limited crew - to the ISS. "Once we get into
orbit, you can really make use of it. It doesn't matter if it's going to the
space station, habitat modules or what...what we need is low-cost access to low
Earth orbit."
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