Primary among those advantages, at least at first, will be Sierra Nevada's ability to support space-station research with substantial “down-mass” capability and low-g runway landings.
“The idea of bringing something home to a soft landing on a runway and getting access to it almost immediately became pretty enticing for science,” he says.
Beyond that, Sierra Nevada wants to make the Dream Chaser as utilitarian as possible to exploit potential new markets, including delivering cargo as well as crew to orbit, remaining there as a free-flying autonomous research platform, and servicing satellites.
Sirangelo says Dream Chaser will be “an SUV” to the space shuttle's moving van—it can add or remove seats as needed for hauling and other jobs.
The vehicle's composite structure will allow the company to build additional vehicles for cargo and other applications relatively inexpensively, since the molds already have been built and used to shape engineering and atmospheric test vehicles. In a fine irony, the lifting-body shape those molds reflect has heritage that goes back to the Soviet BOR-4 subscale spaceplane that once figured prominently in the Soviet Military Power yearbook published during the Cold War by the Defense Intelligence Agency.
NASA based its HL-20 experimental lifting body on the Soviet craft, and the Dream Chaser retained the outer mold line to take advantage of the data generated by 1,200 wind-tunnel tests NASA ran on that vehicle, Sirangelo says. The resulting commercial vehicle will be well positioned to compete with the Russian Soyuz capsule, developed by the same Soviet aerospace industry that produced the BOR-4, as well as with the U.S. competition.
“We're not trying to create new science here,” says Sirangelo. “We're trying to create a reliable, safe, predictable, reusable system.”
Like Boeing and Blue Origin, Sierra Nevada chose the Atlas V as its initial launcher, although in the longer term Sirangelo stresses that his company is “rocket agnostic” and willing to use other vehicles if it makes sense. However, the 402 variant of the Atlas V that the Dream Chaser would ride has no solid-fuel booster, which is a safety consideration, and is part of a family of rockets that has flown without failure 32 times.
Riding without a fairing on top of the two-stage launch vehicle, the Dream Chaser would rely on its hybrid-propulsion motors to “fly off” the Atlas in the event of a failure on ascent, or use them for in-space propulsion en route to its orbital destination. Virgin Galactic has bought similar motors from Sierra Nevada for its SpaceShipTwo suborbital tourist/researcher vehicle.
Sirangelo brought the hybrid motor technology, which uses a stable rubber compound for fuel, with him to Sierra Nevada from SpaceDev Inc. when, as CEO, he merged with the aviation specialist and took over as head of its new space portfolio.