Dream Chaser vehicleThis is one of the key US commercial human spaceflight projects now in development by NASA.  Sierra Nevada Corporation’s (SNC) proposed the Dream Chaser vehicle.

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The design calls on a concept initially studied by NASA about 20 years ago called the HL-20. SNC’s vehicle would launch vertically atop a rocket like the Atlas 5. It would carry a crew of seven.
Missions might include crew rotation and cargo re-supply at the International Space Station, but there would be other destinations and duties for an adaptable vehicle like this as well.

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Sierra Nevada Corporation was given the biggest award ($20m) last February in Nasa’s “seed fund” programme to develop a private crewship capability.
Known as the Commercial Crew Development (CCDev) Program, it will soon announce another, larger round of financing; and SNC expects to be at the front of the queue again.
SNC used last year’s Nasa money to further work on the hybrid rockets that will power the Dream Chaser.

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The drop test of a model Dream Chaser returned important aerodynamic data
It was able to show Nasa that it could run these motors for the sorts of durations demanded on a full mission, and, critically, demonstrate a stop-start capability. In the rocket business, re-igniting a motor in the vacuum of space is a big deal.
SNC also built the basic structure, or chassis, of the first flight vehicle, and conducted drop tests on a scaled model. These drop tests, begun from a height of 4,000m, returned important aerodynamic data.

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via bbc