Spaceflight Insider

Sierra Nevada completes Dream Chaser’s milestone 15a for prior phase of Commercial Crew

SNC's ORBITEC Completes RCS testing in Vacuum Chamber to Simulate Orbit Environment

Photo Credit: SNC

Colorado-based Sierra Nevada Corporation was not selected to continue forward under NASA’s Commercial Crew transportation Capability (CCtCap) phase of the agency’s effort to send crews to orbit via private companies. However, SNC is still completing milestones under earlier phases of the Commercial Crew Program. One of these, Milestone 15a, was recently completed and in so doing helped validate the Reaction Control System (RCS) propulsion risk reduction for the company’s Dream Chaser space plane.

Milestone 15a is the twelfth of 13 milestones under the Commercial Crew integrated Capability or “CCiCap.” According to a release issued by SNC, the company has received 96 percent of the award amount under CCiCap.

SNC has stated that the compact prototype of the thruster, was successfully tested in a vacuum chamber. In so doing, SNC has simulated what the thruster would encounter on orbit. These thrusters are part of Dream Chaser’s Reaction Control System (RCS) and would be used to guide the spacecraft during orbital maneuvers. The RCS system is also used to guide Dream Chaser back to a landing at a runway.

The thruster was tested by Orbital Technologies Corporation (ORBITEC ), a subsidiary of SNC. As SNC is no longer working under CCP, Dream Chaser is, in essence, a spacecraft without a place to fly to. There is only one destination currently for U.S. crew-rated spacecraft to travel to – the International Space Station (ISS).

On Sept. 16, NASA announced that the two firms which had been selected to proceed under CCtCap, would be Boeing’s CST-100 and Space Exploration Technologies (SpaceX ) Dragon spacecraft. SNC has since filed a protest with the Government Accountability Office regarding the selection process.

Dream Chaser stood out from both CST-100 and Dragon as it is a winged spacecraft and would land much as NASA’s retired fleet of orbiters did for 30 years.

“Safety is paramount in the design of the Dream Chaser Space System,” said Sierra Nevada Corporation’s Corporate Vice President for Space Systems Mark N. Sirangelo. “It is driven by reliability, rigorous quality assurance, consistent performance, extensive testing, and robust analysis. In passing this milestone, we are able to validate our performance and safety, while decreasing the risk for this critical propulsion system. Reaching this milestone propels us even closer toward the Critical Design Review and orbital flight of our complete system.”

SNC has since announced several initiatives to have Dream Chaser be used by the space agencies of other nations. Both the Japan Aerospace Exploration Agency and European Space Agency have expressed interest in the spacecraft.


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Jason Rhian spent several years honing his skills with internships at NASA, the National Space Society and other organizations. He has provided content for outlets such as: Aviation Week & Space Technology,, The Mars Society and Universe Today.

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