|The SNC Dream Chaser space plane. Is this the true heir to the space shuttle? Graphic c/o SNC.|
by Brian Orlotti
A privately-developed mini space shuttle has successfully completed ground tests in California earlier this week as a run-up to its first flight test.
On Aug 15th, the Sierra Nevada Corporation (SNC) Dream Chaser space plane, was pulled by a pickup truck across various runways, ramps, and hangars at the NASA Dryden Flight Research Center at Edwards Air Force Base.
These taxi tow tests were done at speeds of 16, 32, 64 and 97 km/h to gauge the spacecraft's performance under landing and rollout conditions. In addition to Dream Chaser’s brakes, steering and landing gear, SNC engineers also monitored its flight computer and software, as well as instrumentation (i.e. guidance, navigation and control systems). These tests were the fourth in a series of taxi tow tests and will culminate in full flight tests this fall.
Dream Chaser is a crewed suborbital/orbital spaceplane designed to carry up to seven people to and from low earth orbit, launching vertically atop a rocket and landing horizontally on conventional runways.
As outlined in the August 15th, 2013 Planetary Society blog post "Dream Chaser mini-shuttle prepares for free flight tests," one unique feature of the new space plane is the nose landing gear, which uses a "skid strip" instead of wheels.
|Dream Chaser's predecessor? The North American X-15 suborbital space plane, which utilized rear (instead of front) skid strips.|
Of course, a variety of manned and unmanned missiles and even manned vehicles have operated using skids for landing gear. Cape Canaveral Air Force Station even has a runway named the "skid strip" in honor of the SN-62 Snark intercontinental cruise missile, which utilized skid landings in the late 50s and early 60s.
The vehicle also incorporates a variety of other innovative features derived from lessons learned from the space shuttle program and other areas.
- A built-in crew escape system and autonomous flight capability.
- Maneuvering thrusters that will use a non-explosive ethanol-based fuel, allowing the Dream Chaser (unlike the Space Shuttle) to be handled immediately after landing, reducing turnaround time and costs.
|Dream Chaser mated with United Launch Alliance (ULA) Atlas V rocket. Graphic c/o SNC.|
- A thermal protection system (TPS) consisting of heat-resistant tiles developed at NASA Ames Research Center that (in contrast to the Space Shuttle’s TPS) can be replaced en masse after several flights rather than tile-by-tile after each flight, further reducing turnaround time and costs.
- A propulsion system consisting of two hybrid rocket engines running on powdered rubber and nitrous oxide (aka laughing gas). These substances are both non-toxic and easily stored, making them safer than liquid rocket fuels. Unlike solid-fuel rockets, Dream Chaser's hybrid fuel system would allow the engine to stop and start repeatedly, and be throttleable. This hybrid system was originally developed by SNC for Scaled Composites’ SpaceShipOne, winner of the Ansari X-Prize in 2004. SNC is also developing a similar hybrid engine for Virgin Galactic's SpaceShipTwo.
- Revealing a Canadian connection, an onboard communications system developed by MacDonald, Dettwiler and Associates Ltd. of Richmond, BC.
SNC’s Dream Chaser promises to be a nimbler, smarter successor to the space shuttle. It represents the best kind of technological advance; one that learns from and honours the past while being flexible enough for the future.
|The Mikoyan-Gurevich MIG-105. Another historical analogue for the current Dream Chaser, this manned test vehicle was conceived in response to the American X-20 Dyna-Soar military space project and may have been influenced by contemporary manned lifting body research being conducted by NASA. Photo c/o Wikipedia.|