Dream Chaser suffers landing gear failure after first flight

by Chris Bergin

Sierra Nevada Corporation’s Dream Chaser ETA (Engineering Test Article) conducted her maiden flight at the Dryden Flight Research Center on Saturday. However, the Commercial Crew prospect – after enjoying a perfect flight in the air – suffered a mechanical failure during landing, resulting in her flipping over on the runway.

Dream Chaser:

As announced in 2012, SNC’s Dream Chaser was one of three vehicles selected by NASA for their follow-on to the Commercial Crew Development (CCDev-2) process.

The additional award of $212.5m under the Commercial Crew Integrated Capability (CCiCap) initiative allowed Dream Chaser to progress through design reviews ahead of Saturday’s major event.

Dream Chaser is joined by SpaceX’s Dragon spacecraft – launched via its Falcon 9 ride to orbit, and Boeing’s CST-100, which, like Dream Chaser, will be lofted uphill by a human-rated United Launch Alliance (ULA) Atlas V. Birthed from the HL-20 lifting body vehicle, SNC partnered with the Langley Research Center (LaRC) via a five year partnership that focused on the evolution and substantiation of the Dream Chaser orbital crew vehicle.

Added to the heritage of the Space Shuttle, SNC’s believe their baby orbiter is capable of continuing the legacy, taking over the role of transporting NASA astronauts to the ISS.

The free flight mirrored Shuttle’s legacy, which began with major testing at Dryden via Enterprise and her series of Approach and Landing Tests (ALTs) in the 1970s.

Dream Chaser in captive flightThe ETA first tasted the air on the end of a cable attached to an Erickson Air-Crane helicopter, during two captive carry tests – the first at her home base in Colorado, followed by a second at Dryden.

Testing in California also included runway tow tests tests at various speeds, pulling the ETA via a pickup truck on the concrete runways.

Preparations for Saturday’s major test began earlier in the week, with a series of three captive carry flights taking place on Tuesday. These tests included the ETA mimicking what she was required to conduct when flying on her own, evaluating the flight computer was ready for the series of events during the flight – all of which proved to be nominal.

Z779Notably, the third test involved the helicopter flying at high speed, followed by the ETA dropping her gear at the end of the sequence. This too was classed as a nominal test.

Known as the approach-and-landing free-flight test, Saturday saw the ETA taken on one final captive carry test, ensuring everything on the vehicle was nominal, prior to the test proper.

The start of the test was slightly delayed due to airspace requirements, beginning at 9:45am local time.

With all systems classed as nominal, the command was given to release Dream Chaser via the electrically actuated attach points on the ETA.

Flying on her own for the first time, Dream Chaser enjoyed a period of free-flight, as she began her glide towards the lake bed, prior to making the final approach she will hope to conduct with a crew onboard in the coming years.

Dream Chaser’s approach during a real mission will be targeting a landing speed of 191 knots, after re-entering the atmosphere protected by a Thermal Protection System (TPS) that is similar to that on the Space Shuttle.

The conclusion to her missions will see her touch down on two Main Landing Gear (MLG) just like the shuttle orbiters. However, there is one major difference when the nose is pitched forward, given the Dream Chaser will not be using a traditional Nose Landing Gear (NLG) wheel for its rollout.

Instead, an inbuilt skid strip is employed for completing the touchdown and rollout sequence. SNC have previously noted to NASASpaceFlight.com that this system is a simple, light, safe option.

During the test on Saturday, all systems performed admirably during the free flight, following release from the  Erickson Air-Crane helicopter at 11:10am local time.

“Following release, the Dream Chaser spacecraft automated flight control system gently steered the vehicle to its intended glide slope. The vehicle adhered to the design flight trajectory throughout the flight profile. Less than a minute later, Dream Chaser smoothly flared and touched down on Edwards Air Force Base’s Runway 22L right on centerline,” added SNC in a later release.

Z66However, via what is being classed as a mechanical failure of the left landing gear (failure to deploy), the ETA lost control when “weight on wheels”, and flipped over on the runway. The focus appears to be on the landing gear door, which failed to open.

Notably, the main landing gear on the ETA is not the same as what set to be employed on future Dream Chasers.

“While there was an anomaly with the left landing gear deployment, the high-quality flight and telemetry data throughout all phases of the approach-and-landing test will allow SNC teams to continue to refine their spacecraft design,” added the company.

There is currently no confirmed information on the level of damage on the vehicle, or if she can be repaired.

“SNC and NASA Dryden are currently reviewing the data. As with any space flight test program, there will be anomalies that we can learn from, allowing us to improve our vehicle and accelerate our rate of progress.”

(Images via SNC, NASA and L2)

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