Sierra Nevada ground tests Dream Chaser’s steering, brakes
On Monday, July 17, Sierra Nevada Corporation (SNC) put its full-scale Dream Chaser test vehicle through its paces on the ground at NASA’s Armstrong Research Center in California. According to a report by Spaceflight Now, the ground tests towed the vehicle fast enough to evaluate the performance of its brakes, steering, guidance, navigation, and control systems.
Dream Chaser’s ground testing is similar to pulling a wagon rapidly down the street and then letting it go to see how well the occupant can steer and stop it. In this case, the only occupants aboard Dream Chaser’s test vehicle are the onboard electronics, which are responsible for handling steering and braking on two rear wheels and a forward skid.
The testing also evaluated the craft’s guidance, navigation and control sensors, which will align the spaceplane for an actual landing.
This work comes ahead of additional ground testing, followed by captive-carry flights, where Dream Chaser is suspended underneath a helicopter. After the captive-carry tests are completed, SNC will conduct a series of drop tests, where a helicopter will drop the unpiloted vehicle from an altitude of about 10,200 feet (3,109 meters). It will then glide toward an autonomous landing at Edwards Air Force Base.
That will be the first time Dream Chaser has flown since 2013, when a non-flight version of its landing gear failed upon landing, causing the test vehicle to flip over.
“It’s much more close to the (configuration) of the orbital vehicle now, with flight software,” Sirangelo told Spaceflight Now earlier this year. “It’s fully autonomous, so it will use flight software that we’ll go to orbit with. All the control surfaces, and all the data gathering is all electronic.”
“Getting chatty” about Dream Chaser
SNC spent much of the last year working through a series of three integration reviews with NASA. These reviews brought Dream Chaser up to a preliminary design review (PDR) level of readiness in May. The company has been eager to highlight the vehicle’s progress under its Space Act with the space agency. On Monday, one of their test engineers took over SNC’s Twitter feed as part of the company’s outreach.
As Parabolic Arc commentator Doug Messier described it, “SNC is getting chatty about Dream Chaser as they near drop tests at NASA Armstrong.”
Moving closer to the equivalent of a critical design review, SNC’s ground testing of Dream Chaser’s systems are central to proving flight safety. Such safety will be crucial for SNC’s plans to fly cargo to and from the International Space Station. While the crewed version of Dream Chaser might not have been tapped by NASA to fly astronauts to the orbiting lab (they were down selected in September of 2014) and then return them safely to terra firma, the cargo variant was chosen as part of the second phase of the agency’s Commercial Resupply Services 2 (CRS-2) contract.
Spaceflight Now reported that NASA has, so far, only ordered one space station cargo mission under the new CRS-2 contract, a 2019 resupply flight that went to Orbital ATK. SpaceX and Sierra Nevada expect to receive their first CRS-2 mission authorizations in the near future.
When fully operational, Dream Chaser should be able to fly up to 12,125 pounds (5,500 kilograms) of cargo to the space station and return almost 4,400 pounds (2,000 kilograms) via a runway landing at a specific location. Its first orbital test is currently scheduled for 2019 when it is slated to be launched atop a United Launch Alliance Atlas V rocket. If everything goes as it is currently planned, the spacecraft should conduct at least six missions between 2019 and 2024.
Bart Leahy is a freelance technical writer living in Orlando, Florida. Leahy's diverse career has included work for The Walt Disney Company, NASA, the Department of Defense, Nissan, a number of commercial space companies, small businesses, nonprofits, as well as the Science Cheerleaders.