WASHINGTON — Sierra Nevada Corp. (SNC) said July 28 its Dream Chaser vehicle is ready for a second round of test flights in California as it presses ahead with development of a version of that vehicle to transport cargo to the International Space Station.

SNC said an engineering test article of the lifting body vehicle, having completed modifications at the company’s Louisville, Colorado, facility, is ready to ship to NASA’s Armstrong Flight Research Center in California for a series of tests, including at least one glide flight scheduled for late this year

The tests build upon an earlier series the company carried out using the same vehicle in 2013, culminating with a free flight where the vehicle was released from a helicopter and glided to a runway landing at Edwards Air Force Base. That test was a milestone in a Commercial Crew Development 2 agreement that the company had with NASA.

That flight was marred by the failure of one part of the main landing gear to deploy, causing the Dream Chaser to skid off the runway after landing. However, both SNC and NASA considered the flight a success, concluding that earlier agreement.

This upcoming test will close out SNC’s Commercial Crew Integrated Capability (CCiCap) award that it received from NASA in 2012 to continue development of Dream Chaser as a potential crew transportation vehicle. That Space Act Agreement remains in place, and has been extended several times, even though SNC did not win a commercial crew contract from NASA in 2014.

SNC plans to carry out a similar set of tests of the Dream Chaser in California as it did in 2013, starting with ground tests and culminating with a free flight. There will be additional tests of upgraded software in the vehicle.

“They want to get more data and fly the Dream Chaser in a more robust flight environment so they can test more of their systems,” Phil McAlister, director of commercial spaceflight development at NASA, told a meeting of the NASA Advisory Council’s human exploration and operations committee July 26.

The free flight of Dream Chaser is tentatively scheduled for December, although the latest extension of the CCiCap agreement runs through June 2017. “We put some margin into the agreement” in the event of delays in that flight test, McAlister said.

While SNC lost out on a commercial crew contract, the company says that the upcoming flight tests will aid in the development of a cargo version of Dream Chaser. The company was one of three to win Commercial Resupply Services 2 (CRS-2) contracts from NASA in January to deliver cargo to and from the ISS from 2019 through 2024.

“These tests are significant for us in multiple ways: building on our previous flight test, completing a significant milestone under our commercial crew program agreement, as well as gathering crucial data that will help complete the design of the vehicle being built for our CRS-2 contract,” said Mark Sirangelo, corporate vice president of SNC Space Systems, in a statement.

In addition to the upcoming Dream Chaser testing, SNC has completed the first two milestones in its CRS-2 contract, covering the overall program implementation plan and development of certification criteria. The company said completion of those milestones have kept development of the cargo version of Dream Chaser on schedule.

Sirangelo, speaking in June at the NewSpace 2016 conference in Seattle, said he expects the first Dream Chaser mission to the ISS to take place in the second half of 2019, pending decisions NASA will make later this year on manifests for CRS-2 missions, which also include Orbital ATK’s Cygnus and SpaceX’s Dragon spacecraft. “There’s a minimum of six flights” guaranteed to SNC under that contract, he said then, “but there’s probably going to be a lot more than that.”