SpaceX’s Dragon capsule, the free-flying spacecraft designed to deliver both cargo and people to low-Earth orbit, has taken another step toward flying astronauts to and from the International Space Station.

SpaceX’s most recent milestone was passing NASA’s “certification baseline review.” This required the company to exactly how it plans to ferry crews to and from the space station, specifically using the company’s Dragon capsule and Falcon 9 rocket, under  SpaceX’s Commercial Crew Transportation Capability contract with NASA.

“This milestone sets the pace for the rigorous work ahead as SpaceX meets the certification requirements outlined in our contract,” said Kathy Lueders, manager of NASA’s Commercial Crew Program in a statement. “It is very exciting to see SpaceX’s proposed path to certification, including a flight test phase and completion of the system development.”

The Commercial Crew Program has been encouraging private companies to develop American spacecraft to achieve more cost-effective access to the International Space Station and low-Earth orbit. The program seeks to return astronauts to space from U.S. soil as NASA has relied on using Russian Soyuz spacecraft since the shuttle fleet was grounded in 2011.

On Sep. 16, 2014, NASA revealed its selection of SpaceX and Boeing to transport U.S. crews to and from space, using their Dragon and CST-100 spacecraft respectively. This would allow for the current crew of six on the space station to be increased and enable more research to take place in its microgravity laboratory.

Relying on the private sector for transportation to low-Earth orbit should allow NASA to devote more resources to exploring the further reaches of space. This would include advancing the skills and techniques needed to explore Mars, agency officials said.

SpaceX still has a long way to go before it will be ferrying astronauts to the space station. The company is still expected to show how their systems will handle the rigors of space travel. This will ultimately culminate in at least one test flight with a NASA astronaut on board to verify the capsule can in fact perform as expected.

The original statement can be read here.