In advance of a congressional hearing next week on the status of the commercial crew program, NASA’s Commercial Crew Program (CCP) has released new dates for when Boeing and SpaceX will conduct flight tests of their CST-100 Starliner and Crew Dragon spacecraft. All the tests will still take place this year according to the new schedule, but SpaceX’s have slipped several months.

Each company will first fly their vehicle without a crew and then with a crew prior to commencing operational flights to the International Space Station (ISS).

NASA last reported the schedule on October 5, 2017. The new schedule, released yesterday, shows the same dates for Boeing’s tests, but the SpaceX flights are delayed. In October 2017, SpaceX’s Demo Mission 1 was expected in April 2018 and Demo Mission 2 in August 2018. Now they are August 2018 and December 2018.

NASA has not been able to launch people into space since the space shuttle was retired in 2011. It must rely on Russia to ferry crews back and forth to the ISS on Russian Soyuz spacecraft. Once operational, these commercial crew systems will return the United States to an era when “American astronauts are launched on American rockets from American soil” as the program’s advocates often say.

The commercial crew program is a public-private partnership where the companies and the government share development costs (though NASA is funding the largest share by far — as much as 80-90 percent) and the government pledges to purchase a certain amount of services. Beyond that, the companies are expected to find other customers to make their business cases close.

In 2014, NASA chose Boeing and SpaceX as the winners of the Commercial Crew Transportation Capability (CCtCAP) competition, the final phase of the commercial crew development program, for firm fixed price contracts of $4.2 billion (Boeing) and $2.6 billion (SpaceX) respectively. Sierra Nevada Corporation (SNC), another competitor with its Dream Chaser spacecraft, protested the award, but the Government Accountability Office (GAO) denied the protest. SNC later won a contract to use Dream Chaser to deliver cargo to the ISS.

The Space Subcommittee of the House Science, Space, and Technology committee will hold a hearing next Wednesday on the commercial crew program’s status. Witnesses include Boeing’s John Mulholland and SpaceX’s Hans Koenigsmann, along with NASA’s Bill Gerstenmaier.

Two other witnesses are Patricia Sanders, chair of NASA’s Aerospace Safety Advisory Panel (ASAP), and Cristina Chaplain of the Government Accountability Office (GAO). ASAP and GAO have each expressed concerns about the program. ASAP’s most recent report on safety issues associated with commercial crew and other NASA programs was released yesterday. GAO concluded in a February 2017 report that certification of the two spacecraft likely would slip into 2019 based on information from NASA’s own CCP office.