NASA has named the astronauts chosen to fly on commercial spacecraft made by Boeing and SpaceX to and from the International Space Station, the research laboratory that orbits around Earth.

Their voyages are scheduled to begin next year, and they would be the first American astronauts to launch from United States soil since 2011. NASA retired its space shuttle fleet that year, and started sending astronauts to the I.S.S. aboard the Russian Soyuz spacecraft, at a cost that has risen to $81 million per seat.

“What an exciting and amazing day,” Jim Bridenstine, NASA’s administrator, said at the announcement at NASA’s Johnson Space Center in Houston. (Watch the full video here.)

But a Government Accountability Office report published last month raised alarm bells that the project is running behind schedule, and could miss key deadlines. The delays could even result in a gap in American access to the space station, because NASA has contracted for seats on Soyuz only through November 2019, the report found.