NASA announced on Friday the assignments of the first nine astronauts riding commercial spacecraft to the International Space Station, naming five to the first two Boeing flights and four to SpaceX's flights.

The astronauts are a part of NASA's Commercial Crew program, which is the agency's solution to once again launch U.S. astronauts from U.S. soil. Since the end of the Space Shuttle program in 2011, astronauts have flown aboard Russian Soyuz — at a cost to NASA of more than $70 million per seat.

NASA's new program is competitive, with contracts up for grabs for Boeing to win with its Starliner capsules and SpaceX with its Dragon capsules.

Delays have plagued the program since 2014, when NASA first handed out multi-billion dollar contracts to SpaceX and Boeing. Boeing announced on Wednesday that its first Starliner test flight would be pushed from August to later this year, at the earliest.

Meanwhile, NASA confirmed Thursday that SpaceX's first test flight for Dragon would delay to November. NASA was expected to certify Boeing in December 2019 and SpaceX in January 2020, according to analysis earlier this year, but a GAO report in July says further delays are expected.

Boeing's timeline already causes a one-month gap, at minimum, in NASA's contracts for seats with Russia, and the first launches of Boeing and SpaceX. NASA is considering a number of solutions to resolve the gap, the GAO report said.

NASA administrator Jim Bridenstine presented the astronauts who will ride on the first four Commercial Crew flights, including three who have never flown to space before. Here are the companies and flights they were assigned to on Friday: