52-year-old Williams will be accompanied by Josh Cassada, 45, on NASA's first contracted Starliner mission.
Leading up to the a ceremony at the Johnson Space Center here, NASA Administrator Jim Bridenstine said it was a historic moment for the space agency, saying: "We are going to launch American astronauts from American soil".
Veteran NASA astronauts Bob Behnken and Doug Hurley will fly on SpaceX's first crewed Crew Dragon flight. Announced today is the initial crew manifest for both the test flight and the first mission each company will undertake.
The Starliner test flight astronauts named by the agency are Eric Boe, Christopher Ferguson, and Nicole Aunapu Mann, while the Crew Dragon test flight astronauts would be Robert Behnken and Douglas Hurley. NASA also named today the astronauts for those flights: Victor Glover and Mike Hopkins will fly aboard the first operational Crew Dragon, while John Cassada and Sunita Williams will fly aboard the first operational Starliner.
Meanwhile, the U.S. Government Accountability Office recommended NASA pursue a backup plan for getting astronauts to the ISS, as its contract with Russian Federation to send them to the station via Soyuz launches in Kazakhstan ends at the end of 2019.
Once the first crewed test flights are complete, two more crews will fly on Crew Dragon and Starliner for long-duration missions to the space station.
Victor Glover, 42, and Michael Hopkins, 49, will launch on the premier operational mission of SpaceX's crewed Dragon. NASA had originally expected the companies to have their spacecraft ready for missions to the International Space Station by the end of previous year, but neither were able to meet that target. The Boeing Company and SpaceX have developed the test flights and the missions of latest commercial spacecraft will be operated by them.
"Safely and reliably flying commercial crew missions for NASA remains the highest priority for SpaceX", said Benji Reed, SpaceX Director of Crew Mission Management. The astronauts were selected for test flights, scheduled to occur in 2019, and for the first formal missions to follow. Boeing's CST-100 "Starliner" will be blasted to orbit by United Launch Alliance Atlas 5 rockets from pad 41 at the nearby Cape Canaveral Air Force Station. Hurley is a retired Marine Corps colonel and test pilot who has also piloted space shuttles Endeavor and Atlantis.
The first flight is expected sometime next year. Journey on one of the last shuttle missions to witness some final "firsts" made aboard this unique spacecraft.
"As a test pilot it doesn't get any better than this", Mann told the audience, when asked about being the first to fly a new spacecraft. If any further delays creep up, NASA's astronauts may be temporarily stranded on Earth. The NASA official states, "that NASA's two-pair crewmates will fly to the station with Russian cosmonauts and worldwide astronauts to be announced at a later date". In any case, SpaceX is now the presumed leader of the race to capture the flag left on the station by the final space shuttle crew-a flag that has been waiting to return to Earth for eight years and counting.