Suni Williams, who is best known for running the Boston Marathon on an ISS treadmill, will be joined by rookie astronaut Josh Cassada.
Mr. Behnken, Mr. Boe, Mr. Hurley and Mr. Williams were named in 2015 as NASA's "commercial crew cadre" and have been working with Boeing and SpaceX on the development of the spacecraft and the simulators that will be used to train astronauts to fly.
Prior to their maiden crewed missions, both Boeing and SpaceX plan uncrewed test flights in late 2018 or early 2019. "Today's announcement advances our great American vision and strengthens the nation's leadership in space".
Sunita Williams, a veteran astronaut with roots in Needham, is going back into space. He flew on two flights of the space shuttle including the final mission, Atlantis's STS-135.
The move marks a significant shift in the US space program, which will now combine NASA-trained astronauts with private sector space capsules.
NASA on Thursday said it expects SpaceX to fly its first astronauts in April of 2019 and Boeing will follow, launching astronauts into space in the middle of next year. On the right, NASA astronauts conduct a fully-suited exercise in Boeing's CST-100 Starliner mock-up trainer in early May at the agency's Johnson Space Center in Houston.
For the past seven years, Russian rockets have been the only way to get people into orbit.
NASA astronauts Eric Boe and Nicole Aunapu Mann are slated for the test flight of Boeing's Starliner, accompanied by former NASA astronaut Chris Ferguson, who now works as a commercial astronaut for Boeing.
This will be the first trip into space for Mr. Glover, Mr. Cassada and Ms. Mann. Crew members have worked years with companies to get here and they said they can not wait for the flights to begin next year.
Ferguson commanded the final mission of the space shuttle program, and Hurley was the pilot on that flight. Mr. Ferguson will become the first former NASA astronaut to return to orbit as a company's crew member when he flies.
The two astronauts that the SpaceX company will send later will be Mike Hopkins, who spent 166 days in the space lab, and Victor Glover, who will be making his debut.
NASA has been paying billions of dollars to SpaceX and Boeing to develop the crew capsules to pick up where the shuttles left off, while also paying billions for cargo deliveries to the space station by SpaceX and Northrop Grumman.
The test flights and missions aboard Boeing's CST-100 Starliner and SpaceX's Crew Dragon spacecraft, slated for as early as April 2019, will "begin a new era in America spaceflight", the USA space agency said.
NASA has named the crew of astronauts tasked with reviving America's prowess in extraterrestrial travel.
Crew for each flight will include at least a flight commander and a pilot.
It is on the subsequent missions that the crew capsules will head to the space station and dock. It won't be the first time SpaceX trounces Boeing. As a naval aviator, she flew combat missions during operations Iraqi Freedom and Enduring Freedom before becoming a naval test pilot.