By Paul Rincon
The science editor is on the website.
The image is from NASA.
The image caption is.
Two years of intensive training will be required for the astronauts.
The new class of astronauts could fly to the space station and on future missions to the moon.
They went through an interview process with several rounds, team exercises, and a medical check.
A pool of about 12,000 people applied for the six men and four women.
The candidates will have two years of training before graduating.
Bill Nelson, the administrator of Nasa, said that the frontier is now upwards out into the universe.
The basic Astronaut Candidate training programme is designed to develop the knowledge and skills the group will need when they are selected for a flight.
The candidates are required to complete military water survival exercises, fly Nasa's T-38 training jets, and become scuba-qualified to prepare them for the spacewalk training which takes place in a huge pool at Johnson Space Center in Houston.
The final selection as an astronauts is not guaranteed, they need to complete the training to a satisfactory level.
If the programme is not delayed, those who graduate will be eligible for flights to the space station and the moon. They are unlikely to be assigned to flights immediately, as they continue to develop their skills after becoming fully-fledged astronauts.
The image is from NASA.
The new astronauts are:
A major in the US Air Force is from Colorado.
Marcos Berros is a US Air Force major. He was born in Guaynabo, Puerto Rico.
A former track cyclist with the US team, Christina Birch has a doctorate in biological engineering.
A lieutenant in the US Navy reserve and a drilling engineer from Wasilla, Alaska, is Deniz Burnham.
A retired major in the US Marine Corps and a research pilot at Nasa.
A staff member at the University, Douglas has served in the US Coast Guard.
A commander in the US Navy who hails from Connecticut is Jack Hathaway.
The first private flight to the International Space Station was launched by a flight surgeon for Musk's company.
Christopher Williams is a medical physicist who grew up in Maryland.
Jessica Wittner is a lieutenant commander in the US Navy.
Pam Melroy, a former Nasa astronaut and the agency's deputy administrator, told the candidates that each of them has amazing background. "You bring diversity in so many ways to our corps of astronauts and you stepped up to one of the most exciting and exciting forms of public service."
Christine Birch was a former US track cyclist. "If you do the little things well, they add up to something big," she said.
Last month, the first two astronauts from the previous class made their first flights into space. The path to a flight assignment can take several years longer for successful candidates.
The shuttle was the only way to get into space in the 1990s and 2000s. The candidates join the agency at a challenging and exciting time.
"We are in the golden age of human spaceflight", said the Nasa astronaut.
Candidates need to demonstrate a working knowledge of Russian and understand the systems aboard the International Space Station in order to communicate with cosmonauts.
Some will be assigned to fly on either of the two spaceships that Nasa has developed to fly to the International Space Station. Others will be selected for missions to the moon.
The agency plans to use landers to get to the moon, and these astronauts will need a deep understanding of the craft. The vehicle to be used for the first lunar landing since 1972 is likely to be based on Musk's Starship craft, currently under development at a SpaceX facility in southern Texas.
