NASA assigns four astronauts to SpaceX mission scheduled for 2021

New York(CNN Business) NASA and its international partners named four astronauts to crew a SpaceX mission to the International Space Station in spring 2021 — beefing up staffing on board the orbiting laboratory.

The crew, all veterans of previous ISS missions, will include Akihiko Hoshide with Japan's JAXA space agency, Thomas Pesquet of the European Space Agency and NASA's Shane Kimbrough and Megan McArthur — who two months ago watched her husband Robert Behnken co-pilot the first-ever crewed flight of SpaceX's Crew Dragon capsule.

Putting four astronauts on SpaceX's spring 2021 mission, dubbed Crew-2, will bring the number of people staffing the ISS to seven, allowing "NASA to effectively double the amount of science that can be conducted in space," the agency said Tuesday.

Five people are currently on board the ISS: Two Russian cosmonauts and NASA's Chris Cassidy, Douglas Hurley, and Behnken, The latter two arrived at the space station in May after commanding SpaceX's Crew Dragon capsule on its historic journey. It marked the first time in history that a commercial vehicle carried humans into orbit and the first crewed launch from US soil since NASA's Space Shuttle retired in 2011.

But that mission isn't over yet. Behnken and Hurley are expected to return home from the ISS as soon as this weekend, and their safe return could grant the Crew Dragon vehicle official certification as a human-worthy spacecraft. And that will pave the way for a Crew Dragon capsule to be launched on its first fully operational mission to the space station, Crew-1, which is slated for late September.

NASA has waited for years to regain the ability to fly its own astronauts to and from the space station. After the Shuttle program ended, the space agency had to rely on Russia's Soyuz vehicles to ferry NASA crews to the ISS, and the United States has paid Russia as much as $90 million per seat for those trips.

Rather than building its own replacement for the Space Shuttle, however, NASA asked the private sector to develop spacecraft capable to design and develop its own vehicles so that the space agency could focus on exploring deeper into the solar system.

In 2014, NASA awarded two fixed-price contracts: $4.2 billion for Boeing and $2.6 billion to SpaceX, which planned to design a crew-worthy version of the Dragon capsule that had already been flying cargo to and from the International Space Station.

After both companies struggled with development delays, SpaceX beat Boeing to the launch pad with Hurley and Behnken's crewed test mission earlier this year.

Boeing, which suffered significant setbacks during a test in December, is planning to repeat an uncrewed test mission later this year.

Still, having Crew Dragon in its spacecraft arsenal will grant NASA much more control over staffing the US-run portion of the ISS. And, because SpaceX will be permitted to sell extra seats aboard its spacecraft, NASA astronauts may one day find themselves sharing a ride with tourists, corporate scientists and even movie stars.