Above: The Crew Dragon “Endeavour” launches atop a Falcon 9 rocket on Apr. 23 from Kennedy Space Center. Credit: NASA

Four astronauts joined the International Space Station (ISS) crew late last month, marking the second-ever operational commercial crew flight conducted by SpaceX and NASA.

The crew launched in the early hours of Apr. 23 from Kennedy Space Center aboard a reused Crew Dragon space capsule and Falcon 9 rocket. The mission is the first to send humans to space on a reused booster rocket.

The crew members were NASA astronauts Shane Kimbrough and Megan McArthur, ESA astronaut Thomas Pesquet, and JAXA astronaut Akihiko Hoshide. After safely arriving at the ISS, the crew has now started a six-month science mission.

Their objectives include deepening our understanding of Earth’s climate and making preparations for the Artemis missions to the moon. An important focus of research will be tissue chips—small devices that contain human cells enclosed in a 3D matrix. The research will examine how cells respond to stress, drugs and genetic changes in space and ultimately learn more about how spaceflight and microgravity affect the human body.

The newly arrived crew brings the current count of international astronauts aboard the ISS to 11. Crew 2 is scheduled to return to Earth no earlier than Oct. 31, 2021.

Left to Right: ESA astronaut Thomas Pesquet, NASA astronauts Megan McArthur and Shane Kimbrough, JAXA astronaut Akihiko Hoshide. Credit: NASA.