The mission, aimed at simulating the stresses and routines of lunar and Martian exploration, marks a major milestone for India’s human spaceflight ambitions.

The splashdown off San Diego closed out a 148-day mission for two NASA astronauts, a Japanese flier and a Russian cosmonaut.

Four astronauts are returning to Earth after nearly five months on board the International Space Station. NASA’s Anne McClain and Nichole Ayers along with Russian and Japanese astronauts are scheduled to splash down off the Southern California coast.