Four astronauts are safely back on Earth after the first-ever medical evacuation of the International Space Station.

Four International Space Station crewmembers splashed down in the Pacific Ocean on Thursday, NASA footage showed, after the first ever medical evacuation in the orbital lab's history.

A pack of dolphins greeted Zena Cardman, Mike Fincke, Japan’s Kimiya Yui and Russia’s Oleg Platonov at splashdown and remained at the site while NASA recovery vessels circled the capsule.