Shukla’s mission began with a launch from NASA’s Kennedy Space Center on July 1, as part of the privately operated Axiom Space Mission-4. His arrival at the ISS marked a national milestone — the second Indian in space since Rakesh Sharma’s 1984 mission, and the very first to reach the orbiting laboratory.

A private spaceflight featuring the first astronauts in more than 40 years from India, Poland and Hungary came to a close Tuesday with a Pacific splashdown.

For India, Poland and Hungary, the launch marked the first human spaceflight of each country in more than 40 years and the first mission ever to send astronauts from their government's respective spac...