Astronauts Suni Williams and Butch Wilmore, who were stranded at the International Space Station for nine months after they were forced to abandon Boeing Starliner due to thruster issues, are finally back on Earth after a successful splashdown Tuesday at 5:57 p.

Their return caps a protracted space mission that was fraught with uncertainty and technical troubles and turned a rare instance of NASA's contingency planning - and the latest failures of Boeing's Starliner - into a global spectacle.

Mission has created controversy as US leader Donald Trump and adviser Elon Musk criticised former president’s commitment to bring crew back.