Shuks' mission to splash down off San Diego at...

Astronaut Shubhanshu Shukla and three others of the commercial Axiom-4 mission are on track to return to Earth with a splash down off San Diego in California on Tuesday, capping a 22.5-hour journey after an 18-day stay at the International Space Station.

The Dragon 'Grace' spacecraft carrying Shukla, commander Peggy Whitson, and mission specialists Slawosz Uznanski-Wisniewski of Poland and Tibor Kapu of Hungary, undocked from the space station at 4:45 pm IST on Monday.

'Dragon and the @Axiom_Space Ax-4 crew are on track to reenter Earth's atmosphere and splash down off the coast of San Diego at ~2:31 am PT tomorrow (3:01 pm IST, Tuesday),' SpaceX, the transporter for the Axiom-4 mission, said in a post on X.

It said the spacecraft will also announce its arrival with a brief sonic boom prior to splashing down in the Pacific Ocean.

The de-orbit burn is expected to take place at 2.07 pm IST over the Pacific Ocean as the spacecraft re-enters the Earth's atmosphere.

Final preparations include detaching the capsule's trunk (at 2.26 pm IST) and orienting the heat shield ahead of atmospheric entry, which will expose the spacecraft to temperatures nearing 1,600 degrees Celsius.

Parachutes will deploy in two stages -- first stabilising chutes at about 5.7 km altitude at 2:57 pm IST, followed by the main parachutes at roughly two km before splash down.

The spacecraft will be hauled up on a special recovery ship where the astronauts will be brought out from the capsule.

The Axiom-4 crew will undergo a series of medical checks on board the ship before boarding a helicopter for a ride back to the shore.

The four astronauts are expected to spend seven days in rehabilitation as they adjust back to life on Earth under the influence of gravity, unlike the weightlessness experienced in orbit. 

After hugs and handshakes, the four astronauts entered the Dragon spacecraft on Monday, donned their spacesuits and closed the hatch connecting the spacecraft to the ISS at 2.37 pm IST.  -- PTI