BENGALURU: AS you read this, India’s Group Captain and astronaut Shubhanshu Shukla (call sign Shux) has completed over half his journey back to Earth. In a few hours from now Shux will start the exercise to descend and make a splashdown landing off California coast at 3pm, subject to weather conditions, as a part of the Axiom-4 (Ax-4) space mission – the commercial four-agency collaboration of Axiom Space, National Aeronautics and Space Administration (NASA), Indian Space Research Organization (ISRO) and the European Space Agency (ESA).
The Ax-4 mission’s space capsule SpaceX Dragon spacecraft, named Grace, undocked from the International Space Station (ISS) at 4.50pm IST on July 14 – 10 minutes behind schedule due to technical reasons. After the 12 capture hooks of the space capsule were released to facilitate the undocking procedure, thrusters were manually operated by Shux and Ax-4 mission commander Peggy Whitson to enable the capsule to distance itself from the ISS.
The subsequent procedures would involve reducing the orbital altitude of Grace from 400 Km. ISRO scientists familiar with the undocking procedure and the process of return to Earth, explained that after undocking, the capsule would continue to orbit as an independent entity till the thrusters are fired to reduce its speed for a safe landing. The crucial time for that would begin at 2 pm (IST) on Tuesday, an hour before the scheduled splashdown.
The thrusters of the capsule, piloted by Shux and mission commander Peggy Whitson, will be fired to drastically reduce the capsule’s speed from 26,200 km/hour to just 24 km/hour in less than an hour to facilitate its descent to an altitude of 80km from where the parachutes would come into play to ensure a safe and successful splashdown.
Only Monday, at 4.48pm IST, two minutes before the undocking was completed, Expedition 73’s seven crew members on board the ISS (who the four Ax-4 mission crew members joined on the space station on June 26 afternoon), relayed a message, “Have a Safe Journey Back Home,” to the Ax-4 crew members.
They also instructed the Ax-4 mission crew members not to cross the “imaginary boundary” of the ISS until they completed four orbits around Earth before starting the de-orbiting manoeuvres for Tuesday’s splashdown.
Shux and his three crew mates – which include the two mission specialists, European Space Agency (ESA) project astronaut Sławosz Uznanski-Wisniewski of Poland and Tibor Kapu of Hungary – spent a total 21 days in space, of which 18 were spent on the ISS. The Ax-4 mission was launched on June 25 and docked with the ISS on June 26, 2025.
The four astronauts had bid their farewells to the seven member crew at the ISS on July 13. After Grace’s hatch was closed, the space suits-donning four-member Ax-4 mission crew had buckled up into their spacecraft in the early morning hours of July 14.
The four astronauts are carrying back 580 pounds of cargo, which includes hardware, items from space and samples of 60 scientific experiments they conducted.
These samples will be handed over to the scientists and researchers on July 15 for further analysis. Of these, Shux conducted seven microgravity experiments on Indian strain of tardigrades, myogenesis, sprouting of methi and moong seeds, cyanobacteria, microalgae, crop seeds and Voyager Display (which studied the physical and cognitive impact of using computer screens in microgravity).