Astronaut Shubhanshu Shukla, part of the Axiom-4 (Ax-4) mission, is set to return to Earth on July 15, 2025, after spending 18 days at the International Space Station (ISS). The undocking from the ISS is scheduled for July 14 at 4:35 p.m. IST (7:05 a.m. ET), with the splashdown expected off the coast of California around 3:00 p.m. IST on July 15.
The Mission's Conclusion and Return Journey
The Ax-4 mission, a collaboration between Axiom Space, SpaceX, and NASA, launched on June 25, 2025, aboard a SpaceX Falcon 9 rocket. The mission's original duration of 14 days was extended. Commander Peggy Whitson led Pilot Shubhanshu Shukla, Mission Specialist Sławosz Uznański-Wiśniewski, and Mission Specialist Tibor Kapu.
The return journey involves a series of orbital maneuvers after undocking, with the SpaceX Dragon spacecraft slowing down to re-enter Earth's atmosphere. The spacecraft's service module will be jettisoned, and the capsule will perform a deorbit burn. As it descends, the capsule's heat shield will endure extreme temperatures of around 1,600 degrees Celsius. Parachutes will deploy to ensure a safe splashdown in the Pacific Ocean.
Experiments and Contributions
During his time on the ISS, Shukla contributed to over 60 experiments. These experiments spanned various fields, including biology, artificial intelligence, materials science, and human health. Shukla's key contributions included the Sprouts Project, which studied the effects of microgravity on seed germination. He also worked with microalgae to explore their potential as a source of food, oxygen, and biofuels for future space missions. Additionally, he tested glucose monitors in microgravity, aiming to make spaceflight more accessible for individuals with diabetes. Other experiments included studies on tardigrades, muscle loss, and the growth of seeds in space.
Rehabilitation and Readjustment to Earth's Gravity
Upon splashdown, Shukla will undergo a seven-day rehabilitation program under the supervision of a flight surgeon to help him readjust to Earth's gravity. This program is crucial because prolonged exposure to microgravity can cause several physiological changes, including muscle atrophy, bone density loss, and cardiovascular deconditioning. The rehabilitation program will likely involve exercises and therapies designed to restore muscle strength, bone density, balance, and cardiovascular function.
Post-Mission Plans
After the initial rehabilitation, Shukla will be transported to NASA's Johnson Space Center in Houston for medical evaluations and debriefings. These evaluations will cover physical fitness, balance, reflexes, cardiovascular function, and immune response. Data from his mission experience and experiments will be valuable for future collaborative space missions between Axiom Space and ISRO.
Shukla's return marks a significant milestone for India's space program. ISRO invested approximately ₹550 crore in his ISS travel, an experience that will contribute to the planning and execution of the Gaganyaan mission, India's human spaceflight program, targeted for 2027. He is expected to be recognized by Indian scientific institutions and may receive honors for his achievements in space exploration.
Shukla's family is eagerly awaiting his return, preparing a grand welcome with his favorite home-cooked meals. His mother, Asha Shukla, expressed her relief and happiness, stating that the family is praying for his safe return and looking forward to having him back home.
The Axiom-4 mission has not only expanded scientific knowledge but also paved the way for future space exploration and collaboration, with Shubhanshu Shukla playing a pivotal role in this new era of space travel.
