What does it really mean for an astronaut to come home not merely to Earth, but to the arms of loved ones and the gravity of normal life? For Group Captain Shubhanshu Shukla, India’s first visitor to the International Space Station (ISS), the response was simple yet profound: “Holding them felt like home.” But behind this sentimental reunion there is a complex dance of science, engineering, and the psychology of human spaceflight.
The Axiom-4 mission, conducted by Houston-based Axiom Space and utilizing SpaceX’s Crew Dragon, was much more than a commercial flight. Its crew of four seasoned commander Peggy Whitson, Shukla as mission pilot, and specialists Slawosz Uznanski-Wisniewski and Tibor Kapu had an 18-day journey that brought a historic return of astronauts from India, Hungary, and Poland to orbital research following four decades (288 orbits of the Earth). For India, Shukla’s presence was not symbolic; it was an investment in the country’s crewed Gaganyaan program, planned for 2027.
Shukla’s appointment was a result of a diplomatic NASA-ISRO collaboration, providing ISRO with a precious window into real-time mission operations, astronaut training, and international crew integration (order of operations). As mission pilot, Shukla trained to watch over Dragon’s systems during launch, docking, and re-entry, prepared to take control manually if needed a task requiring both technical expertise and psychological toughness.
And the science of returning home is as difficult as the science of departing. After 20 days in weightlessness, space travelers experience a cascade of physiological changes. The sudden exposure to Earth’s gravity induces muscle atrophy, loss of bone density, and cardiovascular deconditioning, according to research. Astronauts have been found to lose 1–2% of bone mass each month in space, and up to 20% of muscle mass in merely two weeks. Shukla and his fellow crew members, after splashdown off the coast of California, needed help standing and walking a test repeated by all long-duration space travelers.
The rehabilitation process is carefully designed. Shukla will spend a seven-day program under the watch of flight surgeons, with emphasis on the restoration of balance, cardiovascular system, and muscle power (rehabilitation program). The program comprises strength and cardiovascular exercise, vision and balance tests, and immune function monitoring. Astronauts commonly complain of dizziness, orthostatic intolerance, and even cognitive shifts as their brains and bodies re-adapt to gravity. “Studies have shown that astronauts lose up to 1–2% bone density per month, equivalent to a decade’s aging in just a few weeks at the ISS,” reports a recent review.
But the psychological and emotional aspects are just as important. Prolonged isolation, disrupted circadian rhythms, and the stresses of living in tight spaces can produce irritability, sleep problems, and a condition called “asthenization.” For Shukla’s family, reunion was a joyous celebration of survival. His wife, Kamna, spoke of the excitement of bringing warmth and routine back to his life, cooking his favorite home recipes an activity that, for astronauts, is as therapeutic as any medical regimen.
Scientific legacy of the mission is no less remarkable. Shukla performed microalgae experiments on the ISS, investigating sustainable sources of food and oxygen for deep space missions. Shukla was also involved in research into cerebral blood flow, neuroadaptive technologies, and impact of microgravity on perception and learning information that will shape future astronaut health as well as the mental support design of habitats for long-duration flights.
The Axiom-4 mission, with its integration of commercial drive and global collaboration, presented ISRO with a “single-window entry” to expedite its human spaceflight program. The experience gained from emergency procedures and live telemetry to the psychological complexities of crew consolidation will inform India’s Gaganyaan program and, maybe, its plans for a lunar landing in the future.
As Shukla acclimates to gravity and domestic life, his mission remains both a personal and national benchmark. “Human spaceflight missions are magical, but they are made magical by the humans,” he penned. The magic, it appears, is as much in the science of survival as it is in the mere act of returning home.
