Why Shubhanshu Shukla will go to rehab upon return to Earth

Indian astronaut Shubhanshu Shukla is back on Earth. A SpaceX Crew Dragon capsule carrying him and his three crewmates, including NASA retiree Peggy Whitson, made a splashdown in the Pacific off the Southern California coast around 3 PM IST on Tuesday (July 15).

The Dragon spacecraft undocked from the International Space Station (ISS) at around 4.35 pm IST on July 14. About 22.5 hours since the undocking, the spacecraft with the four astronauts of the Axiom-4 Mission landed in the Pacific Ocean. As Shukla returns from space, he will spend seven days in a rehabilitation programme. But why?

We will explain.

How space travel affected Axiom-4 astronauts

Space travel has an impact on nearly every part of the astronaut’s body. After reaching outer space where there is microgravity, some astronauts experience space motion sickness, such as headaches, nausea, and vomiting.

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This is because space affects spatial orientation, head-eye and hand-eye coordination, balance, and locomotion, as per the National Aeronautics and Space Administration (Nasa). The condition does not last long, ending in a couple of days as the body adjusts to microgravity.

Shukla had said during an interaction from the ISS while getting acclimatised to microgravity, “It’s the first time for me, so I don’t know what to expect (upon return). The only hope is — I did have some symptoms coming up — so I am hoping that I will not have it going down. Unless and until I get the worst of both worlds and I get it both times.”

Due to a lack of gravity, bodily fluids move upward, resulting in facial swelling. As the fluids shift towards the head, it puts pressure on the eyes and causes vision problems.

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Astronauts in space also get exposed to space radiation.

Muscle and bone mass also start to diminish in space. To tackle this, astronauts aboard the ISS perform two and a half hours of daily strength and cardio training.

Speaking to NPR, Dr Natacha Chough, a NASA flight surgeon, said, “We definitely track muscle mass and bone mineral density preflight and postflight because weightlessness is what I refer to as a ‘use it or lose it’ environment. If you’re not regularly exercising in flight, your body is not going to expend the energy to preserve your muscles and bones.”

The impact of long spaceflights on the body is still being studied.

Shubhanshu Shukla’s 7-day rehabilitation

After an 18-day stay at the ISS as part of the Axiom-4 mission, Indian Air Force (IAF) Group Captain Shubhanshu Shukla is back home. After adjusting to microgravity in space, he will now have to readjust to gravity on Earth.

After splashdown, Shukla and his crewmates will be removed from the Dragon spacecraft using a SpaceX recovery vehicle, where they will undergo their first medical checks. They will then be brought to land.

On the way back home 🌍#Ax4 #IGNIS #astro_slawosz@Axiom_Space @SpaceX @esa @MRiTGOVPL @POLSA_GOV_PL pic.twitter.com/zRlj57a8iv

— Sławosz Uznański-Wiśniewski (@astro_slawosz) July 14, 2025

Shukla and others will be screened on several health parameters. Based on these, they will get a personalised reconditioning plan to improve their mobility, balance, strength, flexibility, aerobic conditioning, and endurance, as per an Indian Express report.

“Post splashdown, the Gaganyatri [Shukla] will undergo a rehabilitation program (about seven days) under the supervision of Flight Surgeon to adapt back to Earth’s gravity,” the Indian Space Research Organisation (ISRO) said in a statement earlier.

“ISRO’s flight surgeons are continuously monitoring and ensuring the overall health and fitness of the Gaganyatri through participation in private medical/psychological conferences. Gaganyatri Shubhanshu is in good health and in high spirits,” it added.

Why rehabilitation after space travel is necessary

The body has to be retrained after experiencing weightlessness in space. According to Dr Chough, who monitors astronauts’ healthcare before, during, and after missions, the first thing they check for is motion sickness upon return to Earth.

“Your inner ear kind of shuts off more or less in weightlessness,” she told NPR. “So when you reintroduce that sense of gravity, it can be a little bit disorienting.”

The vestibular system in the inner ear consists of sensory organs that help maintain one’s sense of balance. In space, the system gets mixed signals and is unable to determine which way is up or down.

This becomes a challenge when astronauts return to Earth as they encounter problems standing up and walking.

A special team of doctors help astronauts readjust to gravity on Earth. During the rehabilitation process, they are reaccustomed to balance, coordination, and core strength.

“There is an incredible group of dedicated athletic trainers and physical therapists who manage and implement the post-flight rehabilitation for crew. This starts the very next day after landing and involves two hours per day for six weeks of progressive physical training,” Dr Chough said, as per an article in the University of Texas Medical Branch website.

“Your balance and neuromuscular coordination require re-training because in weightlessness, your brain becomes almost entirely dependent on your visual input for orientation,” she explained. “If you ask a returned astronaut to stand with their eyes closed in the early post-landing phase, they can have difficulty keeping their balance when that visual input is taken away, because their inner ear and cerebellum, both of which rely on gravity for inputs and normally assist the eyes with balance, coordination, and orientation, haven’t been as active while in space.”

According to Dr Chough, it takes seven to 10 days for astronauts to regain their pre-flight baseline balance, allowing them to restart daily tasks like driving.

With inputs from agencies