'Gravity stinks': Sunita Williams and Butch Wilmore reflect on microgravity's aftermath and recovery challenges

When NASA astronauts Sunita Williams and Butch Wilmore launched aboard Boeing’s Starliner capsule in June 2024, they anticipated an eight-day mission to the International Space Station (ISS). However, due to technical issues with the spacecraft, their stay extended unexpectedly to 256 days, turning their brief assignment into a nine-month odyssey in microgravity .

Upon their return to Earth in March 2025, the duo faced significant challenges readjusting to Earth's gravity. In a recent interview, Wilmore humorously remarked, "Gravity stinks for a period," highlighting the immediate discomfort he felt as gravity reasserted itself. He noted that while still floating in the capsule post-splashdown, his neck pain returned—a stark contrast to the relief experienced in weightlessness .

"Right now, we're just coming off of the rehab portion of our return," Wilmore, 62, told Reuters in an interview on Wednesday. "Gravity stinks for a period, and that period varies for different people, but eventually you get over those neurovestibular balance type of issues." The astronaut duo have spent at least two hours a day with astronaut strength and reconditioning officials within NASA's medical unit while juggling an increasing workload with Boeing's (BA.N), Starliner program, NASA's space station unit in Houston and agency researchers.

Williams shared similar sentiments, describing the fatigue and muscle re-engagement required during her recovery. She mentioned struggling with early mornings until her body gradually readapted, eventually returning to her routine of waking up at 4 a.m. .

Their rehabilitation involved a 45-day program focusing on mobility, flexibility, and muscle strengthening, guided by NASA’s Astronaut Strength, Conditioning, and Rehabilitation specialists. Despite rigorous in-space exercise regimens, both astronauts experienced muscle atrophy and balance issues upon return, underscoring the profound effects of prolonged microgravity on the human body .

Beyond physical challenges, research indicates that extended space missions can lead to structural changes in the brain, such as the brain shifting higher in the skull and expansion of fluid-filled cavities, some of which may persist even after returning to Earth .