Butch Wilmore, a fellow astronaut, stuck in space with Williams, revealed how gravity will be the biggest challenge when the two astronauts return home.

Astronaut Sunita Williams is preparing for a tough transition back to Earth's gravity, after her long mission on the International Space Station (ISS). Her fellow astronaut, Butch Wilmore, emphasized the challenges they will encounter on their return. "Gravity is really tough, and that's what we feel when we get back," Wilmore told CNN.

Sunita Williams and Butch Wilmore flew to the International Space Station's Boeing Starliner on June 5 last year and have been stuck since due to technical problems with the spacecraft.