Sunita Williams and Butch Wilmore bracing for toughest challenge after return – readjusting to Earth’s gravity

Williams and Wilmore have already spent more than eight months in microgravity in space. Wilmore revealed that gravity will be the biggest challenge for them after they return. “Gravity is really tough, and that’s what we feel when we get back,” he told CNN. “Gravity starts pulling everything to lower extremities; fluids will be pulled down, and even lifting a pencil will feel like a workout.”

Williams has also echoed Wilmore’s thoughts, saying adjusting to life on land will be challenging. The sudden change could lead to discomfort and a feeling of heaviness.

How can the astronauts ensure a boost in bone strength?

Experiments recently conducted by the European Space Agency (ESA) showed that the astronauts could face cartilage degradation due to reduced movement. Lack of movement can lead to cartilage thinning and cellular clustering, which are early indicators of arthritis.

The new study, which appeared in the journal npj Microgravity, showed that jumping exercises boosted cartilage in mice. Researchers from Johns Hopkins University, US, also found that jump training thrice a week led to thicker, healthier cartilage with normal cellular structure in the mice.

“Since the next step in human exploration of space is going to Mars and spending long periods of time in permanent bases on the moon, cartilage damage is a really major issue that space agencies need to address despite how very poorly understood it is,” said Marco Chiaberge, an astrophysicist at Johns Hopkins University, the Space Telescope Science Institute, and the ESA.

“The positive effect we saw in these mice is huge, and the magnitude of it was unexpected. They can basically make their cartilage thicker if they jump. Maybe astronauts could use similar training before their flight as a preventive measure,” he added.

Williams will reportedly undergo a rigorous rehabilitation program aimed at regaining strength and bone density. However, despite the difficulties, the astronauts are optimistic about their return. “Floating in space is a lot of fun; I like my crazy hair,” Wilmore has said.

Wilmore and Williams are set to board SpaceX’s Dragon spacecraft for a ride home.