Sunita Williams faces radiation, muscle loss risk on extended ISS mission

Prolonged exposure to space radiation can lead to multiple health problems such as an increased risk of cancer, tissue damage, and complications in the nervous system

Nasa astronauts Sunita Williams and Butch Wilmore are now facing a considerably longer stay aboard the International Space Station (ISS) than originally expected. Both the astronauts, who start their journey to the ISS on June 5 aboard Boeing's Starliner spacecraft, might remain in space until 2025 due to unforeseen technical issues.

Initially planned as a one-week mission, it has now been extended to over eight months. This unexpected turn has turned Boeing's first crewed spaceflight into a potential rescue mission, with Nasa exploring the possibility of using SpaceX's Crew Dragon to bring the astronauts back to Earth.

The prolonged mission duration raises concerns about the astronauts’ health and safety. The ISS, which orbits about 400 km above Earth, is beyond the shield of our planet’s atmosphere and magnetic field. This location subjects astronauts to increased levels of solar radiation, with some parts of the station's orbit experiencing radiation levels over 30 times higher than those on Earth, according to data from the European Space Agency.

 

Health risks due to space radiation

Extended exposure to space radiation can cause a variety of health issues, including a higher risk of cancer, tissue damage, and nervous system complications. Nasa data indicates that radiation levels on the ISS can range from 50 to 20,000 milli-sieverts, which is the equivalent of 150 to 6,000 chest X-rays.

Besides radiation, the longer mission also entails extended exposure to microgravity. This can lead to significant bone and muscle deterioration, with Nasa stating that astronauts may lose around 1 per cent of their bone mass each month in key areas such as the lower spine, hips, and femur.

Currently, Nasa is working on contingency plans to bring back the two astronauts to Earth. Steve Stich, manager of Nasa's Commercial Crew Programme, said, "We have been working with SpaceX to ensure that they are ready to respond on Crew 9... returning Butch and Suni on Crew 9 if we need that."

What was the Starliner’s mission?

The Starliner’s mission, commanded by Wilmore and piloted by Williams, aimed to certify the spacecraft for routine travel to and from the ISS. Launched on June 5, the Starliner successfully docked with the ISS the following day. 

Originally slated to return on June 14, the mission was intended to provide Nasa with an alternative to SpaceX’s Crew Dragon. Currently, the Crew Dragon capsule -- capable of carrying up to seven passengers to and from Earth orbit -- is the only provider of crew transportation services for the ISS.