Is Sunita Williams’ Nine-Month Stay In Space As Risky As It Is Made Out To Be? | Explained - News18 (2025)

Last Updated:March 11, 2025, 10:11 IST

Astronauts in the past have stayed much longer at International Space Station. Scientists are trying to fully understand the changes which occur in human cells due to microgravity

Sunita Williams has spent a total of 322 days in space over the course of her two previous missions – 195 days in 2006-2007, and 128 days in 2012. (Photo: NASA)

When NASA astronaut and veteran of two space missions, Sunita Williams, returns to Earth next week, she will have already completed nine months at the International Space Station (ISS).

The 59-years old Williams and 62-year old Butch Wilmore have been stranded in space since June 5, 2024 — a visit that was expected to last only eight days.

All because the Boeing’s troubled Starliner spacecraft, which took off on its first-ever crewed test flight, malfunctioned and encountered technical issues with helium leaks and thrusters — rendering it unfit for the crew’s safe flight back home. It was then flown back to Earth un-crewed in September. Now, as another SpaceX Dragon spacecraft gears up for the ‘rescue mission’, concerns have risen over the safety and health of the two stranded astronauts.

What Happens To Human Body After Prolonged Stay In Space

Firstly, microgravity or weightlessness usually reduces bone density, and can cause muscle atrophy and some fluctuations in body fluid distribution. While most of it can be recovered over time, some effects may persist. Scientists are still trying to fully understand the changes which occur in human cells and tissues due to microgravity, and the post-recovery.

But it is not a new experience for a veteran like Williams, who has spent a total of 322 days in space over the course of her two previous missions – 195 days in 2006-2007, and 128 days in 2012. With 50 hours and 40 minutes, she is also second on the list of total cumulative spacewalk time by a female astronaut.

The key worry, however, is the radiation exposure in space – unlike on Earth, where people are protected by its magnetic field. While the ISS module is also designed with built-in protection to limit the ionizing radiation from space, scientists say it is not as safe as one would like it to be.

Astronauts are typically exposed to ionizing radiation in doses, which are equivalent to 150 to 6,000 X-rays, show studies. So, the crew is required to sign an undertaking before embarking on the mission.

“Nominal radiation is always present, but it’s the cumulative effect that can be damaging for health. Every extra day in space increases the risk of radiation exposure exceeding normal levels, which is always a concern. Especially, when the solar activity is high and there are solar flares. However, the present case is not an emergency situation, otherwise, the astronauts would have already been brought back," noted Indian astrophysicist Dr P Sreekumar told News18.

For over two decades, over 270 people from 21 countries have lived and worked aboard the ISS, which provides continuous year-round life support and habitation, making research breakthroughs not possible on Earth. The big microgravity laboratory has been orbiting the Earth at an altitude of 370 to 460 km since 1998.

Astronauts Who Have Stayed Longer In Space

It is not the first time that humans have stayed in space for that long. “Astronauts have stayed in space for much longer, and NASA monitors their health parameters regularly, and ensures all standards are met. Although, there is definitely some impact on the health, like loss in bone density, it is not permanent. Future missions such as those to Mars, will require astronauts to spend even more time in space. So, at this stage, scientists are also focusing on gathering all possible information on any potential health risks, without compromising astronauts’ safety," distinguished space scientist Professor Jayant Murthy tells News18.

Last year, two Russian cosmonauts Oleg Kononenko and Nikolai Chub returned home safely after creating a record for the longest continuous stay at ISS for 374 days. The 59-years old Kononenki, in fact, holds the record for the longest cumulative time in space at 1,111 days in orbit in five missions. Previously, another Russian duo Sergei Prokopiev and Dmitry Petelin, and American Francisco stayed in space for 370 days in September 2023.

It is also difficult to ascertain exact impacts because this health data of astronauts is not made public by space agencies.

The ISS clearly remains a critical testbed for NASA. As the space economy expands, and long-term ambitions to travel deep into space grow, the need to understand the health risks in space will become more important than ever. The future interplanetary missions such as those to Mars will also require a much longer stay in space. The renewed interest in commercial space flights and opportunities in low-earth orbit have further fueled the research.

Location :

New Delhi, India, India

First Published:

March 11, 2025, 08:30 IST

News explainers Is Sunita Williams’ Nine-Month Stay In Space As Risky As It Is Made Out To Be? | Explained