Doctors have warned of the health effects three astronauts could experience once they are back on Earth, including impaired vision and loss of bone density, after being forced to spend an extra six months in space.
American Frank Rubio and Russian cosmonauts Dmitry Petelin and Sergey Prokopyev are due to return on September 27 on a rescue spacecraft.
The Russian Soyuz craft that took them to the International Space Station on September 21 last year suffered catastrophic damage – reportedly from meteor strike – causing a coolant leak that could not be repaired.
Because no spacecraft was lined up to take them back to Earth, their mission, which was meant to last six months, was extended by another six.
With an additional 180 days spent in microgravity conditions, health experts fear their bodies could experience adverse effects that are a common result of extended space missions.
Nausea and wobbly legs
Dr Sana Kausar, head of aviation medicine at King’s College Hospital Dubai, said as well as long-term effects, the astronauts were also likely to face immediate health issues on their return.
“Physically, the astronauts may experience sensations such as nausea, dizziness and a feeling of heaviness as the body readapts to gravity on Earth," she told The National.
“It would be challenging to walk and move around due to muscle and bone changes from external weightlessness.”
It is common to see astronauts, particularly those returning from six-month or longer missions, struggling to walk once they leave their spacecraft, but these effects are not permanent.
“The sights, sounds and smells of Earth can be overwhelming after time spent in a controlled spacecraft,” Dr Kausar said.
“Even things like weather and the presence of other people will take time to adjust to.
“Of course, this varies according to each person. It’s an incredible journey, both physically and psychologically, and a lot depends upon the resilience of the person involved."
Impaired vision and muscle atrophy
Some of the long-term health effects associated with extended space travel include impaired eyesight and loss of bone density.
Dr Anil Grover, a specialist in internal medicine with Prime Hospital in Dubai, said the fluids in a human body undergo changes when they are in a microgravity environment.
“The fluid shifts affecting the eyes can cause changes in vision or cause cataracts,” he said.
“The loss in bone density, even if partially recovered, can make astronauts more prone to fractures later in life, hence the need of regular exercise in space, along with diet.
“Once back on Earth, astronauts undergo extensive rehabilitation and medical evaluation to address and mitigate these health effects.
“After a year in space, the astronauts will need a thorough assessment and possibly prolonged rehabilitation.”
Adverse health effects from previous space missions
Nasa astronaut Scott Kelly spent a total of 520 days on the ISS, with a consecutive 340 days in 2015 and 2016.
His health was compared with his twin brother on Earth.
It was found Mr Kelly's eyesight, height and health had been affected by zero gravity.
His heart shrank by 25 per cent and after a year on board the ISS. Nasa researchers found he had grown 5cm and was taller than his identical twin Mark, who is also an astronaut.
Record time in space
The extra six months means a record time spent by an American astronaut in space will be set.
Mr Rubio will beat the record of Mark Vande Hei, who spent 355 consecutive days on the ISS from 2020 to 2021.
Anton Shkaplerov and Pyotr Dubrov, who were on the same mission as Mr Hei, set a record time for Russians on the ISS. Mr Petelin and Mr Prokopyev are set to beat that, too.
Cosmonaut Valery Polyakov, who died last year, holds the world record for the longest single stay in space. He spent 437 days on the Mir space station.