Health risks for Mars missions

Astronaut exercising aboard the International Space Station

NASA astronaut Nicole Stott exercising aboard the International Space Station. Astronauts lose 40% of their capacity for physical work over long periods.

  • Muscles deteriorate on long space flights
  • Not even exercise seems to help
  • 30-year-old can return with muscles of 80-year-old

Astronaut muscles waste away on long space flights, reducing their capacity for physical work by more than 40%, according to new research.

This is the equivalent of a 30- to 50-year-old crewmember’s muscles deteriorating to that of an 80-year-old.

The destructive effects of extended weightlessness to skeletal muscle—despite in-flight exercise—pose a significant safety risk for future manned missions to Mars and elsewhere.

The study, led by Robert Fitts of Marquette University (Milwaukee, Wisconsin), was recently published online by The Journal of Physiology and will be in the September printed issue.

It comes at a time of renewed interest in Mars. NASA currently estimates it would take a crew 10 months to reach Mars, with a one-year stay, for a total mission time of approximately three years.

Fitts, Chair and Professor of Biological Sciences at Marquette, believes if astronauts were to travel to Mars today their ability to perform work would be compromised and, with the most affected muscles such as the calf, the decline could approach 50%.

Crewmembers would fatigue more rapidly and have difficulty performing even routine work in a space suit.

Even more dangerous would be their return to Earth, where they’d be physically incapable of evacuating quickly in case of an emergency landing.

The study—the first cellular analysis of the effects of long duration space flight on human muscle—took calf biopsies of nine astronauts and cosmonauts before and immediately following 180 days on the International Space Station (ISS).

Soichi Noguchi exercises aboard the International Space Station

Japan Aerospace Exploration Agency astronaut Soichi Noguchi exercises using the advanced Resistive Exercise Device in the Unity node of the International Space Station.

The findings show substantial loss of fibre mass, force and power in this muscle group.

Starting fitter doesn’t help

Unfortunately starting the journey in better physical condition did not help.

Ironically, one of the study’s findings was that crewmembers who began with the biggest muscles also showed the greatest decline.

The results highlight the need to design and test more effective exercise countermeasures on the ISS before embarking on distant space journeys.

New exercise programmes will need to employ high resistance and a wide variety of motion to mimic the range occurring in Earth’s atmosphere.

Fitts doesn’t feel scientists should give up on extended space travel.

‘Manned missions to Mars represent the next frontier, as the Western Hemisphere of our planet was 800 years ago,’ says Fitts. ‘Without exploration we will stagnate and fail to advance our understanding of the Universe.’

In the shorter term, Fitts believes efforts should be on fully utilising the International Space Station so that better methods to protect muscle and bone can be developed.

‘NASA and ESA need to develop a vehicle to replace the shuttle so that at least six crew members can stay on the ISS for 6-9 months,’ recommends Fitts.

‘Ideally, the vehicle should be able to dock at the ISS for the duration of the mission so that, in an emergency, all crew could evacuate the station.’

Adapted from information issued by Wiley-Blackwell / NASA.

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