Medically evacuating an astronaut from space is difficult and expensive, and a new model predicts that one in three long-duration moon missions may require it.
One in three missions to the moon is at risk of requiring an astronaut to be medically evacuated back to Earth. This process would be difficult and costly – a medical emergency in space is an altogether tougher situation than one on Earth – but a new tool to calculate the probability of such crises could help us prevent them.
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| Astronauts on missions to the moon will need training to avoid medical emergencies that would require evacuation Merlin74/Shutterstock |
Generally, major space agencies like NASA reduce the risk of medical evacuation being required by only selecting astronauts in extremely good health. However, missions are getting increasingly complicated, with astronauts preparing for long-duration trips to the moon in the next decade or so, and possibly even flights to Mars after that. “It’s probably only going to get harder from here,” says Erik Antonsen at Massachusetts General Hospital, who was not involved in this work.
To update the health risks involved in this new era of space flight, Arian Anderson at the University of Colorado and his colleagues used a NASA-developed model called Informing Mission Planning through Analysis of Complex Tradespaces (IMPACT) to identify and quantify the risk that a medical issue requiring evacuation would pop up during a nine-month mission to the moon with four crew members.
They found that the chance of such an event was 32 per cent, with the most frequent issues being wrist fractures, eye injuries and problems related to changes in atmospheric pressure similar to those faced by scuba divers. All of these would require relatively quick treatment beyond the capabilities of current onboard medical systems to avoid permanent damage.
The finding came as a bit of a surprise. “I think we anticipated that that number would be lower, just based on historical evidence – NASA has never had to medically evacuate in the history of the space programme,” says Anderson. Only three astronauts have ever been evacuated from space for medical reasons, all of them from the Soviet space programme.
Medical evacuation from low-Earth orbit is relatively straightforward, but an evacuation from the moon or Mars could take months and cost billions of dollars. To avoid it, we will need to prepare the missions for the health issues identified in the IMPACT model, whether that is through increased medical training for astronauts or better equipment.
It isn’t as simple as just sending up a smorgasbord of wrist splints and eye-washing stations. “When you make decisions about what to put on a spacecraft because you have very limited room for stuff, every one of those decisions come with risk,” says Antonsen. “This model will help us balance those risks in a dispassionate way, allowing us to compare apples and oranges to make these important decisions about, say, do we bring a defibrillator or more fuel.”
The potential problem is compounded for even longer and even more involved missions, so models like IMPACT will be more important still as space agencies around the world begin to look toward Mars.
“I don’t think any of this data is a dealbreaker to say Mars is way less feasible than it used to be or anything like that – it’s just saying that our approach needs to adapt to our changing mission profile,” says Anderson. “There might be ways to manage some of these conditions that might not be the first choice in a hospital on Earth, but could help someone limp along until it’s time for the mission to end.”
Journal reference:
Acta Astronautica DOI: 10.1016/j.actaastro.2024.08.026