NASA assembled a working group of medical experts to assess health risks during spacewalks for the agency's Artemis missions. The group reviewed data on decompression sickness, blood clot formation in space, and whether a patent foramen ovale — a hole in the heart that persists from birth — should disqualify astronauts, according to findings released by NASA's Office of the Chief Health and Medical Officer.
The group concluded that a small patent foramen ovale does not pose a significant risk for spacewalkers. The working group also determined that no changes to astronaut selection criteria are recommended with respect to blood clots in space. For those with a larger patent foramen ovale, NASA will not automatically exclude them from flight but will inform them of their status and offer surgical closure if desired.
The panel found that while identifying air bubbles during preparation is desirable, the predictive value of bubble presence for decompression sickness remains uncertain, particularly for lunar surface operations. The group recommended that ground-based research protocols balance subject safety with population representativeness, allowing people with these conditions to participate if they are fully informed of their status and any associated risks.
Additionally, the working group called for clear clinical guidance regarding medication use before spacewalks. Specifically, protocols are needed to address aspirin use for both decompression sickness prevention and pain relief, and guidance on analgesics before and after spacewalks, since these medications can mask decompression sickness symptoms.