NASA Working Group Reviews Decompression Sickness and Blood Clot Risks for Artemis Astronauts

NASA's Office of the Chief Health and Medical Officer formed a working group in August 2026 to review recent data on health risks facing astronauts during extravehicular activity, including decompression sickness, venous thromboembolism, and a heart condition known as patent foramen ovale.

The group examined data related to prebreathe testing procedures used ahead of spacewalks, along with occurrences of decompression sickness and in-flight blood clot events, as part of a broader effort to inform medical guidance for NASA's Artemis program, which aims to return astronauts to the Moon and support future deep-space missions.

Building on Past Research

The working group's recommendations build upon and integrate findings from earlier panels convened by the same NASA office, reflecting an ongoing, iterative process of reviewing astronaut health risks as mission profiles evolve, including longer-duration lunar missions planned under Artemis.

Patent foramen ovale, a small hole in the heart present in some individuals from birth, has drawn attention in aerospace medicine because of its potential to increase the risk of decompression-related complications during activities involving pressure changes, such as spacewalks. The working group's review considered how this condition factors into overall risk assessments for crew members.

NASA has not detailed specific policy changes resulting from the working group's review, though the findings are expected to inform medical screening and operational procedures for upcoming Artemis missions involving extravehicular activity on the lunar surface or in transit.

Further guidance based on the working group's recommendations is expected to be incorporated into NASA's ongoing astronaut health and safety protocols.