NASA forms group to study decompression risks during space missions

NASA’s Office of the Chief Health and Medical Officer created a new working group in August 2026 to examine the latest data on extravehicular activity (EVA) prebreathe testing, decompression sickness (DCS), in‑flight venous thromboembolism (VTE) and the role of patent foramen ovale (PFO) as the agency prepares for Artemis lunar missions and beyond. The panel will assess how these medical risks could affect astronauts during longer stays on the Moon and future deep‑space flights.

The move comes as NASA ramps up EVA schedules and plans more complex surface operations. Past missions have recorded isolated DCS events and a handful of VTE cases, prompting concerns that current safety protocols may not keep pace with the increased workload. At the same time, research shows that a small opening in the heart, known as a PFO, can allow bubbles to pass into the bloodstream, potentially worsening DCS symptoms. These factors have converged to make a comprehensive review urgent.

The working group will scrutinize recent prebreathe test results, which determine how long astronauts must breathe pure oxygen before a spacewalk to flush nitrogen from their blood. It will also compile all reported DCS incidents and VTE occurrences from the International Space Station and previous lunar missions. Specialists will evaluate whether individuals with a PFO are at higher risk and if screening or mitigation steps are needed. The panel’s recommendations will build on findings from earlier OCHMO working groups that addressed similar health concerns in low‑gravity environments.

NASA expects the group to deliver a set of updated medical guidelines before the Artemis III crew begins its lunar surface activities later next year. The guidance could reshape EVA timelines, introduce new pre‑flight screening for heart defects, and add preventive measures against blood clots. By tightening health safeguards, the agency aims to protect crew members as they venture farther from Earth, ensuring that medical risk does not limit the pace of exploration.