NASA Reviews EVA Decompression Risks and PFO Impact for Artemis Missions

NASA’s Office of the Chief Health and Medical Officer (OCHMO) announced in August 2026 that it has convened a new working group to examine the latest data on extravehicular activity (EVA) prebreathe testing, decompression sickness (DCS) incidents, in‑flight venous thromboembolism (VTE) events, and the role of patent foramen ovale (PFO) in these risks. The group’s mandate is to assess how current EVA protocols and medical screening procedures impact astronaut safety during the Artemis lunar and beyond missions.

The working group will build on the findings of earlier OCHMO panels, integrating recent clinical and operational data to evaluate risk factors and effectiveness of existing countermeasures. Its analysis will focus on identifying gaps in prebreathe timing, monitoring for VTE during flight, and determining whether PFO screening should be expanded or modified to reduce DCS incidence. The recommendations produced will inform updates to EVA procedures, medical screening guidelines, and crew health monitoring systems.

By refining EVA safety protocols and medical oversight, the OCHMO aims to enhance crew health protection and mission reliability for Artemis. The forthcoming recommendations are expected to guide NASA’s next‑step policy updates and support the agency’s broader goal of sustainable human exploration beyond Earth orbit.