Astronaut well-being has been a focal point since the inception of space exploration. Various issues like motion sickness, disorientation, muscle degeneration, and bone density reduction have impacted all space travelers. NASA has developed treatments using medication and rigorous exercise to address many of these conditions during space missions. However, more severe health challenges could hinder future extended missions to the moon and Mars, prompting scientists to delve deeper into understanding the potential health risks for long-distance astronauts.
While serious health incidents in space are uncommon, a notable event occurred in January 2026 when astronaut Mike Fincke underwent the very first medical evacuation in the International Space Station’s 25-year history due to a non-life-threatening issue. The cause of Fincke’s medical emergency has not been disclosed by NASA for privacy reasons, but he confirmed his ongoing recovery.
Despite their rarity, close health calls in space are scrutinized to enhance comprehension of how microgravity influences human health. A recent study from Simon Fraser University investigated blood clot formation in microgravity after a female astronaut was diagnosed with a clot in her neck while on the space station in 2019. Swift action by ground and space teams led to the development of a treatment plan to manage the clot effectively.
Researchers discovered in a study published in the journal Acta Astronautica that blood clots formed in microgravity are more resilient than those formed on Earth. Subsequent research comparing clot formation in males and females in a microgravity setting is ongoing.
Both Fincke and the unnamed female astronaut were diagnosed using a portable ultrasound device, a standard tool for astronauts on the space station for health assessments in weightlessness. However, limited equipment in space restricts the extent of medical interventions available to astronauts once issues are detected.
In a weightless environment, fluid redistribution to the upper body can lead to conditions like facial swelling and leg atrophy, making blood clots more critical as they could potentially pose severe risks if dislodged near the brain. The condition of Space-Associated Neuro-Ocular Syndrome (SANS), affecting vision due to pressure changes in the optic nerve, has been identified as a prevalent issue among astronauts during long-term space missions.
Space-related injuries are common, with musculoskeletal injuries frequently occurring on astronauts’ hands, often attributed to exercise. However, some medical conditions, especially those requiring open surgery like appendicitis, cannot be managed in space due to the challenges of operating in a weightless environment, necessitating a swift return to Earth for treatment.
The International Space Station is equipped with essential medical resources and personnel to address most health concerns on-site. However, for future missions to the moon and Mars, where return trips are prolonged, the development of Earth-Independent Medical Operations (EIMO) is crucial. This strategy aims to establish autonomous medical care systems for astronauts to manage potential health issues independently during extended missions. Preemptive health monitoring and care will be pivotal for ensuring astronauts’ well-being on long-duration space missions.
In the unfortunate event of a fatality in space, NASA has outlined detailed protocols, including the utilization of a space suit as a temporary containment unit until the astronaut’s return to Earth. However, such occurrences remain rare, and efforts are focused on ensuring the safety and health of astronauts during space exploration endeavors.
