Quarantines upon return to Earth ended in 1971, after NASA concluded that the Moon did not pose a biological risk.
Astronauts on NASA’s Artemis II mission have entered quarantine as preparations intensify for humanity’s first manned mission to orbit the Moon in more than 50 years. The mission, with release scheduled for February 6thmarks an important milestone in NASA’s plan to return humans to deep space and, eventually, the lunar surface.
The four-member Artemis II crew is currently isolated in Houstonfollowing NASA’s health stabilization program, a long-standing protocol created to prevent astronauts from getting sick before launch. This practice dates back to the Apollo era and was formally introduced during Apollo 14 in 1971, after previous missions were interrupted by illnesses such as respiratory infections and viral gastroenteritis. NASA later reported a “notable reduction in diseases” after the implementation of quarantine measures.
Ensuring that astronauts are in perfect physical condition is crucial, as even a minor illness can delay the launch. About six days before launch, the Artemis II crew will move to the Kennedy Space Centerin Florida, where he will continue to be quarantined in the astronaut crew quarters while he completes the mission’s final training. During this period, they are allowed limited contact with friends, family and colleagues who follow quarantine guidelines. The use of masks, physical distancing and avoiding public places continue to be mandatory, explains the .
While pre-launch quarantine remains standard practice, post-mission isolation no longer necessary. During the Apollo program, astronauts were quarantined for up to three weeks after returning to Earth due to concerns that unknown lunar microbes might represent a threat to life on Earth. Spacecraft, equipment and lunar rocks were also isolated as part of this planetary protection effort.
These fears turned out to be unfounded. With Apollo 15 in 1971, NASA finished post-flight quarantines after concluding that the Moon did not pose a biological risk.
Today, NASA’s health focus has turned to managing medical emergencies during spaceflight. Earlier this month, the agency carried out its first medical evacuation from the International Space Station following an onboard medical incident that required ultrasound examinations. NASA did not release details about the astronaut’s health status.
To prepare for such scenarios, astronauts receive extensive medical training, including CPR, first aid, treatment for decompression sickness, and even protocols for dealing with a death in space. During Artemis II and future missions, crews will also participate in long-term health studies, providing blood and saliva samples to help scientists understand how radiation and microgravity affect the human body.
