What is BioSentinel? - NASA

Editor’s Note: This article was updated Nov. 21, 2025 shortly after BioSentinel’s mission marked three years of operation in deep space. Astronauts live in a pretty extreme environment aboard the International Space Station. Orbiting about 250 miles above the Earth in the weightlessness of microgravity, they rely on commercial cargo missions about every two months to deliver new […]