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 supplies and experiments. And yet, this place is relatively protected in terms of space radiation. The Earth’s magnetic field shields space station crew from much of the radiation that can damage the DNA in our cells and lead to serious health problems. When future astronauts…