For retired astronaut Kathryn Sullivan, life is about exploring whatever is around you.

As a NASA astronaut, she became the first American woman to walk in space. On Earth, she played a pivotal role in the development of the Hubble Space Telescope, ensuring that future spacewalkers would have the tools necessary to fix the satellite’s instruments long after it launched. And this summer, she visited the deepest point of the ocean, the Mariana Trench. (Her friends jokingly call her “a woman who has extreme ups and downs,” she said.)