India, July 30 -- NASA astronaut and microbiologist Kate Rubins retired Monday after 16 years with the agency. During her time with NASA, Rubins completed two long-duration missions aboard the International Space Station, logging 300 days in space and conducting four spacewalks.

"I want to extend my sincere gratitude to Kate for her dedication to the advancement of human spaceflight," said Steve Koerner, acting director of NASA's Johnson Space Center in Houston. "She is leaving behind a legacy of excellence and inspiration, not only to our agency, but to the research and medical communities as well. Congratulations, Kate, on an extraordinary career."

Rubins' first mission to the orbiting laboratory began in July 2016, aboard the first t...