D rad Bacteria: Candidate Astronauts . ... Amazingly, they even have the ability to repair their own DNA , usually with 48 hours. Known as an extremophile , bacteria such as D. rad are of interest to NASA partly because they might be adaptable to help human astronauts survive on other worlds. A recent map of D. rad's DNA might allow biologists to augment their survival skills with the ability to produce medicine, clean water, and oxygen. ... NASA Official: Jay Norris. ...