Astronaut Mark Kelly officially retiresPosted: Updated:
TUCSON, Ariz. -- Congresswoman Gabrielle Giffords' astronaut husband is hanging up his wings.
Mark Kelly officially retired Saturday from NASA and the U.S. military.
The former Navy combat and test pilot commanded the space shuttle Endeavour's final mission this summer.
Now he's working with Giffords on writing a memoir, expected to be published next month.