Giffords' press secretary, Mark Kimble, tells The Associated Press that the Arizona congresswoman will leave Houston on Wednesday to attend the ceremony that's being presided over by Vice President Joseph Biden.
Following the ceremony, Kimble says Giffords will return to Houston where she is recovering after being shot in January outside a Tucson grocery store.
Kelly was the commander of the last mission of space shuttle Endeavour in May. He is writing a memoir with his wife that is set to be released Nov. 15.
