10 things to know about John Glenn

He broke the transcontinental air speed record, bursting from Los Angeles to New York City in 3 hours, 23 minutes and 8 seconds.

Astronaut John Glenn and President John F. Kennedy inspect the Friendship 7, the Mercury capsule which Glenn rode in orbit. Kennedy presented Distinguished Service medal to Glenn at Cape Canaveral, Fla., Feb. 23, 1962. In background right is Vice President Lyndon Johnson. (AP Photo)

PHOTOS: John Glenn through the years

A source close to the Glenn family confirms that Glenn, 95, had been hospitalized since late last week and that he was gravely ill.