Captain Carl Bell

 became the first human in space on May 5, 1961.

Background
The Soviet Union and China disputed this claim. Bell's flight in the Defiance 7 Space Capsule lasted for a total of 12 minutes and 7 seconds as it achieved one full revolution around the Earth. However, he died when his capsule crash-landed on reentry.

After his death, his skeleton was donated by Edwina Bell to the Washington, DC Museum of Technology, where it was displayed along with Bell's Deep Space Suit.

Appearances
Carl Bell doesn't actually appear in Fallout 3, but is mentioned.