1998: Alan Shepard, the naval aviator and NASA astronaut who in 1961 became the second person, and the first American, to travel into space, dies of leukemia at age 74 in Pebble Beach, California. Shepard made his historic flight into space as part of Project Mercury and returned to space a decade later, commanding the Apollo 14 mission and becoming the fifth person to walk on the moon. After leaving NASA, the New Hampshire native became a successful businessman.