From his official NASA biography:
Neil A. Armstrong, the first man to walk on the moon, was born in Wapakoneta, Ohio, on August 5, 1930. He began his NASA career in Ohio.
After serving as a naval aviator from 1949 to 1952, Armstrong joined the National Advisory Committee for Aeronautics (NACA) in 1955. His first assignment was with the NACA Lewis Research Center (now NASA Glenn) in Cleveland. Over the next 17 years, he was an engineer, test pilot, astronaut and administrator for NACA and its successor agency, the National Aeronautics and Space Administration (NASA).
As a research pilot at NASA's Flight Research Center, Edwards, Calif., he was a project pilot on many pioneering high speed aircraft, including the well known, 4000-mph X-15. He has flown over 200 different models of aircraft, including jets, rockets, helicopters and gliders.
Armstrong transferred to astronaut status in 1962. He was assigned as command pilot for the Gemini 8 mission. Gemini 8 was launched on March 16, 1966, and Armstrong performed the first successful docking of two vehicles in space.
As spacecraft commander for Apollo 11, the first manned lunar landing mission, Armstrong gained the distinction of being the first man to land a craft on the moon and first to step on its surface.
Here's what we're learning from Twitter:
Neil Armstrong died from complications from heart operations he had 3 weeks ago, NBC News' Jay Barbree reports -— Breaking News (@BreakingNews) August 25, 2012
NBC Space Reporter Jay Barbree confirms reports that astronaut Neil Armstrong has passed away— Al Roker (@alroker) August 25, 2012
*goes to weep in a corner*— Michael McFarlane (@crossdrilled) August 25, 2012
Few people deserve to be remembered for the rest of human existence, Neil Armstrong is one of those people.— Andrew Kaczynski (@BuzzFeedAndrew) August 25, 2012
There is no picture more American than this. twitter.com/BuzzFeedAndrew…— Andrew Kaczynski (@BuzzFeedAndrew) August 25, 2012
RT— Nolan Hicks (@ndhapple) August 25, 2012
@dangillmor: Neil Armstrong, R.I.P. He was the most notable member of a huge team that put humans on another world. He wished we hadn ...
The best thing that Neil Armstrong ever did, was to let us all imagine we were him. RIS (Rest in Space)— SarcasticRover (@SarcasticRover) August 25, 2012
"We haven't been back to the moon in almost 50 years," former astronaut Tom Jones notes on Fox News. Armstrong was disappointed, he thinks.— Brian Stelter (@brianstelter) August 25, 2012
Photos: NASA, Getty