John Houbolt (1919-2014), US aerospace engineer, at a blackboard, showing his space rendezvous concept for lunar landings. Houbolt is best known for leading the team behind the Lunar Orbital Rendezvous (LOR) mission mode, a concept that was used to successfully land humans on the Moon and return them to Earth during the Apollo program. Although Houbolt did not invent the idea of LOR, he was the person most responsible for pushing it at NASA. Photographed on 24th July 1962.