John Houbolt

John Cornelius Houbolt (April 10, 1919 – April 15, 2014) was an American aerospace engineer for NASA. He is best known for his work on the lunar mission mode called "lunar orbit rendezvous" (LOR). This was chosen for Apollo program in early 1962. He was born in Altoona, Iowa.
Houbolt died from natural causes on April 15, 2014 in Scarborough, Maine, aged 95.