Duane Edgar Graveline (MD, MPH) is an American physician and was a NASA astronaut. He was one of the six scientists selected in 1965, in NASA's fourth group of astronauts, for the Apollo program. He is best known for being immersed in water for seven days as part of his zero gravity deconditioning research while a United States Air Force (USAF) research scientist. He was consultant to magician David Blaine for Blaine's week of water immersion in 2006, correctly predicting Blaine's profound weakness from deconditioning.