Heike John (now Heike Walpot; born 19 June 1960) is a retired German swimmer and former astronaut candidate.
She won a bronze medal at the 1977 European Aquatics Championships.
She competed at the 1976 Summer Olympics in the 100 m and 200 m backstroke events but did not reach the finals.
During her career she won five national titles in the 100 m (1977) and 200 m (1977, 1978) backstroke and 200 m medley (1977, 1978).
She missed the 1980 Summer Olympics because of their boycott by West Germany.
After her swimming career, she studied medicine at RWTH Aachen and earned a doctorate in 1987.
In the same year she was selected as one of five West German astronaut candidates for the Spacelab D-2 mission, along with Hans Schlegel, Ulrich Walter, Gerhard Thiele and Renate Brümmer.
She served as Cap com during the D-2 mission in 1993, but was never assigned to a spaceflight herself.
After retiring as an astronaut, she became a professional pilot for Lufthansa.