Hellmuth Walter was a German engineer who pioneered research into rocket engines and gas turbines. His most noteworthy contributions were rocket motors for the Messerschmitt Me 163 and Bachem Ba 349 interceptor aircraft, so-called Starthilfe jettisonable rocket propulsion units used for a variety of Luftwaffe aircraft during World War II, and a revolutionary new propulsion system for submarines known as air-independent propulsion (AIP).