1894-1989 1906-1969 1939-1945 20thcentury astronautics biography coldwar duitsers germany hermann history influenceehricke influenceley influenceoberth influencevonbraun kraffta moralandethicalaspects politicsandgovernment propulsion research rocketry rockets rockets(ordnance) ruimtevaart science scientists spaceflighttothemoon spacerace unitedstates vonbraun wernher willy worldwar