UPDATE 1-U.S. Air Force sees launch prototype contracts as soon as September
April 29, 2015 at 17:53 PM EDT
WASHINGTON, April 29 (Reuters) - The U.S. Air Force said on Wednesday it could award contracts for prototypes of new U.S.-fueled launch vehicles as early as September, a key step to ending U.S. reliance on using Russian rocket engines to launch military and intelligence satellites.