%0 Generic %T NASA at a crossroads : reasserting American leadership in space exploration : hearing before the Subcommittee on Space, Science, and Competitiveness of the Committee on Commerce, Science, and Transportation, United States Senate, One Hundred Fourteenth Congress, second session, July 13, 2016. %U https://ezaccess.libraries.psu.edu/login?url=https://www.heinonline.org/HOL/Page?handle=hein.cbhear/fdsysaqbw0001&id=1&size=2&collection=congrec&index=cbhear