In 2014, the United States Government Accountability Office (GAO) reported that the National Aeronautics and Space Administration’s (NASA) major projects continued a general positive trend of limiting cost and schedule growth, maturing technologies, and stabilising designs, but that NASA faced several challenges that could affect its ability to effectively manage its portfolio, such as completing a series of complex and expensive projects within constrained budgets and competing priorities. This book assesses the current performance of NASA's portfolio of major projects; NASA's progress in developing and maturing critical technologies and stabilising design; and NASA’s initiatives to reduce acquisition risk and work that remains to strengthen management of the agency’s largest, most complex projects. It also provides data on past and current NASA appropriations as well as proposed NASA appropriations for FY2015 and proposed authorisations of NASA appropriations for FY2015 and FY2016.