"Cost increases and schedule delays on NASA's projects are long-standing issues for the Agency. A 2004 Congressional Budget Office study compared the initial and revised budgets of 72 NASA projects between 1977 and 2000. The initial budgets for these projects totaled $41.1 billion, while their revised budgets totaled $66.3 billion, a 61 percent increase. Moreover, since its first annual assessment of NASA projects in 2009, the Government Accountability Office (GAO) has consistently reported on cost growth and schedule delays in the Agency's major projects. For example, in its 2012 assessment GAO reported an average development cost growth of approximately 47 percent, or $315 million, much of which was attributable to JWST. As GAO noted, cost and schedule increases on large projects like JWST can have a cascading effect on NASA's entire portfolio."
NASA learns the dark side of a sunny outlook, Federal Computer Week
"Then the IG noted the "Hubble Psychology." The report defined it as "an expectation among NASA personnel that projects that fail to meet cost and schedule goals will receive additional funding and that subsequent scientific and technological success will overshadow any budgetary and schedule problems." In other words, NASA officials believe that major NASA projects will get funding for science's sake, despite how the projects are managed. The Hubble Space Telescope is one major project that exemplifies the risks of optimism in the report. The program has had its problems, but they have been mostly forgotten, the IG wrote."