Since 2011, NASA has been upgrading a mobile launcher originally built for the Ares I vehicle to fit its massive Space Launch System rocket. The project is well over budget—when all is said and done, the revamp of the $234 million tower is expected to cost an additional $678 million, per Ars Technica—but that might not be its only issue. As NASASpaceFlight.com reports, the 355-foot-high launch tower is now "leaning," possibly due to the recent addition of connecting arms. NASA acknowledges "some deflection and imperfections" but says the launcher is "structurally sound" and does not need any design modifications.
"While NASA seems to believe this lean is not enough to require additional construction, it will likely mean that the Mobile Launcher won’t be used for more than one or two launches," writes Avery Thompson at Popular Mechanics. That's partly because the tower would need yet another upgrade after its initial launch anyway—to accommodate larger payloads—and it might well be faster and cheaper in the long run to build a second one. NASA's Aerospace Safety Advisory Panel has recommended doing just that for $300 million. The maiden launch is expected to take place in 2020. (A NASA spacecraft took the farthest photos ever taken.)