During the design and the first construction stage, a heated debate ensued about the high cost of the project (the last estimate was $8.25 billion). An especially recurrent argument was the contrast with NASA's contribution to the International Space Station, which was of similar amount. Critics of the project argued that the US could not afford both of them.
The project was eventually canceled by Congress in 1993 after 14 miles of tunnel were already dug and 2 billion dollars spent.