Plan of NASA was to carry on the lunar manned missions through Apollo 20. However, there was turning out of the history in a different manner. The last 3 missions i.e. Apollo 18. Apollo 19 and Apollo 20 were canceled. They were in stages of planning. Hardware which never reached the moon turned out to be exhibited in the museum. Multiple reasons were there for the cancelation of the 3 expeditions. This included budgets that were tighter which the administration of Nixon and the Congress imposed. This was the chief factor. Spending of NASA touched peak in the middle of the 1960s. Labor force consisting of contractors and staffers at that time totaled to about 400,000.