The Boeing X-20, also known as DynaSoar, was a United States Air Force (USAF) program to develop a spaceplane that could be used for a variety of military missions, including aerial reconnaissance, bombing, space rescue, satellite maintenance, and as a space interceptor to sabotage enemy satellites. The program ran from 1957 to 1963, cost US$660 million, and was cancelled just after spacecraft construction had begun. However, along with X-15, the studies conducted for this project later contributed greatly to the success of the Space Shuttle and X-37B programs decades later
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