The first official study of the concept was conducted in 1986 by NASA's Marshall Space Flight Center in the aftermath of the Space Shuttle Challenger disaster. It was promoted as one of the alternatives for launching uncrewed cargo and would have potentially allowed a restarted lunar program as well. There were, however, no funds available to NASA for building any new vehicles while the Space Shuttle program continued. The idea was shelved and NASA concentrated on fixing and operating the Space Shuttle instead.