Imagine taking off from any U.S. airport and landing on any other runway in the world in less than two hours. Or making a quick hop from that same airport to the International Space Station and back — a trip that normally takes days or weeks — to drop off science experiments, provisions and new equipment. Sound Far-Fetched? Not anymore. Technology now being developed by NASA and its partners could — within two decades — achieve such rapid trip times, yielding limitless possibilities for international travel, commerce and access to space.