5,000 MPH Approximate top speed clocked by the X-43A hypersonic scramjet aircraft on March 27
720 MPH Relative speed of sound
11 SECONDS Approximate duration of the X-43A’s powered flight
15 MILES Distance traveled
2 HOURS Estimated flight time from New York to Hong Kong traveling 5,000 mph
1 MILLISECOND Time the X-43A engine takes to generate thrust
2,200 MPH Previous record for a jet aircraft
1,350 MPH Average cruising speed of Concorde jet
4,000â€4,500 F Temperature inside a scramjet engine
2,500â€2,700 F Melting point of steel
6,750 MPH Anticipated speed of NASA’s third and final X-43A hypersonic aircraft, scheduled to fly this fall
Source: NASA
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.


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