The WaveRider traveled more than 230 miles in six minutes, making it the longest hypersonic flight of its kind.

NPR: Experimental Air Force Aircraft Goes Hypersonic

The sleek, missile-shaped WaveRider was released from a B-52 bomber 50, 000 feet above the Pacific and was initially accelerated by a rocket before the scramjet kicked in.

NPR: Experimental Air Force Aircraft Goes Hypersonic

Though the WaveRider was designed to reach Mach 6, or six times the speed of sound, program officials were satisfied with its performance in the latest test.

NPR: Experimental Air Force Aircraft Goes Hypersonic

The X-51A WaveRider flew for more than three minutes under power from its exotic scramjet engine and hit a speed of Mach 5.1, or more than five times the speed of sound.

NPR: Experimental Air Force Aircraft Goes Hypersonic