The U.S. Air Force plans a key test of an experimental aircraft designed to fly at six times the speed of sound, or about 5,800 km/h.

The aircraft is intended to allow the Pentagon to deliver strikes around the globe within minutes.

The Los Angeles Times reports the unmanned X-51 WaveRider is expected to reach Mach 6 on Tuesday when it's dropped by a B-52 bomber and takes flight off the California coast.

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An X-51A WaveRider hypersonic flight test vehicle is uploaded to an Air Force Flight Test Center B-52 in this 2009 photo. (U.S. Air Force/Associated Press)

Engineers hope it sustains its top speed for 300 seconds, twice as long as it's gone before.

In its most recent test last year, the Boeing-designed X-51 fell for about four seconds before its booster rocket ignited, but the aircraft failed to separate from the rocket and plunged into the ocean.