Explained: Why World's Fastest Plane Crashed

Scientists behind the "world's fastest plane" have revealed it was ripped apart by speeds of around 13,000mph before it plunged into the Pacific Ocean.

Extensive analysis has been carried out since the test flight of the US military's $320m (£199m) unmanned Falcon Hypersonic Technology Vehicle HTV-2 last August.

The Pentagon hopes the vehicle will eventually be developed to allow it to carry bombs to strike targets anywhere across the globe within an hour.

And in releasing the results of its analysis, the Defence Advanced Research Projects Agency (Darpa) indicated the test was not the failure it was initially thought to be.

The craft was launched off the back of a rocket fired from an air force base in California, and flew at 20 times the speed of sound (Mach 20) for around nine minutes before it was taken on a "controlled descent" and ditched into the sea.

The engineers behind the plane said that while they expected some of its skin to peel off during the flight, "larger than anticipated portions" were affected by temperatures of 2,000C.

This harmed the vehicle's aerodynamics, causing it "shockwaves" that were 100 times what it had been designed to withstand.

Air Force Major Chris Schulz said the test flight, which was the plane's second, provided important data on the craft.

"HTV-2's first flight test corrected our models regarding aerodynamic design within this flight regime," he said.

"We applied that data in flight test two, which ultimately led to stable aerodynamically controlled flight.

"Data collected during the second test flight revealed new knowledge about thermal-protective material properties and uncertainties for Mach 20 flight inside the atmosphere."

He said that calculations had been drawn from assumptions based on 'normal' flights, but that the test now allowed them to use data from actual hypersonic flights.

Major Schulz added: "The result of these findings is a profound advancement in understanding the areas we need to focus on to advance aerothermal structures for future hypersonic vehicles. Only actual flight data could have revealed this to us."