'Son of Concorde': Lockheed Martin and NASA start production of supersonic X-59 plane that would create a sound 'as loud as closing a car door'

When completed, the plane will travel at a speed of 1,512 kilometres per hour

Lockheed Martin, in association with NASA, has started production of the experimental supersonic plane, officially named X-59 Quiet Supersonic Technology (QueSST), which could see the return of supersonic passenger travel over land.

Lockheed described the latest development as "a milestone to bring supersonic commercial travel over land one step closer to reality."

Earlier this year, the American space agency offered Lockheed Martin a contract worth nearly £195 million (US$250 million) to develop a plane that would be able to cruise at supersonic speed without creating the loud sonic boom.

Current air travel regulations in the U.S. prohibit supersonic passenger jets from operating over land. The last supersonic passenger flight in the world was completed by the Concorde in October 2003.

Some aviation fans have started calling X-59 Quiet, the 'Son of Concorde'. The plane is being designed to travel at an altitude of nearly 17,000 metres and at a speed of 1,512 kilometres per hour (Mach 1.27). According to NASA, X-59 will be built in such a way that when flying at supersonic speeds, people on the ground will hear a sound not more than a sonic thump.

The first test flight of the plane is scheduled for 2021.

"I'm confident that the contributions the X-59 QueSST will make to our nation and the world will ensure its place among the greatest NASA X-planes ever flown," Jaiwon Shin, NASA's associate administrator for aeronautics, said in June.

Lockheed is constructing X-59 at its Skunk Works plant in Palmdale, California.

Earlier this month, the space agency started conducting tests with two F/A-18's near Texas Gulf Coast to see if residents hear the noise produced by the jets travelling at supersonic speeds. NASA has recruited 500 people to answer a survey about the noise produced by the fighter jets to ensure that the flights of X-59 are quiet when as it flies over Texas.

Once all test flights of X-59 are completed and the plane is declared safe to fly within the National Airspace, NASA and Lockheed will commence supersonic flights of X-59 over some select communities in the U.S. to collect residents' feedback about the noise they hear.

The results of these surveys will then be presented to the U.S. and international regulators to help them come up with new rules on noise levels for supersonic flight over land.