NASA‘s ‘Son of Concorde’ supersonic aircraft has broken the sound barrier for the first time, paving the way for ultra–fast air travel.
The $247 million jet, dubbed X–59, hit a top speed of Mach 1.1, or 713 miles per hour (1,150 km/h), during a test flight on Friday, June 5.
Test pilot Jim ‘Clue’ Less took off and landed from Edwards Air Force Base, California, soaring to 43,400 feet (13,200m) before setting the new speed record.
While the flight lasted just 81 minutes, this is the first step towards supersonic flights from London to New York in under four hours since Concorde was retired.
However, the space agency has plans to push its experimental aeroplane even further.
NASA administrator Jared Isaacman says that X–59 will fly again and hit Mach 1.4, or 925 miles per hour (1,490 km/h), within ‘the coming days’.
These flights will test whether the jet’s unconventional design really does reduce the sonic boom to a quiet ‘thump’ as NASA hopes.
Mr Isaacman says: ‘X–59 is getting ready for its quiet supersonic debut.’
NASA’s ‘Son of Concorde’ supersonic jet (pictured) has broken the sound barrier for the first time, hitting a top speed of 713 miles per hour (1,150 km/h)
The X–59 has been designed to solve one of the big problems with supersonic flights, which is the intolerable volume of the deafening sonic boom.
As a jet moves through the sky, it pushes the air out of the way like a boat moving through water, creating ripples in the form of sound waves.
At supersonic speeds, the plane outruns this wake of sound waves, causing the ripples to bunch up and compress into a single massive shockwave.
That means supersonic jets, like the Concorde, are constantly trailing a wake of powerful shockwaves, which are heard as a ‘boom’ when the craft passes overhead.
Because these booms can be as loud as 110 decibels – similar to a loud rock concert – supersonic flights are generally banned over populated areas.
To solve this problem, NASA has been working to develop ‘Quiet SuperSonic Technology (Quesst)’ that would muffle the boom into a muted ‘thump’.
The X–59 supersonic jet is the culmination of that effort, and should make supersonic flight quiet enough to pass over populated areas.
The aircraft has been developed by American aerospace firm Lockheed Martin’s ‘Skunk Works’ division after being awarded the $247.5 million design contract by NASA in 2016.
Test pilot Jim ‘Clue’ Less took off and landed from Edwards Air Force Base, California, soaring to 43,400 feet (13,200m) before setting the new speed record. Pictured: The pilot’s view from inside the cockpit
It features a radically redesigned geometry in which every feature is designed to diffuse and muffle the sonic boom.
The most obvious difference from a normal jet is the thin, tapered nose, which accounts for almost a third of the plane’s entire length and is shaped to break up the shockwave.
The downside of this novel design is that the cockpit is located around halfway down the length of the vehicle and doesn’t have any forward–facing windows.
Instead, the single pilot uses a system of cameras and augmented reality displays, known as the eXternal Vision System, to see out the front.
According to NASA, this reduces the volume of the shockwave heard at the ground to something between distant thunder and a car door shutting 20 feet (six metres) away.
Mr Isaacman says: ‘I’m grateful to the NASA team and Lockheed Martin Skunk Works for their help getting us to this point, and I hope this is the first of many collaborations as we rebuild NASA’s X–plane portfolio.’
Since its first flight in October 2025, the Son of Concorde has already undergone dozens of increasingly demanding tests in a process known as ‘envelope expansion’.
This first supersonic flight is just the latest milestone in that gradual process, taking NASA’s quiet jet into its next phase of testing.
Part of the reason that Concorde was eventually discontinued was that the sonic boom produced by breaking the sound barrier could be extremely loud for people on the ground
During the test, the experimental aircraft was chased by a supersonic F15 jet equipped with a probe to record the shockwave
During the test, the X–59 was monitored by a NASA F 15 chase plane, which flew nearby to monitor its progress.
The loud sonic boom from the F15 covered up the sound produced by the X–59, meaning that NASA couldn’t be sure how quiet it was.
However, the chase jet is equipped with a specialised probe to take initial measurements of the X–59’s shock waves.
Michael Kratsios, Assistant to the President for Science and Technology and Director of the Office of Science and Technology Policy, says: ‘The X–59’s first supersonic flight is a testament to America’s enduring leadership in science, engineering.’
In the next few days, NASA will send the X–59 on its first ‘mission conditions’ flight, reaching a cruising speed of Mach 1.4 at 55,000 feet (16,764 metres).
While these flights will also be accompanied by a chase plane, it will be a major step towards testing the quiet sonic boom.
This test is important because those speeds and altitudes are what the X–59 will be tested at when it is allowed to fly over several US communities.
Finally, test pilots will push the jet to its absolute limit, reaching a top speed of Mach 1.6 at 60,000 feet – around twice the height and speed of a commercial airline.
According to NASA, the sonic thump produced by X–59 passing overhead will be quieter than the sound of a car door shutting 20 feet away
The X–59’s aerodynamic profile has been designed so that it breaks up the shockwave formed by passing the sound barrier and is much quieter in flight. Pictured: The sonic boom from a scale model of the aircraft during wind tunnel tests
After that flight, NASA will move into the next stage of testing, focusing on its sound profile in order to verify its quiet thump capability.
The plane will be flown over populated areas of the US to see how people perceive the thump of X–59 passing overhead.
NASA says that it will share this data with US and international regulators to ‘help establish new data–driven noise standards to enable a future viable market for supersonic commercial flight over land’.
In the future, that could open the door to commercial supersonic flights that don’t cause major inconveniences for those on the ground.
The history of Concorde
Concorde was a turbojet–powered supersonic passenger jet that was operated from 1976 until 2003.
It had a maximum speed over twice the speed of sound at Mach 2.04 (1,354mph or 2,180k per hour at cruise altitude) and could seat 92 to 128 passengers.
It was first flown in 1969, but needed further tests to establish it as viable as a commercial aircraft. Concorde entered service in 1976.
It is one of only two supersonic transports to have been operated commercially. The other is the Soviet–built Tupolev Tu–144, which ran as a passenger aircraft only for a few years in the 1970s due to safety issues.
Concorde was the world’s first supersonic airliner and operated for 27 years, but it was grounded in October 2003. Pictured is British Airways Concorde G–BOAB taking off with its landing gear still extended over the Cotswolds town of Fairford, Gloucestershire on July 20, 1996, during the annual RAF Fairford airshow
Concorde was jointly developed and manufactured by Aérospatiale and the British Aircraft Corporation (BAC) under an Anglo–French treaty. Concorde’s name, meaning harmony or union, reflected the cooperation on the project between the UK and France.
Concorde was retired in 2003 due to a general downturn in the commercial aviation industry after its only crash in 2000, the September 11 attacks in 2001, and a decision by Airbus, the successor to Aérospatiale and BAC, to discontinue maintenance support.
It wasn’t the first plane to break the sound barrier, however; that achievement was managed by the Bell X–1, piloted by Chuck Yeager, in October 1947.
The legendary rocket engine–powered aircraft, designed and built in 1945, achieved a speed of 700 miles (1,127 kilometers) per hour.
