The era of mass-supersonic travel is upon us!
NASA is aiming to revolutionize the commercial air transportation industry with recently announced plans to build a new “low-boom” supersonic jet as part of its New Horizons Aviation initiative.
“NASA is working hard to make flight greener, safer and quieter — all while developing aircraft that travel faster, and building an aviation system that operates more efficiently,” said NASA administrator Charles Bolden. “To that end, it’s worth noting that it's been almost 70 years since Chuck Yeager broke the sound barrier in the Bell X-1 as part of our predecessor agency's high speed research. Now we’re continuing that supersonic X-plane legacy with this preliminary design award for a quieter supersonic jet with an aim toward passenger flight."
Commercial supersonic flight has been the dream of the aviation industry and its passengers for decades. Starting in 1976, Concorde supersonic jets flew international commercial flights of up to 128 passengers at a cruising speed of Mach 2.04 (~1,354 mph or 2,179 km/h) until 2003, when a host of issues from economic feasibility to environmental and public safety concerns grounded the industry.
These jets greatly reduced travel time over the Atlantic Ocean and private companies are still pursuing the dream of supersonic flight with promises of cutting international travel times nearly in half.
Yet a major obstacle for the supersonic flight industry both current and past, is the thunder-like sonic booms people on the ground hear as sonic aircraft travel overhead.
According to NASA, air reacts like a fluid to supersonic objects. As objects travel through the air, the air molecules are pushed aside with great force and this forms a shock wave much like the wake created by a boat. The bigger and heavier the aircraft, the more air it displaces.
The shock wave forms a cone of pressurized air molecules which move outward and rearward in all directions and extend to the ground. As the cone spreads across the landscape along the flight path, the molecules create a continuous sonic boom along the full width of the cone's base. The sharp release of pressure, after the build-up by the shock wave, is heard as a sonic boom.
As NASA explains, the change in air pressure associated with a sonic boom is only a few pounds per square foot — about the same pressure change experienced riding an elevator down two or three floors. It is the rate of change, the sudden onset of the pressure change, that makes the sonic boom audible.
The disturbance to the public from sonic booms was a contributing factor to the grounding of the supersonic flight industry in the early 21st century and led to restrictions for supersonic flights traveling over land.
Nasa hopes to revive the industry and convince governing bodies to reverse the flight restrictions by proving that supersonic flight can be achieved without the severe disruption of sonic booms.
After conducting feasibility studies and working to better understand acceptable sound levels across the country, NASA's Commercial Supersonic Technology Project asked industry teams to submit design concepts for a piloted test aircraft that can fly at supersonic speeds, creating a supersonic "heartbeat" — a soft thump rather than the disruptive boom currently associated with supersonic flight.
Now NASA has selected a team led by Lockheed Martin Aeronautics Company of Palmdale, California, to complete a preliminary design for Quiet Supersonic Technology (QueSST).
“Developing, building and flight testing a quiet supersonic X-plane is the next logical step in our path to enabling the industry's decision to open supersonic travel for the flying public," said Jaiwon Shin, associate administrator for NASA’s Aeronautics Research Mission.
NASA plans to develop its New Aviations Horizon program over ten years and use radically different plane designs to achieve new standards in the reduction of fuel use, emissions and noise.
According to NASA, the X-planes are expected to be about half-scale of a production aircraft and are likely to be piloted. Design-and-build will take several years with aircraft starting their flight campaign around 2020, depending on funding.