Science & Space

How NASA Is Quietly Pushing The Boundaries of Supersonic Flight With X-59 QueSST?

After the debacle of the Concord program, the world parted itself away from the supersonic commercial passenger jet program towards the profitable jumbo jet program. The Jumbo Jets has proven sustainable over the supersonic because it was capable of carrying more passengers at a sustainable rate which generated a more profitable market over the supersonic market.

Jumbo jet only has one disadvantage which is speed but it has been carrying more than 200 million passengers each year since 1966. The prominent passenger jet makers: Boeing and Airbus are now dominating the passenger jet market.

Now the revival of the supersonic jet market is knocking on the door again after NASA has teamed up with Lockheed Martine and General Electric Aviation to bring this ambitious plan to reality. It could one day revive supersonic travel for the general public.

NASA's Supersonic Dream: Lockheed Martine X-59 QueSST

NASA is working on a prototype supersonic jet X-59 QueSST. "QueSST" stands for Quiet Super Sonic Technology. It is being developed at "Skunk Works" for NASA's Low-Boom flight demonstration project. In 2016, NASA awarded the primary design contract of $247.5 million to Lockheed Martine to deliver the prototype by 2020 timeframe, but the project has been delayed due to the Covid Pandemic. The timetable was later revised to deliver in 2021 and flight testing in 2023, but it was again delayed due to a variety of factors and market constraints. The work on the project is still ongoing and NASA is quietly achieving the target of Supersonic during its wind tunnel testing.

Between February and April 2017, a 9% scale model was to be wind tunnel tested from 0.3 Mach to 1.6 Mach. The X-59 plane is being built 94 feet(24m)long and has a wingspan of 29.5 feet(9m). The aircraft, like Concord, has a 38-foot-long nose attached to its fuselage. The aircraft will be powered by an F-414GE-100 engine, which will be manufactured by General Electric Aviation. The engine has been modified in order to reduce the intensity of sound, which is the primary goal of this prototype program.

The aircraft is being built to travel at a speed of 1.4 Mach at altitudes of 5500 feet(1676.4 meters), creating a low 75-perceived level decibel(PLdb) thump to evaluate supersonic "transport acceptability". This is not the first time the world will have a transport or commercial supersonic aircraft; prior to this program, the world had the magnificent Concord commercial supersonic aircraft, but why it failed and how the program came into existence should be known.

The Mighty Concord!

Concord was a joint project of France and Great Britain. The study of Concord supersonic jets started in 1954 and it was jointly been produced by Sud Aviation and British Aircraft Corporation(BAC). The program cost was estimated at 70 million pounds (equivalent to 1.39 billion pounds in 2021). The construction of 6 prototypes began in February 1965, and the first flight took off from Toulouse on 2nd March 1969.

The concord fuselage permitted a 4-abreast seating for 92 to 128 passengers. The aircraft could maintain a supersonic speed up to Mach 2.04(2,167km/hr or 1347mph) at an altitude of 60,000 ft(18.3km). The aircraft was powered by 4-Rolls-Royce/Snecma Olympus 593 turbojets.

Concord was forced to retire from active duty in 2003 due to a number of factors. One major factor was that the aircraft was too noisy and expensive to operate, limiting flight availability. Because the operating costs were too high, the jet was not commercially viable and it prohibited a certain section of passengers to avail of that jet.

As the cost of operation was too high which is why the resulting financial losses led both British Airways and Air France to make New York City their only regular flight destination. Even the New York flight was restricted due to the noise that the aircraft generated.

Finally, the unfortunate event of 2000 put the last nail in Concord's coffin. In 2000 Air France's Concorde's engine failure and subsequent crash killed all 109 passengers on board and 4 people on the ground. Many believed that the event accelerated the retirement of Concord in 2003. Following the 2000 event, even after its existing extensive fanfare, it took its last solo flight 19 years ago and forcedly retired from its 27 years of service.

Apart from Concord the Soviets also operated a Supersonic passenger jet: Tupolev Tu-144. The last passenger flight of the Tu-144 was in June 1978 and was last flown in 1999 by NASA. All of these Supersonic Passenger jets were retired for two main reasons: excessive noise generation during take-off and sonic boom during flight.

Why NASA is trying to revive the Supersonic age again and what new technology they are working on?

NASA is attempting to break the sound barrier in an exciting new way. When something breaks the sound barrier, it usually causes a massive sonic boom that can be heard for miles depending on the plane's altitude. NASA's X-59 plane, on the other hand, will attempt to break the sound barrier without causing a sonic boom.

As we have witnessed the sound barrier problem for every supersonic jet, this time NASA is attempting to develop technology that will reduce loud sound booms to quiet thumps. The technology NASA is trying to develop comes under the QueSST mission program. According to NASA, the first sonic boom rang out across the California desert more than seventy-five years ago. When it happened, NASA’s X-1 team managed to do what many believed impossible.

NASA's supersonic journey began with the Bell X-1 jet. After all that time, many other organizations tested their own versions of supersonic jet models, but none ever achieved the goal that X-59 did and will do. This program will revolutionize the market of supersonic sustainable and affordable commercial jets. The jet is also being designed to use less gasoline and cause less damage to the Ozone layer of problems.

Scientists have learned about the ozone layer problem from the lesson they learn from Concord and Tupolev Tu-144. Concord generated a severe sonic boom due to its 2.04 Mach and its engine also exhausts huge gasoline waste that damaged the ozone layer.

The Russel Train warned that a fleet of 500 SSTs flying at 65000 ft(20km) for a period of years could raise stratospheric water content by as much as 50% to 100%. It hampers the formation of the ozone layer. Later, an additional threat to the ozone was hypothesized as a result of the exhaust's Nitrogen Oxides. Several scientists have published several research papers on Nitrogen Oxide's effect on the formation of the ozone layer.

NASA's target is to reduce the formation of sonic booms as well as the formation of Nitrogen oxides. They are trying to build a jet that will be sustainable and environmentally friendly.