The X-59’s engine fired up for testing for the first time.

NASA’s Quest mission (“Quiet SuperSonic Technology”) recently reached a milestone as it began testing the engine that will power X-59, an experimental supersonic aircraft developed by Skunk It works for NASA’s Low-Boom Flight Demonstrator project.

Initial engine tests, which began on October 30, 2024 at Lockheed Martin Skunk Works in Palmdale, allow the X-59 team to confirm that all aircraft systems work together under their own engine power, unlike previous tests that relied on sources of external power supply. These engine tests are an essential step in preparing the X-59 for its first flight.

According to NASA, testing is done in phases, with the first phase involving running the engine at low rpm without ignition to check for leaks and ensure all systems are communicating properly. After checking these systems, the team fueled the aircraft and began testing the low-power engines to ensure trouble-free or leak-free operation.

Jay Brandon, NASA’s X-59 Chief Engineer, explained:

This first phase of engine testing was a warm up to confirm everything looked good before starting the engine.

I then performed the initial engine start, which took the engine out of installation preservation mode. This first start was an opportunity to ensure that the engine and related systems such as hydraulics, electricals and environmental controls were all working as expected.

Supersonic air travel largely ended with the retirement of two notable aircraft: the Soviet Union’s Tupolev Tu-144 and the Concorde, a French-British collaboration developed by Aérospatiale and BAC. The Soviet Tu-144, which made its first flight three months before Concorde, was only in service between 1975 and 1978 and achieved limited success. In contrast, the Concorde it had a longer commercial life, operating from 1976 until 2003, when it was withdrawn following a tragic accident on 25 July 2000 at Charles de Gaulle Airport in Paris. However, both aircraft struggled with the high operating costs and noise restrictions imposed on traditional supersonic flight.

The new low-arm technology, which uses an extended fuselage to soften the sonic arm, aims to produce a softer “thump” than loud bangs which led to the banning of supersonic overland flights.

For half a century, the US and other countries have restricted such flights because of the disturbance caused by these sonic booms. The X-59, which measures 99.7 feet long with a wingspan of 29.5 feet and is flown by one person, is designed to produce a quieter boom that maintains acceptable noise levels. NASA reports that the X-59’s boom will be below 75 dB perceived on the ground – about a third quieter than Concorde’s noise level, which ranged from 100 to 110 dB. That quieter profile could help convince the FAA to lift the longstanding ban on supersonic land travel, in place since 1973.

X-59, which was revealed during a launch ceremony from Lockheed Martin Skunk Works in Palmdale, Calif., in January 2024 is designed to produce a softer “boom” than the traditional sonic boom because it travels faster than sound, forming the cornerstone of NASA’s Quest mission. The mission aims to gather data on how people perceive these quieter sounds, which could inform regulatory changes regarding supersonic overland flight.

Powered by a modified F414-GE-100 engine with 22,000 pounds of thrust, the X-59 is expected to reach Mach 1.4, or 925 mph, at 55,000 feet. The unusual placement of the engine above the aircraft helps reduce noise.

The pilot will fly the aircraft using a unique cockpit design without a conventional forward-facing window. Instead, a central 4K monitor acts as the “window”, giving the pilot a clear view of the surrounding air traffic and providing visual guidance for approaches, landings and take-offs. This monitor, a key component of the aircraft’s External Visibility System (XVS), shows merged images from two external cameras combined with terrain data from an advanced computer system. While the cockpit includes real windows on the sides and a traditional canopy to help the pilot maintain a view of the horizon, the displays below the XVS screen provide critical information about the aircraft’s systems and trajectory to ensure safe flight.

In May of this year, an independent Flight Readiness Review Board, made up of experts from various parts of NASA, completed its review of the X-59 Project Team’s safety protocols to protect both the public and personnel in during ground and flight tests. This review involved a thorough examination of the team’s analysis of potential risks, with particular attention to safeguards and risk assessment.

The flight readiness assessment was a crucial step in the initial phase of obtaining flight approval.

The latest engine tests are part of a wider series of ground checks essential to ensuring safe and efficient flight. With these significant testing phases underway, first flight is anticipated in early 2025. The team will continue through critical ground tests, resolving any technical issues that may arise with this unique aircraft, with the goal of establishing a specific date for first flight as a test. progress.

Testing is taking place at Lockheed Martin’s Skunk Works facility in Palmdale, California. In later phases, the team will test the engine at higher power levels with rapid throttle changes and replicate real flight conditions.

The success of these tests represents the culmination of eight years of my career. This is just the beginning of our journey. It’s like hearing the first note of a symphony – years of teamwork are now being put to the test, and we can’t wait to see the project come together as we progress towards flight.

Paul Dees, NASA’s deputy director of propulsion for the X-59.

Following the engine tests, the X-59 team will perform aluminum bird tests, providing data on both normal and simulated failure conditions. They will then perform taxi tests, move the aircraft to the ground and complete the final steps leading to the maiden flight.

After the first flight, the X-59 will continue with its first quiet supersonic flight. The Quest team will initially conduct several test flights at Skunk Works before moving the aircraft to NASA’s Armstrong Flight Research Center in Edwards, California, which will become its primary base of operations. Once the flight tests are successfully completed, NASA plans to fly the X-59 over several US cities to collect data on the sound the aircraft makes and how it is perceived by people on the ground. This information will be shared with the Federal Aviation Administration and international regulatory bodies.