NASA's X-59 supersonic research jet nears first flight to test 'quiet' sonic signature

NASA's X-59 quiet supersonic research aircraft is entering the final safety and systems checks ahead of an initial flight test that will begin at low speed and altitude, agency officials and project partners said.

Developed by Lockheed Martin under a contract awarded in 2016, the single-pilot X-59 is designed to exceed the speed of sound while producing a much reduced sonic signature — described by NASA engineers as a "thump" rather than the loud sonic boom associated with earlier supersonic airliners such as Concorde. The jet is expected to reach speeds up to about 990 mph in later tests and, in theory, could cover a transatlantic trip such as London to New York in roughly three hours and 44 minutes; conventional commercial flights typically take seven to eight hours for the route.

Project engineers said the aircraft will not approach those top speeds on its first sortie. Instead, the initial flight will consist of a 240 mph, lower-altitude circuit to verify system integration and the craft's basic handling before crews clear it for a phased series of higher-velocity and higher-altitude evaluations. The aircraft was undergoing final safety system evaluations at the U.S. Air Force Plant 42 complex in California when NASA and Lockheed officials briefed media.

Key to the X-59's design is an unusually long, slender nose that breaks up shock waves generated during supersonic flight, reducing the abrupt pressure change that creates a traditional sonic boom. NASA describes this altered pressure signature as much quieter and more acceptable for operations over populated areas. The flight-test campaign will measure the actual ground-level sound produced by the X-59 and deliver the data to national and international regulators.

"As NASA's one-of-a-kind X-59 quiet supersonic research aircraft approaches first flight, its team is mapping every step from taxi and takeoff to cruising and landing — and their decision-making is guided by safety," a spokesperson for NASA's Armstrong Flight Research Center said.

The program — sometimes referred to by the NASA-internal Quesst name — is explicitly intended to provide validated measurements of the airframe's acoustic signature. Regulators, including the Federal Aviation Administration and the International Civil Aviation Organization, have identified the lack of validated low-sonic-signature data as a barrier to approving routine overland supersonic passenger service. The X-59's measurements are intended to inform potential policy changes on where and when supersonic flights might be allowed.

The aircraft was built under a roughly $247.5 million design contract and represents a government-industry effort to demonstrate quiet supersonic technology rather than to become a commercial airliner itself. NASA Deputy Administrator Pam Melroy said the programme marked "a major accomplishment made possible only through the hard work and ingenuity from NASA and the entire X-59 team," noting the project's potential to reduce travel times.

Some team members have pushed back on media nicknames linking the X-59 directly to Concorde. Peter Coen, mission integration manager for the programme, has called the "Son of Concorde" label inaccurate, saying the aircraft differs substantially from the earlier supersonic transport aside from a general wing planform.

Following the planned low-speed first flight and subsequent system checks, the X-59 will progress through a series of flights to verify airworthiness and gather acoustic and aerodynamic data at higher speeds and altitudes. The programme's findings are expected to take shape over multiple years of testing and analysis and will be delivered to regulators assessing the feasibility and environmental acceptability of renewed supersonic passenger operations over land.