NASA has pushed back the first flight of its X-59 Quesst supersonic demonstrator aircraft to next year as it works through “several technical challenges identified over the course of 2023,” the agency announced late last week.

The Mach 1.4 X-59 will be used to gather data on public response to a softer thud—rather than a sonic boom—that may be possible with modern supersonic aircraft. This data could pave the way for the eventual return of supersonic flight over land.

Built at Lockheed Martin’s Skunk Works facility in Palmdale, California, the X-59 was anticipated to fly this year. NASA noted that the aircraft combines new technology with systems and components from a range of established aircraft such as landing gear from an F-16 fighter and life-support system adapted from the F-15.

“Extra time is needed to fully integrate systems into the aircraft and ensure they work together as expected,” NASA said, adding that the team also is working through “intermittent issues” with safety-redundant computers controlling aircraft systems.

The aircraft is undergoing integrated testing, and once complete, will proceed to flight readiness review. At that point, the agency expects to release a more specific timeline for the first flight.

Even so, NASA noted that the Quesst aircraft has checked off a number of milestones as it progresses toward its first flight, including the “finishing touches” to the X-59 tail structure. This enabled the team to finalize electrical wiring and proceed to ground tests. The aircraft has moved from assembly to the flight line for structural testing.

After initial flight tests, NASA plans to fly the X-59 over various communities to gather noise data for quieted sonic booms that will then be delivered to U.S. and international regulators to consider allowing overland sonic flights. NASA noted this makes it imperative that the aircraft’s safety is verified before the first flight but in the long term as it flies over communities.