Lockheed Martin has completed final assembly of the X-59 Low Boom Supersonic Demonstrator in Palmdale, California, and is preparing to ship the experimental aircraft to Fort Worth for structural testing, a company executive said. 

The flight-test airframe for NASA’s Quiet Supersonic Technology (QueSST) program will be transported to Texas in December, Greg Ulmer, executive vice president of Lockheed’s Aeronautics Div., told Aviation Week at the Dubai Airshow. 

“It will go back to Palmdale and then we’ll fly sometime next summer,” Ulmer said. 

NASA’s goal is to perform an acoustic survey with the X-59 over communities in 2024, allowing officials of the QueSST program to inform an International Civil Aviation Organization Committee on Aviation Environmental Protection meeting, which is scheduled in 2025 to establish a standard for an allowable loudness level created by a sonic boom. 

The GE Aviation F414-powered X-59 features shaping technologies aimed at lowering the “double thump” of a sonic boom to 75 perceived decibels (PLDB) or less in supersonic cruise at Mach 1.4. The acoustic survey of various communities will be used to validate whether 75 PLDB is quiet enough to avoid bothering people and animals on the ground. 

U.S. and European governments effectively banned overland supersonic travel by civilian aircraft in the early 1970s. At the time, supersonic aircraft, such as the Aerospatiale/BAC Concorde, created a window-rattling boom of 105 PLDB on the ground at supersonic cruise speed.

Lockheed designed the 99.7-ft.-long X-59, including a 30-ft.-long nose section forward of the cockpit, to spread out the supersonic shockwave, which is expected to reduce the high- and low-frequency acoustical peaks of the double-thump boom. 

The aircraft also has been used to demonstrate a new manufacturing philosophy at Lockheed. The airframe was assembled using precisely located pre-drilled holes for fasteners and sectional splices. The process should minimize or eliminate the need to make time-consuming corrections in the assembly process for misaligned holes.