NASA's X-59 reached mission conditions, not a noise standard, because NASA says the aircraft flew Mach 1.4 at 55,000 feet on June 12, the speed and altitude it needs for later community overflights over real neighborhoods. [1]

The paper's June 14 feature on mission conditions before a noise standard drew the same boundary, and Monday's shorter version keeps it visible: the aircraft has entered the right regime for the experiment, not the public rulebook.

NASA's June 12 post says months of performance testing remain before Quesst moves toward acoustic validation, where researchers measure the quiet sonic thump before flying over communities and gathering public-response data. [1]

That sequence is the civic promise of the program: performance, sound measurement, community response, and only then regulatory evidence that could reopen overland supersonic travel on terms residents can judge rather than headline hype about fast test flights.

The first supersonic flight made the caution obvious, since the X-59 reached about Mach 1.1 and 43,400 feet on June 5 with an F-15 chase plane nearby, and NASA said the F-15's louder booms obscured any sound the X-59 made, leaving no public acoustic claim from that flight and no shortcut around measured neighborhood evidence. [2]

-- KENJI NAKAMURA, Tokyo