As such, during the recent tests, NASA staged an F-15D just 47 feet (14 meters) from the X-59 to “confirm there’s compatibility between the two aircraft, even at close proximity,” Lin said.

After that, the F-15D and X-59 were further separated on the ground to sit at a distance of 500 feet (152 meters) from one another, which simulated the conditions in which they will fly together.

“You want to make discoveries of any potential electromagnetic interference or electromagnetic compatibility issues on the ground first,” Lin said. “This reduces risk and ensures we’re not learning about problems in the air.”