For the first time, NASA has captured images of interacting shockwaves from two jets flying faster than the speed of sound about 30 feet apart.

The pictures were made during testing of upgraded equipment that can capture high-quality images of shockwaves, the rapid pressure changes produced when a plane flies at supersonic speeds, a news release from NASA said. When an aircraft exceeds the speed of sound, usually about 700 mph, these shockwaves merge and a sonic boom is created.

NASA says the imaging system will be used to test the design of its X-59 Quiet SuperSonic Technology X-plane. The X-59 QueSST will fly faster than the speed of sound, but its shockwaves will produce a quiet rumble instead of a boom.

This quieter aircraft could be given approval to fly over land. Currently, supersonic planes require clearance in the United States, according to Gizmodo.

The new images were captured during Air-to-Air Background Oriented Schlieren flights, or AirBOS, at NASA’s Armstrong Flight Research Center in Edwards, California.

Schlieren imaging is a way to visualize pressure changes in the air around the planes. The schlieren imaging system allows researchers to capture three times the amount of data in the same period of time, NASA said.

In this test, a pair of T-38s from the U.S. Air Force Test Pilot School at Edwards Air Force Base are flying about 30 feet apart from each other with the trailing aircraft about 10 feet lower than the leading T-38.

“We’re looking at a supersonic flow, which is why we’re getting these shockwaves,” said Neal Smith, a research engineer with AerospaceComputing Inc. at NASA Ames’ fluid mechanics laboratory.

“What’s interesting is, if you look at the rear T-38, you see these shocks kind of interact in a curve,” he said. “This is because the trailing T-38 is flying in the wake of the leading aircraft, so the shocks are going to be shaped differently. This data is really going to help us advance our understanding of how these shocks interact.”

“We’re seeing a level of physical detail here that I don’t think anybody has ever seen before,” said Dan Banks, senior research engineer at NASA Armstrong. “Just looking at the data for the first time, I think things worked out better than we’d imagined. This is a very big step.”

To capture these images, the plane with the cameras, a B-200 King Air, had to arrive at a precise location exactly as the pair of T-38s passed at supersonic speeds about 2,000 feet below. The cameras record for three seconds, so they had to begin recording at the exact moment the supersonic T-38s came into frame.

“The biggest challenge was trying to get the timing correct to make sure we could get these images,” said Heather Maliska, AirBOS sub-project manager. “I’m absolutely happy with how the team was able to pull this off. Our operations team has done this type of maneuver before. They know how to get the maneuver lined up, and our NASA pilots and the Air Force pilots did a great job being where they needed to be.”

“They were rock stars.”