Until Elon Musk can fly us around the world in a rocket, conventional air travel is the fastest way from point A to point B. It hasn’t gotten any faster over the years, though. Commercial flights are limited by the speed of sound because no one wants sonic booms breaking their windows. That’s why NASA and Lockheed Martin are working toward “low boom” technology. To that end, NASA took some photos of supersonic shockwaves, and the images happen to be quite cool.
Any aircraft traveling faster than the speed of sound generates a pressure front that surrounds the frame and forces surrounding air out of the way. People on the ground perceive that shockwave as a sonic boom. To better understand the physics at work and help in designing low-boom aircraft, NASA wanted to get images of supersonic planes in flight. Unsurprisingly, that’s not very easy.
NASA captured the photos using a Beechcraft B200 Super King Air, a twin-turboprop aircraft with a top speed of about 350 miles per hour (570 kilometers per hour). The speed of sound is, of course, considerably faster at roughly 767 miles per hour (1,234 kilometers per hour). The subject of the photos is a pair of T-38 jets with a higher top speed. The B200 didn’t need to keep up, though. It just had to be in the right place at the right time as the jets flew in formation, passing about 600 meters from the observer aircraft.
NASA upgraded the camera aboard the B200 to capture wide frames and improved the connection to data storage so it could snap 1,400 frames per second. The final images are a result of a technique called schlieren imagery, which is used to visualize pressure fields. They also happen to look neat.
The X59 concept aircraft that will test low boom technology in the coming years.
In the coming years, NASA and Lockheed Martin hope to have the experimental X-59 aircraft up and running to prove that low boom hypersonic flight is a possibility. The agency could use this same imaging technique to study how pressure waves form around the fuselage of this plane. The first flight could happen in 2021 or 2022. After that, NASA may be able to convince regulators to allow hypersonic flight over populated areas.
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