Researchers at NASA have reinvented an over 100-year-old photography technique to capture the shock wave generated by a new supersonic jet. The image will be created using the sun as the background.
Developed by a physicist from Germany in 1864, Schlieren imaging captures objects traveling at supersonic speeds. The technique basically tracks small distortions to an illumination with a uniform background, which are generated when a moving object disturbs the air.
The photos captured with the technique are striking; however, classic Schlieren imaging has a limitation in its scale and range.
NASA’s reinvented technique called Background-oriented Schlieren using Celestial Objects uses the sun itself as the backdrop. BOSCO can also be utilized from a chase plane flying at an altitude of 10,000 feet. The telescopic camera aims straight at the sun’s disc and captures the aircraft while it leads to a partial and local eclipse.
Quiet Supersonic Technology
NASA is going to use BOSCO as a part of its Quiet Supersonic Technology program that is geared at creating a supersonic aircraft, which does not make the sonic boom whenever it travels.
The U.S. space agency worked with Lockheed Martin to complete the initial aircraft design QueSST, which will produce a sound more akin to a quiet thump. A craft that does not make the sonic boom can help reintroduce supersonic flights for consumers and also fly overland.
The future Low Boom Flight Demonstration aircraft would probably travel at a height of 60,000 feet. The high altitude, however, indicates that systems on the ground level will not be able to get good images of the plane. The team, therefore, needed to develop a technique that would enable them to create an imagery from high up.
The scientists deployed a miniature size BOSCO, which could fit into a chase aircraft’s wing pod. It allowed the researchers to take photos from as near as 10,000 feet, while the target plane actually traveled at the target height.
“The main objective here was to see what the image looks like at close range, including what kind of shockwave structure we can make out,” said Mike Hill, principal investigator for BOSCO.
Hill also added that the team had to use the new compact camera system to know about the image quality of the shockwaves, created with a smaller system.
With the success of the flight tests, which confirmed the image quality on a smaller photography system and provided information on how to optimally use the imaging systems at close range, NASA can now develop flightworthy hardware. It will be integrated into a high-speed chase aircraft to take similar photos when LBFB takes flight.