1.12.2020

A NASA F/A-18 is towed to the apron at NASA’s Armstrong Flight Research Center in Edwards, California during sunrise over Rogers Dry Lake. The F/A-18 was used to test a transmitter for an air navigation system, called the Airborne Location Integrating Geospatial Navigation System, or ALIGNS. This system, designed to allow pilots to position their aircraft at precise distances to each other, will be critical for acoustic validation efforts of NASA’s next supersonic X-plane, the X-59 Quiet SuperSonic Technology.

Credits: NASA Photo / Lauren Hughes

Two NASA centers on opposite sides of the countries are finding new ways to work together to support the agency’s mission to develop quiet supersonic technology, in spite of thousands of miles of distance and a global pandemic.

Using their available labs, Kennedy Space Center in Florida is building tools in collaboration with Armstrong Flight Research Center in California, which NASA will use in support of the X-59 Quiet SuperSonic Technology X-plane, or QueSST.

Flying at faster-than-sound speeds over communities around the U.S., the X-59 will demonstrate technology to reduce the loud sonic booms, typically heard below aircraft flying at supersonic speeds, to a quieter noise similar to a car door closing in the distance. The X-59 will demonstrate to regulators through collected data that quiet supersonic flight is possible.

However, before the X-59 begins community overflights, NASA researchers need to validate the X-plane’s acoustic signature through tests.

A project under NASA’s Aeronautics Research Mission Directorate called SCHAMROQ, which stands for Schlieren, Airborne Measurements, and Range Operations for QueSST, is preparing the tools and test techniques to execute these tests at Armstrong. When a reduced capacity to develop these tools materialized during the COVID-19 pandemic, Armstrong turned to Kennedy to provide a helping hand, and to help ensure the project’s progress.

A 2019 design of the Shock Sensing Probe, a cone-shaped aeronautical test instrument, extends from the nose of a NASA F-15 aircraft. As the aircraft flies through the shockwaves of a nearby F/A-18 aircraft, the probe, designed to capture high-quality measurements of shock waves created by supersonic aircraft in flight, used five “pressure ports” to measure the pressure on the surface around the instrument, which is shaped like a cone. This method will help NASA validate the acoustic signature of the X-59 Quiet SuperSonic Technology X-plane.

Credits: NASA Photo / Ken Ulbrich

“It’s neat working with a space center,” said Matthew Moholt, deputy project manager for SCHAMROQ. “Their willingness and eagerness to help out a sister center is welcomed and appreciated. When you have another center willing to help out and do critical work that’s critical to your schedule, that’s really significant.”

During supersonic flight, planes create shockwaves that merge together as they travel through the air to produce the sonic boom. Moholt says SCHAMROQ aims to build and test multiple tools to help researchers observe and validate these same shockwaves during quiet supersonic flight.

These tools include the Shock Sensing Probe, a device that will evaluate the characteristics of the X-59's shockwaves while in flight, a schlieren photography technique to visualize the X-59's shockwaves as they distort light through a camera, and a navigation software that will allow pilots to fly accurately during X-59 tests.

Moholt said all of this technology will be placed on a NASA F-15 research aircraft, which will take on the role of a chase plane, following the X-59 in the sky during flight tests to collect data.

“We have this big effort to instrument and put all the research systems into the F-15 that allows it to fly all of these technologies,” Moholt said. “As the pandemic hit, it was right in the peak of getting instrumentation wiring put through it so that all of our instrumentation systems could get put in, and our electronic fabrication shop was impacted by that.”

This SCHAMROQ technology needs to be tested to ensure it can withstand the demands of supersonic flight while onboard NASA’s F-15. Deputy instrumentation lead Matthew Waldersen said part of the testing process requires the usage of a network switch with cables – similar to an ethernet network, but for airplanes.

NASA’s X-59 Quiet SuperSonic Technology X-plane, or QueSST, will fly over communities in the United States to demonstrate quiet supersonic. X-59 is designed so that, when flying faster than the speed of sound, people on the ground will hear nothing more than a quiet sonic thump – rather than a loud sonic boom. Scientifically valid data gathered from these community overflights will be presented to U.S. and international regulators, who will use the information to help them come up with rules based on noise levels that may enable new commercial markets for supersonic flight over land.

Credits: Lockheed Martin

Waldersen explained that, to help ensure the project remained on schedule, Kennedy Space Center was contacted to build cables for the network switch.

“We reached out to their branch chief, and they said ‘yeah, we want to take this work on,’” Waldersen recalls. “‘We have the capacity, we’ve got the staff, we’ve got the ability to do it’, so this is fantastic.”

Jeff Crisafulli, branch chief of testing and design in Kennedy Space Center Engineering, said Kennedy identified onsite subcontractors capable of building these cables.

“These are highly skilled technicians, with 25-30 years of experience fabricating and designing, the NASA way,” Crisafulli said. “They’re considered part of the team.”

Crisafulli said each center at NASA has their own unique skillsets that they bring to the table, and that it is good to share knowledge. This collaboration between an aeronautics center like Armstrong and a space center like Kennedy reinforces one of NASA’s goals – working together for the benefit of the future.

“This is a unique opportunity to help out our buddies at Armstrong by providing this fabrication service,” Crisafulli said. “It goes back to the ‘One NASA’ idea – we are ‘One NASA’. This is a good example of pathfinding and opening up the door to some potential future work together.”

Quelle: NASA