NASA F-18 chase plane tests ways to soften sonic booms
KENNEDY SPACE CENTER, Fla. — NASA‘s decades-long aeronautics research continues in Florida throughout this week as Sonic Booms in Atmospheric Turbulence, or SonicBAT, advances its research to better understand sonic booms and the effects they produce in the atmosphere.
The SonicBAT project, which ran a similar study at Edwards Air Force Base in California in 2016, has been carrying out its second series of flights this week, this time at Kennedy Space Center. These flights are slated to continue until the end of the month or early September.
The plan is to use the data gathered in this series of tests along with the previous data collected at Edwards AFB last year to validate tools and models that will be used to develop future aircraft with quiet supersonic capabilities, replacing the current loud sonic booms with a soft thump.
“SonicBAT is a program designed to study the effect of atmospheric turbulence on sonic booms and how sharp, or dull, they are when they hit the ground, which is part of a long-term effort to make supersonic flight quieter for commercial use,” Jim Less (call sign ‘Clue’) one of the program’s pilots who has some 21 years under his belt flying F-111s, F-117s, and F-16s for the U.S. Air Force told SpaceFlight Insider. “We’ve flown 10 missions since we’ve been here, one of those was a rehearsal, just to make sure everything was working right and nine science missions which have all gone very well, I’ve personally flown four of those.”
The data gathered last year at Edwards AFB provided a model for dry atmospheres; however, as scientists are aware, humidity tends to increase the sounds of sonic booms, which is why they have moved locations to Florida (as anyone who has visited the Sunshine State during the summer months can attest to).
Under this program, F-18 jets have been taking off from KSC’s Shuttle Landing Facility and flying at an elevation of 32,000 feet (∼9,750 meters), reaching speeds in excess of Mach 1 – the speed of sound, which, at this altitude, is 672.4 mph (300.6 m/s) – with a network of data collection taking place below and above the turbulence level, as well as within the turbulence area.
These efforts have been taking place under a partnership with NASA, Wyle Laboratories, and Gulfstream Aerospace to use two arrays of microphones, each with 16 microphones to collect data. NASA meteorologists will be armed with anemometers to collect data on wind speed, a sonic wind profiler to gauge wind conditions at low altitudes, and a flux sensor to measure any variations due to humidity.
In addition, NASA utilizes TG-14 motorized gliders with wingtip microphones to collect information at elevations from 4,000 to 10,000 feet (1,219 to 3,048 meters), which are above the low-altitude turbulence layer. In order to collect the sonic signatures, the TG-14 has been temporarily turning off the motor and gliding in order to gather clear, accurate sonic signature information and recordings that are unimpeded by unnecessary noise.
“SonicBAT is the first modern flight effort to purposely measure sonic booms in atmospheric turbulence,” said Ed Haering, the project’s principal investigator. “The SonicBAT effort will develop two different models for the effects of turbulence on supersonic aircraft noise, and is one aspect of the total effort to make supersonic aircraft quieter.”
The data collected will be used to create aircraft such as the recently Lockheed contracted Low-Boom Flight Demonstration, or LBFD, aircraft.
The result of SonicBAT could revolutionize the aerospace and air travel industries, providing new high-quality jobs as well as increasing the quality of life by flyers by reducing their travel time.
In the mean time, those living along the Space Coast may very well be hearing some space shuttle level sonic booms over the next few weeks as the project anticipates 2–3 sonic booms per day until they have achieved their data collection goal of a minimum of 33 sonic booms.
“It’s a little harder flying here, we have to keep a better eye on the weather, out at Edwards, almost every day is clear and sunny,” Less said as a more natural booming sound, thunder, could be heard at the SLF.
This article was updated at 15:05 EDT on Aug. 25, 2017, to clarify the speed of sound at the given altitude.
A native of the Greater Los Angeles area, Ocean McIntyre's writing is focused primarily on science (STEM and STEAM) education and public outreach. McIntyre is a NASA/JPL Solar System Ambassador as well as holding memberships with The Planetary Society, Los Angeles Astronomical Society, and is a founding member of SafePlaceForSpace.org. McIntyre is currently studying astrophysics and planetary science with additional interests in astrobiology, cosmology and directed energy propulsion technology. With SpaceFlight Insider seeking to expand the amount of science articles it produces, McIntyre was a welcomed addition to our growing team.