Here Comes the Boom! Studying the Effects of Rocket Launch Sonic Booms on Neighboring Communities #ASA188

Lower-frequency sonic booms from Falcon 9 launches can feel like little earthquakes.

Media Contact:
AIP Media
301-209-3090
media@aip.org

NEW ORLEANS, May 19, 2025 – Rocket launches are amazing spectacles, but close-up viewers know to bring a set of earplugs or earmuffs to protect their hearing. However, the boom of a launch isn’t reserved for those who sign up to watch it – it can also be heard and felt in surrounding communities.

SpaceX’s Falcon 9 is a rocket used for both human and nonhuman space missions. Since 2010, the rocket has been launched over 400 times, and one of the launch sites for Falcon 9 is the Vandenberg Space Force Base in California.

“Although Ventura County is 60-100 miles from the Vandenberg Space Force Base, sonic booms and other noise from rockets launched over the ocean are sometimes heard on land,” said Brigham Young University physics professor Kent Gee. “As the number of launches with satellite orbits requiring trajectories along the California coastline increases, these booms are being heard more frequently.”

Motivated by noise concerns from residents in Ventura County, a team of researchers from BYU and California State University, Bakersfield collected 132 measurements from sonic booms over an area of 200 square miles during the summer of 2024.

Makayle Kellison, a BYU graduate student, and Gee will present their group’s work Monday, May 19, at 2:20 p.m. CT as part of the joint 188th Meeting of the Acoustical Society of America and 25th International Congress on Acoustics, running May 18-23.

A view of the Falcon 9 rocket launch from a park in Ventura County. Credit: Kent Gee

“Right now, residents may hear a sonic boom up to five times per month, or not at all,” Gee said.

In 2024, the Falcon 9 rocket was launched 46 times out of the Vandenberg base, averaging almost one launch per week. But not every launch makes an audible boom, and not every launch sound is created equal.

“The magnitude of these sonic booms is not uniform across the county and can vary greatly with weather conditions, launch time, vehicle trajectory, and time of year,” Kellison said. “Communities near Edwards Air Force Base, a hub for supersonic aircraft testing, are familiar with occasional sonic booms; however, an aircraft sonic boom differs significantly from a rocket ascent sonic boom.”

Rocket ascent sonic booms are much lower in frequency and can, indoors, sound — and feel — like an earthquake. The boom’s dominant energy is at a frequency of less than 1 hertz, below the range of human hearing, meaning that the booms rattle homes rather than bursting eardrums.

By collecting data on multiple qualities of the Falcon 9 sonic booms, researchers can help discern how different launch-day variables affect a boom’s impact.

“With a better understanding of the underlying rocket sonic boom physics, we hope to inform Base operations and policy makers, allowing for the space launch industry to sustainably grow,” Kellison said.

——————— MORE MEETING INFORMATION ———————
Main Meeting Website: https://acousticalsociety.org/new-orleans-2025/
Technical Program: https://eppro01.ativ.me/src/EventPilot/php/express/web/planner.php?id=ASAICA25

ASA PRESS ROOM
In the coming weeks, ASA’s Press Room will be updated with newsworthy stories and the press conference schedule at https://acoustics.org/asa-press-room/.

LAY LANGUAGE PAPERS
ASA will also share dozens of lay language papers about topics covered at the conference. Lay language papers are summaries (300-500 words) of presentations written by scientists for a general audience. They will be accompanied by photos, audio, and video. Learn more at https://acoustics.org/lay-language-papers/.

PRESS REGISTRATION
ASA will grant free registration to credentialed and professional freelance journalists. If you are a reporter and would like to attend the meeting and/or press conferences, contact AIP Media Services at media@aip.org. For urgent requests, AIP staff can also help with setting up interviews and obtaining images, sound clips, or background information.

ABOUT THE ACOUSTICAL SOCIETY OF AMERICA
The Acoustical Society of America is the premier international scientific society in acoustics devoted to the science and technology of sound. Its 7,000 members worldwide represent a broad spectrum of the study of acoustics. ASA publications include The Journal of the Acoustical Society of America (the world’s leading journal on acoustics), JASA Express Letters, Proceedings of Meetings on Acoustics, Acoustics Today magazine, books, and standards on acoustics. The society also holds two major scientific meetings each year. See https://acousticalsociety.org/.

ABOUT THE INTERNATIONAL COMMISSION FOR ACOUSTICS
The purpose of the International Commission for Acoustics (ICA) is to promote international development and collaboration in all fields of acoustics including research, development, education, and standardization. ICA’s mission is to be the reference point for the acoustic community, becoming more inclusive and proactive in our global outreach, increasing coordination and support for the growing international interest and activity in acoustics. Learn more at https://www.icacommission.org/.

Acoustic Metamaterials for Quality of Life: Engineering Challenges for Low-Height Noise Barriers

Domenico De Salvio – domenico.desalvio2@unibo.it
Instagram: @midrashdds
Department of Industrial Engineering (DIN)
University of Bologna
Bologna, Bologna 40136
Italy

Massimo Garai
Department of Industrial Engineering (DIN)
University of Bologna
Bologna, Bologna 40136
Italy

Popular version of 3pNS3 – Metamaterials application on low-height noise barrier for railways: challenges of real-world scenarios
Presented at the 188th ASA Meeting
Read the abstract at https://eppro01.ativ.me//web/index.php?page=IntHtml&project=ASAICA25&id=3870863

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

If you’ve ever lived near a train line, you know the roar of passing cars can be more than annoying — it can hurt your health. A primary source of this noise comes from transportation; among them, railway lines, having a high density in Europe, can be particularly disturbing for nearby residents. The traditional high noise barriers can help, but they aren’t always practical in urban areas. Low-height noise barriers (LHNBs), typically less than 1 meter high, can be a good alternative. These barriers work well because they can be placed very close to the source of the noise, such as where train wheels interact with the rails, as shown in Figure 1.

Figure 1. A low-height noise barrier is placed next to the railway. Image courtesy of Kraiburg Strail®.

However, for these low barriers to work best, their surface needs to be good at absorbing sound (see Figure 2). Here, acoustic metamaterials can play a key role. These artificial structures have unique properties that natural materials lack, enabling them to absorb sound in ways that conventional materials cannot. Their functionality relies on their geometric configuration rather than solely on the raw materials used, enabling them to be made from weather- and dust-resistant materials.

The effectiveness of an Low-Height Noise Barrier

Figure 2. The effectiveness of an LHNB. The colors represent sound pressure level: red indicates the highest noise levels, while blue shows the lowest. On the left, the noise generated by the wheel-rail interaction. In the middle, the effectiveness of a generic LHNB is shown. On the right, the noise reduction achieved by an optimized sound-absorbing LHNB. The less red there is, the more effective the LHNB is.

This study is part of the European project LIFE SILENT and examines the integration of metamaterials into a specific type of LHNB. It employs two types of acoustic resonators designed within the constraints of a real-world scenario: Neck Embedded Helmholtz Resonators (NEHRs) and Fabry-Pérot (FP) channels. Combining these resonators enables the LHNB to mitigate railway noise.

Designing these complex structures requires a thorough process. The optimal geometry of the metamaterial has been studied through a combination of complex simulations and nature-inspired algorithms. Specifically, the geometry was optimized using a computational technique called “particle swarm” inspired by the social behavior of flocks of birds and schools of fish.

Prototypes of the metamaterial units were 3D printed in plastic because of the need for customization and precision (see Figure 3). Once the efficiency of the metamaterial is tested, serial production of the optimized geometry can also be achieved through traditional industrial molding techniques, thus, in real-world scenarios.

Figure 3. Example of 3D printed metamaterial NEHRs (on the left) and FP (on the right), the units that compose the sound-absorbing LHNB surface.

This work demonstrates how metamaterial engineering can be applied to everyday situations. The study tackles practical limitations and constraints, the need for durability against outdoor conditions, and the challenges of manufacturing complex structures. The research outlines the essential steps to transition from a lab idea to a potentially mass-produced solution against noise pollution by developing a focused design, creating physical prototypes, and conducting tests. While recognizing challenges like manufacturing accuracy and the impact of real-world conditions, the project emphasizes that acoustic metamaterials can be designed to be robust and effective for public infrastructure, paving the way for their practical use for a better daily life.

The Silent Service

HONGMIN PARK – hongmini0202@snu.ac.kr

Seoul National University, Gwanak-ro, Gwanak-gu, Seoul, Republic of Korea, Seoul, Seoul, 08826, South Korea

WOOJAE SEONG
Professor of Seoul National University
http://uwal.snu.ac.kr

Popular version of 2aEA9 – A study of the application of global optimization for the arrangement of absorbing materials in multi-layered absorptive fluid silencer
Presented at the 187th ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0035138

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

Underwater Radiated Noise (URN) generated by naval vessels is critically important as it directly impacts survivability. Underwater Radiated Noise (URN) refers to the sound emitted by objects, like ships or submarines, into the water. This noise is generated by various sources, including the vessel’s machinery, propellers, and movement through water. It can be detected underwater, affecting their ability to remain undetected. So various studies have been conducted to reduce URN for submarines to maintain stealth and silence.

This study focuses on the ‘absorptive fluid silencer’ installed in piping to reduce noise from the complex machinery system. An absorptive fluid silencer is similar to a car muffler, reducing noise by placing sound-absorbing materials inside.

We measured how well the silencer reduced noise by comparing sound levels at the beginning and end of the silencer. Polyurethane, a porous elastic material, was used as the internal sound-absorbing material, and five types of absorbent materials suitable for actual manufacturing were selected. By applying a ‘global optimization method,’ we designed a high-performance ‘fluid silencer.’.

The above graph shows a partial analysis result, It can be observed that using composite absorbing materials provides superior sound absorption performance compared to using a single absorbing material.

Pickleball Courts in a Legal Pickle #ASA186

When advising on the noise associated with pickleball, loudness is just one of many concerns, and solutions require infrastructure or limitations on play.

Media Contact:
AIP Media
301-209-3090
media@aip.org

OTTAWA, Ontario, May 17, 2024 – Pickleball Legal Consultant is a job title that likely did not exist a decade ago, but as pickleball courts infiltrate neighborhoods to satiate an appetite for a sport whose namesake is a snack, communities take issue with the resulting influx of noise. Now homeowners’ associations and city councils face litigation by those whose lives are disrupted by pickleball’s din.

Charles Leahy, an attorney, retired mechanical engineer, and former HOA board member became interested in this issue after his HOA dismissed the recommendations of noise consultants and failed to install noise absorbing barriers. Litigation over noise nuisance ensued and threatens closure of the courts.

Leahy sought to understand how acoustic engineers assess the noise, how they fashion their recommendations, and what best practices engineers can employ to persuade the community that the noise is real and needs to be mitigated. He will present his work Friday, May 17, at 8:35 a.m. EDT in a session dedicated to pickleball as part of a joint meeting of the Acoustical Society of America and the Canadian Acoustical Association, running May 13-17 at the Shaw Centre located in downtown Ottawa, Ontario, Canada.

Experts recommend HOAs and communities consider the “popping” noise associated with pickleball when deciding to build courts near homes. Image credit: AIP

“Compared to tennis, pickleball is a much smaller court, easier to learn, and especially accessible to seniors,” said Leahy. “Each tennis court can become up to four pickleball courts. Tennis involves a soft and compressible ball and a racket with strings. Pickleball is a hard plastic ball and a hard paddle. Tennis produces a ‘thunk’ sound versus pickleball ’pop,’ which is louder, sharper, more piercing, and more frequent. Thus, more annoying.”

Communities looking to invest in – and those facing lawsuits because of – the courts often seek out engineering consultants to advise them. Leahy examined over 70 pickleball consultant noise reports and compared their recommendations with the American National Standard Institute. He found many reports considered only the decibels associated with the noise, but other factors are important too.

“It’s not just the loudness, it’s the impulsive sharpness and randomness of the ‘pops,’” said Leahy. “It’s the persistence and repetition of the random noises over many hours a day, usually seven days a week.”

His best recommendation is to build courts far from homes, at least 600-800 feet away to allow the sound to naturally dissipate. Less desirable (or more difficult or costly) solutions include enclosing the courts within a building or wall barriers or using less noisy paddles and balls.

“Pickleball has a highly impulsive noise, with each court generating about 900 pop noises per hour,” said Leahy. “It’s incompatible with residential living. Cities can also locate pickleball in industrial and commercial neighborhoods rather than close to homes.

“The benefits of pickleball to the players are undeniable, and the demand for more pickleball courts is real and genuine. However, there needs to be more research, more planning and prevention, and more effort to avoid ending up in front of the judge and jury.”

———————– MORE MEETING INFORMATION ———————–
Main Meeting Website: https://acousticalsociety.org/ottawa/
Technical Program: https://eppro02.ativ.me/src/EventPilot/php/express/web/planner.php?id=ASASPRING24

ASA PRESS ROOM
In the coming weeks, ASA’s Press Room will be updated with newsworthy stories and the press conference schedule at https://acoustics.org/asa-press-room/.

LAY LANGUAGE PAPERS
ASA will also share dozens of lay language papers about topics covered at the conference. Lay language papers are summaries (300-500 words) of presentations written by scientists for a general audience. They will be accompanied by photos, audio, and video. Learn more at https://acoustics.org/lay-language-papers/.

PRESS REGISTRATION
ASA will grant free registration to credentialed and professional freelance journalists. If you are a reporter and would like to attend the in-person meeting or virtual press conferences, contact AIP Media Services at media@aip.org. For urgent requests, AIP staff can also help with setting up interviews and obtaining images, sound clips, or background information.

ABOUT THE ACOUSTICAL SOCIETY OF AMERICA
The Acoustical Society of America is the premier international scientific society in acoustics devoted to the science and technology of sound. Its 7,000 members worldwide represent a broad spectrum of the study of acoustics. ASA publications include The Journal of the Acoustical Society of America (the world’s leading journal on acoustics), JASA Express Letters, Proceedings of Meetings on Acoustics, Acoustics Today magazine, books, and standards on acoustics. The society also holds two major scientific meetings each year. See https://acousticalsociety.org/.

ABOUT THE CANADIAN ACOUSTICAL ASSOCIATION/ASSOCIATION CANADIENNE D’ACOUSTIQUE

fosters communication among people working in all areas of acoustics in Canada
promotes the growth and practical application of knowledge in acoustics
encourages education, research, protection of the environment, and employment in acoustics
is an umbrella organization through which general issues in education, employment and research can be addressed at a national and multidisciplinary level

The CAA is a member society of the International Institute of Noise Control Engineering (I-INCE) and the International Commission for Acoustics (ICA), and is an affiliate society of the International Institute of Acoustics and Vibration (IIAV). Visit https://caa-aca.ca/.

Noise Survey Highlights Need for New Direction at Canadian Airports #ASA186

Annoyance data gathered during pandemic reveals flaws in existing methods to assess and mitigate noise impacts.

Media Contact:
AIP Media
301-209-3090
media@aip.org

OTTAWA, Ontario, May 16, 2024 – The COVID-19 pandemic changed life in many ways, including stopping nearly all commercial flights. At the Toronto Pearson International Airport, airplane traffic dropped by 80% in the first few months of lockdown. For a nearby group of researchers, this presented a unique opportunity.

Low-flying aircraft can lead to noisy and unhealthy neighborhoods, and a pioneering survey can help track their impact around Canadian airports. Image Credit: Julia Jovanovic

Julia Jovanovic will present the results of a survey conducted on aircraft noise and annoyance during the pandemic era Thursday, May 16, at 11:10 a.m. EDT as part of a joint meeting of the Acoustical Society of America and the Canadian Acoustical Association, running May 13-17 at the Shaw Centre located in downtown Ottawa, Ontario, Canada.

“For many years, researchers like me have looked to assess the impacts of aircraft noise on communities surrounding airports, particularly in terms of annoyance,” said Jovanovic. “The travel restrictions due to COVID and the resulting sustained reductions in noise gave us an unprecedented opportunity to test the correlation between noise and annoyance.”

In early 2020, the NVH-SQ Research Group out of the University of Windsor surveyed residents living around the airport to gauge how their annoyance levels changed with the reduction in noise. A follow-up survey in 2021 provided even more data for the researchers, and according to Jovanovic, they highlight flaws in the tools authorities use to assess and manage the impacts of aircraft noise on communities.

“The industry has, for too long, erroneously relied on noise complaints as a proxy measure for annoyance,” said Jovanovic. “These surveys show that complaints and annoyance are different phenomena, triggered by different mechanisms. Only annoyance has a proven correlation to overall noise levels.”

According to their data, while noise complaints dropped overall during the pandemic, many of the people sending those complaints continued to do so, and some areas even saw an increase in complaints. This demonstrates the need for collecting survey data on annoyance specifically, something Canadian authorities overseeing air transport have been reluctant to do.

“Even though the annoyance metric draws much criticism due to its subjective nature, it is still indicative of the overall effect of aircraft noise on individuals and the resulting possible long-term health impacts,” said Jovanovic. “These types of surveys are conducted in most developed nations on a regular basis. To the best of our knowledge, we are unaware of any similar efforts in any other Canadian airport.”

Jovanovic and her colleagues hope these results will spur regulatory agencies to collect better data and use it to develop more updated standards and guidelines for protecting the public from aircraft noise and protecting the future of airport operations from continuous residential encroachment.

“The survey should be repeated around all of our nation’s airports to get an accurate representation of the effects of aircraft noise on Canadian communities and update Transport Canada’s severely outdated guidelines for the management of aircraft noise,” said Jovanovic.

———————– MORE MEETING INFORMATION ———————–
Main Meeting Website: https://acousticalsociety.org/ottawa/
Technical Program: https://eppro02.ativ.me/src/EventPilot/php/express/web/planner.php?id=ASASPRING24

ASA PRESS ROOM
In the coming weeks, ASA’s Press Room will be updated with newsworthy stories and the press conference schedule at https://acoustics.org/asa-press-room/.

LAY LANGUAGE PAPERS
ASA will also share dozens of lay language papers about topics covered at the conference. Lay language papers are summaries (300-500 words) of presentations written by scientists for a general audience. They will be accompanied by photos, audio, and video. Learn more at https://acoustics.org/lay-language-papers/.

PRESS REGISTRATION
ASA will grant free registration to credentialed and professional freelance journalists. If you are a reporter and would like to attend the in-person meeting or virtual press conferences, contact AIP Media Services at media@aip.org. For urgent requests, AIP staff can also help with setting up interviews and obtaining images, sound clips, or background information.

ABOUT THE ACOUSTICAL SOCIETY OF AMERICA
The Acoustical Society of America is the premier international scientific society in acoustics devoted to the science and technology of sound. Its 7,000 members worldwide represent a broad spectrum of the study of acoustics. ASA publications include The Journal of the Acoustical Society of America (the world’s leading journal on acoustics), JASA Express Letters, Proceedings of Meetings on Acoustics, Acoustics Today magazine, books, and standards on acoustics. The society also holds two major scientific meetings each year. See https://acousticalsociety.org/.

ABOUT THE CANADIAN ACOUSTICAL ASSOCIATION/ASSOCIATION CANADIENNE D’ACOUSTIQUE

fosters communication among people working in all areas of acoustics in Canada
promotes the growth and practical application of knowledge in acoustics
encourages education, research, protection of the environment, and employment in acoustics
is an umbrella organization through which general issues in education, employment and research can be addressed at a national and multidisciplinary level

The CAA is a member society of the International Institute of Noise Control Engineering (I-INCE) and the International Commission for Acoustics (ICA), and is an affiliate society of the International Institute of Acoustics and Vibration (IIAV). Visit https://caa-aca.ca/.

Taking Pictures of the Sound of a Rocket

Grant W. Hart – grant_hart@byu.edu
Brigham Young University
Provo, UT 84602
United States

Kent Gee (@KentLGee on X)
Eric Hintz
Giovanna Nuccitelli
Trevor Mahlmann (@TrevorMahlmann on X)

Popular version of 1pNSa8 – A photographic analysis of Mach wave radiation from a rocket plume
Presented at the 186th ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0026810

The rumble of a large rocket launching is one of the loudest non-explosive sounds that mankind has ever made. Where does that sound come from? Surprisingly, it doesn’t come from the rocket itself, or even the exhaust nozzle, but rather from the plume of exhaust that shoots out of the back. The plume is supersonic when it comes out of the rocket, and it emits sound as it slows down in the atmosphere.

This process was visualized in some recent pictures taken by Trevor Mahlmann of a Falcon 9 launch from Cape Canaveral. The launch was just after dawn, and Mahlmann took a series of striking pictures as the rocket passed in front of the sun. Two of those pictures are shown below. If you look at the edge of the sun in the later picture you can see distortions caused by the intense sound waves coming from the rocket.

Recognizing the possibility of gaining more information from these pictures, researchers at Brigham Young University got permission from Mr. Mahlmann to further analyze them. The third picture below shows a portion of the difference between the first two pictures. The colors have been modified to show the sound waves more clearly. The waves clearly are coming from a region far down the plume of the rocket, rather than the nozzle of the rocket. The source was typically about 10-25 times the diameter of the rocket down the plume.

The sound is also directional – it doesn’t go out evenly in all directions, but rather goes out most strongly at about 20-30 degrees below the horizontal. Most rockets sound loudest to people watching the launch when they are 20-30 degrees above the ground. This is all consistent with the models of the sound being produced by the processes that slow down the exhaust from supersonic speeds. A good introduction to rocket noise is found in a recent article in Physics Today.

The researchers first had to line up the images so that the sun was in the same place in each frame. They were then able to subtract the later image from the first one to get the difference and leave just the distortions caused by the waves in the second image. To find the source of the waves, it was necessary to draw a line backward from the wave’s image and find where it met the rocket’s path across the Sun. Since it took time for the wave to get from the source to where it was observed, they had to find where the rocket was at the time the sound wave was given off. They did this by finding how far the sound had traveled and used the speed of sound to find the time it took to get there. With that information the researchers could find the position of the source and the direction of the wave.

Figure 1. A Falcon 9 rocket about to pass in front of the Sun. Image courtesy of Trevor Mahlmann. Used by permission. Higher resolution versions available from the photographer.

Figure 2. A Falcon 9 rocket passing in front of the Sun. Note the distortions of the edge of the Sun caused by the sound waves produced by the rocket. Image courtesy of Trevor Mahlmann. Used by permission. Higher resolution versions available from the photographer.

Figure 3. A portion of the difference between the two previous figures, showing the enhanced sound waves. The bottom of the rocket is at the top of the image. Image adapted from Hart et al.’s original paper.