Can we detect volcanic eruptions and venusquakes from a balloon floating high above Venus?

Siddharth Krishnamoorthy – siddharth.krishnamoorthy@jpl.nasa.gov

NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA, 91109, United States

Daniel C. Bowman2, Emalee Hough3, Zach Yap3, John D. Wilding4, Jamey Jacob3, Brian Elbing3, Léo Martire1, Attila Komjathy1, Michael T. Pauken1, James A. Cutts1, Jennifer M. Jackson4, Raphaël F. Garcia5, and David Mimoun5

1. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, USA
2. Sandia National Laboratories, Albuquerque, New Mexico, USA
3. Oklahoma State University, Stillwater, OK, USA
4. Seismological Laboratory, California Institute of Technology, Pasadena, CA, USA
5. Institut Supérieur de l’Aéronautique et de l’Espace (ISAE-SUPAERO), Toulouse, France

Popular version of 4aPAa1 – Development of Balloon-Based Seismology for Venus through Earth-Analog Experiments and Simulations
Presented at the 184 ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0018837

Venus has often been described as a “hellscape” and deservedly so – the surface of Venus simultaneously scorches and crushes spacecraft that land on it with temperatures exceeding 460 degrees Celsius (~850 F) and atmospheric pressure exceeding 90 atmospheres. While the conditions on the surface of Venus are extreme, the temperature and pressure drop dramatically with altitude. At about 50-60 km above the surface, temperature (-10-70 C) and pressure (~0.2-1 atmosphere) resemble that on Earth. At this altitude, the challenge of surviving clouds of sulfuric acid is more manageable than that of surviving the simultaneous squeeze and scorch at the surface. This is evidenced by the fact that the two VeGa balloons floated in the atmosphere of Venus by the Soviet Union in 1985 transmitted data for approximately 48 hours (and presumably survived for much longer) compared to 2 hours and 7 minutes, which is the longest any spacecraft landed on the surface has survived. A new generation of Venus balloons is now being designed that can last over 100 days and can change their altitude to navigate different layers of Venus’ atmosphere. Our research focuses on developing technology to detect signatures of volcanic eruptions and “venusquakes” from balloons in the Venus clouds. Doing so allows us to quantify the level of ongoing activity on Venus, and associate this activity with maps of the surface, which in turn allows us to study the planet’s interior from high above the surface. Conducting this experiment from a balloon floating at an altitude of 50-60 km above the surface of Venus provides a significantly extended observation period, surpassing the lifespan of any spacecraft landed on the surface with current technology.

We propose to utilize low-frequency sound waves known as infrasound to detect and characterize Venus quakes and volcanic activity. These waves are generated due to coupling between the ground and the atmosphere of the planet – when the ground moves, it acts like a drum that produces weak infrasound waves in the atmosphere, which can then be detected by pressure sensors deployed from balloons as shown in figure 1. On Venus, the process of conversion from ground motion to infrasound is up to 60 times more efficient than Earth.

Figure 1: Infrasound is generated when the atmosphere reverberates in response to the motion of the ground and can be detected on balloons. Infrasound can travel directly from the site of the event to the balloon (epicentral) or be generated by seismic waves as they pass underneath the balloon and travel vertically upward (surface wave infrasound).

We are developing this technique by first demonstrating that earthquakes and volcanic eruptions on Earth can be detected by instruments suspended from balloons. These data also allow us to validate our simulation tools and generate estimates for what such signals may look like on Venus. In flight experiments over the last few years, not just several earthquakes of varying magnitudes and volcanic eruptions, but also other Venus-relevant phenomena such as lightning and mountain waves have been detected from balloons as shown in figure 2.

Figure 2: Venus-relevant events on Earth detected on high-altitude balloons using infrasound. Pressure waves from the originating event travel to the balloon and are recorded by barometers suspended from the balloon.

In the next phase of the project, we will generate a catalog of analogous signals on Venus and develop signal identification tools that can autonomously identify signals of interest on a Venus flight.

Copyright 2023, all rights reserved. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004).

Noise reduction for low frequency sound measurements from balloons on Venus

Taylor Swaim – tswaim@okstate.edu

Oklahoma State University
Stillwater, Oklahoma 74078
United States

Kate Spillman
Emalee Hough
Zach Yap
Jamey D. Jacob
Brian R. Elbing (twitter: @ElbingProf)

Popular version of 2pCA6 – Infrasound noise mitigation on high altitude balloons
Presented at the 184 ASA Meeting
Read the article in Proceedings of Meetings on Acoustics

While there is great interest in studying the structure of Venus because it is believed to be similar to Earth, there are no direct seismic measurements on Venus. This is because the Venus surface temperature is too hot for electronics, but conditions are milder in the middle of the Venus atmosphere. This has motivated interest in studying seismic activity using low frequency sound measurements on high altitude balloons. Recently, this method was demonstrated on Earth with weak earthquakes being detected from balloons flying at twice the altitude of commercial airplanes. Video 1 shows a balloon launch for these test flights. Due to the denser atmosphere on Venus, the coupling between the Venus-quake and the sound waves should be much greater, which will make the sound louder on Venus. However, the higher density atmosphere combined with vertical changes in wind speed is also likely to increase the amount of wind noise on these sensor. Thus development of a new technology to reduce wind noise on a high altitude balloon is needed.

Video 1. Video of a balloon launch during the summer of 2021. Video courtesy of Jamey Jacob.

Several different designs were proposed and ground tested to identify potential materials for compact windscreens. The testing included a long-term deployment outdoors so that the sensors would be exposed to a wide range of wind speeds and conditions. Separately, the sensors were exposed to controlled low-frequency sounds to test if the windscreens were also reducing the loudness of the signals of interest. All of the designs showed significant reduction in wind noise with minimal reduction in the controlled sounds, but one design in particular outperformed the others. This design uses a canvas fabric on the outside of a box as shown in the Figure 1 combined with a dense foam material on the inside.

Figure 1. Picture of balloon carrying the low frequency sound sensors. Compared an early design to no windscreen with this flight. Image courtesy of Brian Elbing.

The next step is to fly this windscreen on a high altitude balloon, especially on windier days and with a long flight line to increase the amount of wind that the sensors will experience. The wind direction at the float altitude of these balloons will change in May and then rapidly increase, which this will be the target window to test this new design.

What is a webchuck?

Chris Chafe – cc@ccrma.stanford.edu

Stanford University
CCRMA / Music
Stanford, CA 94305
United States

Ge Wang
Stanford University

Michael Mulshine
Stanford University

Jack Atherton
Stanford University

Popular version of 1aCA1 – What would a Webchuck Chuck?
Presented at the 184 ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0018058

Take all of computer music, advances in programming digital sound, the web and web browsers and create an enjoyable playground for sound exploration. That’s Webchuck. Webchuck is a new platform for real-time web-based music synthesis. What would it chuck? Primarily, musical and artistic projects in the form of webapps featuring real-time sound generation. For example, The Metered Tide video below is a composition for electric cellist and the tides of San Francisco Bay. A Webchuck webapp produces a backing track that plays in a mobile phone browser as shown in the second video

Video 1: The Metered Tide

The backing track plays a sonification of a century’s worth of sea level data collected at the location while the musician records the live session. Webchuck has fulfilled a long-sought promise for accessible music making and simplicity of experimentation.

Video 2: The Metered Tide with backing track

Example webapps from this new Webchuck critter are popping up rapidly and a growing body of musicians and students enjoy how they are able to produce music easily and on any system. New projects are fun to program and can be made to appear anywhere. Sharing work and adapting prior examples is a breeze. New webapps are created by programming in the Chuck musical programming language and can be extended with JavaScript for open-ended possibilities.

Webchuck is deeply rooted in the computer music field. Scientists and engineers enjoy the precision that comes with its parent language, Chuck, and the ease with which large-scale audio programs can be designed for real-time computation within the browser. Similar capabilities in the past have relied on special purpose apps requiring installation (often proprietary). Webchuck is open source, runs everywhere a browser does and newly-spawned webapps are available as freely-shared links. Like in any browser application, interactive graphics and interface objects (sliders, buttons, lists of items, etc.) can be included. Live coding is the most common way of using Webchuck, developing a program by hearing changes as they are made. Rapid prototyping in sound has been made possible by the Web Audio API browser standard and Webchuck combines this with Chuck’s ease of abstraction so that programmers can build up from low-level details to higer-level features.

Combining the expressive music programming power of Chuck with the ubiquity of web browsers is a game changer that researchers have observed in recent teaching experiences. What could a Webchuck chuck? Literally everything that has been done before in computer music and then some.

Diving into the Deep End: Exploring an Extraterrestrial Ocean

Grant Eastland – grant.c.eastland.civ@us.navy.mil

Naval Undersea Warfare Center Division, Keyport, Test and Evaluation Department., Keyport, Washington, 98345, United States

Popular version of 4aPAa12 – Considerations of undersea exploration of an extraterrestrial ocean
Presented at the 184 ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0018848

As we venture out beyond our home planet to explore our neighbors in our solar system, we have encountered the most extreme environments we could have imagined that provide some of greatest engineering challenges. Probes and landers have measured and experienced dangerous temperatures, atmospheres, and surfaces that would be deadly for human exploration. However, no extraterrestrial ocean environments have been studied beyond observation, which are the mostly unexplored portions of our planet. Remarkably, pass-by planetary probes have found the possible existence of oceans on two of Jupiter’s moons Europa and Ganymede and the existence of a potential ocean, as well as lakes and rivers on Titan, a moon of Saturn. Jupiter’s moon Europa could have a saltwater ocean that could be between 60 and 90 miles deep, covered in up to 15 miles of ice. The deepest point in Earth’s Ocean is a maximum of about 7.5 miles for comparison about 10 to 15 times shallower. Those extreme pressures experienced at that depth would be difficult to withstand with current technology and acoustic propagation could potentially behave differently also. At those pressures, water might not freeze above 8°F (~260 K), causing liquid water at temperatures not seen in our oceans. The effects of this would be found in the speed of sound, which are shown in Figure 1 through a creative and imaginative modelling scheme numerically simulated. The methods used were a mixture of using Earth data with predictive speculation, and physical intuition.

Figure 1. Imaginative scientific freedom determining the speed of sound in the deep ocean on Europa beneath a 30 km ice sheet. The water stays liquid down to potentially 260 K (8 degrees F), heated by currently an unknown mechanism probably related to Jupiter’s gravitational pull.

On Titan, a moon of Saturn, there are lakes and rivers of hydrocarbons like Methane and Ethane. For these compounds to be liquid, the temperature would have to be about -297°F. We know how sound interacts with Methane on Earth, because it is a gas for our conditions, but we would have to get it to cryogenic temperatures to study the acoustics as a liquid. We would have to build systems that could swim around in such temperatures to explore what is underneath. At liquid water temperatures, like potentially some of the extraterrestrial oceans predicted to exist, conditions may still be amenable to life. But to discover that life will require independent systems, making measurements and gathering information for humans to see through the eyes of our technology. The drive to explore extreme ocean environments could provide evidence of life beyond Earth, since where there is water, life is possible.

Helping Acoustic Concepts Resonate with Students #ASA183

Helping Acoustic Concepts Resonate with Students #ASA183

An experimental music piece can help teach concepts of resonance in a more interesting way.

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

NASHVILLE, Tenn., Dec. 7, 2022 – “I am sitting in a room, different from the one you are in now.” With these words, Alvin Lucier begins a fascinating recording where his voice warps and becomes indistinguishable over time — solely because of how sound reflects in the room. For physics students, this audio can be used to reveal details of the surrounding room and teach important lessons about acoustic resonance.

When a sound is made and recorded in a room, then replayed and rerecorded repeatedly, it becomes distorted. Frequencies that correspond to the room itself are emphasized. Credit: Andy Piacsek

Andy Piacsek, of Central Washington University, will discuss how he employs Lucier’s project in the classroom during his talk, “Students are sitting in a room.” The presentation will take place on Dec. 7 at 12:10 p.m. Eastern U.S. in the Lionel room, as part of the 183rd Meeting of the Acoustical Society of America running Dec. 5-9 at the Grand Hyatt Nashville Hotel.

To create this interesting audio, Lucier recorded seventy seconds of speech in a room, played it back over a speaker, and repeatedly rerecorded the result. Eventually, the feedback overwhelms the original recording, and the words are replaced by a collection of distorted frequencies.

In the first iteration of Lucier’s recording, his speech contains the typical range of sound frequencies that make up a human voice. When sounds at most frequencies bounce off the walls in the room, they get jumbled together and eventually fade out. But some frequencies ‘fit’ perfectly in the distances between opposite walls, and these frequencies resonate and grow louder with each recorded iteration.

“Each pair of walls has a set of natural frequencies,” said Piacsek. “By analyzing the frequencies that make up the recording, especially in the later stages, students can determine which frequencies are resonances of the room. The tricky part is figuring out which frequencies go with which pair of walls. This is a bit of a puzzle… and puzzles are fun!”

After identifying the resonant frequencies, students can apply their knowledge of physics to calculate the distance between pairs of walls, and therefore the size of the room Lucier used for his recording. More advanced students can try to make a version of the recording in their own rooms and see if their calculations match their measured room dimensions.

“At the introductory level, especially, many students come to a science class with the notion that science is dry and abstract, not something they identify with,” said Piacsek. “When they see how their classroom learning applies to scenarios they can relate to, it becomes less abstract and they remember it better.”

———————– MORE MEETING INFORMATION ———————–
Main meeting website: https://acousticalsociety.org/asa-meetings/
Technical program: https://eppro02.ativ.me/web/planner.php?id=ASAFALL22&proof=true

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 300 to 500 word summaries 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 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 (ASA) 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/.

Martian Dust Devil Analogues in the Mojave Desert #ASA183

Martian Dust Devil Analogues in the Mojave Desert #ASA183

Identifying and characterizing dust devils on Earth can inform their formation and lifecycles on Mars, where dust storms can make or break missions.

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

NASHVILLE, Tenn., Dec. 7, 2022 – In the Mojave Desert, the sun beats down on the ground and makes pockets of low pressure. Cool air rushes into these areas, where it warms and rises, creating vortices that pick up dust. These types of dust devils aren’t limited to Earth: they are found on Mars at sizes reaching 1,600 meters in diameter.

A dust devil in the Arizona desert (left) and on Mars (right). Credit: NASA/U. of Michigan

Dust devils could play a large role in the Martian climate, and they are crucial to understand during missions to the red planet. Louis Urtecho of NASA JPL and the California Institute of Technology will describe efforts to identify the vortices using data from the Mojave Desert in his presentation, “Automated detection of dust-devil-induced pressure signatures.” The talk will take place on Dec. 7 at 10:40 a.m. Eastern U.S. in the Golden Pass room, as part of the 183rd Meeting of the Acoustical Society of America running Dec. 5- 9 at the Grand Hyatt Nashville Hotel.

“The abundance of dust devils on Mars could have implications for the lifetimes of many missions. In fact, dust devils have already played a role in past missions,” said Urtecho. “Opportunity and Spirit rovers’ lives were extended because friendly dust devils blew dust off their solar panels. But Opportunity eventually succumbed to a global dust storm on Mars, showing the importance of dust loading in the atmosphere.”

It is difficult to find and study dust devils on Mars, so Urtecho and his team hope to study them on Earth, then extend the analysis to scale for the different atmosphere. Based on microbarometer data from the Mojave Desert, they built an algorithm to look for the pressure activity indicative of a dust devil. The vortices have a distinct drop in pressure near their centers, and their pressure fluctuates to look like an electrocardiogram (EKG) signal over time.

“The hope is that with our dust devil detector we will be able to learn more about the formation characteristics of convective vortices and how they move across various landscapes,” said Urtecho. “This will improve the accuracy of Martian weather models, which has a direct impact not only in understanding dust cycles on Mars and the role they have played in its evolution, but also the operation of future robotic and possibly crewed missions.”

———————– MORE MEETING INFORMATION ———————–
Main meeting website: https://acousticalsociety.org/asa-meetings/
Technical program: https://eppro02.ativ.me/web/planner.php?id=ASAFALL22&proof=true

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 300 to 500 word summaries 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 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 (ASA) 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/.