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Taking the pulse of an ocean world

ASU researchers have their sights — and ears — set on listening to Europa.
May 9, 2017

An ASU-designed 'planetary stethoscope' could help us find out what lies in Europa's global ocean

Jupiter's moon Europa is definitely an odd place. Discovered in 1610 by Galileo Galilei, it was first seen in detail only in the late 1970s, after spacecraft visited the jovian system.

Slightly smaller than our own moon, Europa could hardly appear more different. Both have interiors of rock and metal. But Europa is wrapped in a global saltwater ocean and covered by a bright shell of ice. The shell is scarred with cracks and faults and mottled places where the ice has been breached by liquid from below.

Scientists have speculated for decades what lies within that ocean. It is larger in volume than all the oceans of Earth put together.

A NASA-funded seismometer under development at Arizona State University holds the promise of landing on Europa's ice shell — and listening to it.

The seismometer would use Europa's natural tides and other movements to discover the shell's thickness, see whether it holds pockets of water — subsurface lakes — within the ice, and determine how easily, and how often, ocean water could rise and spill out on the surface.

"We want to hear what Europa has to tell us," said Hongyu Yu, of ASU's School of Earth and Space Exploration. "And that means putting a sensitive 'ear' on Europa's surface."

Exploration systems engineer Yu heads up a team of ASU scientists that includes seismologist Edward Garnero, geophysicist Alyssa Rhoden, and chemical engineer Lenore Dai, director of the School for Engineering of Matter, Transport and Energy in the Ira A. Fulton Schools of Engineering.

Technology investment

While there are no current plans to send a lander to Europa, the team has received a grant from NASA to develop and test a miniature seismometer no larger than about 4 inches (10 centimeters) on a side, which could be crucial in advancing future Europa exploration. Fittingly, considering where it is being created, the project is titled Seismometers for Exploring the Subsurface of Europa, or SESE.

Most seismometers, whether for use on Earth or other planets, rely on a mass-and-spring sensor concept to detect passing earthquake waves. But that type of seismometer, says Yu, has to be set down in an upright position, it must be put in place carefully with no major jolts or shaking, and the chamber where the sensor operates needs a complete vacuum to ensure accurate measurements.

"Our design avoids all these problems," Yu explains. The SESE seismometer uses a micro-electromechanical system with a liquid electrolyte as the sensor. "This design has a high sensitivity to a wide range of vibrations, and it can operate at any angle to the surface.

"And if necessary," he adds, "they can hit the ground hard on landing." Yu notes that the team tested the prototype by hitting it with a sledgehammer. It survived.

Besides being extremely rugged, the SESE seismometer promises to push ahead the state of the art in sensors as well. "We're excited at the opportunity to develop electrolytes and polymers beyond their traditional temperature limits," says team member Dai. "This project also exemplifies collaboration across disciplines."

Firm touchdown needed

The ability to withstand a hard landing is a great help, says team member Garnero. "Seismometers need to connect with the solid ground to operate most effectively." Sitting on loose surface materials can isolate the instrument from seismic waves passing through the body of the moon or planet — or, on Europa, its ice shell.

Landers, which would carry seismometers, "typically have four or six legs," Garnero said. "If each leg carries a seismometer, these could be pushed into the surface on landing, making good contact with the ground."

In addition, he said, having a number of sensors on a lander gives scientists the opportunity to combine the data recorded at each. This lets them overcome the variable seismic vibrations recorded by each instrument, and it allows scientists to tell what direction quake waves come from.

"We can also sort out high frequency signals from longer wavelength ones," Garnero explained. The wider the spectrum the instrument can sense, the more phenomena it will detect. "For example, small meteorites hitting the surface not too far away would produce high frequency waves, and tides of gravitational tugs from Jupiter and Europa's neighbor moons would make long, slow waves."

So what would Europa sound like?

Garnero laughed. "I think we'll hear things that we won't know what they are."

But, he said, "ice being deformed on a local scale would be high in frequency — we'd hear sharp pops and cracks. From ice shell movements on a more planetary scale, I would expect creaks and groans."

Ocean world

Europa can be glimpsed in binoculars from the backyard as it circles Jupiter once every 85 hours. But it's just a point of light, looking no different from what Galileo saw when he discovered it.

The Europa that scientists study today, however, is more properly considered an ocean world. This is because of two flyby spacecraft (NASA's Voyager 1 and 2) and an orbiter (NASA's Galileo) that spent eight years at Jupiter. Long-distance observations of Europa also have come from the Hubble Space Telescope orbiting Earth, which detected plumes of water vapor erupting from the shell in 2012 and 2016.

"At Europa, we're trying to use seismometers to determine where the liquid water lies within the ice shell," team member Rhoden said. "We want to know how active the ice shell is."

The answers to these questions are important to the future exploration of this moon and its habitability, she said. "An active shell with pockets of water creates more niches for life and more ways to transport nutrients from the ocean to the surface."

Locating these pockets on Europa would allow future lander missions to possibly sample ocean water brought up through the ice shell.

Just how active is Europa?

"We don't know," Rhoden said. The surface is geologically young, with an approximate age (based on numbers of craters) of 50 to 100 million years. "It may have undergone an epoch of activity early in that period and then shut down." But it's equally possible, she says, that the shell is experiencing fractures, uplifts, offsets, and melt-throughs today.

"Hubble's recent plume observations last fall appear to support that."

As Europa orbits Jupiter, it gets repeated tugs from the gravity of neighbor moons Io and Ganymede. These tugs keep Europa's orbit from becoming circular and that lets Jupiter stress the shell — and then let it relax — over and over, endlessly. Thus, Rhoden said, seismometers on the surface should detect any ongoing activity in the shell.

The team developing the SESE seismometer has its sights on Europa, but they are also looking beyond, because the design is robust and adaptable. This could let it become something of a universal instrument for seismology on other worlds.

As team leader Yu explains, "With modification to fit local environments, this instrument should work on Venus and Mars, and likely other planets and moons, too."

Top photo: Europa's surface is a shell of ice covering a global ocean and displaying amazing features. Long, linear cracks and ridges crisscross the surface, broken by regions of disrupted terrain where the surface ice crust has cracked and refrozen into new patterns. The colors seen in this image from the Galileo mission in the late 1990s are approximately what the human eye would see. Image by NASA/JPL-Caltech

Robert Burnham

Science writer , School of Earth and Space Exploration


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Personal hurdles drive innovation among ASU student entrepreneurs

ASU student entrepreneurs create innovative solutions when faced with obstacles.
May 9, 2017

Immigration aid, anxiety-reducing device among winning New Venture projects

Necessity — and sometimes desperation — drive innovation, and several Arizona State University students have been rewarded for creating amazing solutions to problems they dealt with firsthand.

A woman who faced obstacles in her path to citizenship and a man who watched his newborn son struggle were among the members of five teams that won cash and services for their inventions at the New Venture Challenge entrepreneurial competition recently. The teams divided a $100,000 cash prize and $25,000 in services.

This spring, 10 student-led companies were selected to take a class taught by Scott Wald, a software entrepreneur who earned an MBA from ASU. They worked with Wald and other mentors on specific areas of entrepreneurship, such as financial forecasting and using storytelling. The five finalists pitched their ventures on May 5, winning cash or services such as accounting help, marketing and space.

Tanairi Ochoa-Martinez

Tanairi Ochoa-Martinez shared her own immigration story in describing her venture. Ochoa-Martinez, who earned a master’s of public administration degree this week, created Mi Beneficio Legal, a web platform that helps Spanish-speakers navigate and fill out government forms to acquire legal status or get a green card to work.

“I am the customer,” she said. “I was undocumented, and I became a citizen a year ago. I have lived the fears, and I have felt lonely. I have felt that nobody was able to help me.”

Ochoa-Martinez said the $10,000 cash investment and $5,000 worth of services she won from New Venture will pay for software development and testing the platform this summer. She hopes to launch in the fall.

Spanish-speaking users will log onto Mi Beneficio Legal and choose a form to fill out. The platform will ask a series of questions in Spanish that the users answer, and at the end the form is automatically filled out. An avatar called “Lupe” will pop up to guide them. The goal is to simplify the process and reduce errors through an online format that is more affordable than going to an attorney.

Ochoa-Martinez thought of the idea after helping her father and numerous family members with their paperwork.

“I don’t have the capacity to help everyone. Why not create something that could replicate what I can do?”

The other teams that won cash and services at the New Venture Challenge were:

• KinderFeed, a feeding system for babies who have cleft palates, won $10,000 in cash and $5,000 in services. The CEO of the company, Callie LaMarche, was inspired after working with teammate Patrick McFarland, whose son was born with a cleft palate, which makes feeding very difficult. Existing bottles for babies with this condition are difficult to use.

“Patrick told me a story of when he was feeding his son, he would have to stop feeding, clean out the bottle and then start feeding his son again. I can only imagine how devastating this would be for a parent,” she said. Both are biomedical engineering majors.

The KinderFeed bottle system is leak-free and easier to squeeze formula into the baby’s mouth than existing bottles.

• Billibars, a detachable handlebar system for bicycles, won $35,000 in cash and $12,500 in services. Founder Trevor Heder worked as a professional bicycle mechanic to pay his way as an undergrad at Brigham Young University, where he earned a degree in Mandarin. Then he lived in China for a year, where he was a consultant for an industrial design company.

“I knew I needed to make a pivot in my career choice,” said Heder, who is now a graduate student in industrial design at ASU.

Heder, who also lived for two years in Taiwan, saw many people using bikes — and also having to store them in tiny apartments.

“That’s what sparked the idea of trying to solve the bike problem. I thought, ‘You’ve got to do something about these handlebars — they’re always grabbing you when you walk in the door,” he said.

Billibars, which come in three styles, can be used on any bike and attach and detach quickly. An accessory turns the handlebars into a wall rack for the bike. Heder has already secured a global patent and hopes to sell the system for about $100.

• AVMSec, a network security system, won $20,000 in cash and $2,500 in services.

CEO Ankur Chowdary, a doctoral student in computer science, has already gotten $1.8 million in grants — including from the U.S. Department of Defense — to research his system.

Chowdary used a photo of cartoon duck to illustrate his concept.

“If this duck is setting statically in front of you, it’s easy to shoot the duck,” he said.

“But imagine the duck is flying all around the place. It’s hard to shoot this duck. We leverage the same concept with security.”

Chowdary said his system can predict attacks and move data around the cloud.

“Users we have identified as secure get access to a key, but for users identified as suspicious, we play a shell game with them. For them, the data is moving around very fast in the cloud, and it’s difficult for them to do any malicious act in the system.”

Chowdary predicts revenue of $100 million by 2021.

• Hoolest Performance Technologies, a company that has created device to reduce performance anxiety, won $25,000 in cash.

Founder Nick Hool, a doctoral student studying the neuroscience of human performance, was inspired by his own experience. In 2011, he was invited to play the World Golf Junior Tournament in Florida.

“I show up at the course, go through my warm-up routine and everything is good until I step up to first tee, and that’s where my anxiety kicked in,” said Hool, who described how his heart was pounding. He played terribly and was eliminated.

He and his team invented wireless ear buds that block the effects of anxiety through vagus nerve stimulation, using small electrical impulses. The impulses slow the heart rate.

Hool said the ear buds would initially be marketed to reduce performance anxiety among athletes, but eventually also for the medical anxiety market, such as people who have post-traumatic stress disorder.

“At Hoolest, we have a vision of helping hundreds of millions of people overcome their anxiety without the use of drugs,” Hool said.

Mary Beth Faller

Reporter , ASU News