‘We’re the First’: Spacecraft En Route to Conduct UT’s Search for Water on Europa

By Alex Lamb

Reporting Texas

The next time you look up at the moon, imagine that it is covered miles thick with layers of ice instead of white dust. Imagine that below that ice exists an ocean of liquid water twice the volume of Earth’s ocean, and seven times deeper. Now imagine that what you’re looking at isn’t our moon at all but rather another moon the same size and shape as ours orbiting hundreds of millions of miles away around the largest planet in our solar system. 

What you would be imagining is Europa, one of Jupiter’s 95 moons. For decades, this celestial body has been an object of intense fascination in the scientific community because of the likelihood it harbors the conditions necessary for life to evolve, most notably the abundant presence of liquid water.

That community includes about a dozen scientists working for the University of Texas at Austin’s Institute for Geophysics in the Jackson School of Geosciences. 

Over the course of the past decade, they have developed airborne radar equipment capable of seeing through Europa’s thick layers of ice to determine whether water is present. They call this equipment REASON (Radar for Europa Assessment and Sounding: Ocean to Near-surface). 

On Oct. 14, REASON launched aboard NASA’s Europa Clipper spacecraft on a five-year journey toward the distant orbit of Jupiter, along with a variety of instruments from scientific teams around the world comprising hundreds of people. Upon arrival it will spend years flying over every inch of Europa’s surface, scanning it and peering deep within to answer questions that have intrigued scientists since the 1970s. 

“The thing is, we can sit here and talk about it, but it ain’t cartoons. These are testable hypotheses. We will see it,” said Don Blankenship, a UT research professor in the Institute of Geophysics and director of the REASON project. “Radar sounding has never been done in the outer planets. We’re the first.”

Blankenship and his team at UT conceived of REASON and set the parameters for what they wanted it to do, however its physical design and construction was done by the Jet Propulsion Laboratory at Caltech, a frequent collaborator and engineer of NASA projects. The project first received funding from UT in 2014. Over the past decade, UT and JPL have together spent about $300 million on the radar instrument. 

“It’s a huge project,” said Natalie Wolfenbarger, a former doctoral student of Blankenship’s now employed at Los Alamos National Laboratory in New Mexico. “There’s a lot going on. So many people have been involved in working on this. It just launched, but people have been dreaming about this since the late ‘70’s and ‘80’s,” going back to the two Voyager spacecraft. 

“Our mission is taking on one of the big questions in our society and our civilization, which is ‘Are we alone in the universe?’” Wolfenbarger said.

Originally, the core technology utilized in REASON was not developed to study extra-planetary bodies, but to study our own planet — specifically to inform climate change research by studying the ice shelves in Antarctica as well as what lies beneath them. 

This was how Blankenship began his career in the 1970s, ultimately leading to him being hired by UT in 1991 as a research scientist specializing in using airborne radar to study geophysics on Earth.

Eventually, word got out to planetary scientists interested in studying Europa, including the late astronomer and author Carl Sagan, who thought the technology developed by Blankenship and his colleagues could be useful in studying this unique moon.

“I was challenged in 1998,” Blankenship said, “by the director of JPL to write a feasibility study for doing radar sounding of Europa. So I brought everybody in the world who knew how to do it — there’s about 20 of us — and we basically couldn’t find a reason that it couldn’t be done. 

“We wrote up a model of how we thought Europa worked, how radar worked, how radar and ice worked, and put all those together and said, ‘Radar from orbit through ice on Europa should put you in a position where you can test the hypotheses that the community thinks are important,’ ” Blankenship recalled.

While we do have ice shelves on Earth, our entire planetary surface is not covered in them, nor are they dozens of miles thick. 

“Europa has this live ice system on its surface, where it’s constantly regenerating its surface,” said Hunter Reeves, a second-year UT doctoral student and the newest member of Blankenship’s team. “We don’t really know where the ice comes from. One of the leading hypotheses is that it kind of plumes up from the ocean below and goes through the ice shelf and kind of has this nice circulation — kind of like ice tectonics.”

Another curious point to consider about Europa is how liquid water could exist in the first place on a world covered in ice so far from the heat of the sun. The REASON team believes this is possible because of the massive tidal gravity pulls coming from Jupiter that constantly tug on and squeeze Europa, in turn creating heat below its surface.

“When Europa orbits Jupiter it gets sometimes a bit closer or farther, and that (tidal energy) will hit Europa,” said Cyril Grima, a research assistant professor who has worked with Blankenship since 2011. “Europa will recharge in energy during each orbit, and an orbit is just three to four days around Jupiter. It’s fast. So you have this kind of squish on Europa that provides a lot of energy.”

During the next five years as the Europa Clipper makes its journey, members of the REASON team will still be at work. They will continue airborne radar flights over Antarctica to study its parallels with icy Europa, and they will be making adjustments to the software that runs REASON as new information becomes available.

Next spring will see the first test of Clipper’s capabilities. It will fly by Mars in late February and early March and turn on all its equipment early to ensure that the machines are in good working order, and not interfering with each other. 

Scientists are not sure exactly what they expect to find beneath Europa’s surface, but the chance that some form of life may be found is not out of the question. 

“I think through the discovery of life that isn’t on Earth it would help us build a more unified perspective,” Wolfenbarger said. “Perspectives like, ‘We are this planet in this solar system in this universe. We as a civilization are a team.’ I think especially given the current era that’s an important thing to hold onto.”