Probe seeking life on Saturn’s moon earns student team a spot at international space conference

June 13, 2012

by Mark Riechers

Saturn moon

A probe-based satellite on the surface of Enceladus, a moon of Saturn, is shown in a rendering by students from the College of Engineering at the University of Wisconsin-Madison. The students designed equipment to travel the 832 million miles to the moon to search for extraterrestrial life in a subglacial ocean. Their design earned them an invitation to present at the International Planetary Probe Workshop in Toulouse, France.

Somewhere beneath as much as 30 miles of ice on the surface of Saturn’s moon Enceladus, extraterrestrial life could be waiting to be discovered under a subglacial ocean.

And a team of UW-Madison engineering mechanics and astronautics students want to be the people who find it.

For their senior design course, Alex Gonring, Capri Pearson, Samantha Robinson, Jake Rohrig and Tyler Van Fossen designed a mission that would take a probe from Earth to deep below Enceladus’ icy surface, where an array of science instruments would look for carbon-based life.

Of course, astrobiology is the “easy” part of this venture.

Transporting the scientific gear 832 million miles across the solar system is considerably more difficult. The team’s spacecraft design builds on previous NASA mission designs like the Cassini and Galileo satellites, employing solar electric propulsion—with chemical propellant propulsion for maneuvering—to make the bulk of its journey.

For the approach to the moon’s surface, the team proposes a technique known as “aerocapture,” which involves slowing down the probe-bearing satellite by flying through the atmosphere of another of Saturn’s moons, Titan. A heat-resistant enclosure called an aeroshell would protect the science instruments on board as the probe decelerated to a velocity manageable enough to guide the life-seeking probe to the surface of Enceladus via a moon lander.

But the team found that designing an aeroshell large enough proved to be a considerable challenge.

“We have the largest aeroshell ever proposed,” Van Fossen says. “The problem is fitting everything inside of that and still building a stable, aerodynamic craft. There weren’t a whole lot of examples to look to when it came to designing a craft that size that could remain controllable at speeds up to 14,500 miles per hour.”

The shape of the UW-Madison satellite design is different from anything that’s ever flown before, Robinson says. 

Fred Elder was the students’ instructor. An adjunct professor of mechanical engineering and engineering physics at UW-Madison, he says these are design problems that he encourages his students to find on their own in the course of the design.

“My goal is to take them from student to engineer,” says Elder. “People in the real world aren’t going to define the problem and tell you to go design two beams; they’re just going to say, ‘Design something for me.’“

Elder’s charge to his students is similarly open-ended.

“They need something that flies, something that goes in space, or something that goes under the ocean that has a minimum load capacity of 500 pounds. They take it from there,” says Elder.

He helps students work through the details of the execution, but students are on their own to define their mission’s potential pitfalls—and to find creative ways to overcome them.

The team’s creativity paid off in this case. The team has been invited to present at the International Planetary Probe Workshop, a worldwide conference collecting the latest and greatest in proposals for unmanned space missions, held this year in Toulouse, France, from June 18-22. Hosted by the European Space Agency, NASA and other academic and corporate sponsors, the conference presents an invaluable opportunity to those students invited to participate, particularly when it comes to future career possibilities.  

“A lot of the things we based our design on were in published proposals,” says Rohrig. “The fact that we’re going to have a published proposal in circulation that other people can see and get ideas from is pretty exciting.”

The networking potential for an international conference — particularly for students about to enter the next phase of their professional lives — cannot be discounted either.

“I think they will interact with professional peers at a level that they’re not used to. I think that’s a very valuable thing at this stage in their lives,” says Elder.

While networking certainly has value for engineers just entering the job market, Elder says the students’ most-expenses-paid trip to France also is an experience of a lifetime.

“I know what they will definitely get,” he says. “A great international travel experience.”