Mars 2020 rover's RIMFAX radar will 'see' deep underground
Toronto researcher tested technology in Canada's High Arctic
NASA's next Mars rover will be able to detect ice and stream beds buried dozens of metres below its wheels, thanks in part to a Canadian scientist.
Rebecca Ghent, an associate professor of earth sciences at the University of Toronto, will help develop the Radar Imager for Mars' Subsurface Exploration (RIMFAX), as part of a team led by Svein-Erik Hamran, the Norwegian Defence Research Establishment in Norway. The device was one of seven tools chosen by NASA for the Mars 2020 Rover from 58 proposals.
It will give the Mars rover something akin to X-ray vision so it can "see" right through rocks and dirt, and spot features buried underground.
"The most important thing about it is it gives us information in the third dimension, in the vertical dimension," Ghent said. "That's something we don't often have in planetary observations."
Until now, most observations of Mars have come from orbiters and rovers that can see only the surface of the planet. At best, NASA's current rover mission, Curiosity, has been able to drill several centimetres into the ground.
RIMFAX is a ground-penetrating radar device that will be able to peer dozens of metres into the ground, looking for buried sand dunes, lava flows, stream channels and salt layers, which may help scientists understand the geological processes that shaped the Red Planet.
Ghent said industries such as mining use similar technology to check the integrity of ice roads in the Arctic, or even to look for cracks in buildings.
The technology works by sending radio waves into the Earth and using an antenna to "listen" for reflections as the waves bounce off different layers underground, similar to the way sonar works. The "sound" and timing of the reflections is affected by density, grain size and conductivity of the subsurface layers, as well as their depth.
By scanning the radar back and forth over a surface, the Mars rover will be able to generate a 3D map of the layers underneath it, Ghent said.
It will also be able to follow surface structures such as old lava flows that slope into the ground to see how deep they go.
Ghent is currently testing the conductivity and electrical properties of different minerals and other materials to see how they will affect the radar signals at different depths. That will help scientists interpret the data from the Mars rover, which is set to be launched in 2020.
Ghent is also working on the antenna that the researchers hope to test on Earth – at a site that's dry and rocky like Mars – during next year's field season.
High Arctic tests
She has already done some tests in Canada's High Arctic, during a trip to Eureka on Ellemere Island in 2010. At that time, she had already started thinking about the possibility of using ground-penetrating radar on Mars.
"Mars is thought to have layers of subsurface ice, and I've been curious for a long about ways we could improve ways to detect and characterize those using radar," she said.
In the Arctic, melting permafrost can generate sinkholes that expose subsurface layers around them. That makes them a perfect testing ground for the radar – researchers can scan from on top of the layers and compare the signals they receive with what they see in the exposed cross-section of layers.
Ghent was invited to work on the RIMFAX team because she had worked on a device on NASA's Lunar Reconnaissance Orbiter mission with David Paige, deputy principal investigator for RIMFAX and a researcher at the University of California, Los Angeles. She had also done radar work with fellow RIMFAX team member Lynn Carter.
NASA announced the seven instruments for the next Mars rover at the end of July.
Ghent said she heard her team's proposal was accepted just minutes before the news conference: "I was just really excited."
The goal of the Mars 2020 rover is to gather information and test technologies that will help pave the way for human exploration of Mars. Its toolkit includes devices that will make oxygen from carbon dioxide in the atmosphere and provide detailed weather measurements, including the size of the dust particles blowing around the Red Planet.
- The RIMFAX team is led by Svein-Erik Hamran of the Norwegian Defence Research Establishment, not David Paige of the University of California, Los Angeles, as an earlier version of this story reported. Paige is the deputy principal investigator for the team.Aug 19, 2014 3:09 PM ET