Dr. Lora Koenig, an expert in remote sensing of ice sheets and snow, provided scientific input for the design of the Goddard Remotely Operated Vehicle for Exploration and Research, or GROVER. The autonomous vehicle will rove through Summit, Greenland and monitor how much snow falls over the country’s ice sheets.
NASA Tech Briefs: To set the stage, what is GROVER, also known as the Greenland Rover, or Goddard Remotely Operated Vehicle for Exploration and Research?
Dr. Lora Koenig: GROVER is a great connection between scientists, engineers, and educators. GROVER was designed as an autonomous robot to carry science payloads, and it was designed by Engineering Boot Camp students. The engineers actually came to me and said, “We are looking for science payloads onboard the robots that we will build.” And it’s from that starting point that GROVER came to be. They wanted an autonomous rover, and I provided input on how GROVER could be used for ice sheet science.
NTB: What will we learn from its measurements?
Koenig: From the measurements that GROVER will be taking, we’ll learn about how much snow falls over the ice sheets. Each year, in the center of the ice sheet where it’s cold, snow accumulates. Every year, snow falls and creates a new layer of snow, and you can count those layers just like tree rings. GROVER, with its radar, will be roving over areas where accumulation occurs, and it will be able to map those stratographic layers. From that, we can determine how much snow fell in the previous years.
NTB: What kinds of instruments are on this rover? What kinds of technology are making these measurements happen?
Koenig: The rover has just one radar onboard. It’s an ultra-high-frequency radar, FMCW [frequency-modulated continuous-wave] radar. It sweeps between about 8 and 18 Gigahertz, a very wide bandwidth. That gives us very high vertical resolution in the snow to monitor those annual layers.
NTB: Can you describe the technical challenges? I imagine it’s difficult, and a lot of the technical challenges are related to the hostile environment that it has to operate in.
Koenig: Yes, those are most of the technical challenges that we’re undergoing right now – it being GROVER’s first time out on the ice sheet. Just like we don’t know how many warm clothes we need in different temperatures, GROVER’s kind of going through that same thing. Not only is it the cold temperatures, but it’s the bouncing around on the relatively hard surface with its tracks. A lot of the technical difficulties are making sure that all of the electrical systems are well put together, that the structures that hold the instruments are enclosed so that no blowing snow gets into the electronics boxes. We also keep track of, on a technical side, how much snow sticks to the solar panels and how snow drifts into the tracks, because the snow can build up.
We’re doing a lot of stress testing of GROVER to see how he does in the cold. He spent his first night out in -30° temperatures, and he did start up the next morning and the tracks did just fine. He had one electrical problem with one motor, and that has been fixed.
NTB: Is that where you’re at right now with GROVER? It’s now undergoing testing?
Koenig: Yes, right now [May 17, 2013] he is a little over a week into a 5-week test period, and he’s still undergoing tests quite close to camp, and undergoing the stress tests before he gets sent out. He’s already proved his ability to rove autonomously. He has done very well in the different types of snow. His locomotion is very good, and his power consumption is very good. There have been a few issues with some of the electrical components, which have been fixed.
NTB: And you mentioned its ability to rove autonomously. What kinds of technology enable that?
Koenig: He can rove autonomously under two different technologies. One is just a wireless network. We have a high-gain antenna, so we can get about 3 km away on the wireless network, and then he also can go anywhere in the world using his iridium links.
NTB: You also mentioned power. This is a solar-powered rover?
Koenig: Yes, he’s solar-paneled, and I believe he has six batteries that sit very low in the tracks to give him a low center of gravity and keep him from blowing over in the high winds.
NTB: What is your day-to-day work with GROVER?
Koenig: I actually, as a science advisor, do not work with GROVER on a day-to-day basis, but the students who have built him and are working with him are up in Summit, Greenland right now. Summit, Greenland is pretty much in the center of the Greenland ice sheet, at one of the highest points on the ice sheet.
In the mornings, right now, sometimes he’s sleeping outside and sometimes he’s sleeping in the garage still. They get up, they drive him around, doing the different tests. We have a list of things that we’re checking to make sure all the systems are operational. He has roved probably about 2 km right now, and we’re hoping to get him up into the hundreds of kms range by the end of the season.
NTB: And then, say, months from now, where do you hope to see GROVER?
Koenig: Because it is a testing season, we’ll keep him pretty much within a 50-km radius of summit. In future years, we hope to see him be able to rove all over the center of the ice sheet. As ice flows towards the edges, the ice sheets experience more melt. In Greenland, they have melt ponding, and they have crevasses. GROVER would never work in those areas, so the center of the Greenland ice sheet is the area that we would be expecting him to rove.
NTB: What kinds of teams are working on this project?
Koenig: The teams actually built the robot. There were actually two prototypes built in 2010 and 2011, and that was through the Goddard Engineering Boot Camps. They asked scientists for input on the robot building. I gave input on the robot building, and the students built the robots; I am not an engineer. So I would go over and look at the robots and give them ideas. I would give presentations to the students on the kind of science that I do, and give them requirements for building GROVER. So that’s how they got built.
One of the students was quite interested in polar research as well as robotics, and he decided to go to graduate school at Boise St. University, and he is the student who is kind of the lead on the GROVER project right now. He has been working with GROVER, so GROVER, though he was built by the big teams, is being continued by a smaller group.
NTB: And GROVER aside, can you talk about some of the exciting things you’re doing currently? Are there any other technologies that you’re working on?
Koenig: As a glaciologist, I always get to do quite exciting work. I travel quite a bit to the ice sheets of both Greenland and Antarctica to study how the surface processes are changing. Specifically, I look at accumulation and different melt that is occurring on the ice sheets. I get to go to the ice sheets, drive around on snowmobiles, take ice core [samples], and really learn about what is going on with surface processes and accumulation. I always try to relate that back then to the signals we see from space.
NTB: Are you talking about satellites?
Koenig: Yes, all of the fieldwork that I do is really to get better spatial validation of field measurements so we can use those with our satellite observations, and to develop better satellite algorithms. The ice sheets are very large places. Greenland is a third of the size of the US, and Antarctica is one and a half times the size of the United States. We can never monitor things that happen over them well if we’re not using satellites. We take ground measurements, and then relate those to our satellite measurements and continue to improve our satellite measurements so we can understand more holistically what’s going on with the ice sheets.
What is your favorite part of the job?
Koenig: My favorite part of the job is always doing exciting science and working with exciting people who are driven to look at Earth systems in new ways. GROVER was a very exciting project to me because I never thought about robotics. I usually drive snowmobiles, and it’ll keep my hands much warmer in the office if a robot can be dragging radars around. I think this is a really exciting project, moving ice sheet science and glaciology forward using robotics.
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