Feature
Robotic Rovers to the Rescue
05.13.08
Who Are NASA's Earth Explorers?
The elementary school student questioning if El Niño occurs anywhere besides the Pacific Ocean. The researcher investigating connections between Arctic ozone depletion and global climate change. The citizen scientist interested in how changing land cover and use affects animal migration patterns. And the businessperson projecting future needs for harvest, delivery and storage of crops. All of these people are Earth Explorers -- they are all connected by their curiosity about Earth system processes. This monthly series will introduce you to NASA Earth Explorers, young and old, with a variety of backgrounds and interests.
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Derrick Lampkin trudges through snow on Niwot Ridge, a high-elevation research site about 20 miles west of Boulder, Colo. Image Credit: Derrick Lampkin
For scientists studying ice in extreme environments -- in places like Antarctica and Greenland -- the harsh, subzero setting poses a unique set of bone-chilling challenges. Derrick Lampkin is doing what he can to make these challenges a bit less daunting. With a grant from NASA, the Penn State University geography professor is designing robotic rovers to help scientists study icy locations from the comfort of their laboratories.Lampkin’s rovers are small, suitcase-sized machines with instruments packed inside them. They will be wirelessly controlled -- deployable by researchers from anywhere in the world. Lampkin imagines the rovers will scuttle to spots on the ice that are of specific interest to researchers. There, the rovers will measure atmospheric conditions as frequently and for as long as they are told.
Scientists could use data collected by the rovers to learn more about the vast ice sheets that cover Antarctica and Greenland. They could also use the rovers to study ice shelves -- the portions of the ice sheets that extend out over the ocean.
The ice at Earth's poles is a critical part of the planet's climate system, and studying it has become imperative for climate scientists. This research has taken on a new urgency in recent years because of rising global temperatures. Polar ice is now melting faster than scientists thought possible.
A major portion of the world's fresh water is locked up in the kilometers-thick ice sheets that cover Antarctica and Greenland. Scientists fear that the melting ice could raise sea levels, affecting coastal communities around the world. Disappearing ice sheets could also speed up global warming. Ice reflects some of the solar radiation falling on the Earth. But as the ice melts, the darker surfaces underneath absorb more energy from the sun.
Lampkin and other scientists want to know the answers to some vital questions about the ice: How much are the ice sheets shrinking? How fast is this change happening? Where is the ice melting the most? What factors are affecting this melt?
Wirelessly controlled instruments that measure the atmosphere will be carried across icy terrain by a moving platform that uses tracks similar to an army tank. Image Credit: Derrick Lampkin
The rovers could help them answer these questions by observing the atmosphere above the ice. Lampkin explains that the atmosphere and ice are closely connected. For example, the ice sheet absorbs energy in the form of light and heat from the atmosphere, which causes the ice to melt. On the other hand, snow that falls from the atmosphere adds to the ice sheet's mass."Things like the direction of the wind, wind speeds, the temperature of the atmosphere can all influence the health of the ice sheet," Lampkin added.
The rovers will measure solar energy, air temperature, wind speed and wind direction, as well as changes in atmospheric pressure. Right now, automatic weather stations collect this data. The stations are spread out all over Greenland and Antarctica, spaced far apart to span as much territory as possible. But sometimes there is a gap in coverage just where a scientist needs to measure local weather conditions.
For instance, Lampkin said, the western part of Greenland's ice needs extensive study. There, as ice melts, the water percolates down toward the land underneath. Glaciers can slip on this water layer and move toward the ocean faster, raising the sea level.
Another deficiency in automatic weather stations is their inability to monitor floating ice shelves. These shelves act as dams to keep glaciers from falling into the ocean: Sea levels would rise if the shelves were to disintegrate.
The rovers will be an extension of the automatic weather stations, according to Lampkin, with the key difference being that "scientists would have much more control over where these devices go or how long and how often they monitor."
In the future, Lampkin imagines a few rover stations, scattered across icy expanses, where rovers could be charged and stored safely. A scientist could go online and command the rovers to maneuver from the station to a certain spot and take measurements every day for, say, a month. "Teachers and students could also use the rovers for projects to study the ice sheet and how it is changing," Lampkin said.
The rovers consist of two main components: a moving platform and the instrument package. The moving platform uses tracks similar to an army tank so that it can move over rough, icy terrain. The instrument package goes on top of this platform.
But things are not that simple. Lampkin and the group of mechanical engineering students who designed the rovers had to keep special requirements in mind.
The first challenge was that the instruments must be at least 1.5 meters (4.9 feet) above the ice surface to take accurate atmospheric measurements. That means putting the instruments on a mast. But the mast cannot be up when the rovers are moving. So the researchers had to design the rovers to keep the instruments covered when moving, and raise the mast with the instrument package when stationary.
Second, the rovers must be able to withstand harsh, icy conditions. The track system is designed to move over snow and ice, and the mast and instrument packages are designed to bear high wind velocities without breaking. In addition, Lampkin said that the researchers are building a shell around some of the components to protect some of the electronics from wind and snow.
A few more challenges remain for Lampkin and his students to tackle. They need to combine the rover's moving platform and instrument package with the power systems. Then, they will test the rovers at an alpine research site near Denver, Colo., where the conditions are very similar to the Antarctic. The rovers should then be ready to set out on their icy missions.
Lampkin's research is supported by a grant under NASA's Advanced Information Systems Technology program. Please visit http://education.nasa.gov/edprograms/fellowgrants/index.html for a complete list of NASA grants and fellowships.
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