The trek across the Antarctic ice sheet is a long, hazardous, and costly journey for scientific researchers working in the world’s most remote location. Astronomers, geologists, and biologists regularly spend much of their field season and over 70% of their hard-earned grant money on logistical support – an intricate choreography of supply planes, snowmobiles, and tractors meant to move gear to where it needs to be.
One of the most significant time sinks is the crevasse-detection process, which involves a massive snowcat tractor treading its way slowly across the ice. As Laura Ray, a Professor of Engineering at Dartmouth College, describes it, a 6-meter long pole extends from the front of the vehicle with a ground penetrating radar (GPR) instrument at its end. As the driver inches forward, the system surveys the subsurface like a metal detector-wielding beachcomber tentatively looking for buried treasure. Sitting nearby is a technician, eyes glued to a screen that displays the GPR data in real time. Inch by inch, data streams across the monitor: if the look-out thinks it indicates a crevasse, she has two seconds to press an emergency stop button. Making the right choice could be the difference between smooth passage and a costly, time-consuming, dangerous crash.
It’s an important and likely life-saving program – one born from frightening mishaps – but it soaks up a lot of time. “It’s tedious and tiring,” says Ray, “and there are few people that do it well.”
Extreme conditions, long hours, and tedium: just the job for a robot. Ray and her colleagues have spent years developing such a tool, and the latest edition of the Yeti autonomous vehicle offers important financial and scientific benefits.
The South Pole Traverse (SPoT) is a 1660-kilometer slog from McMurdo Station – the primary American base in Antarctica – to the South Pole. The most dangerous leg of the journey is a 6-kilometer wide shear zone, where cracks in the ice form as the Ross and McMurdo ice shelves scrape against each other, but GPR surveys must precede travel along the entire route. Ray explains that roboticizing the traverse would render air support unnecessary and facilitate more trips than the tractor method allows, generating cost savings of roughly $4 million per year.
The financial implications were anticipated when the program began; less apparent were the scientific advancements that Yeti has brought to the table. The robot and its on-board software is particularly adept at identifying crevasses when approached from a shallow angle – something human operators have struggled with. A more complete data set is giving glaciologists the data to, as Ray says, “look at the migration of the crevasse field over time as an indication of the condition of an ice sheet – is it stable, or chaotic, and could it calve off?”
The GPR front end is customizable, opening the door to other research projects. The current radar has a 400 MHz antennae, penetrating 15 meters into the ice, but other instruments could look deeper or provide higher resolution at shallower depths. Scientists have recently discovered signs of a complex, high-flux network of subglacial rivers; perhaps a team of autonomous Yetis will one day provide a detailed map of this hydrologic system.
If tools such as Yeti prove proficient at both facilitating research and collecting data, Ray’s Antarctic work could preview a new era in the relationship between human scientists and robotic field assistants, one that may eventually play out on the surface of Mars.