Zoë, the first robot to map microbial life during a 2005 field expedition in Chile’s Atacama Desert, is returning for another go-around. This month, on a NASA astrobiology mission led by Carnegie Mellon University and the SETI Institute, the autonomous and solar-powered robot is headed back into the world’s driest desert equipped with a one-meter drill to search for subsurface life.
As in the initial mission, Zoe will be testing new technologies and techniques necessary for exploring life on Mars. These new technologies will help NASA decide how to equip the rover set to follow in Curiosity’s tracks, finding life-friendly areas on Mars, in 2020.
“Direct evidence of life, if it exists, is more likely underground, beyond the current reach of rovers,” said David Wettergreen, research professor in Carnegie Mellon’s Robotics Institute and the principal investigator for the Life in the Atacama project. Zoë has been fitted with a drill made by Honeybee Robotics than can bore deep into the ground to search for those signs. “Chances improve with greater depth but we are first developing one-meter capability and integrating with a mobile robot,” Wettergreen added.
The robot will dredge up soil samples using the auger and analyze them with several on-board instruments, including the Mars Microbeam Raman Spectrometer. The Spectrometer, an early candidate for the 2020 Mars mission, can analyze mineral and elemental composition of soil.
“We are measuring the subsurface habitats in which life survives, determining what factors are important, and learning about one of the Earth’s harshest climates,” said Planetary Geologist Nathalie Cabrol, senior research scientist at the Carl Sagan Center of the SETI Institute. Cabrol is the science lead for the Life in the Atacama project.
The project collaborators include Honeybee, the Universidad Catolica del Norte in Chile, the University of Tennessee, Washington University and the Jet Propulsion Laboratory (JPL).
In the first year of the three year project, the team visited a variety of sites in the Atacama without Zoe, using a neutron detection instrument that measures hydrogen abundance to quantify moisture. They also tested several spectrometers to measure mineral and elemental composition of soils, and other instruments, including boring holes with hand-held drilling equipment and manually operated instruments.
These findings will provide a comparison to what the robot can do automatically during field experiments over the next two years.
The team confirmed the presences of microorganisms are present in the Atacama soils, even though they are extremely scarce. They also discovered a problem with one of the instruments, called the Dynamic Albedo of Neutrons (DAN). The radioactive tritium in the DAN’s neutron generator had decayed to the point that it could no longer function. NASA had planned to use an identical DAN that is already onboard Curiosity later in the mission, but the Atacama test revealed that the instrument would not survive as long as planned.
In preparation for two weeks of scientific field experiments, Zoe will undergo engineering tests in Chile this week. The robot will venture into the desert on Jun 17 and will cover an 18-30 mile journey in the hyper-arid core of the desert. The team anticipates one to two drilling operations each day. They will be posting updates during the experiment timeframe on the project website.
Zoë’s previous expeditions have focused on technology for autonomous operation for the robot. Wettergreen said that this expedition’s focus will be on gathering scientific data. “Now, we think of the robot as a tool to collect specific data from specific locations, rather than as a machine that drives around,” he said.
A specific goal of the project is to have multiple days of completely autonomous operation executing the scientists’ plans regarding where they want the robot to go and how much data to collect at each point. Zoë will then hibernate for the night and automatically resume its plan when the sun returns.
A four-wheeled robot approximately nine feet long and six feet wide, Zoë is powered by a solar array measuring three square meters that lies flat atop its body, generating power with high-efficiency gallium arsenide solar cells. The robot operates primarily during the day due to being totally solar powered, though they do anticipate it doing some processing of scientific samples overnight.