Summit Camp, Greenland--The guts of a thermal drill spilled out over a table and onto the wood-planked floor of a domed five-person tent. Five highly caffeinated planetary scientists from the Jet Propulsion Laboratory in Pasadena, Calif., continued updating the 122-centimeter-long, 7.6-centimeter-wide device with the software, firmware and hardware needed for its first field test. A square hole cut in the floor revealed the material that would serve as a Martian analogue.

The mission: to have the device, named Chronos, melt its way into Earth's ice sheet above the Arctic circle as a test of its worthiness for the coveted NASA mission to Mars in 2011. If chosen, Chronos would drill into our neighbor's northern ice cap. "Ice is probably the only accessible climate record on Mars; if there is a climate record, it is preserved in those ice caps" as variations in isotope abundance, explains lead engineer Greg Cardell.