Figure 1: The Northwest Passage Drive Expedition (2009-2011) was a 750 km vehicular traverse across the Arctic carried out as part of the NASA Haughton-Mars Project (HMP) and led by HMP Principal Investigator Pascal Lee. During stops of the HMP Okarian rover on sea-ice along the expedition route, grit and snow samples were collected inside and around the vehicle to measure the extent to which human-associated microbes disperse onto the local pristine environment. The results, published by Andrew Schuerger and Pascal Lee in the June 2015 issue of Astrobiology, show that forward contamination of the arctic snow was extremely limited. (Photo Mars Institute/HMP/NWPDX/P.Lee).

Humans exploring Mars with pressurized rovers are unlikely to contaminate the planet biologically. So concludes a ground-breaking study by microbiologist Andrew C. Schuerger of the University of Florida and NASA Kennedy Space Center, and planetary scientist Pascal Lee of the Mars Institute, the SETI Institute, and NASA Ames Research Center. Their finding is reported in this month’s issue of Astrobiology, the leading peer-reviewed journal dedicated to advancing our understanding of life’s origin, evolution, and distribution in the universe.

From 2009 to 2011, Lee led, with support from the Mars Institute, the SETI Institute, and NASA, the Northwest Passage Drive Expedition, a record-setting 750 km crewed vehicular traverse in the Arctic. The goal of the expedition was to drive the Haughton-Mars Project (HMP) Okarian vehicle, a modified Humvee simulating a pressurized rover for future human Mars exploration, from the North American mainland to the HMP Research Station on Devon Island, High Arctic, by way of the Northwest Passage. The expedition took three field seasons to complete and was ultimately a success. “It was a challenging journey” recalls Lee, “but it taught us a lot about future road trips on Mars”.

During the 2009 field season, the HMP Okarian journeyed 500 km on sea-ice from Kugluktuk to Cambridge Bay, Nunavut, Canada, with multiple overnight and science stops. Along the way, samples of grit and snow were collected from inside and outside the vehicle to investigate whether, and the extent to which, human-associated microbes (bacteria and fungi) transported by the Okarian and her crew of five, might have found their way onto the surrounding pristine snow surface outside the vehicle.

Figure 2: A pressurized rover on Mars. Future human road trips on the Red Planet will likely not present a high risk of forward contamination. This is the conclusion suggested by the Arctic field study published by Andrew Schuerger and Pascal Lee in the June 2015 issue of Astrobiology. (Painting by P. Lee).

The samples collected by Lee were shipped frozen to Schuerger’s lab at NASA Kennedy Space Center for analysis. The result: only a minute fraction of microbial species identified on board the rover were detected outside the vehicle. “Forward contamination was surprisingly very low”, says Schuerger. “Furthermore, the number of microbial species inside the rover decreased over time, due to the expedition’s isolation and the harshness of Arctic conditions.”

The authors of the study conclude that given how much harsher the Martian surface environment is, compared to the Arctic, significant forward contamination of Mars during pressurized rover traverses, even with multiple stops and EVAs (Extra-Vehicular Activity or spacewalks), is unlikely.

The researchers acknowledge that theirs is a preliminary study, with so far only limited seed funding to enable it. “We need to remain cautious. More detailed studies are necessary to confirm our initial results” recognizes Lee. “But this early finding is cause for some encouragement and reassurance. Road trips on Mars might not automatically result in a planetary protection disaster”. Schuerger concurs: “I agree we need to remain careful, but this does bode well for the human exploration of Mars.” The scientists hope to be able to confirm these initial findings with additional field studies.

For more information:

Article in Astrobiology by Schuerger & Lee:

Schuerger, A. C., and P. Lee 2015. Microbial ecology of a crewed rover traverse in the Arctic: Low microbial dispersal and implications for human Mars missions. Astrobiology, 15(6), 478-491.


Andrew C. Schuerger: E-mail:

Pascal Lee: E-mail:

Northwest Passage Drive Expedition:

Polar Trek to Mars , a SETI Talk by Pascal Lee:

Mars Institute:

Christopher Hoftun, CEO, Mars Institute. E-mail:

About the Mars Institute

The Mars Institute is an international, non-governmental, non-profit research organization dedicated to advancing the scientific study, exploration, and public understanding of Mars. The Mars Institute conducts leading research in Mars Science and Exploration. The Institute also studies the Earth’s Moon, Near-Earth Objects, and the moons of Mars, Phobos and Deimos, viewed as key stepping-stones in the exploration of Mars. The Mars Institute is committed to conducting high quality peer-reviewed research and to sharing the knowledge and benefits of space exploration with students and the general public worldwide. Mars Institute USA is headquartered at the NASA Ames Research Park, Moffett Field, California, U.S.A. Mars Institute Canada is headquartered in Toronto, Ontario, Canada. Mars Institute Norway is headquartered in Stavanger, Norway. The Mars Institute operates the Haughton-Mars Project Research Station on Devon Island, High Arctic. For more information, visit: