From all of the data collected and scientific discoveries made recently on Mars, some simple conclusions can be made about what life, if there was any, would have been like on the red planet, said a professor involved in NASA’s ongoing rover missions.

“It would have been smelly and acidic, and the pH levels would have eaten your feet,” said Raymond Arvidson, deputy mission scientist, NASA Mars Exploration Rovers, and professor in the Department of Earth and Planetary Sciences at Washington University in St. Louis. “You wouldn’t want to have been there when this environment was happening.”

Arvidson spoke at the Department of Atmospheric, Oceanic and Space Sciences (AOSS) seminar series April 16. In a speech that was part of the AOSS Mars Exploration Celebration, he detailed the journeys of the Spirit and Opportunity rovers, which landed successfully on Mars and began their work earlier this year.

“January was a historical time period, and a very exciting time for me and my colleagues,” Arvidson said. “We had a bet among us that if we would have one successful landing, we would not hear from the other one at all. So, having two successful landings was remarkable.”

Arvidson said both rovers have exceeded expectations—and warranties, if they would have had them. He said the missions were expected to last 30-60 days, but passed 100 sols last week (a Mars sol, or day, is equal to 1.08 Earth days). Arvidson added that the missions have secured funding through September.

“We went to Mars to find evidence of water to understand its past,” Arvidson said. “We are still looking, but there is some indication that it has been there.”

The first rover, Spirit, landed in Gusev Crater Jan. 3 and has traveled more than 700 meters, Arvidson said. It has explored mostly rocks, but scientists will drive it to the nearby Columbia Hills, arriving sometime in June. The hills have the best chance of providing evidence of water on Mars, he said.

The second rover, known as Opportunity, landed Jan. 24 in Meridiani Planum, where Arvidson said it has found textural, mineralogical and chemical evidence of surface water. Opportunity recently shattered the record for a single day’s drive—140.9 meters (462 feet). He said the goal was to log 40 meters per day.

Both rovers continue to take rock and soil samples while digging and marking up the landscape. Arvidson showed photos of tracks, holes and trenches made by the rovers while navigating the planet’s surface.

“If Mars were a national park, we would be in trouble right now,” he joked. “But Mars will probably have no trouble repairing itself over many thousands of years.”

In the question-and-answer period, Arvidson fielded a query about sending humans to Mars. He said humans would do better traveling longer distances on the surface—the rovers travel on only 100 watts of power, similar to a light bulb—but that the ability to examine many working hypotheses is better suited for robotics.

Arvidson said the right mix is important.

“As we get more information about the past climate of Mars, then there will be any number of humans who will want to go there,” he said. “But it is a matter of national and international priorities.”

Information on the Mars rover missions can be found at http://marsrovers.jpl.nasa.gov/home/index.html.