Physicist to Showcase U of G Work With Mars Rovers

October 16, 2009 - News Release

A University of Guelph physics professor will join some of the world's leading scientists, thinkers and writers in the fields of physics and space exploration at this month's Quantum to Cosmos Festival, hosted by the Perimeter Institute for Theoretical Physics in Waterloo.

Prof. Ralf Gellert, who is lead scientist for the alpha particle X-ray spectrometer (APXS) on board the Mars Exploration Rovers Opportunity and Spirit, as well as the next rover, Curiosity, scheduled for launch in 2011, will be a featured guest in an Oct. 24 panel discussion titled “Worlds Beyond Earth.”

“This is a great opportunity to showcase the exciting contributions being made by U of G researchers in exploring the solar system and understanding our place in the universe,” says Gellert. “I’m especially looking forward to seeing the full- sized model of the new rover that will be on display. I’ve been involved in this project for several years, and this will be the first time I’ve seen the complete vehicle.”

The pop-can sized APXS, mounted on the rover’s robotic arm, uses X-rays to examine the chemistry of rocks and soil in search of signs of water, salts or elements that would indicate Mars may have, or once had, the necessary ingredients for life.

The 10-day festival, which celebrates Perimeter’s 10th anniversary, runs until Oct. 25 and features hands-on exhibits and presentations, lectures, a film festival, concerts and other arts and cultural events.

It’s a high-profile opportunity for one of Canada’s quiet success stories in space exploration and comes nearly a year after Gellert and his team delivered the “new and improved” APXS to the National Aeronautics and Space Administration’s Jet Propulsion Laboratory in Pasadena, Calif. The new Mars Science Laboratory (MSL) rover mission had been scheduled to launch this fall but has been postponed until the next launch window opens in March 2011.

Gellert’s team, which includes scientists at U of G as well as Canadian and international partners, has made the most of the delay.

“It’s still a busy time,” he says. “We have two working instruments on Mars that continue to deliver exciting new data. Plus, we have more time to prepare for MSL with a model of the new device in our lab, where we are doing calibrations 24/7. Working with Prof. Iain Campbell’s group here at Guelph, we are improving our methods and data analysis, which also benefits the analysis of existing data from Mars.”

The new APXS incorporates lessons learned from the previous rover missions. It can take measurements three times faster, assess light compounds such as water better and operate in a wider range of temperatures, day or night.

Gellert is also responsible for the day-to-day APXS operations on Opportunity and Spirit. The rovers were expected to last only a few months after they landed in early 2004, but they continue to function more than five years later, exploring the Martian surface, taking and analyzing samples and sending new data back to Earth.

“Whenever I see new data from Mars that indicate the instruments still work, I am relieved, thinking of the hundreds of electrical connections I soldered back in 2002,” says Gellert. “The instruments are exposed to the harsh Martian environment, where the temperature goes from around -80 C to 0 C each day.”

The team is still poring over data received this summer when Opportunity discovered a pumpkin-sized rock (about 60 centimetres in diameter and weighing half a ton) that may provide valuable clues about the red planet’s environmental history.

“There’s no question that it’s an iron-nickel meteorite,” says Gellert. “We already investigated several spots that showed intriguing elemental variations on the surface. This might tell us if and how the metal was altered since it landed on Mars.”

The rock is bigger than any other meteorite found on Mars so far. It’s too massive to have hit the ground without disintegrating unless, when it fell, Mars had a much thicker atmosphere than it has now. Atmosphere slows the descent of meteorites. Additional studies may also provide clues about how weathering has affected the rock since it fell.

Two years ago, Gellert, Campbell and colleague Prof. Joanne O’Meara found the first “on-the-spot” evidence for water on Mars bound up in subsurface salty soil churned up by the rover Spirit.

The next-generation rover is twice as large and is designed to carry 10 times the science payload of its predecessors. Curiosity will also be able to travel longer distances over rougher terrain.

“It’s a much more robust and more mobile scientific lab,” says Gellert. “Instruments inside the rover’s belly can investigate powdered samples in depth for mineralogy and organic matter. The APXS will play a key reconnaissance role to quickly measure and select the most interesting samples the rover comes across. Then the sample processing begins, and instruments inside the rover do the detailed work, which will take days and even longer.”

For more information, contact U of G Communications and Public Affairs: Lori Bona Hunt, 519-824-4120, Ext. 53338 or, or Barry Gunn, Ext. 56982 or

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