For the past month, a sterile vacuum chamber at the University of Guelph has served as a stand-in for the surface of Mars
Scientists needed to mimic the thin Martian atmosphere to conduct realistic tests on a new piece of space hardware that represents Canada's next major contribution to the exploration of the Red Planet.
The ingenious device, known as an Alpha Particle X-Ray Spectrometer (APXS), is smaller than a pop can, but it accurately measures the composition of soil and rock samples - data that may eventually help to unlock the secret of whether Mars ever has or ever could support life.
If everything goes according the plan, the finished version of the device will be attached to the robotic arm of a six-wheeled U.S. rover that will be launched from Cape Canaveral, Fla., next year and land on Mars in 2010.
Similar devices have been part of earlier rover missions. But the Canadian-built hardware will be the most sophisticated APXS unit yet sent to Mars.
"It's better, faster and more precise," said Ralf Gellert, an assistant professor at the University of Guelph and the scientist overseeing Canada's part in the U.S.-led space venture.
The new rover, called the Mars Science Laboratory, will be huge - measuring 2.8 metres (nine feet) in length and weighing 775 kilograms (1,700 pounds). That makes it twice as long and about four times as heavy as the twin rovers Spirit and Opportunity that continue to roam the rust-coloured Martian landscape.
The massive rover, jam-packed with a payload of scientific instruments from a variety of countries, will be searching for signs of Martian microbial life - either past or present.
"If you have more instruments, you have less time per instrument and therefore we had to make improvements to fit into the more hectic schedule of scientific investigations," Dr. Gellert said.
He noted that previous versions of the APXS often required eight to 10 hours to analyze one sample. The new model should be able to do the job in two or three hours.
Dr. Gellert certainly has the expertise to make those instrument changes. He used to work at the Max Planck Institute for Chemistry in Germany, where the APXS units for previous Mars rovers were designed and tested.
"My former boss, Rudi Rieder, is often called the grey-haired wizard of the APXS," said Dr. Gellert, who is a physicist by training. "I was more or less his actual hands and put together the electronics, wrote the software and did the calibrations to make it work."
However, Dr. Rieder retired in 2005 and the Max Planck Institute decided to close its cosmic chemistry division. As a result, Dr. Gellert needed a new academic base if he was going to carry on the APXS tradition.
And that's when Iain Campbell, a University of Guelph professor, stepped in.
Dr. Campbell is a leading expert on the interpretation of APXS data and had worked closely with the Max Planck team on previous Mars missions.
He helped Dr. Gellert secure a post at Guelph. At the same time, the two scientists approached the Canadian Space Agency to finance the development of a new, improved APXS system for the next generation of Mars rovers.
The CSA agreed to put up the $10-million for the project. MDA, the same company that built the iconic Canadarm for the space shuttle, won the contract to fabricate the piece of high-tech hardware.
And now, Dr. Gellert and fellow researchers at Guelph are frantically running tests on an engineering model so that the real device will be ready for launch next year.
The device essentially works by blasting geological samples with both alpha particles (a type of high-energy helium nuclei) and X-rays. Atoms in rocks are excited by the bombardment and, in turn, emit their own X-rays at specific energy levels. A special detector in the APXS picks up distinctive X-rays that can be analyzed to determine the different atomic elements in the rock. The alpha particles are particularly suited for revealing the presence of lighter elements such as sodium, aluminum, magnesium and silicon. X-rays, on the other hand, work best for revealing heavier elements, including iron, nickel and bromine.
To prepare for the mission, an engineering model of the APXS device is being put through "calibration" tests in the Guelph vacuum chamber. "We take measurements of known materials and see what signals we get," Dr. Gellert explained.
By comparing these readings with those eventually transmitted from the rover, scientists will be able to infer the mixture of elements in the Martian rock and soil samples.
Such data can tell scientists how the material originally formed and if it was later altered by wind, water or ice. Other instruments on the rover can then probe promising samples for the presence of organic molecules - essential clues to the possibility of life on Mars.
For instance, when the Opportunity rover encountered spherical pebbles embedded in bedrock, its onboard APXS was used to decipher the significant geological find. "We determined they were rich in iron and nickel," Dr. Gellert recalled.
Similar spheres are formed on Earth when free-flowing water reacts with minerals in the rocks. So scientists could safely assume that the Martian spheres must have formed in water too. And that means the APXS has provided convincing evidence that the now-arid surface of Mars was once a much wetter place.
Could life forms have existed in those ancient pools near the Opportunity landing site? If they did, the Martian microbes would have been extremely hardy to survive in those hostile conditions, Dr. Gellert noted. Based on the mineral analysis of the surrounding rocks, "it wasn't fresh water - it was more or less sulphuric acid brine," he said.
The new rover should hopefully unlock more of the Red Planet's secrets. And Dr. Gellert will be ready for the unexpected. In fact, a duplicate version of the APXS device will be kept at his lab in Guelph.
If the rover encounters some inscrutable sample during its Martian odyssey, he and his team can run simulations on the mock-up model to help to make sense of the results.
"Everyone agrees we will need an instrument here to do measurements during the mission operations," Dr. Gellert said. "It makes all the sense in the world," he said, especially when that world happens to be another planet.
Paul Taylor is a Globe and Mail writer and editor.