Canadian science — in the form of a sensor that looks like the Rubik’s cube — is playing an integral role in the hunt for life on Mars.

On Nov. 26, an unmanned rocket, with a $2.5 billion nuclear-packed rover nicknamed “Curiosity” sealed safely inside it, blasted off from Cape Canaveral on a nine-month, 600 million kilometre space voyage that should reach Mars in August 2012.

“Science fiction is now science fact,” declared NASA Mars exploration program director, Doug McCuisition, after the takeoff.

Curiosity, the Mars Science Laboratory rover, is on a 23-month astrobiology mission to search for clues — such as organic carbon molecules and clay materials — to Mars’ past to determine if primordial life could have existed or might still exist. It is expected to roam up to a distance of 20 kilometres on Mars.

The most sophisticated robotic explorer ever built by human hands, it boasts a science toolkit housing 10 instruments to enable it to traverse the rugged Martian terrain.

One of those instruments is a made-in-Canada sensor called APXS, or an Alpha Particle X-Ray Spectrometer, designed to poke and probe the ancient Martian soil for any signs of past or present microbial life. Mounted at the end of the rover’s robotic arm, it is placed against the surface of a sample that is then bombarded with alpha particles and X-rays to assess its chemical composition and trace elements.

The Canadian-built spectrometer is the only instrument among the 10 that has history to it, having previously flown to Mars on the Pathfinder, Spirit and Opportunity missions. The one attached to Curiosity is an improved version, whose design and development was led by Dr. Ralf Gellert of the University of Guelph.

“We have increased the radioactive source, doubled it in fact, and also reduced the distance between the source and the sample being analyzed,” said Stéphane Desjardins, space exploration project manager at the Canadian Space Agency (CSA). “As a result, we expect faster returns that all add up to more science on the ground.”

The CSA managed the development and building of the instrument with MacDonald, Dettwiler and Associates Ltd. The Brampton-based company also designed and built the original Canadarm used in the U.S. space shuttle program.

Super rover Curiosity will scour Gale Crater — found near the equator of Mars — for remnants of ancient life, firing a laser at rocks and scooping up soil samples for instant analysis inside its six-wheeled mobile geology lab. However, it does not have the capability of detecting living organisms.

While Curiosity will be controlled from the United States, Canada’s home-made technology to be used on Mars, “will itself be run from our own country, the first time this has happened,” according to Alain Berinstain, the CSA’s director of science and academic development, in Saint-Hubert, Que.

Tipping the scales at 900 kilograms and standing over two metres high and almost three metres wide as well as long, Curiosity is bigger than any robotic surveyor to date. In perspective, it dwarfs the current robotic twin residents of Mars, Spirit and Opportunity, by twice their size and five times their mass. And Curiosity’s robotic arm has a reach of more than two metres.

Canada is returning to the Red Planet to plant the Maple Leaf. The red-and-white colours fluttered in the icy cold of Mars’s northern polar cap in 2008 as part of NASA’s Phoenix Mars Lander mission. At that time, the weather station with its lidar instrument, contributed by the CSA, revealed a startling discovery: it snows on Mars. Snowflakes were detected falling from clouds in Mars’ atmosphere about 4 kilometres above the spacecraft’s landing site.

This time around, though, has special meaning: the MSL Curiosity mission will signify Canada’s initial direct involvement investigating the Martian surface. “Deploying the APXS sensor,” said Berinstain, “will enable us to measure chemical elements that are present in the target selected by Curiosity and then see if water impacted it. And our scientists can remotely analyze these compositions back on Earth.”

About Canada’s commitment to space exploration and missions such as Curiosity to Mars, Berinstain is unapologetic: “The CSA follows the model of partnership. We realize that Canadian contributions are modest yet they represent a critical factor in the success of our joint missions. Our expertise is sought out by our partners worldwide, so we know our role is valued.”

And the price tag for Canada’s second trek to Mars?

According to Desjardins, his agency has invested considerable time and energy on the design, construction and operation of the trailblazing APXS device: “We delivered our geology instrument to NASA on time as contracted. The life-cycle cost to support the primary mission is $17.8 million and not a penny more.”

Asked if this is Canada’s final cost for a mission plagued by NASA cost overruns, he stressed that the CSA investment is ironclad and will not change.

Moment to watch in Mars mission

Now that Curiosity is safely Mars-bound, the focus shifts to what many consider the riskiest part of the Mars Science Laboratory mission: touchdown of the spacecraft after it carefully executes a six-minute plunge to its new home, the crater floor.

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Because Curiosity is one very heavy piece of hardware, NASA has adopted an innovative rocket-powered “sky-crane” approach for the rover’s descent to the rock-strewn Martian surface, instead of using traditional airbag or thruster-rocket landings. Depositing it into the Gale Crater will be like lowering a tank onto the floor of the Grand Canyon by helicopter.

While it sounds simple enough, this rover-delivery-by-stork method promises to be the most nerve-racking moment of the mission to Mars. It will also be some of the most exciting minutes for space watchers everywhere. : “NASA . . . has practiced this sky-crane manoeuvre over and over,” Berinstain said. “We are confident Curiosity will enjoy a safe and successful descent.”

Communications with the fourth planet from the Sun are not instantaneous; one-way radio transit time will take nearly 14 minutes to reach Earth from Mars. . . so the public will have to hold its collective breath as a new chapter in the drama of Martian exploration unfolds.