Alien forecast

Alien forecast

By measuring weather in the Martian arctic, Canadian scientists help determine potential life on Mars
May 23, 2008
Illustration of the Phoenix lander

Illustration of the Phoenix lander
NASA Jet Propulsion Laboratory, University of Arizona

Today's forecast calls for zero chance of precipitation, with temperatures between minus 40 to minus 70 degrees Celsius. Look for small ice crystals forming in the early morning, but disappearing as the wind picks up later. The sky will get dusty by afternoon, blocking out most of the sunlight, but it will settle down by evening.

Where on Earth would you hear such a forecast? Nowhere, actually. Instead, it's what the Canadian Space Agency (CSA) and several Canadian scientists anticipate when they send the first-ever Canadian weather instruments to the Martian arctic this month.

The instruments make up part of NASA's Phoenix Mars Lander mission. Previous orbiters found evidence of water on the Red Planet, but Phoenix aims to prove actual water sources exist.

Why the search for Martian water? Not only is water crucial for any future manned missions, but such a discovery on the surface of Mars could indicate Martian life. Scientists have found microbial life in extremely hostile environments that had but a few drops of water, leading to the conclusion that where there is water, there is life.

While the Lander looks underground, the Canadian contingent will search the skies. The main instrument of the CSA weather package is a LIDAR—a radar device that uses laser light instead of sound.

"Canada has a very solid reputation as a pioneer in LIDAR technology that has a huge amount of applications."

The head of the Canadian weather team, Dr. Jim Whiteway, a professor at York University in Toronto, says the LIDAR's measurements of atmospheric dust are fundamental to understanding Martian weather and determining if water (or life) could exist. The LIDAR will also be used to detect any clouds in the Martian arctic. Cloud formation and dust are key ingredients affecting Martian temperature. By better understanding these factors, scientists will be able to determine if water in liquid form and not ice can exist on the planet's surface and for how long.

"The climate models being developed don't know how much dust there is, how high the dust goes, or if the dust settles down at night. The temperature on the surface is determined by the amount of light that makes it to the surface, so on a dusty day, it can be 40 degrees colder," Whiteway explains. The colder it is, the more likely there will be ice and not water.

Whiteway previously used LIDAR in the Australian outback to determine how dusty conditions affected weather, and he also uses LIDAR in the Canadian Arctic to measure ice and snow in the atmosphere. "In the Arctic, we get ice fogs and diamond dust where ice crystals fall through the sky even though there are no clouds," he says. "We're hoping and expecting the measurements [on Mars] to look familiar."

Beyond the complex tasks of gathering weather and water data, the biggest challenge of all will be simply getting to Mars. But NASA and the CSA are both confident the Pheonix will proceed as planned, particularly after having MacDonald, Dettwiler and Associates Ltd. (MDA) Space Missions—known for its work on the Canadarm—build and test the Canadian weather package.

"For space systems, we do two main tests," says Michael Daly, a space engineer at MDA in charge of Phoenix. "We do a shaker test where we try to shake its guts out, similar to the vibration spectrum of the launch vehicle." Then MDA conducts thermal testing, which for Phoenix involved testing in a vacuum with a one percent carbon dioxide atmosphere to recreate the surface of Mars. This was unlike any other procedure MDA had done before.

Testing the LIDAR was no simple feat either. Whiteway and his team had to create an environment where the pressure was 100 times less than on Earth and the temperature was minus 70 degrees Celsius, and then point the LIDAR off a mirror and out a window into the atmosphere. "It was probably the hardest thing I've ever done," says Whiteway.

As a result of the experience gained in preparation for the Phoenix mission, MDA and the CSA have already teamed up to participate on a robotic geologist for 2009's NASA Mars Science Laboratory rover. According to Victoria Hipkin, CSA program scientist for planetary exploration, "Canada has a very solid reputation as a pioneer in LIDAR technology that has a huge amount of applications. Now it's being used to detect clouds on Mars as the first ground-based laser to work on another planet. It's a Canadian niche,†she affirms.

Space scientists from around the world will have their eyes on the Phoenix when it reaches Mars on May 25. The Canadian weather instruments should start running a few days after landing and continue until the end of the mission three months later. With any luck, the weather forecast will be wet.