Rover Uncovers New Clues About Mars, Prof to Discuss at ‘Space Day’

May 28, 2012 - Campus Bulletin

It took many years to get there, but it was worth the wait for more evidence of a once-wetter Mars provided by the Martian rover Opportunity, says University of Guelph physics professor Ralf Gellert. Exploring the rim of an ancient crater, the rover has found new clues about water’s early role on Mars and pointed the way for investigations by Curiosity, a new rover landing on the red planet this summer.

The new findings are discussed in a recent paper co-authored by Gellert and published in the journal Science.

Gellert will also discuss his research June 2 at 1:30 p.m. during U of G’s first “Space Day" in Rozanski Hall. The event features NASA astronaut Mike Good and Bob McDonald, host of CBC Radio’s Quirks & Quarks and will showcase space research in various disciplines across campus.

Opportunity drove 15 kilometres over several years to reach this area, after spending its time since landing in 2004 on a dried-out salt lake full of sulphates,” said Gellert. He is the lead scientist for an instrument called an alpha particle X-ray spectrometer (APXS) mounted on Opportunity. The pop can-sized device measures the chemical composition of rocks and soils.

“This is the very first time that a rover is driving into a region where evidence from orbit for clay and sulphate minerals is seen,” said Gellert, who also heads the international team that developed the new rover’s APXS instrument.

No previous Mars mission had found evidence of clay minerals, common in soils on Earth. “This would a be a big step in our understanding of Mars since it would point to warmer, wetter conditions in the first one billion years of Mars and imply a thicker atmosphere needed to form these minerals.”

Opportunity has explored part of the rim of the 10-mile-wide Endeavour Crater, created by a gigantic impact billions of years ago.

Lacking sulphates found elsewhere on Mars, the rock on the crater edge appears older than the surrounding bedrock and was probably brought to the surface by the impact. It also hints at the effects of water, unlike extremely acidic brine that made the surrounding sulphate bedrock.

Veins of gypsum (used in drywall on Earth) identified by the rover’s APXS probably formed as water-borne sediments in cracks in the rocks.

Scientists now hope to use the rover to investigate likely locations for clay.

“Although Opportunity is way past its warranty, and the mineralogical instruments are not working anymore, it still can take pictures and investigate the chemical composition with the APXS,” Gellert said.

“I see Opportunity even in its current state with severe limitations as a valuable dry run for what we might expect with Curiosity.”

Formally called the Mars Science Laboratory, the new minivan-sized rover will be the largest and most sophisticated piece of equipment ever landed on Mars. It is scheduled to land in August on the 3.5-billion-year-old Gale Crater, where a Mars orbiter has also detected evidence of clays and sulphates.

“There is an analytical lab in the rover’s belly that will be able to investigate selected samples in unprecedented mineralogical and compositional detail to shed more light into the early history of Mars,” Gellert said.

For the Curiosity mission, the Guelph team will support the APXS operations and send instructions for operating the device on the rover. The team will run day-to-day operations and analysis from a specially equipped centre in the MacNaughton Building.

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