March 20, 2013
NASA’s Mars Science Laboratory (MSL, also known as Curiosity rover), was sent to answer a simple question: Was Mars ever hospitable to life? The recent discovery of life-supporting chemical ingredients in a rock sample drilled by the rover on the Red Planet suggests scientists finally have an answer.
Curiosity relies on a suite of science instruments to acquire information about the geology, atmosphere, environmental conditions and potential biosignatures on Mars.
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Arizona State University professors, researchers and students from the School of Earth and Space Exploration, as well as alumni, are involved with several of the rover’s instruments.
Professor Meenakshi Wadhwa is a collaborator with the Sample Analysis at Mars (SAM) instrument, essentially an analytical chemistry system. Located inside the rover, SAM examines the chemistry of samples it ingests. Wadhwa is one of the scientists who guides Curiosity to interesting targets and interprets data from the mission. Amy McAdam, an ASU alumna, also is working on SAM.
Professor Jack Farmer is a science team member for Chemistry and Mineralogy (CheMin), which is designed to examine the chemical and mineralogical properties of rocks and soils. Over the past few months he has been supporting mission operations (mainly the CheMin instrument team and as a Geology Theme Group participant), planning observations and analyzing downlinked data.
Last week, the rover’s science team announced that an analysis of rock by the SAM and CheMin instruments indicates that past environmental conditions were favorable for microbial life.
“CheMin’s initial analysis of a core taken from the Yellowknife Bay bedrock site has confirmed the presence of up to 20 percent by weight phyllosilicates (clays), minerals that require water for their formation. This has significantly advanced our understanding of habitable environments at Gale Crater earlier in the history of Mars,” said Farmer.
A picture is worth a thousand words
The rover also carries a state-of-the-art imaging system comprised of 17 cameras. Professor Jim Bell plays a leading role in the targeting and interpretation of images recovered from the science cameras – Mast Camera (Mastcam), Mars Hand Lens Imager (MAHLI), and the Mars Descent Imager (MARDI).
The rover’s Mastcam, which takes color images and color video footage of the Martian terrain, can also serve as a mineral-detecting and hydration-detecting tool, reported Bell. “Some iron-bearing rocks and minerals can be detected and mapped with Mastcam’s near-infrared filters,” he said.
Using both the infrared-imaging capability of Mastcam and another instrument that shoots neutrons into the ground to probe for hydrogen, researchers have found more hydration of minerals near the clay-bearing rock than at locations Curiosity visited earlier.
Ratios of brightness in different Mastcam near-infrared wavelengths can indicate the presence of some hydrated minerals. The technique was used to check rocks in the Yellowknife Bay area where Curiosity’s drill last month collected the first powder from the interior of a rock. Some rocks in Yellowknife Bay are crisscrossed with bright veins.
“With Mastcam, we see elevated hydration signals in the veins that we don’t see in the rest of the rock,” said Melissa Rice, a postdoc at the California Institute of Technology and one of Bell’s former graduate students. “The bright veins contain hydrated minerals that are different from the clay minerals in the surrounding rock matrix.”
Bell’s research program was responsible for developing the “hydration index” results that Rice presented March 18 at a news briefing at the Lunar and Planetary Science Conference in The Woodlands, Texas.
Professor Alberto Behar is co-investigator on DAN, the Russian-made Dynamic Albedo of Neutrons instrument, which detects hydrogen beneath the rover. Behar is part of the team defining what the DAN instrument does on a sol to sol basis, developing the commands for new investigations, and analyzing the telemetry data to determine the state of health of the instrument.
“Variability in DAN data has been used to identify when we have crossed into a compositionally unique terrain. It has measured the highest water content on terrain traversed to be 7 weight percent water,” said Behar.
On the home front
Not all the fun is 200 million miles away on the Martian surface. Bell, research staff member Austin Godber, and a group of undergraduate and graduate students are developing key parts of the Mastcam color image data-processing pipeline at ASU. Similar data processing work is also going on at ASU for images streaming back from NASA’s older rover, Opportunity, which landed in 2004 but is still operating well. Bell is the lead scientist for Opportunity’s Pancam stereo color imaging cameras.
The rover camera work involves analyzing images of the Mastcam and Pancam color calibration targets and developing computer routines that allow the results from those cal-target images to be applied to images of soils, rocks, and mountain scenes in Curiosity’s Gale Crater field site and along Opportunity’s traverse in Meridiani Planum, half a planet away from Gale Crater.
“We brought swatches of known colors with us to Mars. If we process the images to get those colors right, we know we’re getting the colors right when we look out at the landscape,” said Bell.
One of the other exciting aspects of the work is that ASU students and staff are among the first people on Earth to work with new images radioed back from both rovers on Mars every day.
“Who knows what discoveries we’ll make – but whatever they are, they might be noticed first by an ASU undergrad or grad student, toiling away in the night calibrating some of the latest images from the Red Planet. That’s pretty cool work,” said Bell. Some of that cool work is being conducted on the ground floor of the new Interdisciplinary Science and Technology Building IV in the Mission Operations Center, where Bell, staff, and students process images and hold occasional meetings with scientists and mission operations staff from NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
The School of Earth and Space Exploration is an academic unit of the College of Liberal Arts and Sciences