Student Life Archives (2001-2008)

Undergrads assist in NASA Phoenix mission to Mars

Washington University has become one of the leading institutions in preparing NASA’s Phoenix Mission, which will send a lander to Mars to search for signs of microbial life.

The University’s Department of Earth and Planetary Sciences has worked for several months to assist NASA in choosing a suitable landing site for the spacecraft using imaging data from the High Resolution Imaging Science Experiment (HiRISE), which is an instrument in NASA’s Mars Reconnaissance Orbiter.

“HiRISE showed that our initial landing site had way too many rocks, rocks the size of the lander,” said Ray Arvidson, a professor of Earth and Planetary Sciences. “If you hit a rock, you know, we’re done.”

NASA had already chosen a landing site last fall, but high-resolution images of Mars’ surface indicated that it was covered with too many rocks; junior Tabatha Heet and freshman Lauren Barry worked from September to March looking for a replacement site.

Arvidson, who chairs the Landing Site Working Group responsible for finding a landing site, said that the originally proposed landing site would have only had a 60 to 70 percent success rate. The minimum necessary success rate is 95 percent.

After six months, the students found a landing site rated 98 percent safe and it will be proposed as the final landing site at a NASA conference in June.

Arvidson asked Heet to assist in finding a new landing site. For Heet, a work-study student working for Arvidson, the opportunity to work in such a project initially came as a surprise.

“They started getting back high resolution images of the proposed landing site and they realized it was covered with rocks, so they had to rush to find a new one,” said Heet. “I was the one who got the job of counting the rocks and finding a place that was relatively rock free.”

Large rocks could puncture the spacecraft and the spacecraft might damage itself by landing on a rock and tilting over. Large rocks could also prevent the spacecraft’s solar panels from deploying properly. Without the solar panels, the lander would have no power to operate its seven instruments.

In addition to not having too many rocks, the ground must have a slope of no more than 16 degrees.

Heet had the tedious task of manually analyzing images of large areas of Martian surface for rocks. Using thermal imaging data for easier rock detection and a software program known as ENVI for drawing vectors on them, she could determine how large each rock was, count the number of rocks and then eliminate bad landing sites.

“It was sometimes kind of tedious,” said Barry, who assisted Heet in counting rocks. “But it was really cool to remember that it was Mars, and when you actually thought about that and looked at the image and you realize that you’re looking at rocks on Mars, it’s kind of humbling.”

“Measuring those rock sizes and tabulating all that information, it was pretty much all done by Tabatha Heet and Lauren Barry,” said Arvidson.

The Phoenix mission, spearheaded by the University of Arizona and the California Institute of Technology’s Jet Propulsion Laboratory (JPL), will launch from Cape Canaveral, Florida in August and will arrive at Mars in May of 2008.

Specifically, the mission will land in the high northern latitudes of the Martian surface, where it will dig through and collect water ice, which is just centimeters below the surface and will be analyzed for organic compounds and indicators of life.

“Liquid water is the elixir of life, so it might be one of the last viable habitats for Mars,” said Arvidson.

The University is also responsible for designing the craft’s robotic arm, which scoops up the ice and puts it through a motorized grinder, and for maintaining the Geosciences Node, an online database of planetary data that includes data from the Spirit and Opportunity missions.

Heet also assisted software engineers at the JPL by helping them calibrate software that they developed to detect rocks automatically. With the software near completion, Heet’s rock-counting days appear over.

“I’ve been communicating with the JPL for several months now to get everything fine-tuned,” said Heet.

Her work is not done yet, though. Along with Arvidson, freshman Rebecca Greenberger and graduate student Selby Cull, she will be traveling to Tucson, Arizona over the summer to help operate the spacecraft’s robotic arm while it is on the Martian surface.

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