Was Mars Ever Habitable? Curiosity's SAM Instrument Seeks the Answer
By: Hillary Ossip
After its amazing landing, which felt like it was straight out of a science fiction novel, NASA’s Curiosity rover is now safely on Mars and already at work. “Curiosity was designed to assess whether Mars ever had an environment able to support small life forms called microbes. In other words, its mission is to determine the planet's ‘habitability.’” To do this, Curiosity is equipped with an on-board laboratory that includes instruments ranging from spectrometers and radiation detectors to environmental and atmospheric sensors. Here’s what I learned from my visit to NASA’s Goddard Space Flight Center last week:
Gale Crater, Curiosity’s landing site, is the ideal place to search for evidence of organic compounds on Mars, many of which are the chemical building blocks of life on Earth. Similar to the Grand Canyon (though three times as high!), Gale Crater has exposed layers of rock that NASA hopes will reveal if there ever was life on Mars. Starting at the base of the crater, where the oldest sediments from the planet’s early years can be found, Curiosity will begin roving the area, performing experiments on the crater’s rock layers with its on-board lab.
Bringing the conversation back to Earth for a minute, during my visit to Goddard, I had the opportunity to meet NASA scientists and see the Sample Analysis at Mars (SAM) instrument suite they developed for the Mars Science Lab (the only other one in existence is on Mars on the Curiosity rover). The Earth-based SAM is housed at Goddard in an atmospheric simulation chamber (seen here). This allows scientists to test programs in a "Martian environment" before uploading the commands to Curiosity.
Curiosity’s SAM will analyze the chemistry of rocks, soil and air collected by Curiosity’s arm as the rover investigates Gale Crater. NASA Space Scientist Melissa Trainer explained that SAM, which is approximately the size of a microwave oven, is essentially three instruments in one. These three instruments are a Quadrupole Mass Spectrometer (QMS), a Gas Chromatograph (GC), and a Tunable Laser Spectrometer (TLS). Translation: The QMS and GC work together to separate and identify chemical compounds in rock samples Curiosity collects. The TLS looks for organic (carbon-containing) compounds and determines the ratio of key isotopes -- both vital to unlocking Mars' past.
These tools are essential to Curiosity’s search for life on Mars as the findings will help scientists better understand environmental conditions over time and assess whether Mars could support and preserve evidence of microbial life, either now or at some time in its past. For more on SAM’s investigative procedure, click here.
So, are there organic compounds on Mars? Could they serve as the chemical building blocks of life like those on Earth? Now that the “seven minutes of terror” are over and Curiosity has begun its two year mission on Mars, we will hopefully be able to answer these questions. Scientists like those I met at Goddard are already hard at work programming and preparing to implement Curiosity’s experiments. Fingers crossed that they find signs of life!
Acknowledgments: Many thanks to NASA for allowing me to visit their facilities as part of their August 3, 2012 NASA Social and to Srishti Kashyap, Summer Research Associate in Astrobiology, who so kindly and thoroughly explained the science behind the SAM instrument suite to me.