Dasgupta receives $1.2 million NASA grant
Ion chromatograph could be utilized on Mars
Dasgupta will use the funds to develop "An Ion Chromatograph for Extraterrestrial Explorations." The goal is to create a new system for testing the chemical composition of extraterrestrial soil. Dasgupta's project was one of eight nationwide to be funded recently by the Astrobiology Science and Technology for Instrument Development grant program of the NASA Astrobiology Program.
During past lander missions, examinations of Martian soil have been limited by technology that used ion selective electrodes to probe for specific materials, Dasgupta said. An ion chromatograph, on the other hand, separates and detects ions, which are molecules bearing an electrical charge. The device can look at a broad suite of ions sensitively and identify them with some confidence.
"By creating an easily portable and robustly-designed ion chromatograph, we're hoping to rapidly expand scientists' knowledge of extraterrestrial geology and geochemistry," Dasgupta said. Proving organic ions exist in Martian soil could be a first step to identifying organic compounds, the building blocks of life.
Past Mars missions have heated soils to look for organic vapors coming from samples. None have been detected. But if the recent finding of large amounts of perchlorate in Martian soil proves correct, that discovery would explain why heating soil never shows any organics - the perchlorate would oxidize them.
"Although we cannot address the issue of neutral organics," Dasgupta said, "with this machine, we should be able to unequivocally answer if organic ions are present."
Dasgupta plans to use low-pressure open tubular columns in the design of his chromatograph for NASA, making it uniquely designed for storage in the subfreezing temperatures of space when not in use. The columns typically used for ion chromatography are packed with polymer or silica beads and filled with an aqueous solution. They cannot withstand such freeze-thaw cycles.
The new device would enable researchers to search for organic compounds in a way that is compatible with the chemistry of the Martian soil and would provide answers to questions about organic compounds on Mars, said Alfonso Davila, principal investigator at the California-based Carl Sagan Center for the Study of Life in the Universe and a collaborator on the project.
"If that answer was positive, then the possibility of life on Mars would gain new strength," Davila said.
An ion chromatograph could also detect ions such as nitrate and phosphate in extraterrestrial soil. These are also very important for life and strategically, for human exploration beyond Earth, Davila said.