3:30 PM - 4:00 PM
[AGE31-01] Life search on Mars by Life Detection Microscope (LDM)
Keywords:fluorescent microscope, extraterrestrial life
The Viking mission in 1970’s did not find evidence for life , however, the sensitivity of the GC-MS (mass spectrometer) onboard the Viking mission was found not to be very high, and it was not able to detect 106 microbial cells in 1 gram soil [8, 9], indicating that another life detection program is necessary.
The Life Detection Microscope (LDM) that we have proposed [6, 10] has the potential sensitivity much higher than the Viking instrument. Microscopes directly image life forms and identify their shapes, sizes, and other morphological structures and have the potential to detect a single cell in field of view. Therefore, the sensitivity can be as high as desired just by increasing the volume of sample to be scanned in a reasonable duration of experiment. LDM scans about 1 mm3 and detects less than 104 cells in 1 gram soil at a spatial resolution of 1 µm . LDM differentiates among organic compounds surrounded by membranes or with enzyme activity by staining the samples with fluorescent pigments. This technique is especially useful for the detection of living microorganisms.
Our investigation goals are the followings. 1) Identify cell-like structure in which organic compounds are enveloped by membrane, which may represent Martian life. 2) Search for organic compounds in Mars surface samples. The compounds include cells, other biological materials, and abiotic polycyclic aromatic hydrocarbon (PAH). 3) High-resolution characterization of regolith and dust particles. The search for living microorganisms is important not only for scientific interest but for planetary protection. Before future human missions begin, surveys investigating the presence of living microorganisms should be conducted to mitigate the risk of human contact with Martian microorganisms, which may be harmful to human health. The LDM would be also an effective tool for this purpose.
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