Extraterrestrial Life Signature Detection Microscopy: Search and Analysis of Cells and Organics on Mars and Other Solar System Bodies

This paper presents a review of the space exploration for life signature search with a special focus on the fluorescence microscope we developed for the life signature search on Mars and in other sites. Considering where, what, and how to search for life signature is essential. Life signature search exploration can be performed on the Mars surface and underground, on Venus’ cloud, moon, asteroids, icy bodies (e.g., moons of Jupiter and Saturn), and so on. It is a useful strategy to consider the targeted characteristics that may be similar to those of terrestrial microorganisms, which are microorganisms with uniform spherical or rod structures with approximately 1 μm diameter surrounded by a membrane having a metabolic activity and mainly made of carbon-based molecules. These characteristics can be analyzed by using a fluorescence microscope and a combination of fluorescence pigments with specific staining characteristics to distinguish the microorganism characteristics. Section 1 introduces the space exploration for life signature search. Section 2 reviews the scientific instruments and achievements of past and ongoing Mars exploration missions closely related to astrobiology. Section 3 presents the search targets and analysis of astrobiology. Section 4 discusses the extraterrestrial life exploration methods that use a microscope together with other methods (based on mass spectrometry, morphology, detection of growth, movement, and death, etc. for microscopic and macroscopic organism). Section 5 expounds on the life signature detection fluorescence microscope, for which we have manufactured a bread board model and tested for extraterrestrial life exploration.