New approaches to the exploration: planet Mars and bacterial life
  Planet Mars past environmental conditions were similar to the early Earth, but nowadays they are similar to those of a very cold desert, irradiated by intense solar UV light. However, some terrestrial lifeform showed the capability to adapt to very harsh environments, similar to the extreme condition of the Red Planet. In addition, recent discoveries of water in the Martian permafrost and of methane in the Martian atmosphere, have generated optimism regarding a potentially active subsurface Mars' biosphere. These findings increase the possibility of finding traces of life on a planet like Mars. However, before landing on Mars with dedicated biological experiments, it is necessary to understand the possibilities of finding life in the present Martian conditions. Finding a lifeform able to survive in Martian environment conditions may have a double meaning: increasing the hope of discovering extraterrestrial life and defining the limits for a terrestrial contamination of planet Mars. In this paper we present the Martian environment simulators LISA and mini-LISA, operating at the Astronomical Observatory of Padua, Italy. They have been designed to simulate the conditions on the surface of planet Mars (atmospheric pressure,0.6-0.9 kPa; temperature from -120 to 20 {\deg}C, Martian-like atmospheric composition and UV radiation). In particular, we describe the mini-LISA simulator, that allows to perform experiments with no time limits, by weekly refueling the liquid nitrogen reservoir. Various kind of experiments may be performed in the simulators, from inorganic chemistry to biological activity. They are offered as experimental facilities to groups interested in studying the processes that happen on the Martian surface or under its dust cover. 
Giuseppe Galletta (UniPD), Giulio Bertoloni (UniPd) and Maurizio   D'Alessandro (INAF-OAPD)
astro-ph.EP