Experiment lithopanspermia: test of interplanetary transfer and re-entry process of epi- and endolithic microbial communities in the FOTON-M3 Mission
Abstract
The Lithopanspermia hypothesis assumes that impact-expelled rocks serve as interplanetary transfer vehicles for microorganisms colonizing those rocks. It requires that the microorganisms survive (1) the impact ejection process from the planet of origin; (2) travelling through space; (3) capture and landing on another planet. In the experiment "Lithopanspermia" on board of the FOTON-M3 satellite (14.09.07) steps 2 and 3 of this scenario have been experimentally tested. Assay systems for step 2 were the bipolar epilithic lichen species Rhizocarpon geographicum and Xanthoria elegans on their natural rock substrate as well as their reproduction structures, microbial communities from atacamás halites Chroococcidiopsiss, endolithic communities of Anabaena and Nostoc, and the vagrant lichen species Aspicilia fruticulosa. The samples were exposed to outer space conditions within the BIOPAN-6 facility of ESA. Preparatory space simulation studies (UV solar spectrum radiation and vacuum at 10-2 Pa) performed at the Spasolab-Laboratory of INTA (March-April 2007), have demonstrated the suitability of those lichen species. After flight (10 days exposure to harsh space conditions in low Earth orbit at about 300 km altitude) and recovery, the survival capacity of the microbial communities has been assayed. First analyses have confirmed a fast recovery of the biological activity (chlorophyll a- fluorescence) of the lichens, similar to the high survival rates observed in the experiment LICHENS onboard of the Foton-M2 mission (de la Torre et al., 2007; Sancho et al., 2007). There were no significant changes in relation with the pre-flight values of the epilithic-, endolithicand vagrant lichen samples. First results of Confocal Scanning Laser Microscopy have demonstrated a high vitality of epilithic samples. Ultrastructural changes are being analyzed by Transmission Electron Microscopy and Cryoscanning. Furthermore, concerning the germination capacity of ascospores of Xanthoria elegans up to now no differences were detected between the controls (90 References: De la Torre et al. (2007) BIOPAN experiment LICHENS on the Foton-M2 mission: pre-flight verification tests of the Rhizocarpon geographicum-granite ecosystem, Adv. Space Res. 40, 1665-1671, doi:10.1016/jasr.2007.02.022. Sancho L. et al. (2007) Lichens survive in space. Astrobiology, 7, 443-454. St¨ffler D, et al. (2007) Experimental evidence for the o potential impact ejection of viable microorganisms from Mars and Mars-like planets Icarus, 186, 585-588. Horneck et al. (2007) Microbial rock inhabitants survive hypervelocity impacts on Mars-like host planets: First phase of Lithopanspermia experimentally tested, Astrobiology, in press.
- Publication:
-
37th COSPAR Scientific Assembly
- Pub Date:
- 2008
- Bibcode:
- 2008cosp...37..660D