18th IAA Humans in Space Symposium (2011) 2352.pdf
Interplanetary Transfer of Photosynthetic Organisms in Space
R. de la Torre Noetzel,
1
J.M. Frías,
1
E. Mateo-Martí,
1
F.J. Sánchez Iñigo,
1
L Gª.Sancho,
2
G. Horneck
3
1
INTA (Spanish Aerospace Research Establishment, Dpm. Earth Observation and CAB, Crta. Ajalvir, km. 4,
28850-Torrejón de Ardoz, Madrid, Spain, torrenr@inta.es),
2
UCM (Universidad Complutense Madrid, Facultad de
Farmacia, Madrid, Spain), and
3
DLR (German Aerospace Research Establishment, Cologne, Germany)
Interplanetary transfer of rock inhabiting life by means of meteorites it’s a step proposed by the hypothesis of lithopanspermia [1,2,3,4]. Three experiments have been performed to demonstrate- and intercompare the survival capacity of prokaryotic (endoevaporitic microbial communities and cyanobacterial akinetes) and eukaryotic
(epilithic lichen species: Rhizocarpon geographicum, Xanthoria elegans , vagrant lichen Aspicilia fruticulosa) symbiotic photosynthetic organisms in space. The experiment LICHENS-II (2005) [5] showed for the first time, the high survival capacity by photosynthetic performance (chlorophyll a- fluorescence) of both epilithic lichens to low
Earth orbit conditions. With the following experiment LITHOPANSPERMIA (2007) [6], both previous species survived and a higher recovery of the vagrant one were detected. The third experiment LIFE (Lichens and Fungi
Experiment, 2008), a long term experiment (18 months) integrated on the EXPOSE-E facility (Columbus
Laboratory) of the ISS, has demonstrated the limits of the survival capacity of both epilithic lichens to real space
(UV-extraterrestrial- and cosmic radiation, space vacuum) and Mars (Mars atmosphere and Mars UV radiation) conditions . These experiments have shown that lichens are one of the most resistant organisms to space- and Mars conditions, and therefore suitable candidates for life experiments (Lithopanspermia theory), as well as for planetary protection efforts. Our next objective is the test of Aspicilia fruticulosa to space and Mars conditions (Exposure facility R2) on the ISS, integrated in the experiment BIOMEX (2011-2013). After flight, analysis of the degradation of cell surfaces and pigments, in contact with terrestrial, Lunar and Martian analogue minerals, will be performed.
The results will contribute for installation of an electronic biosignature data base for the most robust organisms, with application in future exploration projects focussed on the search of life in the universe.
REFERENCES
[1] Nicholson W. L., Munakata N., Horneck G., Melosh H., Setlow P. (2000). Resistance of Bacillus endospores to extreme terrestrial and extraterrestrial environments. Microb. Mol. Biol. Rev. 64, 548-572.
[2] Cockell C.S. (2008). The interplanetary exchange of photosynthesis. Orig. Life Evol. Biosph. 38, 87-104.
[3] Horneck G., Stöffler, D., Ott, S., Hornemann, U., Cockell, C.S., Möller, R., Meyer, C., de Vera, J.P., Fritz, J.,
Schade, S., Artemieva, N. (2008). Microbial rock inhabitants survive hypervelocity impacts on Mars-like host planets: First phase of Lithopanspermia experimentally tested. Astrobiology 8, 17-44.
[4] Valtonen M., Nurmi, P., Zheng, J.-Q., Cucinotta, F. A., Wilson, J. W., Horneck, G., Lindegren, L., Melosh, J.,
Rickman, H., Mileikowsky C. (2009). Natural transfer of viable microbes in space from planets in the extra-solar systems to a planet in our solar system and vice-versa, Astrophys. J. 690: 210-215.
[5] Sancho L. et al. (2007). Lichens survive in space. Astrobiology, 7: 443-454.
[6] de la Torre, R., et al. Survival of lichens and bacteria exposed to outer space conditions – Results of the
Lithopanspermia experiments. Icarus (2010), doi:10.1016/j.icarus.2010.03.010.