Project partners

  • Dr. Petra Rettberg, DLR, Köln, Germany
  • Dr. Corinna Panitz, RWTH Aachen, Germany
  • Dr. Elke Rabbow, DLR, Köln, Germany
  • Dr. Kasthuri Venkateswaran, NASA / JPL, USA
  • Prof. Charles Cockell, CEPSAR, UK
  • Prof. Daniela Billi, University of Rome "Tor Vergata", Italy
  • Prof. Helga Stan-Lotter, University of Salzburg, Austria

Project description

Microorganisms account for over 99% of all living matter on Earth, and most of the microorganisms are organized into biofilms and microbial mat communities. Microbial mats are among the oldest clear signs of life on Earth. The earliest mats were probably small, single-species biofilms and these might also be the first forms of life to be detected on other planets and moons of our solar system. Bacteria living in a biofilm adherent to a surface usually have significantly different properties from free-floating bacteria of the same species, as the dense and protected environment of the film allows them to cooperate and interact in various ways. One benefit of this environment is increased resistance to different chemical and physical agents, as the dense extracellular matrix and the outer layer of cells protect the interior of the community.
In the BOSS project the hypothesis will be tested that biofilm-forming microorganisms embedded within self-developed extrapolymeric substances (EPS matrix) are also more resistant to the environmental conditions as they exist in space and on Mars compared to the same bacteria from planktonic cultures. Test parameter will be survival after exposure to space vacuum and simulated martian atmosphere and pressure alone and in combination with extraterrestrial and mars-like solar UV radiation. The experiment BOSS is suggested to be performed as part of the ROSE2Mars consortium in the EXPOSE facility on the ISS. The microbial samples will prepared on ground, subjected to long-term exposure to space and simulated martian conditions and analyzed post-flight in the lab.
Biofilm-forming microorganisms to be investigated in BOSS will be Deinococcus geothermalis, spores of Bacillus horneckiae, different Chroococcidiopsis strains, Halococcus morrhuae within a biofilm of Halomonas muralis and natural biofilms within volcanic rocks. The results of this experiment will contribute to our understanding of life in extreme environments on Earth and on other planets with emphasis on adaption to desiccation and UV radiation. The direct comparison of the survival strategies of different microbial species living in biofilms or as planktonic cells will also give new insights into the adequacy of actual planetary protection measures and may support the development of new life detection technologies for space application.

Fig. 2: FESEM images of sessile (A, B, and C) and planktonic (D, E, and F) cells of D. geothermalis E50051 (Saarimaa et al., 2006)