FIG. 12.

Survival of B. subtilis spores on the LDEF experiment after nearly 6 years in space. The spores in multilayers were either exposed under a perforated dome to the full environment of space or shielded either by a quartz window 2 mm thick, which allowed access of solar UV radiation (λ > 170 nm), or an aluminum cover of 2 mm. (Graph drawn from data in reference 72.)