page_title: Panspermia
section_title: EXOSTACK
hierarchical_section_title: Panspermia / Extremophiles / Research in outer space / EXOSTACK
caption_attribution_description: English: LDEF during photographic survey after retrieval on mission STS-32.
context_page_description: Panspermia is the hypothesis that life exists throughout the Universe, distributed by space dust, meteoroids, asteroids, comets, planetoids, and also by spacecraft carrying unintended contamination by microorganisms. Distribution may have occurred spanning galaxies, and so may not be restricted to the limited scale of solar systems.
  Panspermia hypotheses propose that microscopic life-forms that can survive the effects of space can become trapped in debris ejected into space after collisions between planets and small Solar System bodies that harbor life. Some organisms may travel dormant for an extended amount of time before colliding randomly with other planets or intermingling with protoplanetary disks. Under certain ideal impact circumstances, and ideal conditions on a new planet's surfaces, it is possible that the surviving organisms could become active and begin to colonize their new environment. At least one report finds that endospores from a type of Bacillus bacteria found in Morocco can survive being heated to 420 °C, making the argument for panspermia even stronger.
context_section_description: The German EXOSTACK experiment was deployed on 7 April 1984 on board the Long Duration Exposure Facility satellite.  30% of Bacillus subtilis spores survived the nearly 6 years exposure when embedded in salt crystals, whereas 80% survived in the presence of glucose, which stabilize the structure of the cellular macromolecules, especially during vacuum-induced dehydration.
  If shielded against solar UV, spores of B. subtilis were capable of surviving in space for up to 6 years, especially if embedded in clay or meteorite powder (artificial meteorites). The data support the likelihood of interplanetary transfer of microorganisms within meteorites, the so-called lithopanspermia hypothesis.
caption: EXOSTACK on the Long Duration Exposure Facility satellite.
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