Les usines d'assemblage de la NASA pas stériles

NASA clean rooms breed hardy bacteria
Catalogue made of bugs that survive preparations for space.

Katharine Sanderson


NASA's spacecraft are clean, but not sterile.

The ultra-clean facilities used to assemble NASA's spacecraft are inhabited by some hardy bacteria, which could be hitchhiking their way to space.

Samples from NASA's Jet Propulsion Laboratory (JPL), Kennedy Space Center and Johnson Space Center, show the variety of bacteria that make it into the spaceship assembly areas despite the clean rooms used to build the craft in. The team found an eclectic selection of bacteria, including some that thrive in harsh environments with no food, at high temperatures or pH, or in high levels of chlorine.

Researchers will use the list of found bacteria to compare against any specimens brought back on future space missions. This will help researchers to determine whether any bacteria they encounter really have an extraterrestrial origin, or simply hitchhiked out to space and back from Earth. "We now understand a little better what type of [Earthly] organisms we're dealing with," says Catharine Conley, NASA's planetary protection officer.

Spacecraft are put together in clean rooms that are subject to stringent national and international regulations. The Outer Space Treaty of 1967 was the first to put limits on what humans should, or should not, release into space. These precautions exist to protect extraterrestrial environments from being contaminated, and also to help ensure that any future detections of extraterrestrial life are not false positives.

NASA has its own specific set of rules, which specifies what kind of filters are needed on clean-room air vents, and what kind of protective outfits any people entering the rooms must wear. Spacecraft materials are cleaned with harsh chemical cleansers and bathed in ultraviolet light, and are routinely swabbed to check for bacteria as craft are being built. For Mars landings similar to the Viking mission of 1975, NASA's limits are set to prevent any more than 300 spores landing on a square metre of martian surface.

Not sterile

The fact that some bacteria do survive in NASA clean rooms is not surprising. "The rooms are not sterile," says Michel Viso, an astrobiologist at the French space agency CNES in Paris. What was interesting was to catalogue the diversity of the hardy bacteria, he adds.

Kasthuri Venkateswaran, at the JPL facility at the California Institute of Technology, Pasadena, and his colleagues looked at the genetic and molecular make-up of any bacteria found alive in the three sites.

Each site that was sampled contained very different communities, they found, and some of the bacteria strains included members of the spore-forming Bacillus family that had never been seen before. They also found some extremophile bacteria — those that thrive in extreme conditions. These included Methylobacterium, which is known to be resistant to high levels of chlorine, and bacteria that usually grow at temperatures of about 60 ºC.

The clean rooms aren't necessarily hot, but do have extremely limited nutrients and have other harsh conditions. "It is, by nature, an extreme environment; it's not surprising that extremophiles exist there," says John Rummel, senior scientist for astrobiology at NASA headquarters, Washington DC, of the clean rooms.

Killer light

So should we be worried about these hardy critters ending up on Mars? It is unlikely that they would be tough enough to survive there, says Rummel: "UV radiation kills everything over a period of time anyway."

NASA imposes stricter rules for any craft that might come in contact with liquid water on Mars, and this conservative policy seems to have so far been successful, says Rummel. "Nothing we've sent to Mars would suggest a runaway growth."


Contamination is a real concern, says Conley, but she is less worried about contaminating Mars than dirtying Jupiter's moon Europa, in any future missions. Europa has subsurface liquid water sitting over rock and lava — exactly like a hydrothermal vent on Earth where bacterial communities are known to thrive, she says. One need only look to our own planet to prove that we are capable of causing damage: "If we contaminate places on Earth, it screws things up," she says, and also supports a conservative approach to cleanliness. "Why take the chance?" she adds.

Cleaner clean rooms than the ones used by NASA do exist — for example in microprocessor manufacture, or the pharmaceutical industry. But the costs of these facilities are prohibitive when the clean room is only used once every two years, says Conley.

antoine34 a écrit:
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So should we be worried about these hardy critters ending up on Mars? It is unlikely that they would be tough enough to survive there, says Rummel: "UV radiation kills everything over a period of time anyway."
...

lambda0 a écrit:

antoine34 a écrit:
...
So should we be worried about these hardy critters ending up on Mars? It is unlikely that they would be tough enough to survive there, says Rummel: "UV radiation kills everything over a period of time anyway."
...

"Conan la bactérie" semble assez tolérante aux UV :eeks:
http://fr.wikipedia.org/wiki/Deinococcus_radiodurans
Faut voir ce que ça donnerait sur Mars...

dominique M. a écrit:1. le risque zéro de contamination est pure utopie

2. il peut être dangeureux de chercher à obtenir les milieux les plus indemnes possible de micro-organismes; cela peut aboutir au résultat inverse de celui escompté en permettant à des germes résistants aux conditions extrèmes de se développer car ce développement n'est plus controlé par la présence des autres germes "normaux".
C'est un peu comme lorque vous prenez un antibiotique: votre flore intestinale saprophyte est détruite et les micro-organismes normalement présents vont se développer et envahir le milieu laissé libre.
Et il est beaucoup plus difficile ensuite de se débarasser de ces germes plus résistants.

biscoto66 a écrit:Il me semble avoir lu que les premières sondes envoyées sur Mars n'étaient pas stérilisées, il y en a même une qui a versé de l'eau sur le sol martien, si l'eau n'était pas stérilisée il doit y en avoir des bactéries terriennes sur Mars, si elles ont résisté aux conditions météorologiques extrêmes de la planète.

Pour Pheonix c'est plus délicat son but est de rechercher des molécules organiques.

Heureusement qu'ils l'ont vue maintenant.

will be sterilized to Viking pre-sterilization bioburden levels

Main engine start a écrit:Pour compléter http://www.futura-sciences.com/fr/sinformer/actualites/news/t/astronautique/d/des-bacteries-decouvertes-dans-les-salles-steriles-de-la-nasa_12794/

Biohazard potential of putative Martian organisms during missions to Mars.
Warmflash D, Larios-Sanz M, Jones J, Fox GE, McKay DS.

Department of Biology and Biochemistry, University of Houston, TX, USA. dwarmfla@ems.jsc.nasa.gov

Exploration Class missions to Mars will require precautions against potential contamination by any native microorganisms that may be incidentally pathogenic to humans. While the results of NASA's Viking biology experiments of the 1970s have been generally interpreted as inconclusive for surface organisms, and attributed to active but nonbiological chemistries, the possibility of native surface life has never been ruled out completely. It is possible that, prior to the first human landing on Mars, robotic craft and sample return missions will provide enough data to know with certainty whether future human landing sites harbor extant life forms. If native life were found to exist, it would be problematic to determine whether any of its species might present a medical danger to astronauts. Therefore, it will become necessary to assess empirically the risk that the planet contains pathogens based on terrestrial examples of pathogenicity and to take a reasonably cautious approach to biohazard protection. A survey of terrestrial pathogens was conducted with special emphasis on those whose evolution has not depended on the presence of animal hosts. The history of the development and implementation of Apollo anti-contamination protocol and recommendations of the National Research Council's Space Studies Board regarding Mars were reviewed. Organisms can emerge in Nature in the absence of indigenous animal hosts and both infectious and non-infectious human pathogens are therefore theoretically possible on Mars. Although remote, the prospect of Martian surface life, together with the existence of a diversity of routes by which pathogenicity has emerged on Earth, suggests that the probability of human pathogens on Mars, while low, is not zero. Still, since the discovery and study of Martian life can have long-term benefits for humanity, the risk that Martian life might include pathogens should not be an obstacle to human exploration. As a precaution, it is recommended that EVA (extravehicular activity) suits be decontaminated when astronauts enter surface habitats upon returning from field activity and that biosafety protocols approximating laboratory BSL 2 be developed for astronauts working in laboratories on the Martian surface. Quarantine of astronauts and Martian materials arriving on Earth should also be part of a human mission to Mars, and this and the surface biosafety program should be integral to human expeditions from the earliest stages of the mission planning.

PMID: 17511302 [PubMed - indexed for MEDLINE]

Anubis a écrit:j'ai déjà entendu dans les grands médias québécois qu'il a des groupes d'écologistes plutôt extrémistes qu'ils s'opposant à un vole habité ver Mars pour gardé mars intacte.

biscoto66 a écrit:Petite traduction avec Google Translate, très utile ce petit outil Google.


.../cut/....
Les organizations peuvent émerger en nature en l'absence des centres serveurs animaux indigènes
.../cut/...
Bien que l'extérieur, la perspective de la vie extérieure de Martian, ainsi que l'existence d'une diversité des itinéraires par lesquels la pathogénicité a émergé sur terre, suggère que la probabilité des microbes pathogènes humains sur Mars, alors que le bas, ne soit pas zéro. .

montmein69 a écrit:

Anubis a écrit:j'ai déjà entendu dans les grands médias québécois qu'il a des groupes d'écologistes plutôt extrémistes qu'ils s'opposant à un vole habité ver Mars pour gardé mars intacte.

Il n'est pas utile d'attribuer une telle estimation à des "écologistes extrêmistes". Toute technologie "invasive" sera dommageable à une étude de ce qui existe sur Mars notamment si on veut vraiment que le matériel expérimental ne fausse pas les résultats.
On vient de voir que même avec des sondes respectant les règles du COSPAR, on introduira forcément des organismes (ou leurs composants) sur les lieux mêmes où on veut analyser. Mais on peut estimer que cela sera contenu et que l'on aura répertorié ce qui pourrait fausser les résultats : on fait au mieux avec les technologies dont on dispose.

Si on fait venir des hommes, leur support vie et tous les déchets qui iront avec, il est clair que cette "pollution" sera démultipliée.


Si l'objectif n'est pas d'étudier les conditions existantes sur Mars, mais par exemple "d'exploiter" des ressources alors cela n'a pas une grande importance. Et on se souciera alors plus des effets pathogénes des espèces martiennes sur l'homme et sur les moyens de les éradiquer avec force renfort de fongicide, bactéricide, spermicide, expositions aux UV, aux Gamma.... :lolnasa: