Interplanetary contamination: Difference between revisions

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Line 15: If extraterrestrial life exists, it may be vulnerable to interplanetary contamination by foreign micro-organisms. Some [[extremophile]]s are able to survive space travel to another planet, and foreign life could possibly be introduced by spacecraft from Earth, for example. If extraterrestrial life does not exist, but could potentially thrive in a given location, the site is also considered vulnerable to contamination. In this case, the introduction of life could transform the location from its current pristine state. Locations within the Solar System where life might exist today include the ocean of liquid water beneath the icy surface of [[Europa (moon)\|Europa]], the interior of [[Enceladus]] which is currently sending water into space, and the possible ocean of liquid water which some astronomers believe might exist beneath the surface of [[Titan (moon)\|Titan]] (its surface has oceans of liquid [[ethane]] / [[methane]], but it may also have liquid water below the surface and [[cryovolcano\|ice volcanoes]]).<ref name=smallsolarsystembodies>[http://www.gwu.edu/~spi/COSPAR_OP_PP_Workshop_final_Aug2009.pdf COSPAR Workshop on Planetary Protection for Outer Planet Satellites and Small Solar System Bodies] European Space Policy Institute (ESPI), 15–17 April 2009</ref><ref>[https://science.nasa.gov/media/medialibrary/2011/06/29/Rummel_COSPAR_COPUOS_PPS_9May11_-_TAGGED.pdf COSPAR power point type presentation, gives good overview of the detailed category decisions] {{webarchive\|url=https://web.archive.org/web/20131019160210/http://science.nasa.gov/media/medialibrary/2011/06/29/Rummel_COSPAR_COPUOS_PPS_9May11_-_TAGGED.pdf \|date=2013-10-19 }}</ref> === Mars === Line 120: Since the Moon is now generally considered to be free from life, the most likely source of contamination is from Mars during either a Mars sample return or as a result of colonization of Mars. There are no immediate plans for a Mars sample return, but it remains a high priority for NASA and the ESA because of its great potential biological interest. The European Space Foundation report cites many advantages of a Mars sample return. In particular, it would permit extensive analysis with any of the equipment available on Earth, without the size and weight constraints for instruments sent to Mars on rovers. These analyses could also be carried out without the communication delays for experiments carried out on Martian rovers. It would also make it possible to repeat experiments in multiple laboratories with different instruments to confirm key results.<ref name=esf2012_PP-advanntages>[https://science.nasa.gov/media/medialibrary/2013/01/17/ESF_Mars_Sample_Return_backward_contamination_study.pdf European Science Foundation - Mars Sample Return backward contamination - strategic advice] {{webarchive\|url=https://web.archive.org/web/20160602150139/http://science.nasa.gov/media/medialibrary/2013/01/17/ESF_Mars_Sample_Return_backward_contamination_study.pdf \|date=2016-06-02 }} July, 2012, {{ISBN\|978-2-918428-67-1}} - see 2. From remote exploration to returning samples. (for more details of the document see [http://elib.dlr.de/78092/ abstract] )</ref> Carl Sagan was first to raise and publicise back contamination issues that might follow from a Mars sample return. In Cosmic Connection (1973) he writes: Line 134: {{quote\|Whether a microorganism from Mars exists and could attack us is more conjectural. If so, it might be a zoonosis to beat all others. On the one hand, how could microbes from Mars be pathogenic for hosts on Earth when so many subtle adaptations are needed for any new organisms to come into a host and cause disease? On the other hand, microorganisms make little besides proteins and carbohydrates, and the human or other mammalian immune systems typically respond to peptides or carbohydrates produced by invading pathogens. Thus, although the hypothetical parasite from Mars is not adapted to live in a host from Earth, our immune systems are not equipped to cope with totally alien parasites: a conceptual impasse}} This possibility has been confirmed in all the later studies, as the worst-case scenario. Other possibilities have also been raised such as micro-organisms that have harmful effects on crops, or that disrupt natural cycles, and pathogens that infect other micro-organisms.<ref name=esf2010_PP>[https://science.nasa.gov/media/medialibrary/2013/01/17/ESF_Mars_Sample_Return_backward_contamination_study.pdf European Science Foundation - Mars Sample Return backward contamination - Strategic advice and requirements] {{webarchive\|url=https://web.archive.org/web/20160602150139/http://science.nasa.gov/media/medialibrary/2013/01/17/ESF_Mars_Sample_Return_backward_contamination_study.pdf \|date=2016-06-02 }} July, 2012, {{ISBN\|978-2-918428-67-1}}. (for more details of the document see [http://elib.dlr.de/78092/ abstract] )</ref><ref name=Lederberg>Joshua Lederberg [http://profiles.nlm.nih.gov/ps/access/BBGNMX.pdf Parasites Face a Perpetual Dilemma ] Volume 65, Number 2, 1999 / American Society for Microbiology News 77.</ref><ref name=nrc2009>{{cite report \|title=Assessment of Planetary Protection Requirements for Mars Sample Return Missions \|publisher=National Research Council \|year=2009 \|url=http://www.nap.edu/openbook.php?record_id=12576&page=R1}}</ref><ref name=iMars>http://mepag.nasa.gov/reports/iMARS_FinalReport.pdf Preliminary Planning for an International Mars Sample Return Mission Report of the International Mars Architecture for the Return of Samples (iMARS) Working Group June 1, 2008</ref><ref name=NAS>http://planetaryprotection.nasa.gov/summary/msr Mars Sample Return: Issues and Recommendations. Task Group on Issues in Sample Return. National Academies Press, Washington, DC (1997).</ref> As a result, the possibility of new human pathogens, or environmental disruption due to back contamination, is considered to be of extremely low probability but can't yet be ruled out completely. Line 150: === Suggested precautions for sample returns === Space agencies have already had experience with returning samples thought to be a back contamination risk during the Apollo era, when samples were returned for the first time by Apollo 11. At the time, it was thought that there was a low probability of life on the Moon. The precautions taken then were inadequate by modern standards, however. The regulations used then have been rescinded, and new regulations would be needed.<ref name=race>M. S. Race [http://salegos-scar.montana.edu/docs/Planetary%20Protection/AdvSpaceResVol18(1-2).pdf Planetary Protection, Legal Ambiguity, and the Decision Making Process for Mars Sample Return] {{webarchive\|url=https://web.archive.org/web/20100619123320/http://salegos-scar.montana.edu/docs/Planetary%20Protection/AdvSpaceResVol18%281-2%29.pdf \|date=2010-06-19 }} Adv. Space Res. vol 18 no 1/2 pp (1/2)345-(1/2)350 1996</ref> A different approach would be needed for a modern sample return. ==== Chain of contact ==== Line 160: To receive the returned samples, NASA has proposed to build a biohazard containment facility, known as the Mars Sample Return Receiving facility (MSRRF).<ref name=samplereceivingfacility>[http://www.lpi.usra.edu/pss/presentations/200803/04-Atlas-PPSonMSR.pdf Mars Sample Return Receiving Facility]</ref> The proposed sample return facility must be a [[Biosafety level\|biohazard level]] 4 laboratory. However, the facility must also contain unknown biohazards, as the sizes of any putative Martian micro-organisms are currently unknown. In consideration of this, the ESF proposed additional requirements. Ideally it should contain particles of 0.01 µm, or larger, and release of a particle 0.05 µm or larger is unacceptable under any circumstances.<ref>[https://science.nasa.gov/media/medialibrary/2013/01/17/ESF_Mars_Sample_Return_backward_contamination_study.pdf European Science Foundation - Mars Sample Return backward contamination - Strategic advice and requirements] {{webarchive\|url=https://web.archive.org/web/20160602150139/http://science.nasa.gov/media/medialibrary/2013/01/17/ESF_Mars_Sample_Return_backward_contamination_study.pdf \|date=2016-06-02 }}</ref> The reason for this extremely small size limit of 0.01 µm is because of the consideration of [[Gene transfer agent\|Gene Transfer Agents]] (GTAs). These randomly incorporate segments of the host genome and can transfer them to other evolutionarily distant hosts, and do that without killing the new host. In this way many archaea and bacteria can swap DNA with each other. This raises the possibility that Martian life, if it has a common origin with Earth life in the distant past, could swap DNA with Earth micro-organisms in the same way. Line 170: It also must double as a clean room to preserve the science value of the samples. The problem here is that, while it is relatively easy to simply contain the samples once returned to Earth, researchers would also want to remove parts of the sample and use them in experiments. During all these handling procedures, the samples would need to be contained to prevent contamination of Earth. However at the same time the samples would need to be kept free from contamination by Earth micro-organisms and biological material; even a single amino acid of Earth origin could confuse the analysis. This introduces conflicting requirements. They surely can be reconciled but to date, no facility has had to do this, so new building requirements would need to be imposed. A clean room is normally kept at a higher pressure than the external environment to keep contaminants out, and a biohazard laboratory is kept at a lower pressure to keep the biohazards in. The challenge is to combine these in a single building. Solutions suggested include a triple walled containment facility, and one of the suggestions includes extensive use of robot handlers for the samples.<ref name=MSRRF-clean-room-quote>{{cite report \|title=Mars Sample Return Receiving Facility - A Draft Test Protocol for Detecting Possible Biohazards in Martian Samples Returned to Earth \|year=2002 \|url=http://www.lpi.usra.edu/pss/presentations/200803/04-Atlas-PPSonMSR.pdf\|quote=''A Sample Return Facility will require combining technologies used for constructing maximum containment laboratories (e.g. Biosafety Level 4 labs), which will be needed to ensure protection of Earth from the Mars samples, with cleanroom technologies, which will be needed to protect the Mars samples from Earth contamination.<br><br>• Such an integrated facility is not currently available.<br><br>Planetary Protection Requires Negative Air Flow to Protect Against Environmental Contamination Planetary Science and Planetary Protection Require Positive Air Flow to Protect Samples from Terrestrial Contamination''}}</ref><ref>[http://www.marsinstitute.info/epo/docs/draft_protocol.pdf A Draft Test Protocol for Detecting Possible Biohazards in Martian Samples Returned to Earth] {{webarchive\|url=https://web.archive.org/web/20060222131531/http://www.marsinstitute.info/epo/docs/draft_protocol.pdf \|date=2006-02-22 }}</ref><ref>[http://www.lpi.usra.edu/meetings/lpsc2005/pdf/1395.pdf CLEANROOM ROBOTICS – APPROPRIATE TECHNOLOGY FOR A SAMPLE RECEIVING FACILITY ? 2005 update on the Draft Test Protocol ].</ref><ref>[http://www.nap.edu/reports/13117/App%20G%2008_Mars-Sample-Return-Orbiter.pdf 2010 Mars Sample Return Orbiter decadal survey]: {{quotation\|The NASA Planetary Protection Officer commissioned the development of a draft test protocol that would represent one "necessary and sufficient" approach to evaluate the safety of the samples while safeguarding the purity of the samples from terrestrial contamination. A Draft Test Protocol for Detecting Possible Biohazards in Martian Samples Returned to Earth was published in October 2002 [7]. In 2003, three architectural design teams independently examined the scope, approach, cost, and technology required for the SRF, using the Draft Test Protocol for requirements. The approaches varied from allrobotic handling of samples to more traditional glove box implementations. The studies indicated that the principles and techniques required are generally mature. Biosafety laboratories, the NASA Lunar Sample Facility, pharmaceutical laboratories, and electronic fabrication cleanrooms perform most of the required individual functions. '''''However, there are some areas needing early development, such as ensuring sample preservation and bio-safety together, representing new challenges that were addressed by techniques like dual-walled containers (and gloves) with positive pressure clean inert gas in between the walls. This, as well as some further development in ultra-clean sample manipulation, safe and pure transport of samples, and sample sterilization techniques, are planned in the technology program'''''}} </ref>