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They divide it into 3 categories
 
{{bq|* Large-scale negative pathogenic effects in humans;<br>* Destructive impacts on Earth's ecological systems or environments; and<br>* Toxic and other effects attributable to microbes, their cellular structures, or extracellular products.}}[http://www.nap.edu/openbook.php?record_id=12576&page=45 (page 45)]
{{bq|▼
* Large-scale negative pathogenic effects in humans;
 
* Destructive impacts on Earth's ecological systems or environments; and
 
* Toxic and other effects attributable to microbes, their cellular structures, or extracellular products.
 
}}[http://www.nap.edu/openbook.php?record_id=12576&page=45 (page 45)]
 
They conclude that the last one is unlikely. But for the other two
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=== Concerns with integrity of the sample container ===
 
The 2010 ESF report<ref name=esf2012_PP-capsule-breach>{{cite report |title=Mars Sample Return backward contamination - strategic advice |publisher= European Science Foundation |year=2012 |chapter=4.7 Potential verification methods"|urlhttpsurl=https://science.nasa.gov/science-pink/s3fs-public/atoms/files/ESF_Mars_Sample_Return_backward_contamination_study.pdf}}
▲{{bq|
{{bq|Release due to failure of containment or of the spacecraft surface sterilisation▼
Page 32
 
4.7 Potential verification methods
 
Verification of sterility of the surfaces of spacecraft elements that come into contact with the Earth’s biosphere, either upon return from the Mars surface or due to re-contact at some later date, is difficult. Sensory indications are often not reliable enough to be consistent with the 10-6 requirement. Because of this, only indirect methods of verification might be used. These include exclusion of potential particles from the spacecraft surfaces in the first place, sterilisation of the surfaces at some point prior to re-entry into the Earth’s biosphere by direct or indirect means such as re-entry heating, and ensuring that surfaces are not contaminated after sterilisation via leakage. Initial sealing of the Mars sample can be assured to a high level of reliability via the use of a proven container concept along with a sealing concept that has been shown to be reliable to first order with a sensory back up system, utilising outgassing for example. Although sensory systems are limited, as previously mentioned, the combined low risk of failing to create a seal in the first place and the additional conditional probability of detection using leak detection sensors, should be able to provide the required level of assurance that the sample is encased within the magazine consistent with the risk of release requirement. However, it is possible that the sample magazine could be penetrated by a micrometeoroid during transit from Mars, thereby causing exterior contamination and release upon entry. While sensory systems that detect leakage might be limited in risk protection, potential sensory systems that would detect any penetration of the Earth Return Vehicle to a high level of reliability should be feasible. Upon return to Earth, the sample would still have to be transported from the landing site to the curation facility. While the Study Group was not tasked with considering human factors, it has to be highlighted that the use of human handling in this process and the transport itself entails the risk of human error and the potential for accidental release. For this reason, care must be taken to minimise human interaction with the sample and to provide adequate protection via transport containment to guard against an accident during transport to the curation facility.
For there to be a risk, as opposed to a hazard,
there must exist an event that would initiate an
exposure of the environment to the components of
the Mars sample. In principle, there are four main
ways for an environmental exposure to be initiated
from the accidental/deliberate release a Mars sample into the Earth’s biosphere:
 
Page 33
• A break-up of the container during atmospheric▼
entry (due to a design fault or sabotage),
• An unsuccessful full sterilisation of the Earth
Entry Capsule, potentially having Mars particles
attached to its outside surfaces,
• Damage to the vehicle due to heavy impact with▼
the Earth,
• Escape of material during transport or from the▼
laboratory.
 
▲{{bq|Release due to failure of containment or of the spacecraft surface sterilisation
In the first and (possibly) second cases, there is
 
potential for contamination over a quite wide area
For there to be a risk, as opposed to a hazard, there must exist an event that would initiate an exposure of the environment to the components of the Mars sample. In principle, there are four main ways for an environmental exposure to be initiated from the accidental/deliberate release a Mars sample into the Earth’s biosphere:
(especially if the capsule breaks up at high altitude).
 
However, the sample will be small (the quantity of
▲• A break-up of the container during atmospheric entry (due to a design fault or sabotage),
unsterilised particles even smaller) and therefore
• An unsuccessful full sterilisation of the Earth Entry Capsule, potentially having Mars particles attached to its outside surfaces,
deposition per unit area will be very low.
▲• Damage to the vehicle due to heavy impact with the Earth,
In the two latter cases, the release would be a
▲• Escape of material during transport or from the laboratory.
point source. Based on failure of containment of
 
pathogenic material in the past, it is reasonable to
In the first and (possibly) second cases, there is potential for contamination over a quite wide area (especially if the capsule breaks up at high altitude). However, the sample will be small (the quantity of unsterilised particles even smaller) and therefore deposition per unit area will be very low.
assume that the most likely cause of a release would
 
be due to human error or a deliberate human act
In the two latter cases, the release would be a point source. Based on failure of containment of pathogenic material in the past, it is reasonable to assume that the most likely cause of a release would be due to human error or a deliberate human act following the introduction of the material into the laboratory.
following the introduction of the material into the
laboratory.}}</ref> considers several possible failure modes with the sample container.
 
* The container could rupture if the parachute fails during the landing (rupture of a sample container has already occurred during the [[Sample_return_mission#Current|sample return of the Genesis capsule]]).
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This describes the issues, see the risk mitigation section for the solutions proposed for these issues.
 
The ESF report points out that the facility must also double as a clean room, to keep Earth micro-organisms away from the sample. As a result, this greatly adds to the complexity of the facility, and so to the risk of failure, since clean rooms and biohazard rooms have conflicting requirements (biohazard containment facilities are normally built with negative air pressure for instance, to keep organisms in, and clean rooms with positive air pressure to keep organisms out). It will be the first such facility ever to be built. [NEEDS CITE - NOT IN ESF REPORT]
 
The ESF report also points outsays that biohazard facilities are designed to contain known hazards. The new facility must contain unknown hazards as well. It'sand aknowledge muchabout harderMars problembiology to(if containany) unknownwill hazards,have especiallya withsteep thedevelopment diversitycurve.. of life forms now known to be potentially hazardous such as GTAs and ultramicrobacteria (as described above).▼
 
{{bq|Unless future Mars landers and/or rovers discover living organisms on Mars and gather significant information before a Mars sample is returned, knowledge about Mars biology (if any) will have a very steep development curve with an MSR: the sample will land overnight and the scientific investigations will have no or only limited preliminary steps. This differs significantly from, for example, the incremental development of synthetic biology that becomes increasingly complex, building upon past experience and experiments.}}
▲The ESF report also points out that biohazard facilities are designed to contain known hazards. The new facility must contain unknown hazards as well. It's a much harder problem to contain unknown hazards, especially with the diversity of life forms now known to be potentially hazardous such as GTAs and ultramicrobacteria (as described above).
 
Other risks mentioned in these studies, and by the Planetary Protection Office include the possibility of human error, accidents, natural disasters, security breach, actions by terrorist or 'activist' groups or crime, leading to release of the materials, once the samples are on the Earth surface.<ref name=esf2012_PP-crime-etc>{{cite report |title=A Draft Test Protocol for Detecting possible biohazards in martian samples returned to Earth|publisher=NASA |year=2002 |quote="ProceduresQuestions forabout handlingthe a breachadequacy of the SRF due to differentmaintain causesthe (e.g.new leak,life disasterform must also be addressed, securityincluding breachthe etc)possible shouldneed beto consideredadd inequipment, hechange developmentoperations, ofreview emergency plans, foror handlingupgrade athe breachfacilities because of what has been found. Concerns about security should also be reconsidered, epeciallyespecially in view of the potential disruptive activities of any terrorist or 'radical' groups that may be opposed to sample return. (page 10193) .... The breach could be the result of an accident or a crime - as a result of activity either outside or within containment (page 10496)"|url=httphttps://planetaryprotectiondiscovery.larc.nasa.gov/file_download/10pdf_files/MSRDraftTestProtocol.pdf}}</ref>
 
==== Target probabilities for proposed biohazard facilities ====
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{{bq|The release of a single unsterilised particle larger than 0.05 µm is not acceptable under any circumstance<ref name=esf2010_LAWKI/>}}
 
To deal with issues of the novelty of the facilities and of human error, the studies recommended that the receiving facility is operational and the staff trained several years before the Mars samples are brought into Earth's environment. The 2008 report of the IMARS working group report detailed a total of twelve years from initial planning to lander launch.<ref name=imars>[https://web.archive.org/web/20130124081409/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> Three architectural firms were approached who provided preliminary plans, the FLAD, IDC and LAS plans, the last of these, the LAS has a fully robotic work force to handle the samples.<ref>Jeremy Hsu [http://www.astrobio.net/exclusive/3329/keeping-mars-contained Keeping Mars Contained] Astrobiology Magazine 12/03/09</ref><ref>Beaty DW, Allen CC, Bass DS, Buxbaum KL, Campbell JK, Lindstrom DJ, Miller SL, Papanastassiou DA. [http://www.ncbi.nlm.nih.gov/pubmed/19845446?report=abstract Planning considerations for a Mars Sample Receiving Facility: summary and interpretation of three design studies.] Astrobiology. 2009 Oct;9(8):745-58. doi: 10.1089/ast.2009.0339.</ref><ref>[http://www.nap.edu/openbook.php?record_id=5563&page=31 Mars Sample Return: Issues and Recommendations](1997)] Task Group on Issues in Sample Return, National Research Council (page 31)</ref>
 
They were not asked to consider human factors and so do not report on ways to mitigate these, except to suggest that care must be taken to minimize human interaction with the sample.<ref name=esf2012_PP-human-factors>{{cite report |title=Mars Sample Return backward contamination - strategic advice |publisher= European Science Foundation |year=2012 |chapter=4.7 Potential verification methods"|urlhttpsurl=https://science.nasa.gov/science-pink/s3fs-public/atoms/files/ESF_Mars_Sample_Return_backward_contamination_study.pdf |quote=''While the Study Group was not tasked with considering human factors, it has to be highlighted that the use of human handling in this process and the transport itself entails the risk of human error and the potential for accidental release. For this reason, care must be taken to minimise human interaction with the sample and to provide adequate protection via transport containment to guard against an accident during transport to the curation facility.''}}</ref>
 
===Concerns about incubation period===
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