Background material for How Valuable is Pristine Mars for Humanity - Opinion Piece? for those who want to research into the official studies on back contamination issues and design of the Mars Sample Receiving Facility.

This is an article I wrote for wikipedia. It summarizes material from the United States National Research Council, the European Science Foundation, the Office of Planetary Protection and other mainstream studies on sample return missions and also covers some minority views. The Wikipedia article was merged away. Copying it to this blog post is permitted under the wikipedia CC By SA license. As required, this modified version is also released under CC By SA. I now have a copy in my Astrobiology encyclopedia as Planetary protection for a Mars sample return

There are several proposals for a Mars sample return mission (MSR) to bring back to Earth rock and dust samples from Mars to study. It is currently unknown whether or not life forms exist on Mars. If such life exists, a MSR could potentially transfer viable organisms resulting in a risk of back contamination — the introduction of extraterrestrial organisms into Earth's biosphere.

One of the early proposals for a Mars Receiving Facility - the LAS version with extensive use of robotic handlers for the samples

The NRC and ESF studies concluded that, though the potential for large-scale negative effects appears to be very low, it is not demonstrably zero[1] .

The NRC and ESF findings on risks of environmental disruption are accepted by most participants in this debate (with the notable exception of Robert Zubrin[2][3]). As a result, it is agreed by most researchers that a full and open public debate of the back contamination issues is needed at an international level.[4] This is also a legal requirement.[5][6]

Because of these concerns, there are proposals to build a Mars Sample Receiving Facility. This needs to be of a novel design, as it has to function both as a clean room and as a biohazard laboratory [7]

It also has to contain possibly novel unknown lifeforms. This page covers the results of studies by NASA and the ESA which examine the need for such a facility, and the risks that need to be mitigated. It also looks into issues of sample containment during return from Mars.

Contents

Plans to return a sample to Earth before detailed examination

A Mars Sample Return (MSR) to the Earth surface has been considered many times since the first proposal in 1979,[8] due to the high science value expected for carefully selected samples from Mars examined with the full range of facilities we have available on Earth.

NASA have no immediate plans for a MSR, but have considered proposals to return a Mars sample direct to Earth, possibly in the 2030s, in its Mars Next Generation program.[9][10] China also has considered a plan to return a sample by 2030.[11]

Samples returned under these proposals would be examined for biosignatures on Mars first, but the proposals suggested so far for a MSR to Earth do not include any plans for detailed examination on the Mars surface, such as with Scanning Electron Microscopes, DNA sequencers, or labelled culture experiments. Also the plans proposed so far do not include tests for biohazard potential in Earth-like environments prior to return to Earth. All these tests would instead be carried out on Earth after the sample return mission.[12]

As a result, these plans depend on adequate containment of the samples during the return journey and in the receiving facility on Earth until the tests can be completed on Earth.[12]

View presented in the NRC and ESF study group reports and Planetary Protection Office summaries

The view in the reports from the National Research Council[13] and the European Science Foundation,[14][15] as well as the Planetary Protection office[16] is as follows:

The risks of environmental disruption resulting from the inadvertent contamination of Earth with putative martian microbes are still considered to be low. But since the risk cannot be demonstrated to be zero, due care and caution must be exercised in handling any martian materials returned to Earth.[17]

To deal with these issues, the NASA Office of Planetary Protection[18] recommends construction of a special a Mars Receiving Facility. They recommend that the facility should be operational at least two years prior to launch,[19] with various estimates on the time taken to build the facility and bring it to operational readiness. Preliminary studies have warned that it may take as many as 7 to 10 years to get it operational.[20]

The official reports stress the need for public debate at the international level due to the ethical issues involved.

RECOMMENDATION 10: Considering the global nature of the issue, consequences resulting from an unintended release could be borne by a larger set of countries than those involved in the programme. It is recommended that mechanisms dedicated to ethical and social issues of the risks and benefits raised by an MSR are set up at the international level and are open to representatives of all countries.[21]

The aim of this article is to present in detail the results of the official NASA studies on the back contamination risks and the science benefits of a Mars sample return and the methods for risk mitigation.

The views of the ICAMSR (advocates against Mars sample return to Earth) and of Zubrin (advocate of the view that back contamination is not a legitimate scientific concern) will be left for separate discussion in another article.

Concerns and issues raised

First a brief overview of the issues.

  • Some researchers [22][23][24][25] are mainly concerned about issues of back contamination of Earth by accidentally released Martian micro-organisms.
  • Others are concerned about the high cost of a MSR on the basis that it will be some time before we know enough about Mars to select suitable samples to examine on Earth, and until then, run a high risk of returning bioligically uninteresting samples.[26][27]
  • Others are concerned that any samples would be contaminated by Earth life during the return journey, so reducing their value for scientific research.[28]

These issues of back contamination of Earth, selection of interesting samples on Mars, and sample contamination by Earth micro-organisms, are also raised in the official reports as well. It is generally agreed by almost all researchers that these are issues that need to be addressed in any plans for a MSR.

Back contamination concerns for a Mars sample return - historical background

These concerns were originally raised by Carl Sagan in 1973 in his book the Cosmic Connection,[22] and Carl Woese.,[23] and later by Lederberg [25]

Carl Woese, who first classified the Archaea, the third domain of life[29] said in an interview:

When the entire biosphere hangs in the balance, it is adventuristic to the extreme to bring Martian life here. Sure, there is a chance it would do no harm; but that is not the point. Unless you can rule out the chance that it might do harm, you should not embark on such a course.[23]

Carl Sagan wrote in his book Cosmic Connection:

...The likelihood that such pathogens exist is probably small, but we cannot take even a small risk with a billion lives.[22]

These concerns centre on the biohazard potential of martian lifeforms

Biohazard potential of martian life - historical background

The potential of Martian life to create a biohazard on Earth was first raised by Carl Sagan in 1973 in his book "Cosmic Connection".[22] The concern has been reviewed many times since then with the same or similar conclusions.

Sagan wrote:

Precisely because Mars is an environment of great potential biological interest, it is possible that on Mars there are pathogens, organisms which, if transported to the terrestrial environment, might do enormous biological damage - a Martian plague, the twist in the plot of H. G. Wells' War of the Worlds, but in reverse. This is an extremely grave point. On the one hand, we can argue that Martian organisms cannot cause any serious problems to terrestrial organisms, because there has been no biological contact for 4.5 billion years between Martian and terrestrial organisms. On the other hand, we can argue equally well that terrestrial organisms have evolved no defenses against potential Martian pathogens, precisely because there has been no such contact for 4.5 billion years. The chance of such an infection may be very small, but the hazards, if it occurs, are certainly very high..[22]

The microbiologist Joshua Lederberg made a similar point

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.[25]

These early concerns have been repeated in the detailed assessments by later study groups.

National Research Council review of biohazard potential of returned samples

The National Research Council review was undertaken in 2009 (and previously in 1997) and published as their "Assessment of Planetary Protection Requirements for Mars Sample Return Missions".[30] They confirm the earlier concerns as still a matter that needs attention.

This report is the basis for the later 2010 ESF report which is in agreement with its conclusions about the biohazard potential of any mars sample return.

They reviewed the then current research on relevant subjects, to come to their conclusion.

  • Potential for habitable conditions on Mars. They concluded that research since the last report has enhanced the prospect that habitable environments were once widespread on Mars, and has improved understanding of the potential for modern habitable environments, and "enhanced the possibility that living samples could be present in samples returned from Mars".[21][31]
  • Capability of micro-organisms to survive on Mars. To assess this, they reviewed recent research in microbial ecology in Chapter 3. They noted the discovery of new extremophiles in an increasing range of habitats, including highly acidic locations, conditions of extreme cold, of ephemeral habitability, and the capability of some micro-organisms to survive in dormant states for at least 250 million years. They noted the discovery of new organisms and ecological interactions.[32]They also noted the discovery of novel single-species ecosystems such as the one inhabited solely by the chemoautotrophic Candidatus Desulforudis audaxviator. Their conclusion was that these researches highlighted the potential of micro-organisms adapted to live in the Martian environment.[33]
  • Biohazard potential of any martian micro-organisms. They noted that extremophiles have not yet been shown to pose significant biological risk to humans. However in chapter 5, they note that there are comparative studies of extremophiles and of human pathogens "suggesting that evolutionary distances between nonpathogenic and pathogenic organisms can be quite small in some instances." As a result they concluded that the potential risks of biological epidemics can't be reduced to zero.[34]
  • Would the sample include micro-organisms not already delivered to Earth on martian meteorites? To assess this, they estimated that several meteorites a year probably impact Earth from Mars. So the transfer of sufficiently hardy life forms from Mars to Earth via meteorite seems plausible.[35] However, they observed that meteorites in current collections spent from 350,000 to 16 million years in space, and though theoretical models show that shorter transition periods are possible, concluded that the much shorter transit time of a sample return protected in a container could preserve lifeforms that would not survive the passage on a meteorite.[36]
  • Could martian lifeforms transferred to Earth in a meteorite have caused mass extinctions on Earth in the past? Their conclusion was that there is no evidence of this in the recent past but it could not be ruled out as a possibility in the more distant past.

Their overall conclusion was:

The committee found that the potential for large-scale negative effects on Earth's inhabitants or environment by a returned martian life form appears to be low, but is not demonstrably zero.

As with previous reports, the latest 2009 study recommended that the sample be treated as a biohazard until proved otherwise.[37]

ESF update on biohazard risks of MSR

The ESF report[14] accepts the general conclusions of the NRC report, but went beyond them in several areas. In particular they made a more detailed assessment of size limits of micro-organisms. Before this study, the accepted size limits [38] were 0.25 µm, derived from a 1999 workshop.[39]

The 2010 ESF study observed that the Mars sample could contain uncultivatable archaea, or ultramicrobacteria. It might contain Martian nanobacteria 0.1 µm if such exist. A recent concern is that it could contain virus-types and genetransfer agents as small as 0.03 µm in size, especially if Mars life and Earth life share a common ancestor at some point.[40] It might also contain forms of life that don't exist on Earth, possibly based on novel life chemistry, which makes it hard to set an absolute lower size.

For the nanobacteria, they accepted recent research that show these 0.1 µm sized cell like objects are mineral deposits, so ruled them out. They discussedultramicrobacteria and concluded that the smallest free-living self-replicating microorganisms observed are in the range of 0.12–0.2 µm.

They considered viruses, i.e. bacteriophages and viruses of archaea.[41] These they considered unlikely to be of concern if released from containment on their own, separately from their putative martian micro-organism host, because they require specific host adaptations to infect Terrestrial micro-organisms. [42]

They then studied GTAs, which cause cross species transfer of DNA in some species of archaea and bacteria. [43] Here they are referring to research reported in Nature and Science in 2010 (after the NRC report).[44][45] In one striking experiment the researchers left GTAs (conferring antibiotic resistance) and marine bacteria overnight in natural conditions and found that by the next day up to 47% of the bacteria had incorporated the genetic material from the GTAs : [46]

As a result of reviewing this research, the ESF study group concluded that the risk from virus type and GTA type entities is lower than for self replicating entities and "almost negligible" but still can't be demonstrated to be zero and should be taken account of in their minimum size recommendations.[47]

As a result, they recommended a minimum size of 0.01 µm on the basis that this is nearly half the size of the smallest GTAs known and less than a tenth of the size of the smallest currently known free-living self-replicating microorganisms.

In the case where 0.01 µm can't be achieved at a reasonable cost, and in view of the almost negligible risks from GTAs, they give 0.05 µm as a maximum permitted minimum size. This size was chosen as less than half that of the smallest currently known micro-organisms - so unlikely to contain a free-living microorganism. They recommend that such an increase of the minimum size requirement requires independent review by a panel of experts.[48]

However, in 3.7 Perspectives for the future, they added a caution that it is likely that minimum size limits for viruses and GTAs or free living organisms will reduce further in the future. They thought it unlikely that such a large reduction in size limits will happen again as happened after the 1999 report,[39] though that possibility also can't be completely ruled out.They recommended that the size limits should be continually reviewed depending on the latest research.[49]

Risk Mitigation for back contamination

NASA has addressed back contamination concerns with a proposal to build a special biohazard containment facility to receive the samples, and with a sample return mission designed to break the chain of contact with Mars for the exterior of the sample container[50][51]

In the European Science Foundation study, these risks were studied in more detail and recommendations made to reduce them to levels considered acceptable.

Concerns with integrity of the sample container

The 2010 ESF report[50] considers several possible failure modes with the sample container.

  • There is a low risk of an undetected failure to create a seal when the Mars sample is first enclosed in the container. Another risk is that "the sample magazine could be penetrated by a micrometeoroid during transit from Mars, thereby causing exterior contamination and release upon entry".[4][50][52]
  • If any part of the capsule exterior can be contaminated by Mars materials this provides a possibility of contamination of Earth.
  • Also human error, or management decisions could compromise the safety precautions taken for safe sample return.

Risk mitigation for sample container

  • Risk of rupture: This risk is reduced by requiring that the capsule is capable of withstanding the shock of impact at terminal velocity.
  • Risk of leaks or micrometeorite penetration: These risks are reduced by using multiple seals and use of methods to detect such leaks if they occur.
  • Risk of exterior contamination This risk is managed by a mission design that ensures that no surface that is exposed to the Mars environment is exposed to Earth. One way of doing this is to send another spacecraft to retrieve the container which receives it within the vacuum of space into a larger sealed container that has never been exposed to Mars and then is sealed and returned to Earth.[53][54]
  • Human error: This risk is reduced by training, redundancy, and making sure critical decisions are not made by tired astronauts.

Issues due to novelty of the proposed Biohazard facilities

This describes the issues, see the risk mitigation section for the solutions proposed for these issues.

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.[7]

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.[55]

Target probabilities for proposed biohazard facilities

The space studies board study recognised that the risks of release of hazardous particles from a MSR receiving facility can't be reduced to zero. So it is necessary to set a target probability of release that you aim to achieve.

Consequently, risk-mitigation strategies will focus on eliminating the hazard and/or reducing the probability of a negative event. Both will lead to a risk that is considered acceptable, since achieving zero risk is not possible.[56]

One suggestion for an acceptable level of risk was recommended by the ESF-ESSC Study Group

"Based on standards established and adopted at the national and international levels, the ESF-ESSC Study Group recommends that the probability of release of a potentially hazardous Mars particle shall be less than one in a million.".[50]

Risk mitigation for the MSR receiving facilities

To deal with the issues of unknown possibly very small forms of life in the sample, the ESF referred to their discussion of size limits (above) and concluded (Recommendation 7) that if possible, the facilities should be designed so that probability should be less than one in a million that a single unsterilised particle of 0.01 µm diameter or greater, if possible, and if that's not possible, that

The release of a single unsterilised particle larger than 0.05 µm is not acceptable under any circumstance[40]

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.[57] 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.[58][59][60]

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.[52]

Concerns about incubation period

Carl Sagan first raised this concern:

There is also the vexing question of the latency period. If we expose terrestrial organisms to Martian pathogens, how long must we wait before we can be convinced that the pathogen-host relationship is understood? For example, the latency period for leprosy is more than a decade.[22]

The WHO Leprosy fact sheet[61] gives the incubation period of leprosy, from first infection to onset of symptoms, as up to 20 years.

In the European Space Foundation report, incubation period is listed as the first of the list of unknowns that make it impossible to use standard models for the effects of a release and its consequences [62]

Risk mitigation for incubation period

The ESF report cite incubation period as one of the risk factors that make it "impossible to model the consequence of the potential release of a Mars organism".[63]

They observe that if the onset is slow and the effects are not unusual, significant spread may occur before the nature of the threat is realised.[64]

They recommend that potential release scenarios (including undetected release) are clearly defined and investigated, and response strategies developed for them.

They considered it critical that such containment strategies are implemented as soon as possible at the local level, and that they should include rapid detection of anomalies, effective warning procedures, and analysis, resistance and mitigation procedures.[65]

Views of the 2002 COMPLEX study of lessons to be learnt from the Apollo quarantine

The 2002 COMPLEX study reviewed the experience of the Apollo missions and came to the conclusion that handling of samples was successful even though the quarantine was a failure. They point out that a MSR would not have this human quarantine element.[66][67]

Probability assessment issues

The ESF study found that it is generally agreed that the probability that any martian micro-organism is biohazardous is low. However as no life forms outside of Earth have yet been studied or characterized, it is impossible to do a standard probability assessment.

This is covered in 4.2 Approaching the unknown and considering consequences in the ESF report, under unknown unknowns:

"This lack of knowledge, or uncertainty, prevents definitive conclusions from being reached on major factors that would allow for a real assessment of the risk of contamination posed by an MSR mission, including:
• Whether life exists on Mars or not
• If there are living organisms on Mars, it is not possible to define the probability of a sample (with a given size and mass) actually containing organisms

• If there are living organisms in the sample, it is not possible to definitively assess if (and how) a Mars organism can interact with the Earth’s biosphere."

They concluded that risk assessment has to be carried out by combining knowledge of Earth life with knowledge of Martian geology. They found that it is possible to establish the risk as low, as a consensus of the beliefs of the experts in the field as represented by their experience."

"On the latter point, there is consensus among the scientific community (and among the ESF-ESSC Study Group, as presented above) that the release of a Mars organism into the Earth’s biosphere is unlikely to have a significant ecological impact or other significant effects. However, it is important to note that with such a level of uncertainty, it is not possible to estimate a probability that the sample could be harmful or harmless in the classical frequency definition of probability (i.e. as the limit of a frequency of a collection of experiments). However it is possible to establish the risk as low, as a consensus of the beliefs of the experts in the field as represented by their experience."

Risk assessment survey of microbiologists

This survey shows the diversity of views amongst microbiologists with a special interest in astrobiology, and so may help as background for the ESF comments about uncertainty of probability assessments.

Caution, the respondents views were based on 1998 technology and science in a rapidly developing field. So is based on the biohazard containment capabilities, in situ analysis capabilities, and understanding of exobiology of the time. It is more useful as a way of indicating possibilities of a diversity of views, than as a direct indication of present day views amongst astrobiologists.

In 1998, the ecologist Margaret Race of the SETI Institute with Donald MacGregor of Decision Research [68] carried out a survey of microbiologists attending a special five-session colloquium titled “Prospecting for Extraterrestrial Microorganisms and the Origin of Life: An Exercise in Astrobiology”.[69] This survey showed a wide diversity of views amongst microbiologists, when asked for opinions on, for instance, whether there is life on Mars, and whether it could pose a threat to Earth.

  • Asked if they thought there is life on Mars, 40.3% agreed and 32.3% said “don’t know".
  • Asked whether life on Mars could pose a biological threat to Earth, 42.8% said “don’t know.”, 34.4% disageed, and 22.9% agreed.
  • Asked about our ability to predict with reasonable certainty how life elsewhere would impact our environment, 71.2% disagreed and 10.4% said "I don't know".
  • Asked about various quarantine proposals, approximately half of respondents said that the (then) current proposed methods of quarantine of the samples are either moderately or highly adequate. About a third said “don’t know,”
  • Asked if materials returned to Earth from Mars should be considered hazardous until proven otherwise, all agreed except for 1.5% saying “don’t know,”
  • Asked about the potential for in situ experiments done on the Martian surface to sufficiently determine the safety of Mars samples; 58.2% disagreed, and 21.9% said "Don’t know.”

The authors caution however

"We have at present no evidence that life exists on other planets or bodies in our solar system, thus the cautious views expressed by respondents in the present study reflect the professional responsibility that most members of scientific groups would express when faced with a paucity of real data."

Historical background1978 proposal for orbital Anteus receiving facilities for Mars Sample Return

The idea of a Mars Sample Receiving laboratory was first studied in 1978. The idea then was for an orbiting quarantine facility called Anteus to receive the samples.[8]

Other proposals were explored in the 1980s, including direct entry of sample container to Earth's atmosphere, recovery by the space shuttle, recovery to space station, recovery to a dedicated Antaeus space station, and several intermediate proposals.[70]

See also

(some are aarticles in my user space on wikipedia, will copy them all here)

Content released under CC By SA

This is material originally written for wikipedia and so is released under the CC By SA license In short, you can use it as you like, including commercially, but must credit me as the main author, and any modifications you make must be released under the same license.

Others contributed only very minor edits such as formatting, spelling, and rephrasing. You are not required to credit them.

References

  1. ^ "Assessment of Planetary Protection Requirements for Mars Sample Return Missions", National Research Council, 2009, chapter 5, "The Potential for Large-Scale Effects". "Thus, a key question posed to the committe is whether a putative martian organism or organisms, inadvertently released from containment, could produce large-scale negative pathogenic effects in humans or have a destructive impact on Earth's ecological system or environments." (page 45)
    They divide it into 3 categories
    • 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 product (page 45)

    They conclude that the last one is unlikely. But for the other two

    The committee found that the potential for large-scale negative effects on Earth's inhabitants or environment by a returned martian life form appears to be low, but is not demonstrably zero.(page 48)
  2. ^ Robert Zubrin "Contamination From Mars: No Threat", The Planetary ReportJuly/Aug. 2000, P.4–5
  3. ^ transcription of a tele-conference interview with ROBERT ZUBRIN conducted on March 30, 2001 by the class members of STS497 I, "Space Colonization"; Instructor: Dr. Chris Churchill
  4. ^ a b ?Mars Sample Return backward contamination - strategic advice?(Report). European Science Foundation. 2012. "RECOMMENDATION 10:Considering the global nature of the issue, consequences resulting from an unintended release could be borne by a larger set of countries than those involved in the programme. It is recommended that mechanisms dedicated to ethical and social issues of the risks and benefits raised by an MSR are set up at the international level and are open to representatives of all countries."
  5. ^ Mars Sample Return backward contamination – Strategic advice and requirements see 7.2: Responsibility and liability of States
  6. ^ M. S. Race Planetary Protection, Legal Ambiguity, and the Decision Making Process for Mars Sample Return Adv. Space Res. vol 18 no 1/2 pp (1/2)345-(1/2)350 1996
  7. ^ a b [http://www.lpi.usra.edu/pss/presentations/200803/04-Atlas-PPSonMSR.pdf ?Mars Sample Return Receiving Facility - A Draft Test Protocol for Detecting Possible Biohazards in Martian Samples Returned to Earth?] (Report). 2002. "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.

    • Such an integrated facility is not currently available.

    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    "
  8. ^ a b DAVID S. F. PORTREE Antaeus Orbiting Quarantine Facility (1978) 7th July, 2012
  9. ^ Dwayne Brown, Sarah DeWitt NASA Announces Robust Multi-Year Mars Program; New Rover to Close Out Decade of New Missions (note, proposed mission only, was postponed)
  10. ^ Wall, Mike (September 27, 2012). "Bringing Pieces of Mars to Earth: How NASA Will Do It (note, proposed mission only)". Space.com. Retrieved September 28, 2012.
  11. ^ Staff Writers (Oct 10, 2012). "China to collect samples from Mars by 2030". Mars Daily via Xinhua.
  12. ^ a b ?Vision and Voyages for Planetary Science in the Decade 2013-2022?(Report). 2013. "The site will be selected on the basis of compelling evidence in the orbital data for aqueous processes and a geologic context for the environment (e.g., fluvial, lacustrine, or hydrothermal). The sample collection rover must have the necessary mobility and in situ capability to collect a diverse suite of samples based on stratigraphy, mineralogy, composition, and texture.83 Some biosignature detection, such as a first-order identification of carbon compounds, should be included, but it does not need to be highly sophisticated, because the samples will be studied in detail on Earth"
  13. ^ ?Assessment of Planetary Protection Requirements for Mars Sample Return Missions? (Report). National Research Council. 2009.
  14. ^ a b European Science Foundation - Mars Sample Return backward contamination - strategic advice July, 2012, ISBN 978-2-918428-67-1. (for more details of the document see abstract )
  15. ^ Jeremy Hsu Keeping Mars Contained (illustrated with the FLAD, DC and LAS Mars Receiving Facility designs Astrobiology Magazine, 12/03/09
  16. ^ ?Mars Sample Return: Issues and Recommendations (Planetary Protection Office Summary)? (Report). Planetary Protection Office. 1997. "The potential for large-scale effects, either through pathogenesis or ecological disruption, is extremely small. Thus, the risks associated with inadvertent introduction of exogenous microbes into the terrestrial environment are judged to be low. However, any assessment of the potential for harmful effects involves many uncertainties, and the risk is not zero. ... The SSB task group strongly endorses NASA’s Exobiological Strategy for Mars Exploration (NASA, 1995). Such an exploration program, while likely to greatly enhance our understanding of Mars and its potential for harboring life, nonetheless is not likely to significantly reduce uncertainty as to whether any particular returned sample might include a viable exogenous biological entity-at least not to the extent that planetary protection measures could be relaxed."
  17. ^ ?Assessment of Planetary Protection Requirements for Mars Sample Return Missions? (Report). National Research Council. 2009.
  18. ^ NASA Office of Planetary Protection
  19. ^ Mars Sample Return: Issues and Recommendations (Planetary Protection Office Summary) Task Group on Issues in Sample Return. National Academies Press, Washington, DC (1997)
  20. ^ ?Assessment of Planetary Protection Requirements for Mars Sample Return Missions? (Report). National Research Council. 2009. p. 59. "It has been estimated that the planning, design, site selection, environmental reviews, approvals, construction, commissioning, and pre-testing of a proposed SRF will occur 7 to 10 years before actual operations begin.17,18,19 In addition, 5 to 6 years will likely be required for refinement and maturation of SRF-associated technologies for safely containing and handling samples to avoid contamination and to further develop and refine biohazard-test protocols. Many of the capabilities and technologies will either be entirely new or will be required to meet the unusual challenges of integration into an overall (end-to-end) Mars sample return program."
  21. ^ a b ?Assessment of Planetary Protection Requirements for Mars Sample Return Missions? (Report). National Research Council. 2009. p. 28. "The present committee found that the knowledge gained from both orbital and landed missions conducted over the past decade, combined with findings from studies of martian meteorites, has enhanced the prospect that habitable environments were once widespread over the surface of Mars. In addition, the potential for modern habitable environments, both as transient surface environments asnd as stable habitats in the deep subsurface, is much better understood. This understanding has, in turn, enhanced the possibility that living entities could be present in samples returned from Mars. Therefore the committee concurs with and expands on the 1997 recommendation that no uncontained martian materials should be returned to Earth unless sterilized."
  22. ^ a b c d e f Carl Sagan,The Cosmic Connection - an Extraterrestrial Perspective (1973) ISBN 0521783038
  23. ^ a b c Barry E. DiGregorio The dilemma of Mars sample return August 2001 Vol. 31, No. 8, pp 18–27. - for the quote from Carl Woese see his reference 54
  24. ^ International Committee Against Mars Sample Return.
  25. ^ a b c Joshua Lederberg Parasites Face a Perpetual Dilemma Volume 65, Number 2, 1999 / American Society for Microbiology News 77.
  26. ^ Jeffrey L. Bada, Andrew D. Aubrey, Frank J. Grunthaner, Michael Hecht, Richard Quinn, Richard Mathies, Aaron Zent, John H. Chalmers Seeking signs of life on mars: in situ investigations as prerequisites to sample return missionsIndependent Contribution to the Mars Decadal Survey Panel
  27. ^ Mars Exploration Strategies: Forget About Sample Return D. A. Paige, Dept. of Earth and Space Sciences, UCLA, Los Angeles, CA 90095
  28. ^ Genome Hunters Go After Martian DNA Antonio Regalado, Biomedicine News, MIT Technology Review, October 18, 2012
  29. ^ Carl Woese The Birth of the Archaea: a Personal Retrospective
  30. ^ Assessment of Planetary Protection Requirements for Mars Sample Return Missions, National Research Council, 2009
  31. ^ ?Assessment of Planetary Protection Requirements for Mars Sample Return Missions? (Report). National Research Council. 2009. p. 45. "While the existence of habitable conditions provides no guarantee that life ever originated on Mars, the possibility has increased that a martian life form, whether active, dormant, or fossil, could be included in a sample returned from Mars."
  32. ^ "Assessment of Planetary Protection Requirements for Mars Sample Return Missions", National Research Council, 2009, chapter 3, "Advances in Microbial Ecology".
  33. ^ ?Assessment of Planetary Protection Requirements for Mars Sample Return Missions? (Report). National Research Council. 2009. p. 41. "Geobiological studies of both modern and ancient Mars-relevant environments on Earth have highlighted the potential for samples returned from Mars to contain viable microorganism or their fossilized remains, while supporting the development of new approachs for in situ and laboratory detection of biosignatures in a variety of geological materials."
  34. ^ ?Assessment of Planetary Protection Requirements for Mars Sample Return Missions? (Report). National Research Council. 2009. p. 46. "As reviewed in Chapter 3, extreme environments on Earth have not yet yielded any examples of life forms that are pathogenic in humans. However, it is worth noting in this context that interesting evolutionary connections between alpha proteobacteria and human pathogens have recently been demonstrated for natural hydrothermal environments on Earth, suggesting that evolutionary distances between nonpathogenic and pathogenic organisms may be quite small in some instances. It follows that, since the potential risks of pathogenesis cannot be reduced to zero, a conservative approach to planetary protection will be essential, with rigorous requirements for sample containment and testing protocols."
  35. ^ ?Assessment of Planetary Protection Requirements for Mars Sample Return Missions? (Report). National Research Council. 2009. p. 47. "If the 1:100 ratio is accepted as being representative, then of the roughly 500 meteorites that fall on Earth every year, perhaps five are from Mars."
  36. ^ ?Assessment of Planetary Protection Requirements for Mars Sample Return Missions? (Report). National Research Council. 2009. p. 47. "Transit to Earth may present the greatest hazard to the survival of any microbial hitchhikers. Cosmic-ray-exposure ages of the meteorites in current collections indicate transit times of 350,000 to 16 million years. However theoretical modeling suggests that about 1 percent of the materials ejected from Mars are captured by Earth within 16,000 years and that 0.01 percent reach Earth within 100 years. Thus, survival of organisms in meteorites, where they are largely protected from radiation, appears plausible. If microorganisms could be shown to survive conditions of ejection and subsequent entry and impact, there would be little reason to doubt that natural interplanetary transfer of organisms is possible and has, in all likelihood, already occurred. ...It should be noted that martian materials transported to Earth via a sample return mission will spend a relatively short time (less than a year) in space - all the while protected in containers. (Note that researchers have yet to discover compelling evidence of life in any meteorite, martian or otherwise.) Thus the potential hazards posed for Earth by viable organisms surviving in samples is significantly greater with a Mars sample return than if the same organisms were brought to Earth via impact-mediated ejection from Mars."
  37. ^ "Assessment of Planetary Protection Requirements for Mars Sample Return Missions", National Research Council, 2009, chapter 5, "The Potential for Large-Scale Effects". "Thus, a key question posed to the committe is whether a putative martian organism or organisms, inadvertently released from containment, could produce large-scale negative pathogenic effects in humans or have a destructive impact on Earth's ecological system or environments." (page 45)They divide it into 3 categories
    • 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.
    (page 45)

    They conclude that the last one is unlikely. But for the other two

    The committee found that the potential for large-scale negative effects on Earth's inhabitants or environment by a returned martian life form appears to be low, but is not demonstrably zero.
    (page 48)
  38. ^ Mars Sample Return backward contamination – Strategic advice and requirements see 3. Life as we know it and size limits
  39. ^ a b Size Limits of Very Small Microorganisms: Proceedings of a Workshop ( 1999 ) see Page 2 for the quote, "Given the uncertainties inherent in this estimate the panel agreed that 250 ± 50 nm as a reasonable lower limit for life as we know it"
  40. ^ a b European Science Foundation - Mars Sample Return backward contamination - strategic advice - (see Life as we know it and size limits) - February 23, 2010
  41. ^ David Prangishvili, Patrick Forterre and Roger A. Garrett Viruses of the Archaea: a unifying view - 2006
  42. ^ Quote from the ESF report
    However, as stated above viruses are not able to reproduce by themselves but need a host organism. For potential consequences on the Earth’s biosphere either these putative virus-type Mars entities have to be able to use a terrestrial cell as host, which would require a very specific and sophisticated adaptation to these cell types, or the putative Martian host has to be present in the same Martian sample and has to be alive and metabolically active to enable the replication of that entity
  43. ^ Quote from the ESF report In 3.5 Gene transfer agents (GTAs) they write:

    GTAs resemble small bacteriophages, ranging in size from 30 to 80 nm with 4.4 to 13.6 kb DNA. A universal characteristic of GTAs is that they randomly incorporate segments of the host genome into the viral capsid where they can transfer this to different hosts, including phylogenetically unrelated bacteria and archaea, without resulting in lysis of the host cell. In this manner, it is believed that it is possible for GTAs to incorporate any of the host genes during replication....

    While many questions remain about the origin of GTAs, their prevalence in different species of bacteria and archaea, and their host range including cross-domain infection, there is evidence that a large portion of marine viromes consist of GTAs. Surprisingly, it is now estimated that GTA transduction rates are more than a million times higher than previously reported for viral transduction rates in marine environments. Clearly, GTAs are a major source of genetic diversity in marine bacteria....

  44. ^ Amy Maxmen Virus-like particles speed bacterial evolution published online 30 September 2010
  45. ^ Lauren D. McDaniel, Elizabeth Young, Jennifer Delaney, Fabian Ruhnau, Kim B. Ritchie, John H. Paul High Frequency of Horizontal Gene Transfer in the Oceans Science 1 October 2010: Vol. 330 no. 6000 p. 50 DOI: 10.1126/science.1192243
  46. ^ Quote from the New Scientist article
    The researchers sealed these GTAs in bags filled with seawater collected from different coastal environments, and floated the bags in the ocean to mimic natural conditions as closely as possible. After incubation overnight, up to 47% of the bacteria living in the seawater-filled bags had incorporated the particles and their genetic contents into their genomes
  47. ^ Quote from the ESF report In 3.6 From new knowledge to new requirements:
    The Study Group also concurs with another conclusion from the NRC reports that the potential for large-scale effects on the Earth’s biosphere by a returned Mars life form appears to be low, but is not demonstrably zero. It adds that if this risk appears to be low for free-living self-replicating organisms, considering their specificities and replication requirements, the potential risk posed by virus-type and gene transfer agent-type entities can be considered to be far lower and almost negligible, but still cannot be demonstrated to be zero.
  48. ^ Quotes from the ESF report
    Unsterilised particles smaller than 0.01 µm would be unlikely to contain any organisms, whether free-living self-replicating (the smallest free-living self-replicating microorganisms observed are in the range of 0.12–0,2 µm, i.e. more than one order of magnitude larger), GTA-type (the smallest GTA observed is 0,03 µm, i.e. three times larger) or virus-type (the smallest GTA observed is 0,017 µm, i.e. almost twice as large). This level should be considered as the bottom line basic requirement when designing the mission systems and operation.
    They then go on in view of the almost negligible chance of a GTA potential for large-scale effects on the Earth's biosphere, that
    The release of particles larger than 0.01 µm but smaller than 0.05µm can be considered as tolerable if it can be demonstrated that such a range is the best achievable at reasonable cost.

    They recommend that in that case the requirements would need to be independently reviewed by a panel of experts to determine if it is the best that can be achieved at reasonable cost and if the risk is tolerable.

    Any release of a single unsterilised particle larger than 0.05 µm is not acceptable. The ESF-ESSC Study group considers that a particle smaller than 0.05 µm would be unlikely to contain a free-living microorganism, but that larger particles may bear such an organism. As self-replicating free-living organisms are likely to be the main concern following a release event, the study group considers that the release of a particle larger than 0.05 µm is not acceptable under any circumstance.
  49. ^ Quote from the ESF report
    Based on our current knowledge and techniques (especially genomics), one can assume that if the expected minimum size for viruses, GTAs or freeliving microorganisms decreases in the future, and this is indeed possible, it will be at a slower pace than over the past 15 years.However, no one can disregard the possibility that future discoveries of new agents, entities and mechanisms may shatter our current understanding on minimum size for biological entities. As a consequence, it is recommended that the size requirement as presented above is reviewed and reconsidered on a regular basis.
  50. ^ a b c d European Science Foundation - Mars Sample Return backward contamination - strategic advice February 23, 2010, ISBN 978-2-918428-67-1 - see Back Planetary Protection section. (for more details of the document seeabstract )
  51. ^ Jeremy Hsu Keeping Mars Contained Astrobiology Magazine, 12/03/09
  52. ^ a b ?Mars Sample Return backward contamination - strategic advice?(Report). European Science Foundation. 2012. "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."
  53. ^ Mars Sample Return Using Commercial Capabilities: ERV Trajectory and Capture Requirements Details of one way such a return could be done, by first returning sample to moon orbit. There the return vehicle is left in orbit around the Moon and the sample is then transferred to the interior of a larger container sent from Earth on a SpaceX dragon capsule. This larger capsule is then sealed and returned to Earth.
  54. ^ Mars Sample Return: Mars Ascent Vehicle Mission and Technology Requirements NASA Technical Report
  55. ^ ?A Draft Test Protocol for Detecting possible biohazards in martian samples returned to Earth? (Report). NASA. 2002. ""Procedures for handling a breach of the SRF due to different causes (e.g. leak, disaster, security breach etc) should be considered in he development of plans for handling a breach. Concerns about security should also be reconsidered, epecially in view of the potential disruptive activities of any terrorist or 'radical' groups that may be opposed to sample return (page 101) .... The breach could be the result of an accident or a crime - as a result of activity either outside or within containment (page 104)""
  56. ^ Assessment of Planetary Protection Requirements for Mars Sample Return Missions (2009) Space Studies Board
  57. ^ Preliminary Planning for an International Mars Sample Return MissionReport of the International Mars Architecture for the Return of Samples (iMARS) Working Group, June 1, 2008
  58. ^ Jeremy Hsu Keeping Mars Contained Astrobiology Magazine 12/03/09
  59. ^ Beaty DW, Allen CC, Bass DS, Buxbaum KL, Campbell JK, Lindstrom DJ, Miller SL, Papanastassiou DA. 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.
  60. ^ Mars Sample Return: Issues and Recommendations(1997)] Task Group on Issues in Sample Return, National Research Council (page 31)
  61. ^ Leprosy Fact Sheet World Health Organization
  62. ^ European Science Foundation - Mars Sample Return backward contamination - strategic advice - (see 5.3 Direct consequences for human health) - July, 2012
  63. ^ quote and paraphrase
    • "Incubation period
    • Transmissibility from person to person/number of secondary cases per infected individual
    • Time window of transmission
    • Case fatality rate
    • Hospitalisation of patients – hospitals can increase transmission and amplify outbreaks
    • Transmission routes (aerosol, ingestion, etc.)
    • Survival/reproduction in the environment
    • Can it infect animals/plants
    • Duration of the symptomatic phase"

    Since all these factors are unknown, they concluded that "it is impossible to model the consequence of the potential release of a Mars organism".

  64. ^ quote and paraphrase

    "From a crisis management position, if the effects of the release are unusual and of rapid onset, it is most likely that the causative agent will be identified fairly quickly and actions can be taken to try to limit the spread. However, if the onset is slow and the effects are not unusual, significant spread may occur before the nature of the threat is realised.

    If the Mars life form has an unknown, fundamentally different biochemistry to life forms on Earth but nonetheless is able to cause adverse consequences in the Earth’s biosphere, this must be considered to be an extreme worst case scenario. If this were to be the case, a major rethink of the applicability of current strategies for dealing with pathogens would be required. Some of the questions that could arise include:

    • Can it be assumed that the consequences are limited to one or a few species?
    • Are currently available biocides effective?
    • How can the presence of the life form(s) be detected?
    • Susceptibility of population"

    They considered the extreme worst case scenario, where the Mars life form has an unknown, fundamentally different biochemistry to life forms on Earth but nonetheless is able to cause adverse consequences in the Earth’s biosphere. They identiried several factors that would need to be evaluated to help contain the hazard.

    • Can it be assumed that the consequences are limited to one or a few species?
    • Are currently available biocides effective?
    • How can the presence of the life form(s) be detected?
    • Susceptibility of population

  65. ^ ?Mars Sample Return backward contamination - strategic advice? (Report). European Science Foundation. 2012. "It is critical that such strategies are designed to be implemented as soon as possible and at the local level and that they encompass:
    • observation of pre-defined indicators
    • rapid detection of anomalies
    • effective warning procedures
    • analysis, resistance and mitigation procedures    "
  66. ^ Quote from http://www.nap.edu/openbook.php?record_id=10138&page=60

    The preliminary examination, curation, and distribution for study of lunar samples from the LRL were generally successful. A community of outside investigators had been selected and funded by the time the Apollo 11 crew returned to Earth, and they had had some time to equip their laboratories and simulate analyses of lunar samples. Real lunar samples were distributed to them a few weeks after Apollo 11 (and subsequent missions) returned to Earth. The samples were allocated in a reasonably rational way, and with some exceptions they were protected from serious contamination.

    On the other hand, the quarantine program would have to be judged a failure. It greatly complicated sample processing, yet if lunar material had contained lethal microorganisms Earth would have been infected in two places: the Pacific Ocean, and Houston, Texas.
  67. ^ The Quarantine and Certification of Martian Samples National Academy Press (2002), Chapter 8, Conclusions and Recommendations (page 60)
  68. ^ decisionresearch.org
  69. ^ Donald MacGregor (Decision Research) Margaret S. Race, (SETI Institute)Microbiologists’ Perceptions of Planetary Protection
  70. ^ Mars Sample Recovery&Quarantine (1985) DAVID S. F. PORTREE 02.14.13