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Mars 2020/Curiosity and planetary protection by Blackstar on 04 Aug, 2017 18:38
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A good discussion of the current issues:
http://www.sciencemag.org/news/2017/08/planetary-protection-office-grabs-scientists-rail-against-limits-mars-exploration
With planetary protection office up for grabs, scientists rail against limits to Mars exploration
By Paul VoosenAug. 3, 2017 , 2:00 PM
Since its arrival on Mars in 2012, NASA’s Curiosity rover has zapped and drilled ancient rocks in the hopes of finding evidence for past life. But it may never get a chance to investigate something far more exciting: the possibility that martian microbes exist today. In the coming years, as the rover trundles up the side of Aeolis Mons, it will pass rocks that, seen from orbit, seem to host mysteriously intermittent dark streaks—perhaps marking seasonal water seeps. But NASA’s planetary protection office, charged with keeping earthly microbes from colonizing other bodies, has said it may nix a visit. It fears that Curiosity could contaminate this so-called special region because the rover was not fully sterilized before launch.
To Alberto Fairén, a planetary scientist at Cornell University, that makes no sense. Sooner or later humans—biped rovers that can’t be sterilized—will set foot on the planet, hopelessly confounding any hope of finding indigenous life, he and several colleagues argue in an op-ed in press this month in the journal Astrobiology. “We need to investigate Mars’s special regions carefully and fully prior to human missions,” he says.
Bureaucratic changes at NASA could create an opening for his view, which some Curiosity team members share. In July, NASA announced, through a blunt job posting, that the planetary protection office was moving out of its longtime home in the science directorate to NASA’s Office of Safety and Mission Assurance in Washington, D.C., a place more accustomed to translating protocols into engineering practice. Cassie Conley, the planetary protection office’s longtime chief, will face competition to keep her job, and she could be replaced by someone with less strict views on sterilization requirements. Meanwhile, by the end of this year, the National Academies of Sciences, Engineering, and Medicine are expected to complete a head-to-toe examination of how the office works and whether it keeps abreast with current science, and later this year NASA is holding a major workshop that could lead to a redefinition of special regions on Mars, the warm and wet areas that are off-limits for all but the most sterile of spacecraft.
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#1 by Vultur on 09 Aug, 2017 03:51
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IMO these concerns are long out of date.
Modern technology -- metagenomics -- allows us to distinguish between Earth life and alien life.
If its DNA is recognizable, it's contamination. If it doesn't have DNA, or its DNA falls outside Earth's tree of life, it's native life (or transferred by meteors in an early era of the Solar System).
Contamination will not "hopelessly [confound] any hope of finding indigenous life". Curiosity's or Mars 2020's instruments may not be able to tell the difference, but current technology is entirely capable of making the distinction. -
#2 by Lar on 09 Aug, 2017 04:23
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I think life evolved here, and if it evolved elsewhere it was independent. But that's a belief. Assuming that all DNA can be categorized as contamination or not is perhaps a bit of folly. If all that can be found are fragments, it's not for sure they are or aren't brought from modern times earth.
I consider the "earth life was seeded from elsewhere" theory REALLY remote. But am not willing to rule it out entirely absent evidence.
And yet I still think that Curiousity should go investigate this wet area. -
#3 by Star One on 09 Aug, 2017 08:08
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I think life evolved here, and if it evolved elsewhere it was independent. But that's a belief. Assuming that all DNA can be categorized as contamination or not is perhaps a bit of folly. If all that can be found are fragments, it's not for sure they are or aren't brought from modern times earth.
I consider the "earth life was seeded from elsewhere" theory REALLY remote. But am not willing to rule it out entirely absent evidence.
And yet I still think that Curiousity should go investigate this wet area.
I think it's more likely that if life started on Mars it could have either seeded Earth or vice a versa. The two planets exchange so much material that this likelihood must be considered reasonable high that if life occurred Mars that both planets have a common origin. -
#4 by Dalhousie on 22 Aug, 2017 01:54
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Sooner or later humans—biped rovers that can’t be sterilized—will set foot on the planet, hopelessly confounding any hope of finding indigenous life,
I find this statement staggeringly silly. If true then it would be impossible to determine the ancestry of life on earth because of cross contamination.
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#5 by Star One on 22 Aug, 2017 06:45
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Sooner or later humans—biped rovers that can’t be sterilized—will set foot on the planet, hopelessly confounding any hope of finding indigenous life,
Nature does not arrange things for humanities convenience.
I find this statement staggeringly silly. If true then it would be impossible to determine the ancestry of life on earth because of cross contamination. -
#6 by Blackstar on 28 Aug, 2017 21:59
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http://spacenews.com/nasa-proposes-rapid-mars-sample-return-architecture/
NASA proposes rapid Mars sample return architecture
by Jeff Foust — August 28, 2017
WASHINGTON — NASA is studying a “lean” architecture for Mars sample return that could allow the agency to bring back Martian rocks as soon as the end of the 2020s.
The concept, discussed at an Aug. 28 meeting of a National Academies committee performing a midterm review of the 2011 planetary science decadal survey, would focus on getting samples cached by the upcoming Mars 2020 mission off the planet and back to Earth as soon as possible.
“This is a much more lean architecture,” said Thomas Zurbuchen, NASA associate administrator for science. “It goes straight for what I would consider the jugular issue, which is how to land and take off the planet.”
The concept, which he said is just one of many the agency is looking into, would involve the launch of a Mars lander no earlier than 2026, equipped with a sample collection rover and a rocket, known as a Mars ascent vehicle. The spacecraft would land near the Mars 2020 landing site and dispatch its rover to collect the samples cached by the earlier mission, returning them to the lander.
Those samples would be loaded onto the Mars ascent vehicle on the lander, which would then launch them into Mars orbit. A sample collection orbiter, launched separately, would then rendezvous and grab the sample for a return either direct to Earth or to cislunar space.
Zurbuchen didn’t give an explicit schedule for when those samples would arrive back at Earth. A “notional” timeline presented in one chart showed the sample collection lander launching at the beginning of “Year 1” with the samples arriving back on Earth in the latter half of “Year 3.”
That rapid schedule would require the sample collection lander to deploy its rover, pick up the cached samples, and return them for launch into Mars orbit in just nine months. That largely rules out putting scientific instruments on that collection rover. “I’m sure somebody’s going to ask me to add science,” he said, “and they better have a really, really, really good argument.”
That emphasis on a near-term timeframe and rapid pace of the mission, he said, would eliminate the need to launch another spacecraft to serve as a communications relay. A schedule with a launch in 2026, he said, could use existing spacecraft in Mars orbit, including Mars Reconnaissance Orbiter (MRO), MAVEN and Europe’s Trace Gas Orbiter, which are currently being used or have the ability to be used as communications relays for spacecraft on the surface. The sample collection orbiter could also be used for communications, he said.
“If we go relatively quickly, I don’t need another orbiter,” he said. Should the launch of the sample collection lander be delayed beyond 2026, he said, he would be “less comfortable” with that approach as those existing spacecraft age.
This approach, he added, also provided opportunities for collaboration with both international and commercial partners. That includes, he said, buying communications services from commercial providers. “If you could buy communications by the yard, that’s a lot cheaper,” he said.
That led some meeting attendees to conclude that NASA was losing interest in a future Mars orbiter, known as Next Mars Orbiter or NEMO. That spacecraft, proposed for launch as soon as 2022, would handle both the communications and high-resolution imaging roles of MRO, supporting both sample return missions as well as later human missions to the planet.
“If we manage to do something relatively rapidly, the answer is yes,” Zurbuchen said when asked if this architecture meant no need for another orbiter mission.
That emphasis on sample return could be worth the expense — for which he did not provide an estimate in his presentation — if the science it produces is “civilization scale” in nature, he said. “It’s the kind of science that, once we do it, changes not only what we know but how we think.”
He asked the committee, which is reviewing how NASA is implementing the recommendations of the planetary science decadal survey, to deliberate on the scientific importance of Mars sample return. “The question really is how important is sample return, and how important sample return is going forward for the future of the Mars program,” he said. -
#7 by Star One on 29 Aug, 2017 18:52
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Here's SN's article on the same topic. Will not quote as it's a pretty lengthy one.
https://spaceflightnow.com/2017/08/28/nasa-studies-mission-to-return-samples-from-mars-by-end-of-2020s/ -
#8 by Blackstar on 29 Aug, 2017 20:41
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Here is the presentation.
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#9 by savuporo on 30 Aug, 2017 01:51
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That largely rules out putting scientific instruments on that collection rover. “I’m sure somebody’s going to ask me to add science,” he said, “and they better have a really, really, really good argument.”
In other words, this idea won't go anywhere. -
#10 by Blackstar on 30 Aug, 2017 19:03
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That largely rules out putting scientific instruments on that collection rover. “I’m sure somebody’s going to ask me to add science,” he said, “and they better have a really, really, really good argument.”
In other words, this idea won't go anywhere.
Some people might have a say about that... -
#11 by saliva_sweet on 26 Oct, 2017 08:39
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I think it's more likely that if life started on Mars it could have either seeded Earth or vice a versa. The two planets exchange so much material that this likelihood must be considered reasonable high that if life occurred Mars that both planets have a common origin.
And I think it's entirely conceivable that the whole idea of planetary protection is unworkable because every solid body of any meaningful size in the solar system up to the kuiper belt may already be contaminated by earthly (or wherever they arose) bacteria. Just due to their sheer numbers, resilience and the four billion years they have existed. -
#12 by Dalhousie on 16 Nov, 2017 22:21
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Saying there will be no science instruments is a bit silly since the rover will have cameras, which are scientific instruments. Useful data can also be obtained from from the engineering data as well. So I think a post sample retrieval and delivery collecting at least basic science data is both feasible and desirable.
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#13 by Torbjorn Larsson, OM on 18 Nov, 2017 15:37
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I think it's more likely that if life started on Mars it could have either seeded Earth or vice a versa. The two planets exchange so much material that this likelihood must be considered reasonable high that if life occurred Mars that both planets have a common origin.
And I think it's entirely conceivable that the whole idea of planetary protection is unworkable because every solid body of any meaningful size in the solar system up to the kuiper belt may already be contaminated by earthly (or wherever they arose) bacteria. Just due to their sheer numbers, resilience and the four billion years they have existed.
The contamination issue is mostly practical, how to discern against brought contamination or its potential activity. As Vulture points out we should be able to discern clades that does not derive from our own universal ancestor lineage, there is now a fairly robust gene set associated with it. (See e.g. Martin et al.) Re Lar's comment the UCA lineage is also, arguably, associated with Earth conditions (early and ocean alkaline hydrothermal vents, correlated with early and ocean life) the whole way, so the likelihood for transpermia to Earth has gone from "low" to "low and arguable".
There was a paper modeling Earth's transpermia potential a few years ago. The outer limit goes at Saturn where an ice moon of Enceladus's collisional front area average one hypervelocity impactor caused ejecta during 4 billion years. Seeing how we now know that the global ocean of Enceladus is 4 billion years old it will be an interesting test case if we find life there. [And I saw today that Breakthrough Initiative is looking into sponsoring a rapidly developed ejecta life search experiment, likely using low cost solar sail technology as per the associated interview.] -
#14 by Star One on 27 Nov, 2017 19:11
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This paper seems appropriate for this thread.
Searching for Life on Mars Before It Is Too LateQuoteDecades of robotic exploration have confirmed that in the distant past, Mars was warmer and wetter and its surface was habitable. However, none of the spacecraft missions to Mars have included among their scientific objectives the exploration of Special Regions, those places on the planet that could be inhabited by extant martian life or where terrestrial microorganisms might replicate. A major reason for this is because of Planetary Protection constraints, which are implemented to protect Mars from terrestrial biological contamination. At the same time, plans are being drafted to send humans to Mars during the 2030 decade, both from international space agencies and the private sector. We argue here that these two parallel strategies for the exploration of Mars (i.e., delaying any efforts for the biological reconnaissance of Mars during the next two or three decades and then directly sending human missions to the planet) demand reconsideration because once an astronaut sets foot on Mars, Planetary Protection policies as we conceive them today will no longer be valid as human arrival will inevitably increase the introduction of terrestrial and organic contaminants and that could jeopardize the identification of indigenous martian life. In this study, we advocate for reassessment over the relationships between robotic searches, paying increased attention to proactive astrobiological investigation and sampling of areas more likely to host indigenous life, and fundamentally doing this in advance of manned missions. Key Words: Contamination—Earth Mars—Planetary Protection—Search for life (biosignatures). Astrobiology 17, 962–970.
Rest of the paper.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5655416/ -
#15 by Dalhousie on 28 Nov, 2017 04:50
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This paper seems appropriate for this thread.
Searching for Life on Mars Before It Is Too LateQuoteDecades of robotic exploration have confirmed that in the distant past, Mars was warmer and wetter and its surface was habitable. However, none of the spacecraft missions to Mars have included among their scientific objectives the exploration of Special Regions, those places on the planet that could be inhabited by extant martian life or where terrestrial microorganisms might replicate. A major reason for this is because of Planetary Protection constraints, which are implemented to protect Mars from terrestrial biological contamination. At the same time, plans are being drafted to send humans to Mars during the 2030 decade, both from international space agencies and the private sector. We argue here that these two parallel strategies for the exploration of Mars (i.e., delaying any efforts for the biological reconnaissance of Mars during the next two or three decades and then directly sending human missions to the planet) demand reconsideration because once an astronaut sets foot on Mars, Planetary Protection policies as we conceive them today will no longer be valid as human arrival will inevitably increase the introduction of terrestrial and organic contaminants and that could jeopardize the identification of indigenous martian life. In this study, we advocate for reassessment over the relationships between robotic searches, paying increased attention to proactive astrobiological investigation and sampling of areas more likely to host indigenous life, and fundamentally doing this in advance of manned missions. Key Words: Contamination—Earth Mars—Planetary Protection—Search for life (biosignatures). Astrobiology 17, 962–970.
Rest of the paper.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5655416/
I think it takes an unnecessarily gloomy view of our ability to discover non-terrestrial microbial lineages (if they exist). If the assumptions of this paper were correct, we would not be able to do such work on Earth. -
#16 by Watchdog on 26 Dec, 2017 20:15
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This task is not simple, and yes there is a conflict between protecting these hypothetical life forms from human exploration activities. We not only need to consider "contamination", but also destruction of these potential life forms by consumption or changing environmetal parameters. Bacteria from earth may simply eat them up, phages could find them a good place to replicate, unicellular or multicellular eukaryotic organisms could also start to wipe them out.
How do we protect endangered species on earth? (1) We isolate and propagate them in safe conditions which are artifical but resemble their original conditions. There might be not enough time to comprehensively collect and preserve these hypothetical species. By the way, microbial life forms on Mars could not only be bacteria, they may have evolved to unicellular algae and even multicellular organisms of any kind possessing strange metabolisms very useful to study.
(2) Conservation areas may not only protect the martian life forms from anthropogenic interfereces, but also protect astronauts from any negative impact caused by these organisms on human physiology. The trick could be to find almost completely sterile regions on Mars and send the first settlers there and isolated them as good as possible from the environment. They have to live in enclosed structures anyway to ensure permanent life support. It should not be a big problem to sterilize anything what humans throw away or deposit on Mars. The necessary infrastructur should be part of the first logistics missions. Recycling is mandatory where ever possible.
Even if it turns out, what most scientists assume, that Mars does not harbor any active life forms, planetary protection issues must not be underestimated and need to be weighted carefully against our desire to discover and explore. -
#17 by Dalhousie on 13 May, 2018 06:12
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This task is not simple, and yes there is a conflict between protecting these hypothetical life forms from human exploration activities. We not only need to consider "contamination", but also destruction of these potential life forms by consumption or changing environmetal parameters. Bacteria from earth may simply eat them up, phages could find them a good place to replicate, unicellular or multicellular eukaryotic organisms could also start to wipe them out.
It's extremely unlikely that terrestrial bacteria will eat up any hypothetical martian microbes. The environment will be too hostile for terrestrial organisms to thrive, indigenous forms will out compete them. We see that on Earth. Nor is it likely that that they will eat them, biochemistry will be too alien. As for phages, they are highly adapted to narrow ranges of taxa, it's rare for any disease to jump species barriers, an martian life will be unlikely to have compatible DNA or even DNA at all.
How do we protect endangered species on earth? (1) We isolate and propagate them in safe conditions which are artifical but resemble their original conditions. There might be not enough time to comprehensively collect and preserve these hypothetical species. By the way, microbial life forms on Mars could not only be bacteria, they may have evolved to unicellular algae and even multicellular organisms of any kind possessing strange metabolisms very useful to study.Quote(2) Conservation areas may not only protect the martian life forms from anthropogenic interfereces, but also protect astronauts from any negative impact caused by these organisms on human physiology. The trick could be to find almost completely sterile regions on Mars and send the first settlers there and isolated them as good as possible from the environment. They have to live in enclosed structures anyway to ensure permanent life support. It should not be a big problem to sterilize anything what humans throw away or deposit on Mars. The necessary infrastructur should be part of the first logistics missions. Recycling is mandatory where ever possible.
likewise it is extremely unlikely that organisms adapted to martian conditions, will survive in the human body. It is just too hostile for them.QuoteEven if it turns out, what most scientists assume, that Mars does not harbor any active life forms, planetary protection issues must not be underestimated and need to be weighted carefully against our desire to discover and explore.
Unfortunately what is happening is that planetary protection is more likely to be over-estimated rather than under-estimated. -
#18 by hop on 13 May, 2018 21:32
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likewise it is extremely unlikely that organisms adapted to martian conditions, will survive in the human body. It is just too hostile for them.
Pretty much everyone who works on the subject agrees it's "unlikely". The problem is we have no basis to quantify how unlikely. So if your requirement is, say, to ensure the probability of back contamination to earth is less then 1 in a million, you can't just say that "the odds of Mars life being able to infect Earth live are lower than that so we're done." (edit: oops, that was supposed to be "can't" not "can"
)QuoteUnfortunately what is happening is that planetary protection is more likely to be over-estimated rather than under-estimated.
There's important context for the increasing paranoia of PP: We kept thinking that life wouldn't survive in various environments, and then finding it in those environments when instrumentation improved. Undoubtedly this must end somewhere, but the experience suggests that a gut instinct "nothing can survive that" isn't reliable. -
#19 by Dalhousie on 14 May, 2018 00:00
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likewise it is extremely unlikely that organisms adapted to martian conditions, will survive in the human body. It is just too hostile for them.
Pretty much everyone who works on the subject agrees it's "unlikely". The problem is we have no basis to quantify how unlikely. So if your requirement is, say, to ensure the probability of back contamination to earth is less then 1 in a million, you can just say that "the odds of Mars life being able to infect Earth live are lower than that so we're done."QuoteUnfortunately what is happening is that planetary protection is more likely to be over-estimated rather than under-estimated.
There's important context for the increasing paranoia of PP: We kept thinking that life wouldn't survive in various environments, and then finding it in those environments when instrumentation improved. Undoubtedly this must end somewhere, but the experience suggests that a gut instinct "nothing can survive that" isn't reliable.
We still are yet to find anything that will survive on the surface of Mars. The subsurface is a different story. But for all the talk of special regions on Mars we have yet to is only. Just potential special reasons.
It's actually difficult to find things that can survive extreme conditions on Earth. A few years ago I was working at a desert research facility in Utah. It had operated for more than a dcae with no attempt to constrain biological contamination. Some of us did a PCR and organic geochem study of bacteria on rock surfaces. Even when we were only a few hundred metres from the station, there was no sign of either. Which surprised me. But Mars is far more hostile that Utah.
Reasonable precautions should be taken, but you can pile precaution on precaution until you end up not being able to do anything. The risible paranoia over Curiosity even approaching a possible RSL-like feature on the side of Mt Sharp being a case in point.
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#20 by Watchdog on 01 Jun, 2018 08:48
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"It's extremely unlikely that terrestrial bacteria will eat up any hypothetical martian microbes. The environment will be too hostile for terrestrial organisms to thrive, indigenous forms will out compete them. We see that on Earth. Nor is it likely that that they will eat them, biochemistry will be too alien."
I agree with most of your arguments. However, there is at least one example of fast evolutionary adaptation of an organism to new potential "sources of food" on our planet:
"In 2016, scientists from Japan tested different bacteria from a bottle recycling plant and found that Ideonella sakaiensis 201-F6 could digest the plastic used to make single-use drinks bottles, polyethylene terephthalate (PET). It works by secreting an enzyme (a type of protein that can speed up chemical reactions) known as PETase. This splits certain chemical bonds (esters) in PET, leaving smaller molecules that the bacteria can absorb, using the carbon in them as a food source.
Although other bacterial enzymes were already known to slowly digest PET, the new enzyme had apparently evolved specifically for this job." (https://www.independent.co.uk/news/science/plastic-eating-bacteria-chemist-science-pollution-pet-recycling-a8311811.html).
Therefore, we should not underestimate the ability of terrestrial life forms to adapt and evolve. In order to sustain any permanent human presence on Mars, we need to import lots of earthly life forms (plants, soil microflora and microfauna, small and medium animals). Scientist may want to conduct terraforming experiments involving genetically modified organisms artificially adapted to Mars conditions. But this is exceeding the topic of this thread. -
#21 by mlindner on 16 Jun, 2018 00:01
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I may be in the minority opinion but I consider planetary protection absurd. If there is life, it will be eventually found. Until large scale terraforming efforts start any bacterial life will be uniformly spread across the planet unless it was recently added. Life spreads across a body on the order of decades, not billions of years. All life on Earth shares a huge amount of its DNA. If it's based on life from Earth it will be immediately obvious. If it's actual life from Earth brought with people/rovers then we'll also immediately know.
NASA should immediately remove the office of planetary protection. It's a nuisance and serves no purpose except for perpetuation of non-science appeals to nature. -
#22 by Star One on 16 Jun, 2018 10:20
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I may be in the minority opinion but I consider planetary protection absurd. If there is life, it will be eventually found. Until large scale terraforming efforts start any bacterial life will be uniformly spread across the planet unless it was recently added. Life spreads across a body on the order of decades, not billions of years. All life on Earth shares a huge amount of its DNA. If it's based on life from Earth it will be immediately obvious. If it's actual life from Earth brought with people/rovers then we'll also immediately know.
NASA should immediately remove the office of planetary protection. It's a nuisance and serves no purpose except for perpetuation of non-science appeals to nature.
Thankfully your’s is a minority viewpoint that most sensible people would have nothing to do with. -
#23 by Welsh Dragon on 16 Jun, 2018 10:53
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I may be in the minority opinion but I consider planetary protection absurd. If there is life, it will be eventually found. Until large scale terraforming efforts start any bacterial life will be uniformly spread across the planet unless it was recently added. Life spreads across a body on the order of decades, not billions of years. All life on Earth shares a huge amount of its DNA. If it's based on life from Earth it will be immediately obvious. If it's actual life from Earth brought with people/rovers then we'll also immediately know.
Thank god actual scientists think a bit more than you do.
NASA should immediately remove the office of planetary protection. It's a nuisance and serves no purpose except for perpetuation of non-science appeals to nature. -
#24 by hop on 16 Jun, 2018 21:34
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For anyone doubting the scientific basis of current PP guidelines, I'd encourage you to read some of the papers available on https://planetaryprotection.nasa.gov/documents
For Mars 2020 "A New Analysis of Mars ‘‘Special Regions’’: Findings of the Second MEPAG Special Regions Science Analysis Group" is a good starting point.
There's plenty of room to disagree on the policy details, but the current practice is the result of a lot of hard work by lot of people with a deep of knowledge of the relevant science.
The suggestion that NASA should unilaterally abandon PP also ignores the fact that the US has international obligations: https://cosparhq.cnes.fr/scientific-structure/ppp -
#25 by Star One on 04 Jul, 2018 09:18
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NASA's Planetary Protection Policies Need to Be Updated, Report FindsQuote
A new report recommends that NASA update its policies that protect planets and other solar system bodies from possible contamination during space exploration missions.
The current process for planetary protection policy development is inadequate, according to the report, which was published by the U.S. National Academies of Sciences, Engineering and Medicine. It notes that private-sector space exploration activities are another reason why planetary protection policies need re-examination.
The 170-page report — "Review and Assessment of Planetary Protection Policy Development Processes" — calls for NASA to develop a strategic plan for planetary protection, assess the completeness of policies and initiate a process to formally define requirements that are missing.QuoteSpotlighted in the report are Mars sample-return missions and exploration campaigns to the icy, ocean-harboring moons of Jupiter and Saturn.
https://amp.space.com/41060-nasa-planetary-protection-policies-questioned.html
You can download the free report here.
https://www.nap.edu/catalog/25172/review-and-assessment-of-planetary-protection-policy-development-processes -
#26 by Dalhousie on 06 Jul, 2018 09:14
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"It's extremely unlikely that terrestrial bacteria will eat up any hypothetical martian microbes. The environment will be too hostile for terrestrial organisms to thrive, indigenous forms will out compete them. We see that on Earth. Nor is it likely that that they will eat them, biochemistry will be too alien."
I agree with most of your arguments. However, there is at least one example of fast evolutionary adaptation of an organism to new potential "sources of food" on our planet:
"In 2016, scientists from Japan tested different bacteria from a bottle recycling plant and found that Ideonella sakaiensis 201-F6 could digest the plastic used to make single-use drinks bottles, polyethylene terephthalate (PET). It works by secreting an enzyme (a type of protein that can speed up chemical reactions) known as PETase. This splits certain chemical bonds (esters) in PET, leaving smaller molecules that the bacteria can absorb, using the carbon in them as a food source.
Although other bacterial enzymes were already known to slowly digest PET, the new enzyme had apparently evolved specifically for this job." (https://www.independent.co.uk/news/science/plastic-eating-bacteria-chemist-science-pollution-pet-recycling-a8311811.html).
Therefore, we should not underestimate the ability of terrestrial life forms to adapt and evolve. In order to sustain any permanent human presence on Mars, we need to import lots of earthly life forms (plants, soil microflora and microfauna, small and medium animals). Scientist may want to conduct terraforming experiments involving genetically modified organisms artificially adapted to Mars conditions. But this is exceeding the topic of this thread.
It's fascinating research. Keep the following caveats in mind.
1) The microbes had to be able to live in this environment in the first place - it could not have been too hot/cold/wet/dry etc. Only living (not dormant) and reproducing microbes evolve.
2) There must be an existing relevant biological function that is appropriate to the new environment so that selection can work on (in this case presumably at least some ability to metaploise plastic like substances, even to a small degree)
3) The niche must be vacant otherwise native microbes will outcompete the newcomers
On Mars 1) will only happen (at best) locally and seasonally in the subsurface. Whether these conditions actually exist is unknown. If this is met then 2) may apply, provided the microbes in question can actually do this. However if 3) applies, the chances of survival is small. Human gut microbes can't survive for any great length of time in groundwater, for example.
If 2) and 3) des not then there may be terraforming possibilities I agree, but that's another story.
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#27 by Blackstar on 09 Jul, 2024 15:04
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