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09:09 PM on
12 Aug, 2013
07:55 PM on
18 Sep, 2013
The Astrobiology Strategic Plan: Updating the Astrobiology Roadmap
The 2008 Astrobiology Roadmap has provided clarity to the scientific scope and mission of NASA’s Astrobiology Program, and guidance as to how to achieve NASA’s astrobiology goals. NASA PI’s have used that Strategic Plan to make impressive progress towards answering such questions as:
• How did life on Earth emerge and how did early life evolve with its changing environment?
• What are the environmental limits of life as we know it?
• By what evolutionary mechanisms does life explore the adaptive landscape shaped by those limits?
• What principles will shape life in the future?
• Do habitable environments exist elsewhere in the Universe?
• By what signatures may we recognize life on other worlds as well as on early Earth?
The output of this effort over the past five years can be measured in terms of peer-reviewed publications (more than 5,000), graduate and post-graduate students trained (hundreds), increased public awareness and interest (many press releases, blog posts, tweets, popular science press articles e.g., NY Times, Discover, National Geographic, and public schools programs), as well as in how NASA funds have been leveraged to create new intellectual property (approximately half a dozen invention disclosures) and at least one start-up company. By all these measures, NASA’s Astrobiology Program can be accounted as a resounding success, a testament to the utility of constructing and implementing a programmatic Strategic Plan as well as to the energy and ingenuity of NASA PIs.
The 2014 Strategic Plan is now under construction as a community enterprise. To ensure that the 2014 Plan is aspirational, inspirational, and inclusive of the diversity of the astrobiology community, the Astrobiology Program engaged the services of an innovation consulting firm, KnowInnovation (http://knowinnovation.com/). KnowInnovation has facilitated program development for diverse entities such as the NSF, AAAS and the American Mathematical Society. The Strategic Plan enterprise was launched the week of May 6th with the first in a series of five hour-long webinars, each broadly focused on a topic connected to the 2008 Roadmap but aimed at astrobiology’s future: Early Evolution of Life and the Biosphere, Planetary Conditions for Life, Evolution of Advanced Life, Prebiotic Evolution and Astrobiology for Solar Systems Exploration (https://astrobiologyfuture.org/). Following each of these NASA PI-led webinars, over 500 members of the astrobiology community engaged in a spirited week long, on-line debate that produced a rich record of controversy and critical knowledge gaps.
The second stage of Strategic Plan-making was launched the week of June 17th. Sixty scientists gathered for four days at the Wallops Flight Facility in Wallops Island, VA in a NASA meeting organized by the NRC. In keeping with the broad scope and interdisciplinary nature of astrobiology research, the Strategic Plan working group consisted of biochemists, physicists, geologists, evolutionary biologists and paleontologists, and included participants actually and virtually present. A unifying feature of this working group was that each member’s record of scholarship provided evidence that she or he was comfortable working across disciplinary boundaries and knowledgeable about astrobiologically significant targets of planetary exploration. This common denominator proved essential to successfully working through the organic process envisioned by KnowInnovation facilitators.
The goal of the Wallops Island gathering was to build, by brainstorming, argument and consensus, a collection of working documents, each focused on a broad research theme that could be easily explained and justified, then broken down into set of sub-questions, any one or combination of which would provoke further community input, or even stimulate a specific research project.
This goal and the process for reaching that goal were not initially apparent. By design — and somewhat annoyingly at first! — the KnowInnovation team forced upon the Strategic Plan team an atmosphere of playful openness. Each participant was challenged to write down a set of questions, the answers to which would be “the paper s/he would like to write or to read in 10 years time.” These were discussed by the group as a whole, then whittled down to several dozen questions that were written on sticky notes, posted onto a large whiteboard, and grouped into broad categories. Relative interest in these categories was then assayed by forming “chains of interest” in which one participant pointed to a whiteboard category, and others linked up hand-to-shoulder. Discussion groups nucleated around categories having long interest chains, typically half a dozen participants, who then labored to articulate an overarching question under which the sticky-note questions might be subsumed. These “big questions” opened intellectual paths that eventually led to the current set of Strategic Plan working documents, which can accessed at the astrobiologyfuture.org website. Although very different types of science are represented in these documents, the paths that led to each shared four key features: (i) focus groups invariably included investigators whose research specialty lay in that category and investigators who held a keen general interest, (ii) focus group membership was fluid, with participants freely moving among and contributing to different groups, (iii) the “big questions,” their explanations and justifications, as well as each subsidiary question were iteratively vetted by the Strategic Plan team as a whole through a series of poster sessions, each of which was succeeded by a focus group meetings, (iv) each working document was composed in Google.Docs through real-time collaboration among both focus group members, and until the last day, the Strategic Plan team as a whole. The genesis and refinement of current Strategic Plan documents was therefore truly a group achievement, no mean feat considering that, as a whole, principal investigators are an independent and sometimes feisty lot.
The following example represents the combined efforts of nine participants (L. Achenbach, D. Erwin, A. Goldman, L. Mix, M. Pasek, M. Powell, F. Rosenzweig, E. Smith,and P. Sniegowski) whose expertise ranges from theoretical physics to microbial and population genetics to paleontology.
Title: What are the common attributes of extant living systems, and what can they tell us about all living systems?
Explanation: Living systems from cells to populations of cells share a set of common attributes that distinguish them from non-living systems. An important Astrobiology goal should be to identify the attributes or principles of system composition that, collectively, would enable us — taking correct account of the chemistry upon which a living system might be based – to recognize systems as being alive. A consensus as to the nature of these attributes and an understanding of the roles that chance and necessity play in their origin and elaboration are essential to being able to recognize and describe life on other worlds. Living systems here on Earth share common features that broadly fall into categories related to (i) energetics, (ii) composition, (iii) structure-function, (iv) information content retrieval-transmission. Living systems self-organize and self-perpetuate, and adapt, as individuals and as populations, to spatial and temporal variability in resource availability and physical conditions. Some adaptations result from events that may or may not be repeated, or, if repeated, may not produce the same evolutionary result, whereas others are more likely to recur. Examples of the latter include traits that are ubiquitous because they arise relatively easily in independent lineages then are conserved (e.g., multicellularity) as well as traits that are ubiquitous among unrelated taxa because they solve common problems in a similar way (e.g., flight).
Justification: a better understanding of the common attributes of all living systems on Earth and the degree to which they were formed by contingent or inevitable events will enable us predict – and recognize – the attributes of life on other planets.
A dozen sub-questions are subsumed under this broad theme, such as:
(1) What are the attributes of life that would be recognizable on other worlds, regardless of the chemistry of those worlds (e.g., gas exchange, heat exchange)?
(2) Why is the emergence of individuality such a large factor in driven non-equilibrium processes?
(3) What roles do chance and contingency play in the origin and elaboration of cellular nanomachines?
(4) What roles do chance and contingency play in determining evolutionary processes leading to major evolutionary transitions?
Twenty other, similar working documents represent the output of the June face-to-face Strategic Plan enterprise. Although these documents encompass research themes as diverse as:
• How did bio-relevant elements evolve into molecules?
• How can we best overcome our ignorance about microbial life on Earth?
• How would we find and identify an inhabited planet?
• How can we enhance the utility of biosignatures as a tool to search for life in the Solar System & beyond?
all of these new challenges are directed toward advancing Astrobiology, the study of the origin, evolution, distribution, and future of life in the universe. The workshop also produced a “network map” showing the interrelationships between the twenty-one working papers.
The next steps in the creation of the new Strategic Plan will move the process back on-line. Starting in September, the 21 working documents will be published on the astrobiologyfuture.org website and the astrobiology community will be invited to review them. One webinar will be held for each document, after which community members will be allowed to provide comments. Community members will also be able to add documents if a compelling case can be articulated for the existence of a gap in the existing documents. In the January-to-February 2014 timeframe, the authors of the working documents will gather, either physically or virtually, to incorporate the community’s comments. A face-to-face integration workshop will be held in late February to create a first draft of the Strategic Plan. This draft will be reviewed by the Planetary Science Subcommittee of the NASA Advisory Council and, possibly, an ad hoc committee of the National Research Council. Following the consideration of comments arising from these reviews, a final draft will be published in April 2014.
In conclusion, this is your community and NASA wants your input. Be part of this exciting process and make your voice heard!
Ian James Miller
05:49 PM on
10 Oct, 2014
I believe one problem that has arisen from this discussion has arisen from the single-question approach, which has been highly desirable to stop discussions wandering, but has introduced the difficulty of thinking of the complete set of conditions required to reach the objective. In what follows, I should warn that I am an advocate of a theory that probably has only one follower, but it arises from two considerations: each each planetary system in our solar system appears chemically different, but uniform within the system (as far as our admittedly limited knowledge goes), and also, we have no idea how planetesimals form. I believe the planetary system cores start through chemical processes (Bias – I am a chemist), but in terms of the origin of life, what the planet contains will determine what can evolve from it. As an example, within my approach, The jovian system is deficient in nitrogen and carbon, therefore the probability of life under-ice on Europa is miniscule. In fact there is a further reason i shall mention below in which life cannot evolve under-ice. If anyone is interested in the details, I have self-published an ebook outlining the approach. With about 200,000 words and over 600 references, it is difficult to summarise.
Notwithstanding that, I believe there is one experiment that could be done relatively cheaply on Earth, in a good quality chemistry lab. The proposition is, the first life was based on RNA and it formed through a primitive photosystem, which later evolved to ours. The key discovery, which has been seemingly overlooked, is (Ponnamperuma, C., Sagan, C., Mariner, R., 1963. Synthesis of adenosine triphosphate under possible primitive earth conditions. Nature 199: 222-226.) What this did was to shine energetic UV radiation onto a mix of adenine, ribose and phosphate, and ended up with ATP. The question then is, why? The adsorber was adenine, and it first bound to ribose to make adenosine. There is nothing remarkable about that, but then it went on to make phosphate esters. The question is, how, because any electronic excited state is constrained to the adenine function.
This raises the question, how do you make phosphate esters in water? Phosphate esters can be made by heating an alcohol group plus phosphate to about 200 degrees C, but that is not likely to happen, and even if it did, phosphate esters are rapidly hydrolysed at that temperature when in excess water. In my opinion, the answer is that when adenosine absorbed a photon, it decays but retains vibrational energy. If so, we now see why we need ribose, even though ribose is one of the least stable sugars and when other pyranosides make duplexes with stronger energy. My proposed reason is the furanoside form alone has the vibrational freedom to transmit the energy to the terminal hydroxyl, and it is that vibrational energy that forms the phosphate ester, and permits the growth of polyphosphate.
That cannot be the original mechanism, because the atmosphere would not permit the UV to strike the Earth in sufficient intensity, but there is another way, wherein the necessary components are encased in a micelle, together with porphyrins, which could be made geochemically, the micelle (or vesicle) being made from alkyl chains and alkyl phosphates made geochemically from Fischer Tropsch reactions. The experiment, therefore, is to take these components, encase them in the micelles, and shine visible light on them to excite the Soret pads of the porphyrins. Either it can transmit the vibrational energy or it cannot. Since the modern photosystem also makes ATP, the argument is that it has evolved from something primitive as described. Either it works or it does not. If it does, all life will start with RNA. The experiment could be repeated with another sugar, and that should not work because the pyranoside form should be too rigid. If this works, then the next step is to determine the planetary conditions required for such chemistry to take place.