Skip to main content

Engineering a lunar photolithoautotroph to thrive on the moon – life or simulacrum?

  • A A Ellery (a1)

Recent work in developing self-replicating machines has approached the problem as an engineering problem, using engineering materials and methods to implement an engineering analogue of a hitherto uniquely biological function. The question is – can anything be learned that might be relevant to an astrobiological context in which the problem is to determine the general form of biology independent of the Earth. Compared with other non-terrestrial biology disciplines, engineered life is more demanding. Engineering a self-replicating machine tackles real environments unlike artificial life which avoids the problem of physical instantiation altogether by examining software models. Engineering a self-replicating machine is also more demanding than synthetic biology as no library of functional components exists. Everything must be constructed de novo. Biological systems already have the capacity to self-replicate but no engineered machine has yet been constructed with the same ability – this is our primary goal. On the basis of the von Neumann analysis of self-replication, self-replication is a by-product of universal construction capability – a universal constructor is a machine that can construct anything (in a functional sense) given the appropriate instructions (DNA/RNA), energy (ATP) and materials (food). In the biological cell, the universal construction mechanism is the ribosome. The ribosome is a biological assembly line for constructing proteins while DNA constitutes a design specification. For a photoautotroph, the energy source is ambient and the food is inorganic. We submit that engineering a self-replicating machine opens up new areas of astrobiology to be explored in the limits of life.

Corresponding author
Author for correspondence: A A Ellery, E-mail:
Hide All
Acevedo, F (2000) Use of reactors in biomining processes. Electronic Journal of Biotechnology 3(3).
Adami, C (2006) Digital genetics: unravelling the genetic basis of evolution. Nature Genetics 7, 109118.
Akafa, H (1966) Abundances of selenium, tellurium and indium in meteorites. Journal of Geophysical Research 71(7), 19191923.
Amils, R, Fernandez-Remolar, D, Gomez, F, Aguilera, A, Gonzalez-Toril, E, Rodriguez, N (2003) ‘Importance of the iron cycle relevance to Mars exploration’. In Proceedings of the 3rd European Workshop on Exo-Astrobiology –Mars: The Search for Life (ESA SP-545), Madrid, Spain, 43–46.
Asai, D and Koonce, M (2001) Dynein heavy chain: structure, mechanics and evolution. Trends in Cell Biology 11(5), 196202.
Atsum, T (2001) Ultrasonic motor model for bacterial flagellar motors. Journal of Theoretical Biology 213, 3151.
Baas, P, Karabay, A and Qiang, L (2005) Microtubules cut and run. Trends in Cell Biology 15(10), 518524.
Balcazar, J, Gavalda, R and Siegelmann, H (1997) Computational power of neural networks: a characterization in terms of Kolmogorov complexity. IEEE Transaction of Information Theory 43(4), 11751183.
Baum, E and Haussler, D (1989) What size net gives valid generalization? Journal of Neural Computation 1(1), 151160.
Bedau, M (1992) Philosophical aspects of artificial life. In Varela, F and Bourgine, P (eds). Towards A Practice of Autonomous Systems. Cambridge, MA: Bradford Books/MIT Press, pp. 494503.
Bedau, M (1997) Emergent models of supple dynamics in life and mind. Brain & Cognition 34, 527.
Bedau, M (1998) Four puzzles about life. Artificial Life 4, 125140.
Bedau, M (2003) Artificial life: organisation, adaptation and complexity from the bottom up. Trends in Cognitive Sciences 7(11), 505512.
Bedau, M, McCaskill, J, Packard, N, Rasmussen, S, Adami, C, Green, D, Ikegami, T, Kaneko, K and Ray, T (2000) Open problems in artificial life. Artificial Life 6, 363376.
Beggs, E, Costa, J and Tucker, J (2010) Physical oracles: the Turing machine and the Wheatstone bridge. Studia Logica 94, 122.
Ben-Jacobs, E (2009) Learning from bacteria about natural information processing. Annals of New York Academy of Sciences 1178, 7890.
Benner, S and Sismour, M (2005) Synthetic biology. Nature Reviews Genetics 6, 533543.
Berg, H (1974) Dynamic properties of bacterial flagellar motors. Nature 249, 7779.
Berg, H (1995) Torque generation by the flagellar rotary motor. Biophysical Journal 68, 163s167s.
Berg, H (2003) Rotary motor of bacterial flagella. Annual Reviews Biochemistry 72, 1954.
Bersini, H (2010) Software replica of minimal living processes. Origins of Life & Evolution of Biospheres 40, 121130.
Bich, L and Damiano, L (2007) Theoretical and artificial construction of the living: redefining the approach from an autopoietic point of view. Origins of Life & Evolution of Biospheres 34, 459464.
Bird, L, Bonnefoy, V and Newman, D (2011) Bioenergetic challenges of microbial iron metabolism. Trends in Microbiology 19(7), 33340.
Blair, D (1991) Bacterial rotary motor. Nanotechnology 2, 123133.
Blair, D (1995) How bacteria sense and swim. Annual Reviews Microbiology 49, 489522.
Bland, P, Cintala, M, Horz, F and Cressey, G (2001) Survivability of meteorite projectriles – results from impact experiments. In 32nd Lunar & Planetary Science Conference, abstract no 1764.
Bland, P, Artemieva, N, Collins, G, Bottke, W, Bussey, D and Joy, K (2008) Asteroids on the Moon: projectile survival during low velocity impacts. In 39th Lunar & Planetary Science Conference, abstract no 2045.
Bloom, B (1995) Microbial minimalist. Nature 378, 236.
Boden, M (2003) Alien life: how would we know? International Journal of Astrobiology 2(2), 121129.
Bourgine, P and Stewart, J (2004) Autopoiesis and cognition. Artificial Life 10, 327345.
Brack, A and Trouble, M (2010) Defining life: connecting robotics and chemistry. Origins of Life & Evolution of Biospheres 40, 131136.
Braitenburg, V (1984) Vehicles: Experiments in Synthetic Psychology. Cambridge, MA: MIT Press.
Brizard, A and van Esch, J (2009) Self-assembly approaches for the construction of cell architectures mimics. Soft Matter 5, 13201327.
Bruylants, G, Bartik, K and Reisse, J (2010) Is it useful to have a clear-cut definition of life? On the use of fuzzy logic in prebiotic chemistry. Origins of Life & Evolution of Biospheres 40, 137143.
Burgess, S and Knight, P (2004) Is the dynein motor a winch? Current Opinion in Structural Biology 14, 138146.
Cabessa, J and Villa, A (2014) Interactive evolving recurrent neural networks are super-Turing. In Wermter, S, Weber, C, Duch, W, Honkela, T, Koprinkova-Hristova, P, Magg, S, Palm, G, Villa, A (eds). Lecture Notes in Computer Science, vol. 8681. Cham: Springer Publishers, pp. 5764.
Cabessa, J and Siegelmann, H (2012) Computational power of interactive recurrent neural networks. Neural Computation 24(4), 9961019.
Cairns-Smith, A (1987) Genetic Takeover & the Mineral Origins of Life. Cambridge, UK: Cambridge University Press.
Cairns-Smith, A (1990) Seven Clues to the Origin of Life. Cambridge, UK: Cambridge University Press.
Calabretta, R (1998) Cellular automata in an artificial life perspective. In Bandini, S, Serra, R and Suggi Liverani, F (eds). Cellular Automata: Research Towards Industry. London: Springer-Verlag, pp. 243246.
Canfield, D, Rosing, M and Bjerrum, C (2006) Early anaerobic metabolisms. Philosophical Transactions of the Royal Society B 361, 18191836.
Carter, F (1984) Molcular device computer: point of departure for large scale cellular automata. Physica 10D, 175194.
Chaitin, G (1970) To a mathematical definition of ‘life’. ACM SICACT News 4, 1218.
Chirikjian, G, Zhou, Y and Suthakorn, J (2002) Self-replicating robots for lunar development. IEEE/ASME Transactions on Mechatronics 7(4), 462472.
Chodasewicz, K (2014) Evolution, reproduction and definition of life. Theory Biosciences 133, 3945.
Cockell, C (2011) Synthetic geomicrobiology: engineering microbe-mineral interactions for space exploration and settlement. International Journal of Astrobiology 10(4), 315324.
Cohen, P and Perrault, C (1979) Elements of a plan-based theory of speech acts. Cognitive Science 3(3), 177212.
Collins, G (2012) Moonstruck magnetism. Science 335, 11761177.
Cordova, N, Ermentrout, B and Oster, G (1992) Dynamics of single-motor molecules: the thermal ratchet model. Proceedings of the National Academy Sciences of the United States of America 89, 339343.
Cronin, L, et al. (2006) Imitation game – a computational chemical approach to recognising life. Nature Biotechnology 24(10), 12031206.
Cross, R (2004) Kinetic mechanism of kinesin. Trends in Biochemical Sciences 29(6), 301309.
Cross, R and Carter, N (2000) Molecular motors. Current Biology 10(5), R177R179.
Crutchfield, J (1994) Calculi of emergence: computation, dynamics and induction. Physica D 75(1–3), 1154.
Csanyi, V and Kampus, G (1985) Autogenesis: the evolution of replicative systems. Journal of Theoretical Biology 114, 303321.
Cui, S and Friedman, A (1999) Analysis of a mathematical model of protocell. Journal of Mathematical Analysis & Applications 236, 171206.
Damiano, L and Luigi Luisi, P (2010) Towards an autopoietic redefinition of life. Origins of Life & Evolution of Biospheres 40, 145149.
Deamer, D and Pashley, R (1989) Amphiphilic components of the Murchison carbonaceous chondrite: surface properties and membrane formation. Origins of Life & Evolution of the Biosphere 19, 2138.
Deamer, D, Dworkin, J, Sandford, S, Bernstein, M and Allamandola, L (2002) First cell membranes. Astrobiology 2(2), 371381.
Deming, T (1997) Polypeptide materials: new synthetic methods and applications. Advanced Materials 9(4), 299311.
Deplazes, A and Huppenbauer, M (2009) Synthetic organisms and living machines. Systems & Synthetic Biology 3, 5563.
DeRosier, D (1998) Turn of the screw: the bacterial flagellar motor. Cell 93, 1720.
Deutsch, D (1985) Quantum theory, the Church-Turing principle and the universal quantum computer. Proceedings of The Royal Society A 400, 97117.
Dohner, K, Nagel, C-H and Sodeik, B (2005) Viral stop-and-go along microtubules: taking a ride with dynein and kinesin. Trends in Microbiology 13(7), 320327.
Dutcher, S (1995) Flagellar assembly in two hundred and fifty easy-to-follow steps. Trends in Genetics 11(10), 398404.
Edwards, M (1998) From a soup or a seed? Pyritic metabolic complexes in the origin of life. Trends in Ecology & Evolution 13(5), 178181.
Egelman, E (2003) Actin's prokaryotic homologs. Current Opinion in Structural Biology 13, 244248.
Eiben, A (2014) Grand challenges for evolutionary robotics. Frontiers in Robotics & AI 1(Jun), 18.
Elani, Y, Law, R and Ces, O (2014) Vesicle-based artificial cells as chemical microreactors with spatially segregated reaction pathways. Nature Communications 5, 5305.
Ellery, A (2015) Ultimate smart system – steps towards a self-replicating machine. In Proceedings of the 5th International Conference on Smart Materials & Structures, pp. 225–234.
Ellery, A (2016a) Are self-replicating machines feasible? AIAA J Spacecraft & Rockets 53(2), 317327.
Ellery, A (2016b) How to build a self-replicating machine on the Moon. In Proceedings of the ASCE Earth & Space Conference, Orlando, pp. 713–724.
Ellery, A (2016c) Solar power satellites for clean energy enabled through disruptive technologies. In Proceedings of the 23rd World Energy Congress (Award Winning Papers), Istanbul, Turkey, pp. 133–147.
Ellery, A (2016d) John von Neumann's self-replicating machine – critical components required. In Proceedings of the IEEE International Conference on Systems Man & Cybernetics, Budapest, Hungary, pp. 314–319.
Ellery, A et al. (2004) Bionics & Space Systems Design 1 – Overview of Biomimetics Technology. ESA-ESTEC Technical Note 1, ESA Contract no 18203/04/NL/PA.
Endy, D (2005) Foundations for engineering biology. Nature 438, 449453.
Engelborghs, Y (1994) Microtubules: dissipative structures formed by self-assembly. Biosensors & Bioelectronics 9, 685689.
Ermentrout, B and Edelatein-Keshet, L (1993) Cellular automata approaches to biological modelling. Journal of Theoretical Biology 160, 97133.
Fegley, B and Swindle, T (1993) Lunar volatiles: implications for lunar resource utilization. In Lewis, J, Matthews, M and Gurrieri, M (eds). Resources of Near Earth Space. Tucson, AZ: University of Arizona Press, pp. 367426.
Ferris, H and Minamino, T (2006) Flipping the switch: bringing order to flagellar assembly. Trends in Microbiology 14(12), 519526.
Ferris, J (2005) Mineral catalysis and prebiotic synthesis: montmorillonite-catalysed formation of RNA. Elements 1, 145149.
Ferris, J, Hill, A, Liu, R and Orgel, L (1996) Synthesis of long prebiotic oligomers on mineral surfaces. Nature 381, 5961.
Ferris, J, Joshi, P, Wang, K-J, Miyakawa, S and Huang, W (2004) Catalysis in prebiotic chemistry: application to the synthesis of RNA oligomers. Advances in Space Research 33, 100105.
Fleischaker, G (1989) Autopoiesis: the status of its system logic. BioSystems 22, 3749.
Fontana, W and Buss, L (1994) Arrival of the fittest: toward a theory of biological organisation. Bull Mathematical Biology 56(1), 164.
Forterre, P (2010) Defining life: the virus viewpoint. Origins of Life & Evolution of Biospheres 40, 151160.
Freitas, R & Gilbreath, W (1980) Advanced Automation for Space Missions. In Proceedings of the 1980 NASA/ASEE Summer Study, NASA CP-2255, Santa Clara, CA.
Freitas, R & Merkle, R (2004) Kinematic Self-Replicating Machines. Austin TX: Landes Bioscience.
Frixione, E (2000) Recurring views on the structure and function of the cytoskeleton: a 300 year epic. Cell Motility & the Cytoskeleton 46, 7394.
Froese, T and Stewart, J (2010) Life after Ashby: ultrastability and the autopoietic foundations of biological autonomy. Cybernetics & Human Knowing 17(4), 750.
Gabora, L (2006) Self-other organisation: why early life did not evolve through natural selection. Journal of Theoretical Biology 241, 443450.
Gerdes, K, Meller-Jensen, J, Ebersbach, G, Kruse, T and Nordstrom, K (2004) Bacterial mitotic machineries. Cell 116, 359366.
Gibbs, W (2004) Synthetic life. Scientific American 290(5), 7481.
Goldin, D and Wegner, P (2005) Church-Turing thesis: breaking the myth. In Cooper, S, Lowe, B and Torenvliet, L (eds) Lecture Notes in Computer Science vol. 3526. Berlin/Heidelberg, Germany: Springer-Verlag, pp. 152168.
Goldstein, L (2001) Molecular motors: from one motor many tails to one motor many tails. Trends in Cell Biology 11(12), 477482.
Goudreau, M, Giles, L, Chakradhar, S and Chen, D (1994) First order vs second order single layer recurrent neural networks. IEEE Transactions on Neural Networks 5(3), 511513.
Han, J-W and Meyyappan, M (2014) Device made of nothing: the vacuum transistor could one day replace silicon. IEEE Spectrum (Jul), 3135.
Hanczyc, M (2011) Metabolism and motility in prebiotic structures. Philosophical Transactions of the Royal Society B 366, 28852893.
Hess, H and Vogel, V (2001) Molecular shuttles based on motor proteins: active transport in synthetic environments. Reviews in Molecular Biotechnology 82, 6785.
Hordijk, W (2013) Autocatalytic sets: from the origin of life to the economy. Bioscience 63(11), 877881.
Howard, J, Hudspeth, A and Vale, R (1989) Movement of microtubules by single kinesin molecules. Nature 342, 154158.
Huitorel, P (1988) From cilia and flagella to intracellular motility and back again: a review of a few aspects of microtubule-based motility. Biology of the Cell 63, 249258.
Hutton, T (2002) Evolvable self-replicating molecules in an artificial chemistry. Artificial Life 8(4), 341356.
Hutton, T (2009) Codd's self-replicating computer. Artificial Life 16(2), 99117.
Huxley, A (2000) Mechanics and models of the myosin motor. Philosophical Transactions of the Royal Society B 355, 433440.
Huxley, H (1996) Personal view of muscle and motility mechanisms. Annual Review of Physiology 58, 119.
Itoh, H, Takahashi, A, Adachi, K, Noji, H, Yasuda, R, Yoshida, M and Kinosita, K (2004) Mechanically driven ATP synthesis by F1-ATPase. Nature 427, 465468.
Jacobson, H (1959) Informational content of mechanisms and circuits. Information & Control 2, 285296.
Jones, R, Haufe, P, Sells, E, Iravani, P, Olliver, V, Palmer, C and Bowyer, A (2011) Reprap – the replicating rapid prototyper. Robotica 29(Jan), 177191.
Jorgensen, S and Fath, B (2004) Application of thermodynamic principles in ecology. Ecological Complexity 1, 267280.
Karcher, R, Deacon, S and Gelfand, V (2002) Motor-cargo interactions: the key to transport specificity. Trends in Cell Biology 12(1), 2127.
Karplus, M and Gao, Y (2004) Biomolecular motors: the F1-ATPase paradigm. Current Opinion in Structural Biology 14, 250259.
Kephart, J and Chess, D (2003) Vision of autonomic computing. IEEE Computer 36(1), 4158.
Kinosita, K, Yasuda, R, Noji, H, Ishiwata, S and Yoshida, M (1998) F1-ATPase: a rotary motor made of a single molecule. Cell 93, 2124.
Klavins, E (2004) Universal self-replication using graph grammars. In Proceedings of the International Conference on MEMS, NANO and Smart Systems, Banff, Canada, paper no. 1508947.
Kolesar, E and Dyson, C (1995) Object imaging with a piezoelectric robotic tactile sensor. IEEE Journal of Microelectromechanical Systems 4(2), 8796.
Koonce, M and Samso, M (2004) Of rings and levers: the dynein motor comes of age. Trends in Cell Biology 14(11), 612619.
Korzeniewski, B (2001) Cybernetic formulation of the definition of life. Journal of Theoretical Biology 209, 275286.
Koshland, D (2002) Seven pillars of life. Science 295, 22152216.
Kull, J, Sablin, E, Lau, R, Fletterick, R and Vale, R (1996) Crystal structure of the kinesin motor domain reveals a structural similarity to myosin. Nature 380, 550555.
Kwok, R (2010) Five hard truths for synthetic biology. Nature 463, 288290.
LaBar, T, Adami, C and Hintze, A (2015) Does self-replication imply evolvability? In Proceedings of the 13th European Conference on Artificial Life, pp. 596–602.
Lahoz-Beltra, R (1997) Molecular automata assembly: principles and simulation of bacterial membrane construction. BioSystems 44, 209229.
Laing, R (1975) Some alternative reproductive strategies in artificial molecular machines. Journal of Theoretical Biology 54, 6384.
Laing, R (1979) Machines as organisms: an exploration of the relevance of recent results. BioSystems 11, 201215.
Langton, C (1984) Self-reproduction in cellular automata. Physica D 10, 135144.
Larson, S & Ellery, A (2015) Trainable analogue neural network with application to lunar in-situ resource utilisation. In Proceedings of the International Astronautics Federation Congress, Jerusalem, IAC-15-D3.3.6.
Lazcano, A (2010) Which way to life? Origins of Life & Evolution of Biospheres 40, 161167.
Lee, E (2005) Building unreliable systems out of reliable components: the real time story. Electrical Engineering & Computer Sciences University of California Berkeley Technical Report No. UCB/EECS-20055.
Letelier, J, Marin, G and Mpoodoziz, J (2003) Autopoietic and (M, R) systems. Journal of Theoretical Biology 222, 261272.
Luigi Luisi, P (2003) Autopoiesis: a review and a reappraisal. Naturwissenschaften 90, 4959.
Luigi Luisi, P and Varela, F (1989) Self-replicating micelles – a chemical version of a minimal autopoietic system. Origins of Life & Evolution of the Biosphere 19, 633643.
Luisi, P (1998) About various definitions of life. Origins of Life & Evolution of Biospheres 28, 613622.
Machery, E (2012) Why I stopped worrying about the definition of life … and why you should as well. Synthese 185(1), 145164.
MacLennan, B (2004) Natural computation and non-Turing models of computation. Theoretical Computer Science 317, 115145.
MacNab, R (2003) How bacteria assemble flagella. Annual Reviews of Microbiology 57, 77100.
Mandelkow, E and Mandelkow, E-M (2002) Kinesin motors and disease. Trends in Cell Biology 12(12), 585590.
Margenstein, M (2000) Frontier between decidability and undecidability: a survey. Theoretical Computer Science 231, 217251.
Martin, W and Russell, M (2003) On the origins of cells: a hypothesis for the evolutionary transitions from abiotic geochemistry to chemoautotrophic prokaryotes, and from prokaryotes to nucleated cells. Philosophical Transactions of the Royal Society B 358, 5983.
Maturana, H (1975) Organisation of the living: a theory of the living organisation. International Journal of Man-Machine Studies 7, 313332.
McDaniel, R and Weiss, R (2005) Advances in synthetic biology: on the path from prototypes to applications. Current Opinion in Biotechnology 16, 476485.
McDermott, K, Price, M, Cole, M and Burchell, M (2016) Survivability of copper projectuiles during hypervelocity impacts in porous ice: a laboratory investigation of the survivability of projectiles impacting comets or other bodies. Icarus 268, 102117.
McMullin, B (2004) Thirty years of computational autopoiesus: a review. Artificial Life 10, 277295.
McMullin, B & Varela, F (1997) Rediscovering computational autopoiesis. In Proceedings of the European Conference on Artificial Life, paper no. 97-02-012.
Melosh, H, Freed, A, Johnson, B, Blair, D, Andrews-Hanna, J, Neumann, G, Phillips, R, Smith, D, Solomon, S, Wieczorek, M and Zuber, M (2013) Origin of lunar mascon basins. Science 340, 15521555.
Menezes, A, Montague, M, Cumbers, J, Hogan, J and Arkin, A (2015) Grand challenges in space synthetic biology. Journal of the Royal Society Interface 12, 20150803.
Miki, H, Okada, Y and Hirokawa, N (2005) Analysis of the kinesin superfamily: insights into structure and function. Trends in Cell Biology 15(10), 467476.
Mitchell, M (1998) Computation in cellular automata: a selected review. In Gramss, T, Bornholdt, S, Gross, M and Mitchell, M (eds). Nonstandard Computation. Weinheim, Germany: VCH Publishers, pp. 95140.
Montesi, L (2013) Solving the mascon mystery. Science 340, 15351536.
Moore, E (1956) Artificial Living Plants. Scientific American, 195(4), 118126.
Moreno Bergareche, A and Ruiz-Mirazo, K (1999) Metabolism and the problem of its universalisation. BioSystems 49, 4561.
Morowitz, H, Heinz, B and Deamer, D (1988) Chemical logic of a minimum protocell. Origins of Life & Evolution of the Biosphere 18, 281287.
Moses, M, Ma, H, Wolfe, K and Chirikjian, G (2014) An architecture for universal construction via modular robotic components. Robotics & Autonomous Systems 62(7), 945965.
Mozafari, R (2005) Liposomes: an overview of manufacturing techniques. Cellular & Molecular Biology Letters 10, 711719.
Muller, A (2003) Finding extraterrestrial organisms living on thermosynthesis. Astrobiology 3(3), 555564.
Narisawa, M (2010) Silicone resin applications for precursors and composites. Materials 3, 35183586.
Oakley, B (2000) Abundance of tubulins. Trends in Cell Biology 10(Dec), 537542.
Ochman, H, Lawrence, J and Groisman, E (2000) Lateral gene transfer and the nature of bacterial innovation. Nature 405, 299304.
Oro, J, Kimball, A, Fritz, R and Master, F (1959) Amino acid synthesis from formaldehyde and hydroxylamine. Archives of Biochemistry & Biophysics 86, 115130.
Oster, G and Wang, H (2003) Rotary protein motors. Trends in Cell Biology 13(3), 114121.
Paun, C (2000) Computing with membranes. J Computer & System Sciences 61, 108143.
Pesavento, U (1995) Implementation of von Neumann's self-reproducing machine. Artificial Life 2(4), 337354.
Pinto, J, Gladstone, G and Yung, Y (1980) Photochemical production of formaldehyde in Earth's primitive atmosphere. Science 210, 183185.
Pohorille, A and Deamer, D (2002) Artificial cells: prospects for biotechnology. Trends in Biotechnology 20(3), 123128.
Pross, A (2005a) Stability in chemistry and biology: life as a kinetic state of matter. Pure Applied Chemistry 77(11), 19051921.
Pross, A (2005b) On the emergence of biological complexity: life as a kinetic state of matter. Origins of Life & Evolution of Biospheres 35, 151166.
Pross, A (2008) How can a chemical system act purposefully? Bridging between life and non-life. Journal of Physical Organic Chemistry 21, 724730.
Pross, A and Pascal, R (2013) Origin of life: what we know, what we can know and what we will never know. Open Biology 3, 120190.
Rasmussen, S, Chen, L, Nilsson, M and Abe, S (2003) Bridging nonliving and living matter. Artificial Life 9(3), 269316.
Rasmussen, S, Chen, L, Deamer, D, Krakauer, D, Packard, N, Stadler, P and Bedau, M (2004) Transitions from nonliving to living matter. Science 303, 963965.
Rawlings, A, Bramble, J and Staniland, S (2012) Innovation through imitation: biomimetic, bioninspired and biokleptic research. Soft Matter 8, 66756679.
Reggia, J, Armentrout, S, Chou, H-H and Peg, Y (1993) Simple systems exhibiting self-directed replication. Science 259, 12821286.
Reimold, W, Koeberl, C, Gibson, R and Dressler, B (2005) Economic mineral deposits in impact structures: a review. In Koebert, C and Henkel, H (eds). Impact Tectonics. Impact Studies, vol. 6. Heidelberg: Springer, pp. 479548.
Ringwood, A & Seifert, S (1986) Nickel-cobalt abundance systematics and their bearing on lunar origin. In Proceedings of the Origins of the Moon Conference, pp. 249–278.
Ruiz-Mirazo, K, Pereto, J and Moreno, A (2004) Universal definition of life: autonomy and open-ended evolution. Origins of Life & Evolution of Biospheres 34, 232346.
Saunders, P and Ho, M (1976) On the increase in complexity in evolution. Journal of Theoretical Biology 63, 375394.
Schark, M (2012) Synthetic biology and the distinction between organisms and machines. Environmental Values 21, 1941.
Schmidhuber, J (2007) Godel machines: fully self-referential optimal universal self-improvers. In Goertzel, B and Pennachin, C (eds). Artificial General Intelligence. Berlin, Heidelberg: Springer, pp. 199226.
Schneider, E and Kay, J (1994) Life as a manifestation of the second law of thermodynamics. Mathematical & Computer Modelling 19(6–8), 2548.
Schuindewolf, U (1980) Selenium and tellurium content of stony meteorites by neutron activation. Geochimica et Cosmochimica 19, 134136.
Schultze-Makuch, D and Irwin, L (2004) Life in the Universe: expectations and constraints. In Springer Advances in Astrobiology & Biogeophysics. Berlin, Germany: Springer Publishers.
Schulze-Makuch, D and Irwin, L (2008) Life in the Universe: Expectations and Constraints. Berlin, Germany: Springer Publishers.
Schuster, S and Khan, S (1994) Bacterial flagellar motor. Annual Reviews Biophysics & Biomolecular Structure 23, 509539.
Schwartz, A (1996) Did minerals perform prebiotic combinatorial chemistry? Chemistry & Biology 3, 515518.
Schwede, J, Bargstin, I, Riley, D, Hardin, B, Rosenthal, S, Sun, Y, Schmitt, F, Pianetta, P, Howe, R, Shen, Z-X and Melosh, N (2010) Photon-enhanced thermionic emission for solar concentrator systems. Nature Materials 9, 762767.
Schwegler, H and Tarumi, K (1986) Protocell: a mathematical model of self-maintenance. BioSystems 19, 307315.
Senior, A and Wise, J (1983) Proton-ATPase of bacteria and mitochondria. Journal of Membrane Biology 73, 105124.
Siegelmann, H. (1995) Computation beyond the Turing limit. Science 268, 545–458.
Siegelmann, H and Margenstern, M (1999) Nine switch-affine neurons suffice for Turing universality. Neural Networks 12, 593600.
Siegelmann, H and Sontag, E. (1995) On the computational power of neural nets. Journal of Computer & System Sciences 50, 132150.
Sipper, M, Sanchez, E, Mange, D, Tomassini, M, Perez-Uribe, A and Stauffer, A (1997) ‘Phylogenetic, ontogenetic, and epigenetic view of bio-inspired hardware systems. IEEE Transactions on Evolutionary Computations 1(1), 8397.
Sismour, M and Benner, S (2005) Synthetic biology. Expert Opinion on Biological Therapy 5(11), 14091424.
Skulachev, V (2001) Mitochondrial filaments and clusters as intracellular power-transmitting cables. Trends in Biochemical Sciences 26(1), 2329.
Soong, R, Bachand, G, Neves, H, Olkhovets, A, Craighead, H and Montemagno, C (2000) Powering a inorganic nanodevice with a biomolecular motor. Science 290, 15551558.
Stahlberg, A, Schuster, S, Bauer, M, Baueurlein, E, Zhao, R, Reese, T and Khan, S (1995) Conserved machinery of the bacterial flagellar motor. Biophysical Journal 58(Apr), 168s172s
Stepney, S (2012) Programming unconventional computers: dynamics, development, self-reference. Entropy 14, 19391952.
Sun, G-Z, Chen, H-H, Lee, Y-C and Giles, C (1991) Turing equivalence of neural networks with second order connection weights. In Proceedings of International Joint Conference on Neural Networks, vol. 2, pp. 357–362.
Suthakorn, J and Chirikjian, G (2006) Toward self-replication of robot control circuitry by self-inspection In Ang, M and Khatib, O (eds). Environmental Robotics IX. Berlin: Springer-Verlag, pp. 303309.
Svoboda, K and Block, S (1994) Force and velocity measured for single kinesin molecules. Cell 77, 773784.
Szostak, J (2012) Attempts to define life do not help to understand the origin of life. Journal of Biomolecular Structure & Dynamics 29(4), 599600.
Szostak, J, Bartel, D and Luigi Luisi, P (2001) Synthesising life. Nature 409, 387390.
Szostak, N, Wasik, S, Blazewicz, J (2016) Hypercycle. PLoS Computational Biology 12(4), e1004853.
Tabony, J, Pochon, N and Papaseit, C (2001) Microtubule self-organisation depends upon gravity. Advances in Space Research 28(4), 529535.
Taylor, E (2001) Cell as molecular machine. Molecular Biology of the Cell 12(2), 251254.
Teuscher, C (2014) Unconventional computing catechism. Frontiers in Robotics & AI 1(Nov), 10.
Teuscher, C and Sipper, M (2002) Hypercomputation’ - hype or computation? Communications of the ACM 45(8), 2324.
Thomas, N, Bardy, S and Jarrell, K (2001) Archaeal flagellum: a different kind of prokaryotic motility structure. FEMS Microbiology Review 25, 147174.
Tucker, J and Zilinskas, R (2006) Promise and perils of synthetic biology. New Atlantis (Spring), 2545.
Turing, A (1937) On computable numbers with an application to the entschedungsproblem. Proceedings of London Mathematical Society, Series 2, 42, 230265.
Tuszynski, J, Trpisova, B, Sept, D and Sataric, M (1997) Enigma of microtubules and their self-organising behaviour in the cytoskeleton. BioSystems 42, 153175.
Tyreman, M and Molloy, J (2003) Molecular motors: nature's nanomachines. IEE Proceedings, Nanobiotecnology 150(3), 95102.
Tyson, J and Mackey, M (2001) Molecular, metabolic and genetic control: an introduction. Chaos 11(1), 8183.
Ulanowicz, R and Hannon, B (1987) Life and the production of entropy. Proceedings of the Royal Society B 232, 181192.
Umerez, J (2010) Artificial life: prospects of a synthetic biology. In Angelo L and Queiroz J (eds). Advances in Modelling Adaptive & Cognitive Systems. Brazil: UEFS Open Publishing, pp. 416.
Vale, R (1999) Millenial musings on molecular motors. Trends in Biochemical Science 24(12), M38M41.
Vale, R (2003) Molecular motor toolbox for intracellular transport. Cell 112, 467480.
Vale, R and Milligan, R (2000) The way things move: looking under the hood of molecular motor proteins. Science 288, 8895.
Vallee, R and Stehman, S (2005) How dynein helps the cell find its centre: a servomechanical model. Trends in Cell Biology 15(6), 288294.
van den Ent, F, Amos, L and Lowe, J (2001a) Prokaryotic origin of the actin cytoskeleton. Nature 413, 3944.
van den Ent, F, Amos, L and Lowe, J (2001b) Bacterial ancestry of actin and tubulin. Current Opinion in Microbiology 4, 634638.
Varatharajoo, R (2004) Combined energy and attitude control system for small satellites. Acta Astronautica 54, 701712.
Varela, F, Maturana, H and Uribe, R (1974) Autopoiesis: the organisation of living systems, its characterisation and a model. BioSystems 5, 187196.
von Neumann, J & Burks, A (eds) (1966) Theory of Self-Reproducing Automata. IL: University of Illinois Press.
Wachtershausen, G (2006) From volcanic origins of chemoautotrophic life to bacteria, archaea and eukarya. Philosophical Transactions of the Royal Society B 361, 17871808.
Wachtershauser, G (1990) Case for the chemoautotrophic origin of life in an iron-sulphur world. Origins of Life & Evolution of Biospheres 20, 173176.
Wachtershauser, G (1992) Groundworks for evolutionary biochemistry: the iron-sulphur world. Progress in Biophysics & Molecular Biology 58, 85201.
Wang, H and Oster, G (1998) Energy transduction in the F1 motor of ATP synthase. Nature 396, 279282.
Way, J, Silver, P and Howard, R (2011) Sun-driven microbial synthesis of chemicals in space. International Journal of Astrobiology 10(4), 359364.
Weber, J (2007) ATP synthase – the structure of the stator stalk. Trends in Biochemical Sciences 32(2), 5356.
Weber, B (2010) What is life? Defining life in the context of emergent complexity. Origins of Life & Evolution of Biospheres 40, 221229.
Weber, K, Achenbach, L and Coates, J (2006) Microbes pumping iron: anaerobic microbial iron oxidation and reduction. Nature Reviews Microbiology 4, 752764.
Wemmer, K and Marshall, W (2004) Flagellar mobility: all pull together. General Biology 14, R992R993.
Widdel, F, Schnell, S, Easing, S, Ehrenreich, A, Assmus, B and Schink, B (1983) Ferrous iron oxidation by anoxygenic phototrophic bacteria. Nature 362, 834838.
Wieczorek, M and Phillips, R (1999) Lunar multiring basins and the cratering process. Icarus 139, 246259.
Wieczorek, M, Weiss, B and Steart, S (2012) Impactor origin for lunar magnetic anomalies. Science 335, 12121215.
Wierdermann, J and van Leeuwen, J (2002) Emergent computational potential of evolving artificial living systems. Journal of AI Communications 15(4), 205215.
Wiesenfeld, K and Moss, F (1995) Stochastic resonance and the benefits of noise: from ice ages to crayfish and SQUIDS. Nature 373, 3336.
Wittmann, A and Korotev, R (2013) Iron-nickel-(cobalt) metal in lunar rocks revisited. In 44th Lunar & Planetary Science Conference, abstract no 3035.
Woese, C (1998) Universal ancestor. Proceedings of the National Academy of Sciences of the United States of America 95, 68546859.
Wogan, T (2016) Ceramics made stronger with 3D printing. Chemistry World, 11 January 2016.
Wolfram, S (1985) Undecidability and intractability in theoretical physics. Physical Review Letters 54(8), 735738.
Wolfram, S (2002) A New Kind of Science. Champaign, IL: Wolfram Media.
Yamashita, Y and Nakamura, Y. (2007) Neuron circuit model with smooth nonlinear output function. In Proceedings of the International Symposium on Nonlinear Theory & its Applications, Vancouver, pp. 11–14.
Yildiz, A and Selvin, P (2005) Kinesin: walking, crawling or sliding along? Trends in Cell Biology 15(2), 112120.
Yue, Z, Johnson, B, Monton, D, Melosh, H, Di, K, Hu, W and Liu, Y (2013) Projectile remains in central peaks of lunar impact craters. Nature Geoscience 6, 435437.
Zakeri, B and Carr, P (2015) Limits of synthetic biology. Trends in Biotechnology 33(2), 5758.
Zuravlev, Y and Avetisov, V (2006) Definition of life in the context of its origins. Biogeosciences 3, 281291.
Zykov, V, Mytilinaios, E, Adams, B and Lipson, H (2005) Self-reproducing machines. Nature 435, 163164.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

International Journal of Astrobiology
  • ISSN: 1473-5504
  • EISSN: 1475-3006
  • URL: /core/journals/international-journal-of-astrobiology
Please enter your name
Please enter a valid email address
Who would you like to send this to? *



Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed