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Thread: Callisto colonization -- some crazy ideas

  1. #31
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    As far as crazy ideas go, a few mirror-building construction robots could be sent to Callisto to build solar farms generating electricity by steam turbines. It would be along the lines of the following articles. The power produced would operate robots and space industries on the world. Solar power would be interrupted by night cycles and Jupiter eclipses, but should still do well.

    https://arxiv.org/abs/1902.03523
    Propelling Interplanetary Spacecraft Utilizing Water-Steam
    Jorge Martinez, Jekan Thangavelautham
    We would not use the steam power for propulsion, but for electricity.

    https://www.smithsonianmag.com/scien...farm-91577483/
    Ivanpah Solar Electric Generating System in California. It's run into trouble lately, but the basic idea still applies. Robots would perform maintenance using local materials in an ideal case. Shipping stuff from Earth would be too expensive.

  2. #32
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    This is interesting. Recent tests of the panspermia hypothesis have shown that certain lichens are very resistant to the space environment. Could they withstand the surface of Callisto, in current or genetic-engineered form? The result would be a covering of organic matter on the world, with a thin CO2 atmosphere.


    http://cdsads.u-strasbg.fr/abs/2010Icar..208..735D
    Survival of lichens and bacteria exposed to outer space conditions - Results of the Lithopanspermia experiments
    de la Torre, Rosa; Sancho, Leopoldo G.; Horneck, Gerda; Ríos, Asunción de los; Wierzchos, Jacek; Olsson-Francis, Karen; Cockell, Charles S.; Rettberg, Petra; Berger, Thomas; de Vera, Jean-Pierre P.; Ott, Sieglinde; Frías, Jesus Martinez; Melendi, Pablo Gonzalez; Lucas, Maria Mercedes; Reina, Manuel; Pintado, Ana; Demets, René
    Icarus, Volume 208, Issue 2, p. 735-748. (08/2010)
    Abstract: In the space experiments Lithopanspermia, experimental support was provided to the likelihood of the lithopanspermia concept that considers a viable transport of microorganisms between the terrestrial planets by means of meteorites. The rock colonising lichens Rhizocarpon geographicum and Xanthoria elegans, the vagrant lichen Aspicilia fruticulosa, and endolithic and endoevaporitic communities of cyanobacteria and bacteria with their natural rock substrate were exposed to space for 10 days onboard the Biopan facility of the European Space Agency (ESA). Biopan was closed during launch and re-entry. In addition, in the Stone facility, one sample of R. geographicum on its natural granitic substrate was attached at the outer surface of the re-entry capsule close to the stagnation point, only protected by a thin cover of glass textolite. Post-flight analysis, which included determination of the photosynthetic activity, LIVE/DEAD staining, and germination capacity of the ascospores, demonstrated that all three lichen were quite resistant to outer space conditions, which include the full spectrum of solar extraterrestrial electromagnetic radiation or selected wavelength ranges. This high resistance of the lichens to space appears to be due to their symbiotic nature and protection by their upper pigmented layer, the cortex. In contrast, the rock- or halite-inhabiting bacteria were severely damaged by the same exposure. After atmospheric re-entry, the granite of the Stone sample was transformed into a glassy, nearly homogenous material, with several friction striae. None of the lichen cells survived this re-entry process. The data suggest that lichens are suitable candidates for testing the concept of lithopanspermia, because they are extremely resistant to the harsh environment of outer space. The more critical event is the atmospheric re-entry after being captured by a planet. Experiments simulating the re-entry process of a microbe-carrying meteoroid did not show any survivors.

    http://cdsads.u-strasbg.fr/abs/2019AsBio..19..170O
    Survival, DNA, and Ultrastructural Integrity of a Cryptoendolithic Antarctic Fungus in Mars and Lunar Rock Analogs Exposed Outside the International Space Station
    Onofri, Silvano; Selbmann, Laura; Pacelli, Claudia; Zucconi, Laura; Rabbow, Elke; de Vera, Jean-Pierre
    Astrobiology, Volume 19, Issue 2, pp.170-182 (02/2019)
    Abstract: The search for life beyond Earth involves investigation into the responses of model organisms to the deleterious effects of space. In the frame of the BIOlogy and Mars Experiment, as part of the European Space Agency (ESA) space mission EXPOSE-R2 in low Earth orbit (LEO), dried colonies of the Antarctic cryptoendolithic black fungus Cryomyces antarcticus CCFEE 515 were grown on martian and lunar analog regolith pellets, and exposed for 16 months to LEO space and simulated Mars-like conditions on the International Space Station. The results demonstrate that C. antarcticus was able to tolerate the combined stress of different extraterrestrial substrates, space, and simulated Mars-like conditions in terms of survival, DNA, and ultrastructural stability. Results offer insights into the habitability of Mars for future exploration missions on Mars. Implications for the detection of biosignatures in extraterrestrial conditions and planetary protection are discussed.

    http://cdsads.u-strasbg.fr/abs/2018cosp...42E.778D
    The BIOMEX Experiment on-board the International Space Station: Biomolecular- and Bio-geochemical changes of lichens exposed to space- and to Mars-like conditions
    De la Torre Noetzel, Rosa; Ortega, Maria Victoria
    42nd COSPAR Scientific Assembly. Held 14-22 July 2018, in Pasadena, California, USA, Abstract id. F3.1-11-18. (07/2018 )
    Abstract: Exploration of the solar system is a priority research area of the AstRoMap European Astrobiology Roadmap (Horneck et al., 2015) [1], focusing on several research topics, such as "Life and Habitability" andan other one is "Biomarkers for easy the detection of life". Therefore, "space platforms and laboratories", as the EXPOSE setup installed outside the ISS, are essential to gain more knowledge of space- and planetary environments, which might be an essential basis for improvement of the robotic and human interplanetary exploration (Space, Moon, Mars, Encedalus, Titan, Europa). At the exposure platform EXPOSE-R2 on the ISS (2014-2016), samples of the astrobiological model lichen Circinaria gyrosa [3,4,5,6], a specie which was exposed 18 months to space and simulated Mars-like conditions during the BIOMEX experiment [2] (Biology and Mars Experiment, ESA), was investigated, to study Mars' habitability and resistance to space conditions. The data obtained by this biomarker-study after being exposed to Mars-like conditions will support the analysis of data obtained during future instrumental detection operations in future space missions on Mars (i.e. ExoMars or Mars 2020). After the return of the samples in June 2016, the first preliminary analysis showed a quick and complete recovery of metabolic activity of the control samples exposed to space vacuum and Mars-like atmosphere. In contrast, the samples directly exposed to solar UV radiation showed slow recovery, in reference to their observed original activity. Recent results will be presented that show biomolecular changes of the DNA analysed by PCR-based [7, 8] and complementary sequencing techniques, in correlation with the previous results showing changes in metabolic activity and changes in viability (Electron and fluorescence microscopy techniques), as well as in morphology/ultrastructure - a potential effext due to space vacuum and Mars atmosphere. In addition, the biogeochemical variations have been examined with spectroscopic analyses (Raman) to look for possible degradation of cell surfaces and pigments which were in contact with terrestrial rocks, and Martian analogue regolith. Moreover, differences were observed between samples irradiated directly with solar UV radiation and samples positioned in the shielded area as dark-control. These experiments will contribute to answer questions of the habitability of Mars, on the likelihood of the Lithopanspermia Hypothesis, on the capability to detect biomolecules by life-detection instruments exposed to an extraterrestrial environment and will be of relevance for planetary protection issues.

    http://cdsads.u-strasbg.fr/abs/2019AsBio..19..233B
    Characterization of Viability of the Lichen Buellia frigida After 1.5 Years in Space on the International Space Station
    Backhaus, Theresa; Meeßen, Joachim; Demets, René; de Vera, Jean-Pierre; Ott, Sieglinde
    Astrobiology, Volume 19, Issue 2, pp.233-241 (02/2019)
    Abstract: The lichen Buellia frigida was exposed to space and simulated Mars analog conditions in the Biology and Mars Experiment (BIOMEX) project operated outside the International Space Station (ISS) for 1.5 years. To determine the effects of the Low Earth Orbit (LEO) conditions on the lichen symbionts, a LIVE/DEAD staining analysis test was performed. After return from the ISS, the lichen symbionts demonstrated mortality rates of up to 100% for the algal symbiont and up to 97.8% for the fungal symbiont. In contrast, the lichen symbiont controls exhibited mortality rates of 10.3% up to 31.9% for the algal symbiont and 14.5% for the fungal symbiont. The results performed in the BIOMEX Mars simulation experiment on the ISS indicate that the potential for survival and the resistance of the lichen B. frigida to LEO conditions are very low. It is unlikely that Mars could be inhabited by this lichen, even for a limited amount of time, or even not habitable planet for the tested lichen symbionts.

    http://cdsads.u-strasbg.fr/abs/2008cosp...37..660D
    Experiment lithopanspermia: test of interplanetary transfer and re-entry process of epi- and endolithic microbial communities in the FOTON-M3 Mission
    de La Torre Noetzel, Rosa
    37th COSPAR Scientific Assembly. Held 13-20 July 2008, in Montréal, Canada., p.660 (00/2008)
    Abstract: The Lithopanspermia hypothesis assumes that impact-expelled rocks serve as interplanetary transfer vehicles for microorganisms colonizing those rocks. It requires that the microorganisms survive (1) the impact ejection process from the planet of origin; (2) travelling through space; (3) capture and landing on another planet. In the experiment "Lithopanspermia" on board of the FOTON-M3 satellite (14.09.07) steps 2 and 3 of this scenario have been experimentally tested. Assay systems for step 2 were the bipolar epilithic lichen species Rhizocarpon geographicum and Xanthoria elegans on their natural rock substrate as well as their reproduction structures, microbial communities from atacamás halites Chroococcidiopsiss, endolithic communities of Anabaena and Nostoc, and the vagrant lichen species Aspicilia fruticulosa. The samples were exposed to outer space conditions within the BIOPAN-6 facility of ESA. Preparatory space simulation studies (UV solar spectrum radiation and vacuum at 10-2 Pa) performed at the Spasolab-Laboratory of INTA (March-April 2007), have demonstrated the suitability of those lichen species. After flight (10 days exposure to harsh space conditions in low Earth orbit at about 300 km altitude) and recovery, the survival capacity of the microbial communities has been assayed. First analyses have confirmed a fast recovery of the biological activity (chlorophyll a- fluorescence) of the lichens, similar to the high survival rates observed in the experiment LICHENS onboard of the Foton-M2 mission (de la Torre et al., 2007; Sancho et al., 2007). There were no significant changes in relation with the pre-flight values of the epilithic-, endolithic and vagrant lichen samples. First results of Confocal Scanning Laser Microscopy have demonstrated a high vitality of epilithic samples. Ultrastructural changes are being analyzed by Transmission Electron Microscopy and Cryoscanning. Furthermore, concerning the germination capacity of ascospores of Xanthoria elegans up to now no differences were detected between the controls (90 References: De la Torre et al. (2007) BIOPAN experiment LICHENS on the Foton-M2 mission: pre-flight verification tests of the Rhizocarpon geographicum-granite ecosystem, Adv. Space Res. 40, 1665-1671, doi:10.1016/jasr.2007.02.022. Sancho L. et al. (2007) Lichens survive in space. Astrobiology, 7, 443-454. St¨ffler D, et al. (2007) Experimental evidence for the o potential impact ejection of viable microorganisms from Mars and Mars-like planets Icarus, 186, 585-588. Horneck et al. (2007) Microbial rock inhabitants survive hypervelocity impacts on Mars-like host planets: First phase of Lithopanspermia experimentally tested, Astrobiology, in press.

  3. #33
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    And, as the penultimate display of crazy on Callisto (that was catchy, hmm), we introduce atomic gardening.

    https://en.wikipedia.org/wiki/Atomic_gardening

    This is best done by dumping lichens all over Callisto after putting radiation-emitting nuclear reactors down for creating power for robots and colonists. Presto, you get super-fast mutations, 99.9% of which are bad but 0.1% of which will turn into carnivorous triffids or maybe something actually good, who knows. It's Callisto, it's not like anyone else is doing stuff with it.

    http://interestingengineering.com/at...mma-radiation/

  4. #34
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    Eventually would like to get humans to Callisto, but there's still that darned bugaboo, cosmic radiation, that will make everyone sick or dead on the outbound voyage to Jupiter. Well, to be honest, to Mars as well, and to the Moon unless we can dig fast enough. How bad is an SPE (see below) at Jupiter's distance?

    http://cdsads.u-strasbg.fr/abs/2018cosp...42E1427H

    Towards Space Exploration of Moon, Mars & Neos: Radiation Biological Basis
    Hellweg, Christine; Baumstark-Khan, Christa; Berger, Thomas
    42nd COSPAR Scientific Assembly. Held 14-22 July 2018, in Pasadena, California, USA, Abstract id. PEX.2-20-18. (07/2018)

    Abstract: Radiation has emerged as the most critical issue to be resolved for long-term missions both orbital and interplanetary. Astronauts are constantly exposed to galactic cosmic radiation (GCR) of various energies at a low dose rate. Primarily late tissue sequels like genetic alterations, cancer and non-cancer effects, i.e. cataracts and degenerative diseases of e.g. the central nervous system or the cardiovascular system, are the potential risks. Cataracts were observed to occur earlier and more often in astronauts exposed to higher proportions of galactic ions (Cucinotta et al., 2001). Predictions of cancer risk and acceptable radiation exposure in space are subject to many uncertainties including the relative biological effectiveness (RBE) of space radiation especially heavy ions, dose-rate effects and possible interaction with microgravity and other spaceflight environmental factors. The initial cellular response to radiation exposure paves the way to late sequelae and starts with damage to the DNA which complexity depends on the linear energy transfer (LET) of the radiation. Repair of such complex DNA damage is more challenging and requires more time than the repair of simple DNA double strand breaks (DSB) which can be visualized by immunofluorescence staining of the phosphorylated histone 2AX (gammaH2AX) and might explain the observed prolonged cell cycle arrests induced by high-LET in comparison to low-LET irradiation. Unrepaired or mis-repaired DNA DSB are proposed to be responsible for cell death, mutations, chromosomal aberrations and oncogenic cell transformation. Cell killing and mutation induction are most efficient in an LET range of 90-200 keV/mum. Also the activation of transcription factors such as Nuclear Factor kappaB (NF-kappaB) and gene expression shaping the cellular radiation response depend on the LET with a peak RBE between 90 and 300 keV/mum. Such LET-RBE relationships were observed for cataract and cancer induction by heavy ions in laboratory animals, with varying maximal efficiencies. Furthermore, there is always the added risk of acute exposure to high proton fluxes during a solar particle event (SPE), which can threaten immediate survival of the astronauts in case of insufficient shielding by eliciting the acute radiation syndrome. Its symptoms depend on absorbed total radiation dose, type of radiation, the dose distribution in the body and the individual radiation sensitivity. After the prodromal stage with nausea and vomiting and a subsequent symptom-free phase, depending on dose, the hematopoietic syndrome with suppression of the acquired immune system and thrombocytopenia (0.7-4 Sv), the gastrointestinal tract syndrome (5-12 Sv) or the central nervous system syndrome (> 20 Sv) develop and they are accompanied by exacerbated innate immune responses. Exposure to large SPE has to be avoided by warning systems and stay inside a radiation shelter during the event. Treatment options encompass e.g. the administration of colony-stimulating factors (CSF), growth factors and blood transfusions to overcome the hematopoietic syndrome and the administration of antibiotics against secondary infections. A concerted action of ground-based studies and space experiments is required to improve the radiobiological basis of space radiation risk assessment and countermeasure development.

    Reference:Cucinotta FA, Manuel FK, Jones J, Iszard G, Murrey J, Djojonegro B and Wear M (2001) Space Radiation and Cataracts in Astronauts. Rad Res 156, 460-466

  5. #35
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    Quote Originally Posted by Roger E. Moore View Post
    Eventually would like to get humans to Callisto, but there's still that darned bugaboo, cosmic radiation, that will make everyone sick or dead on the outbound voyage to Jupiter.
    Not to mention, low gravity at the destination moon.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  6. #36
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    Quote Originally Posted by Noclevername View Post
    Not to mention, low gravity at the destination moon.
    Yeah, you're right, I've kind of ignored that. Robots would be fine, people... I dunno.

  7. #37
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    Gravity and radiation are the 2 biggest obstacles to any space colonization efforts. Next is establishing a suitably stable and flexible ecosystem for human life support. I think all these are solvable problems, with sufficient research and experimentation.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  8. #38
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    Here's a Youtube video about Ocean Mechanical Thermal Energy conversion, which is an analog to this sort of energy generation on Earth. The quantities of energy that could potentially be extracted by this method are very large, but the density is low.
    https://www.youtube.com/watch?v=y2JO6cZT0mQ

  9. #39
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    Gravity on Callisto is 0.126 gees; only a bit less than gravity on the Moon. I have high hopes that Lunar gravity will not be a great problem for permanent colonists, and Callisto's gravity should be similar; the main problem would be if any of these colonists wanted to go back to Earth.

  10. #40
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    Quote Originally Posted by eburacum45 View Post
    Gravity on Callisto is 0.126 gees; only a bit less than gravity on the Moon. I have high hopes that Lunar gravity will not be a great problem for permanent colonists, and Callisto's gravity should be similar; the main problem would be if any of these colonists wanted to go back to Earth.
    We just don't have any information on the effects of long term low G.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  11. #41
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    Quote Originally Posted by eburacum45 View Post
    Here's a Youtube video about Ocean Mechanical Thermal Energy conversion, which is an analog to this sort of energy generation on Earth. The quantities of energy that could potentially be extracted by this method are very large, but the density is low.
    https://www.youtube.com/watch?v=y2JO6cZT0mQ
    Interesting, I seem to have missed this. Looked it up on Wikipedia as well. The advantage on Callisto would be that the power station would sit on solid footing. The disadvantage would be that as the power station generates heat, the solid footing will soften. Still extremely cold there, though. I really like this, very cool. Probably a lot better functioning that the propeller turbine thing I was muffing about earlier.

    https://en.wikipedia.org/wiki/Ocean_...rgy_conversion

  12. #42
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    A couple of nutty ideas came to me on the drive home from work. (I try not to stay bored for long.)

    One of Jupiter's hallmarks, recent research points out, is that it throws asteroids, comets, and Centaurs away from Earth as well as toward Earth. A telescope in the Jovian system would be a huge help in identifying possible Earth-busters long before they get to us. I would prefer an orbital platform, though.

  13. #43
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    [Cat has been sitting on my keyboard, now she is sleeping elsewhere.]

    It came to me that an artificial atmosphere could probably be generated that would warm Callisto: a greenhouse-gas atmosphere made of nitrogen-oxygen compounds. Not sure whether it would turn the surface layer into slush, though, but it could be done.

    CO2 of course would work.

    Not sure why we might do this, but hey, it's worth a thought. Maybe we could grow more lichens there and mutate them into a plant Solaris.

    .
    Last edited by Roger E. Moore; 2019-May-07 at 01:25 PM. Reason: adds

  14. #44
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    Well, seems that Carl Sagan beat me to it in the crazy ideas department. He wrote an article on terraforming Mars for Icarus magazine in December 1973 ("Planetary engineering on Mars") in which he proposed covering Mars with dark material from grinding up Deimos and Phobos, or else dump lichens or the like on Mars to lower the global albedo and warm it up with sunlight.

    Same for Callisto. It appears from experiment mentioned above that some kinds of lichen would do fine on Callisto, despite everything, so seeding the world with them would cause Callisto to eventually warm up, produce an atmosphere at some point, melt the surface (or part of it), and make it less hostile.

    It occurs to me that the atmosphere would cut down on the incoming radiation from cosmic rays and solar storms, even if it was not breathable.

    Perhaps a whole new ecology could be developed for the world. It has a surface area of about half of Earth's land masses put together. That's a lot of room to do something.

    https://www.sciencedirect.com/scienc...19103573900262

  15. #45
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    Quote Originally Posted by Roger E. Moore View Post
    Same for Callisto. It appears from experiment mentioned above that some kinds of lichen would do fine on Callisto, despite everything, so seeding the world with them would cause Callisto to eventually warm up, produce an atmosphere at some point, melt the surface (or part of it), and make it less hostile.

    It occurs to me that the atmosphere would cut down on the incoming radiation from cosmic rays and solar storms, even if it was not breathable.
    Would it be less hostile? Right now living on Callisto would be easier than living on the Moon... surrounded by easily workable ice, no weather, no waves. All that would change, with an atmosphere and melting. Ice also makes good C-ray shielding as is. Just sculpt it into caves and inflate some Transhabs inside.

    Vacuum is also the best insulator, atmosphere and water could carry off all your hab's precious heat. When the wind blows...
    Last edited by Noclevername; 2019-May-07 at 04:08 PM.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  16. #46
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    Quote Originally Posted by Noclevername View Post
    Would it be less hostile? Right now living on Callisto would be easier than living on the Moon... surrounded by easily workable ice, no weather, no waves. All that would change, with an atmosphere and melting. Ice also makes good C-ray shielding as is. Just sculpt it into caves and inflate some Transhabs inside.

    Vacuum is also the best insulator, atmosphere and water could carry off all your hab's precious heat. When the wind blows...
    I'm having trouble translating some of the papers into terms I can understand, regarding how much radiation from space (not Jupiter, which is pretty low) impacts the surface of Callisto. I know going to Mars over a long period is very dangerous. More soon.

  17. #47
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    Here we go, a comprehensive overview not behind a paywall. Not much to say right now, will need to read it over.

    https://www.sciencedirect.com/scienc...033?via%3Dihub

    Behavioral effects of space radiation: A comprehensive review of animal studies

    Frederico Kiffer, Marjan Boerma, Antiño Allen
    Life Sciences in Space Research, Volume 21, May 2019, Pages 1-21

    QUOTE: To date, the only humans exposed to interplanetary radiation are the Apollo astronauts, whose missions lasted a maximum of 13 days. The eventual manned missions to Mars will likely last 800–1100 days, of which approximately 500 days will be spent on the planet's surface, depending on final mission design (Drake, 2009). Recent data from Curiosity indicate concerning cumulative levels of daily radiation that may likely be encountered by astronauts on these missions. Behind the shielding provided by the Mars Science Laboratory and en cruise to Mars, the GCR dose rate was approximately 0.481 ± 0.080 mGy/day, during an untraditionally weak solar maximum (Zeitlin et al., 2013). Data from an unshielded Curiosity on the Martian surface suggest a GCR dose rate of 0.210 ± 0.040 mGy/day (Hassler et al., 2014). Mission dose estimates due to GCR are on the order of 25–50 cGy. Additional dosage due to solar particle events (SPE) would depend upon the phase of the 11-year solar cycle during which a mission takes place and the relative intensity of the particular solar cycle, and are estimated to range from 15–50 cGy behind conventional shields (Nelson, 2016; Drake, 2009; Wilson et al., 1997; Kim et al., 2009).

    LATER: This looks pretty bad.

    .
    Last edited by Roger E. Moore; 2019-May-07 at 05:05 PM.

  18. #48
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    Full paper, no paywall, on Galactic Cosmic Radiation effects on a long-duration Mars mission. Ouch ouch ouch, just getting to Callisto will be many times worse than getting to Mars. Callisto is likely to take hits from Galactic Cosmic Radiation, too.

    https://www.nature.com/articles/s41598-017-02087-3

    Non-Targeted Effects Models Predict Significantly Higher Mars Mission Cancer Risk than Targeted Effects Models
    Francis A. Cucinotta & Eliedonna Cacao
    Scientific Reports, volume 7, Article number: 1832 (12 May 2017)

    QUOTES: Cancer risk is an important concern for galactic cosmic ray (GCR) exposures, which consist of a wide-energy range of protons, heavy ions and secondary radiation produced in shielding and tissues. Relative biological effectiveness (RBE) factors for surrogate cancer endpoints in cell culture models and tumor induction in mice vary considerable, including significant variations for different tissues and mouse strains. Many studies suggest non-targeted effects (NTE) occur for low doses of high linear energy transfer (LET) radiation, leading to deviation from the linear dose response model used in radiation protection. Using the mouse Harderian gland tumor experiment, the only extensive data-set for dose response modelling with a variety of particle types (>4), for the first-time a particle track structure model of tumor prevalence is used to investigate the effects of NTEs in predictions of chronic GCR exposure risk. The NTE model led to a predicted risk 2-fold higher compared to a targeted effects model. The scarcity of data with animal models for tissues that dominate human radiation cancer risk, including lung, colon, breast, liver, and stomach, suggest that studies of NTEs in other tissues are urgently needed prior to long-term space missions outside the protection of the Earth’s geomagnetic sphere.

    The health risks from galactic cosmic ray (GCR) exposure to astronauts include cancer, central nervous system effects, cataracts, circulatory diseases, and acute radiation syndromes. Cancer and cataracts are the main concern for space missions in low Earth orbit, while for long-term space missions outside the protection of the Earth’s magnetic field cancer risks are predicted to exceed acceptable risk levels9, and non-cancer risks are of concern for the higher organ doses of long-term space missions compared to missions in low Earth orbit. Annual GCR organ absorbed doses and dose equivalents vary over the solar cycle between 0.1 and 0.2 Gy/y and 0.3 and 0.6 Sv/yr, respectively for average spacecraft shielding thicknesses.

    The high energies of GCR limit practical shielding amounts from providing significant attenuation9. The exploration of Mars will require missions of 900 days or longer with more than one year in deep space where exposures to all energies of GCR are unavoidable and doses only modestly decreased by radiation shielding.

  19. #49
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    Thus my focus on HLLVs getting ever larger: http://up-ship.com/blog/?p=40616

    Just keep increasing the size of vehicles until the point they are massive enough that radiation is no issue.

    And you use this:
    http://www.minimagnetosphere.rl.ac.u...pacecraft.html

  20. #50
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    Quote Originally Posted by Roger E. Moore View Post
    It came to me that an artificial atmosphere could probably be generated that would warm Callisto: a greenhouse-gas atmosphere made of nitrogen-oxygen compounds. Not sure whether it would turn the surface layer into slush, though, but it could be done.

    CO2 of course would work.
    I've changed my mind on this. Not the greenhouse-gas atmosphere (maybe, if we decide we need it) but the use of nitrous oxides. Those are too poisonous and corrosive. CO2 and N2, much better.

  21. #51
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    Quote Originally Posted by publiusr View Post
    Oh!

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    Here are a few relevant comments from a paper I re-read.

    https://web.archive.org/web/20190402...aS_Journal.pdf
    Colonizing Jupiter’s Moons: An Assessment of Our Options and Alternatives
    Thomas B. Kerwick, The Lifeboat Foundation / CEVA, Inc. (Winter 2012)

    QUOTES: The large magnetosphere also has an important function in the region in that it protects the four largest moons of Jupiter − which all orbit within the magnetosphere − from the solar wind. Outside the Jovian radiation belts, the magnetosphere is an important blanket over the region. This is in stark contrast to a hypothetical base on either the Moon or Mars where there is no such blanket. So we can consider the magnetosphere here to provide opportunity and not just deter.

    The mean temperature on Callisto is estimated at 135K with a variation of ±50K [9].

    Being darker, the surface of Callisto is warm relative to Europa and Ganymede (a darker surface reflects less light, and therefore retains more heat/energy), and it also benefits from a much thicker atmosphere [20]. The CO2 component of Callisto’s atmosphere was first detected by the Galileo mission’s imaging spectrometer, NIMS, but recent modeling suggests an even more robust atmosphere. Interaction between a more substantial ionosphere and Jupiter’s magnetosphere reduces electron impact, and the relatively thick atmosphere also protects the surface significantly from radiation flux. To put these figures in context, the surface pressure on Callisto is estimated at 7.5 pbar, while the estimated maximum surface temperature is 170K – still extreme conditions for any astronauts.

    Organic compounds have also been detected through spectroscopic measurements [20]. One proposition for Callisto may be the introduction of genetically-modified vegetation − robust to cold surface temperatures and capable of surviving in a weak CO2 atmosphere, to grow here as renewable food sources.

    As with Ganymede − and unlike Europa − Callisto has abundant accessible resources in silicates and irons that are suitable for mining and construction. A successfully established base here could be augmented over time into a more ambitious industrial base and colony if viable.

    [9] Callisto – Thermal Characteristics. Moore, Jeffrey M. et al. Laboratory for Atmospheric and Space Physics, University of Colorado 2008.
    http://lasp.colorado.edu/~espoclass/...ework/Ch17.pdf

    [20] “Callisto: New Insights from Galileo Disk-Resolved UV Measurements.” Hendrix, A. R., Johnson, R. E. The Astrophysical Journal, November 2008.
    http://people.virginia.edu/~rej/pape...nson-ApJ08.pdf

  23. #53
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    Just a note here: Found an astounding amount of new information on Callisto, for anyone interested. It will take time to digest.

    http://lasp.colorado.edu/~espoclass/...ework/Ch17.pdf (regular http)
    https://web.archive.org/web/20180615...ework/Ch17.pdf (archive.org link)

    Callisto. Moore, Jeffrey M.; Chapman, Clark R.; Bierhaus, Edward B.; Greeley, Ronald; Chuang, Frank C.; Klemaszewski, James; Clark, Roger N.; Dalton, J. Brad; Hibbitts, Charles A.; Schenk, Paul M.; Spencer, John R.; Wagner, Roland. Chapter 17 in Jupiter. The planet, satellites and magnetosphere. Edited by Fran Bagenal, Timothy E. Dowling, William B. McKinnon. Cambridge planetary science, Vol. 1, Cambridge, UK: Cambridge University Press, ISBN 0-521-81808-7, 2004, p. 397-426.

  24. #54
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    Quote Originally Posted by publiusr View Post
    Thus my focus on HLLVs getting ever larger: http://up-ship.com/blog/?p=40616

    Just keep increasing the size of vehicles until the point they are massive enough that radiation is no issue.
    Better yet, asteroid mining. No need to lift materials so expensively when there's already shielding mass up there.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  25. #55
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    Reading through the research suggests that darkening the surface of Callisto would be a good first step to partially terraforming it. On Earth the presence of black carbon (soot) from forest fires does a regrettably fine job of lowering the albedo of glaciers and snow fields, causing them to melt. Other sorts of aerosols or suspensions (dust) could do the same. A previously mentioned paper points out that Callisto is relatively dark compared to other Galilean moons because so much debris has impacted its surface in ages past, Callisto being the outermost moon and the one most likely to get hit (particularly on its leading side.

    An excellent source of dust and dark material would be (tah dah) the outer little moons of Jupiter. A self-replicating robot colony in the outer moons could send deposits of dust to spiral inward toward Callisto and impact it. The dust would serve as a forcing agent to raise the local temperature on Callisto.

    As the temperature rises, part two of the project automatically begins with the building of a greenhouse-gas atmosphere. The surface of Callisto is supposed to have nitrogen, carbon monoxide, carbon dioxide, and other materials that will eventually sublimate into gas.

    At some point the system will stabilize, not sure where. When it stabilizes, then the next stage begins, which is seeding the world with dark lichen and symbiotic bacteria/ microorganisms. This will turn the world in time into a living world, though possibly one not yet fit fir human habitation.

    More soon.
    Last edited by Roger E. Moore; 2019-Jun-05 at 04:10 PM.

  26. #56
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    Okay, attached is a small table I created thanks to Wikipedia's info on the melting and boiling points of various substances that have been found (or might be found) on Callisto.

    We can use this to figure out in what order gases will appear in the atmosphere as the world warms and cools, day and night, or as it warms artificially.

    As we can see, the surface temperature has to come up quite a bit before carbon dioxide sublimates and a CO2 atmosphere rises, setting the world on another warming binge. However, the presence of nitrogen oxides might also warm up the world to help bring it closer to CO2 level. Dumping lichens and symbiotes all over the world will make the terraforming easier, then.

    NEW MATERIAL: Note that, because Callisto's equator (matched with its orbital plane around Jupiter) is going to be unaligned with Callisto's orientation with the Sun, there will be some math fudging here because the subsolar point will not be on the equator. It should not be more than a couple degrees off, however, if I am reading the numbers correctly.

    It appears that some of Callisto's atmosphere freezes out at night and rests on the ground as frost, rising up in the daytime. Only half the world will have a significant atmosphere, then. Interesting thought.


    SPECIAL NOTE: Table has been updated in a later post.
    Attached Images Attached Images
    Last edited by Roger E. Moore; 2019-Jun-05 at 06:33 PM.

  27. #57
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    One particular advantage of terraforming Callisto is that the process could be completely performed by robots, which eliminates the need to send humans to the world, putting them at risk of death from radiation, etc.

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    By way of comparison, Titan (farther out than Callisto and in theory much colder) has a thick atmosphere of 97% nitrogen, about 2-3% methane, and lots of minor stuff. With the moon's lower gravity, the atmosphere of Titan extends a considerable distance from that world, an element that should also be characteristic of Callisto's atmosphere should it get thick enough. Spacecraft data indicate that Titan's atmosphere should be replenished from its interior, as the methane should have been converted by solar radiation into tholins. A similar fate would await methane in Callisto's air.

    https://en.wikipedia.org/wiki/Titan_(moon)#Atmosphere

    https://en.wikipedia.org/wiki/Atmosphere_of_Titan

    The first attached image (Wikipedia) shows Titan's atmosphere to scale, with its different levels. What would Callisto's atmosphere be like it that world was warmed up? Would there be an orange tholins haze, too?

    The second attached image shows Earth's atmosphere. Notice how far out Titan's atmosphere extends. The stratosphere on Titan, for example, is at 300 km, while on Earth it is 30 km, one-tenth the distance. Match heights for the tropopause and other layers. Looks like a factor of 10 to 1, Titan to Earth.

    Note: I am using "world" because of course the giant satellites of our Solar System are not planets. But, they are worlds.
    Attached Images Attached Images
    Last edited by Roger E. Moore; 2019-Jun-05 at 06:07 PM.

  29. #59
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    A 2008 paper mentioned above (link here) points out that complex organic molecules have been detected on Galilean moons, which would tend to color the soil red. The soil itself is uncompacted and loose, making materials in it easily affected by temperature changes. UV from the Sun would tend to break down these organic compounds. Good food for lichens? One way to find out would be to set up "Callisto chambers" and test out various plant life and microorganisms therein. And tardigrades, of course.

    http://people.virginia.edu/~rej/pape...nson-ApJ08.pdf

  30. #60
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    The table of atmospheric gases has been expanded and revised so that the boiling points, not the melting points, are highlighted. Ethane is included as an example of an organic compound found in the air of some outer planets and moons (e.g., Titan in trace amounts).

    NEW: Carbon dioxide appears to compose the majority of what little Callisto has for an atmosphere at present. See 1999 paper below.

    https://web.archive.org/web/20090327.../1/99-0186.pdf
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    Last edited by Roger E. Moore; 2019-Jun-05 at 07:07 PM.

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