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  1. #1
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    Lightbulb Callisto colonization -- some crazy ideas

    There was a NASA proposal back in 2003 to eventually (2040s) send an expedition to Callisto, the outermost Galilean moon of Jupiter, and turn it into a major space base. Details on that in a bit.

    A Crazy Idea: Infinite Hydroelectric Power

    Callisto is thought to have a subsurface saltwater ocean below the 80-150 km thick crust. If this proves true, and if there are no worthwhile organisms inhabiting this underground worldwide sea, then:

    1. Cut a hole through the crust, which might be of low density as the whole world of Callisto is of a lower density than the other Galilean moons;

    2. Lower a huge hydroelectric turbine, with power cables and a mount to attach it to the underside of the crust;

    3. Turn it on.

    The subsurface ocean might be stirred constantly by a tidal-gravity-based combination of Callisto's orbit around Jupiter interacting with the gravity of the other Galilean satellites. It seems logical to place the hydroelectric plant along Callisto's equator or thereabouts to get the maximum effect from being in roughly the same orbital plane as the other satellites and of course Jupiter, taking advantage of age-old currents. I cannot believe the ocean there would be stagnant, but who knows.

    Problems

    1. The subsurface ocean is sure to be corrosive, so the hydroelectric turbine(s) will need constant replacement and repair.

    2. The turbine will produce a bit of drag on the subsurface ocean, which might affect the orbit of Callisto around Jupiter.

    3. The turbine(s) will certainly produce heat, slowly warming up the underground ocean with unknown effects.

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    Lightbulb

    Background on the 2003 proposal. This was a breath-taking overview of a human + robot expedition to Callisto. It was released as a PowerPoint slideshow, produced by the NASA Langley Research Center & Princeton University. The best way to get it is through the Wayback Machine.

    https://web.archive.org/web/20090327...nt/bethke.pdf/

    Revolutionary Concepts for Human Outer Planet Exploration (HOPE)
    by Pat Troutman & Kristen Bethke: February 3, 2003
    Presentation for STAIF-2003 Fission Propulsion Systems for Human Missions

    A bit of humor mixed with a dead-serious proposal to establish a temporary crewed base on Callisto, 2045+, a 5-year mission for 6 astronauts, age 35-45, and an assortment of AI robots. Several advanced propulsion systems are discussed. Assume 100°K operating environment on Callisto. Nuclear reactor for the base will be unshielded and dangerous to humans, so it will need to be isolated. Slideshow is heavily illustrated.

    QUOTES: "A crewed expedition is to be sent to the surface of Callisto to teleoperate the Europa submarine [assumes life was discovered in Europa's underground seas, and a robot sub is sent separately to Europa] and excavate Callisto surface samples.... The expedition will also establish a reusable surface base with an ISRU plant to support future Jovian system exploration."

    Callisto can be explored as the radiation levels there are far lower than for the other three Galilean satellites, where the radiation is fatal to humans.

    Pictures attached show the HOPE booklet cover, a selection of advanced spacecraft to get to Jupiter, and an artist's concept of the Callisto base.

    .
    Attached Images Attached Images
    Last edited by Roger E. Moore; 2019-Apr-17 at 02:11 PM. Reason: add pics

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    Quote Originally Posted by Roger E. Moore View Post
    There was a NASA proposal back in 2003 to eventually (2040s) send an expedition to Callisto, the outermost Galilean moon of Jupiter, and turn it into a major space base. Details on that in a bit.

    A Crazy Idea: Infinite Hydroelectric Power

    Callisto is thought to have a subsurface saltwater ocean below the 80-150 km thick crust. If this proves true, and if there are no worthwhile organisms inhabiting this underground worldwide sea, then:

    1. Cut a hole through the crust, which might be of low density as the whole world of Callisto is of a lower density than the other Galilean moons;

    2. Lower a huge hydroelectric turbine, with power cables and a mount to attach it to the underside of the crust;

    3. Turn it on.

    The subsurface ocean might be stirred constantly by a tidal-gravity-based combination of Callisto's orbit around Jupiter interacting with the gravity of the other Galilean satellites. It seems logical to place the hydroelectric plant along Callisto's equator or thereabouts to get the maximum effect from being in roughly the same orbital plane as the other satellites and of course Jupiter, taking advantage of age-old currents. I cannot believe the ocean there would be stagnant, but who knows.

    Problems

    1. The subsurface ocean is sure to be corrosive, so the hydroelectric turbine(s) will need constant replacement and repair.

    2. The turbine will produce a bit of drag on the subsurface ocean, which might affect the orbit of Callisto around Jupiter.

    3. The turbine(s) will certainly produce heat, slowly warming up the underground ocean with unknown effects.

    1: True, and the local pressure (my WAG is about 2,700 atm, a bit more than twice that at the bottom of the Earth's ocean) may be enough to affect chemistry and behavior of insulators. There would need to be test installations and material qualifications first.

    2: It would have to -- First Law says so -- but even a terawatt of turbines (producing perhaps 700 gigawatts; turbines are not 100% efficient) will take about 1.1 million years to reduce orbital velocity by one part in 10^5.

    3: Changes in the flow field from the turbines may be more important.
    Information about American English usage here and here. Floating point issues? Please read this before posting.

    How do things fly? This explains it all.

    Actually they can't: "Heavier-than-air flying machines are impossible." - Lord Kelvin, president, Royal Society, 1895.



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    Quote Originally Posted by swampyankee View Post
    3: Changes in the flow field from the turbines may be more important.
    I mulled over whether the turbines should be fixed in place or able to swivel, like the rotors on a wind-power generator or a farm's windmill pump, so the turbines could follow changes in the local currents of the underground sea.

    Someone must have thought of this idea before I did and worked it out better than I have here. I'm usually pretty late to the blue-sky party.

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    Quote Originally Posted by Roger E. Moore View Post
    I mulled over whether the turbines should be fixed in place or able to swivel, like the rotors on a wind-power generator or a farm's windmill pump, so the turbines could follow changes in the local currents of the underground sea.

    Someone must have thought of this idea before I did and worked it out better than I have here. I'm usually pretty late to the blue-sky party.
    Use something like vertical axis wind turbines. They're not sensitive to flow direction perpendicular to their axis of rotation, although many are not self-starting.
    Information about American English usage here and here. Floating point issues? Please read this before posting.

    How do things fly? This explains it all.

    Actually they can't: "Heavier-than-air flying machines are impossible." - Lord Kelvin, president, Royal Society, 1895.



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    Quote Originally Posted by swampyankee View Post
    Use something like vertical axis wind turbines. They're not sensitive to flow direction perpendicular to their axis of rotation, although many are not self-starting.
    And some can be collapsed down to fit through a narrow bore, and expanded on the other side.

    As for heat, the turbine would produce less than friction of the unimpeded water would. You're removing energy from the system, after all...the stuff you're powering will be producing heat instead. But this is going to be tiny compared to the other disruptions involved in putting a turbine into the ocean.

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    A detailed method of reaching Callisto was also offered in 2003 in a short booklet put out by the NASA Glenn Research Center in Ohio.

    https://trajectory.grc.nasa.gov/abou...F-2003-177.pdf
    High Power MPD Nuclear Electric Propulsion (NEP) for Artificial Gravity HOPE Missions to Callisto (NASA/TM—2003-212349)
    by Melissa L. McGuire, Stanley K. Borowski, Lee M. Mason, and James Gilland (December 2003)

    QUOTES: "Why Callisto? The key requirements considered in selecting a worthy exploration destination beyond Mars were (1) the opportunities for conducting interesting science and (2) the availability of in-situ resources to support a human mission. The body chosen for the HOPE study was Callisto, the third largest satellite in the Solar System, and the outermost Galilean moon of Jupiter. Orbiting at a distance of ~1.9 million kilometers, Callisto is located beyond Jupiter’s main radiation belts making its local environment more conducive to human exploration. Callisto is an icy, rocky world with a surface gravity of ~0.127 g(Earth) and a composition consisting of water-ice and rock in a mixture ratio of 55:45. Besides having significant quantities of water-ice for propellant production, Callisto’s heavily cratered and ancient landscape (~4 billion years old) has a relatively low albedo indicating that significant quantities of non-ice materials and asteroid dust may reside on its surface."

    "The HOPE mission consists of sending a crew of six on an expedition to Callisto to establish an outpost and propellant production facility near the Asgard asteroid impact site, a region where the surface crust is potentially rich in water ice. An “all NEP” space transportation system architecture is examined in this paper. It uses a split mission approach involving separate multi-megawatt electric (MWe)-class cargo, tanker and piloted vehicles each propelled by hydrogen MPD thrusters. Fully automated cargo and tanker vehicles depart first to pre-deploy both orbital and surface assets at Callisto prior to the arrival of the crew onboard the artificial gravity Piloted Callisto Transfer Vehicle (PCTV). The NEP cargo vehicle delivers three different landers for crew ascent / descent, surface habitation and propellant production. The later carries an In-Situ Resource Utilization (ISRU) processing plant and several combination “bulldozer / rover” surface vehicles used to produce liquid oxygen (LOX) and hydrogen (LH2) propellant from the Callisto surface ice. This propellant is supplied to the reusable crew ascent / descent vehicle allowing crew rotation / re-supply sortie missions between the orbiting PCTV and the surface habitat every 30 days. A small, mobile nuclear surface Brayton power system, also carried on the ISRU lander, provides ~250 kWe to power the ISRU plant and surface habitat, and to recharge the fuel cell power systems of the surface vehicles. The NEP tanker delivers LH2 “return” propellant to Callisto orbit that is subsequently transferred to the PCTV for its trip back to Earth. The tanker remains in orbit where it will function as an orbital propellant depot and refinery once larger scale water extraction and propellant manufacturing operations begin on Callisto. The low thrust trajectory profiles of the cargo and tanker vehicles involve a slow spiral away from the Earth-Moon L1 Lagrange point, a direct heliocentric transfer to Jupiter and then a gradual spiral into Callisto orbit (Melbourne, 1965). Once these vehicles are on station and operating properly, the PCTV departs from L1 using a similar, though higher energy, trajectory to Callisto. After a surface exploration period lasting ~120 days, the “refueled” PCTV begins its spiral escape from Callisto on a direct return to Earth and an eventual capture back at L1."

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    If you have some spare change, you could toss it toward getting a copy of this paper. No clue as to the contents, but relevant to everything above.

    https://aip.scitation.org/doi/abs/10.1063/1.1541373
    Revolutionary Concepts for Human Outer Planet Exploration (HOPE)
    by Patrick A. Troutman, Kristen Bethke, Fred Stillwagen, Darrell L. Caldwell, Jr., Ram Manvi, Chris Strickland, and Shawn A. Krizan

    Abstract: This paper summarizes the content of a NASA‐led study performed to identify revolutionary concepts and supporting technologies for Human Outer Planet Exploration (HOPE). Callisto, the fourth of Jupiter’s Galilean moons, was chosen as the destination for the HOPE study. Assumptions for the Callisto mission include a launch year of 2045 or later, a spacecraft capable of transporting humans to and from Callisto in less than five years, and a requirement to support three humans on the surface for a minimum of 30 days. Analyses performed in support of HOPE include identification of precursor science and technology demonstration missions and development of vehicle concepts for transporting crew and supplies. A complete surface architecture was developed to provide the human crew with a power system, a propellant production plant, a surface habitat, and supporting robotic systems. An operational concept was defined that provides a surface layout for these architecture components, a list of surface tasks, a 30‐day timeline, a daily schedule, and a plan for communication from the surface.

    REM: Paper hidden behind paywall ($30.00 US).

    http://cdsads.u-strasbg.fr/abs/2003AIPC..654..821T
    Abstract page for the above.

    ===

    Also unavailable on the internet is...

    http://cdsads.u-strasbg.fr/abs/2004cosp...35.1013N

    A trade study on radiation exposure for a crewed mission to the Jovian moon Callisto
    by Nealy, J. E.; Clowdsley, M. S.; Wilson, J. W.; de Angelis, G.; Anderson, B. M.; Krizan, S. A.; Troutman, P. A.; Stillwagon, F. H.; Adams, R. B.; Borowski, S. K.
    35th COSPAR Scientific Assembly. Held 18 - 25 July 2004, in Paris, France., p.1013 (2004)

    .
    Last edited by Roger E. Moore; 2019-Apr-17 at 02:57 PM.

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    Quote Originally Posted by Roger E. Moore View Post
    Revolutionary Concepts for Human Outer Planet Exploration (HOPE)
    by Patrick A. Troutman, Kristen Bethke, Fred Stillwagen, Darrell L. Caldwell, Jr., Ram Manvi, Chris Strickland, and Shawn A. Krizan

    Abstract: This paper summarizes the content of a NASA‐led study performed to identify revolutionary concepts and supporting technologies for Human Outer Planet Exploration (HOPE). Callisto, the fourth of Jupiter’s Galilean moons, was chosen as the destination for the HOPE study. Assumptions for the Callisto mission include a launch year of 2045 or later, a spacecraft capable of transporting humans to and from Callisto in less than five years, and a requirement to support three humans on the surface for a minimum of 30 days. Analyses performed in support of HOPE include identification of precursor science and technology demonstration missions and development of vehicle concepts for transporting crew and supplies. A complete surface architecture was developed to provide the human crew with a power system, a propellant production plant, a surface habitat, and supporting robotic systems. An operational concept was defined that provides a surface layout for these architecture components, a list of surface tasks, a 30‐day timeline, a daily schedule, and a plan for communication from the surface.

    REM: Paper hidden behind paywall ($30.00 US).
    Just found a copy of this paper online for free. Here's the url:

    https://ntrs.nasa.gov/archive/nasa/c...0030063128.pdf

    The internet wins again!

    The paper elaborates a bit on a proposal to have Callisto turned into an interplanetary refueling stop, with a processing facility creating LH2 and LOX out of the ices making up the world's surface. It also seems to imply that the base would not be permanently staffed, but would be used by passing spacecraft, assumedly in cooperation with whoever built and owns the base and outlying facilities.

    Curious now as to the delta-vee requirements to leave Callisto and escape from Jupiter's gravitational pull, so as to reach anywhere else in the Solar System. Also, whether it would be more cost-effective to put the base near the world's equator instead of away from it, or whether it would even matter.

    .
    Last edited by Roger E. Moore; 2019-Apr-17 at 07:45 PM. Reason: adds

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    Seems like you should add to the list of problems:

    Digging a hole at least 80 km down in the first place (the best we've managed on Earth is a little over 12 km, and that's a narrow drilled hole, not something you could fit a large turbine down).
    Conserve energy. Commute with the Hamiltonian.

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    Five recent papers relevant to establishing a Callisto colony, covering radiation levels, orbiting spacecraft around Callisto (easily possible), and the underground ocean's characteristics.

    ===

    https://web.archive.org/web/20180504...oper_et_al.pdf
    Energetic Ion and Electron Irradiation of the Icy Galilean Satellites
    by Cooper, Johnson, Mauk, Garrett, & Gehrels (revised May 15, 2000)

    REM: Research paper based on Galileo spacecraft findings, not stored in arXiv.

    ===

    https://www.webcitation.org/5jwBSgPu...l/w08a.jup.txt
    2000 February 29, SPS 1020 (Introduction to Space Sciences), Planetary magnetospheres (continued)

    REM: This astronomy teacher's page also offers information on the radiation environment of the Galilean moons. Not sure if it is accurate, though.

    ===

    https://arxiv.org/abs/1810.03304
    Can Moons Have Moons?
    Juna A. Kollmeier, Sean N. Raymond (Submitted on 8 Oct 2018 (v1), last revised 21 Jan 2019 (this version, v2))

    ABSTRACT Each of the giant planets within the Solar System has large moons but none of these moons have their own moons (which we call submoons). By analogy with studies of moons around short-period exoplanets, we investigate the tidal-dynamical stability of submoons. We find that 10 km-scale submoons can only survive around large (1000 km-scale) moons on wide-separation orbits. Tidal dissipation destabilizes the orbits of submoons around moons that are small or too close to their host planet; this is the case for most of the Solar System's moons. A handful of known moons are, however, capable of hosting long-lived submoons: Saturn's moons Titan and Iapetus, Jupiter's moon Callisto, and Earth's Moon. Based on its inferred mass and orbital separation, the newly-discovered exomoon candidate Kepler-1625b-I can in principle host a large submoon, although its stability depends on a number of unknown parameters. We discuss the possible habitability of submoons and the potential for subsubmoons. The existence, or lack thereof, of submoons, may yield important constraints on satellite formation and evolution in planetary systems.

    ===

    https://arxiv.org/abs/1705.03999
    Geophysical tests for habitability in ice-covered ocean worlds
    Steven D. Vance, et al. (Submitted on 11 May 2017)

    ABSTRACT Geophysical measurements can reveal the structure of icy ocean worlds and cycling of volatiles. The associated density, temperature, sound speed, and electrical conductivity of such worlds thus characterizes their habitability. To explore the variability and correlation of these parameters, and to provide tools for planning and data analyses, we develop 1-D calculations of internal structure, which use available constraints on the thermodynamics of aqueous MgSO4, NaCl (as seawater), and NH3, water ices, and silicate content. Limits in available thermodynamic data narrow the parameter space that can be explored: insufficient coverage in pressure, temperature, and composition for end-member salinities of MgSO4 and NaCl, and for relevant water ices; and a dearth of suitable data for aqueous mixtures of Na-Mg-Cl-SO4-NH3. For Europa, ocean compositions that are oxidized and dominated by MgSO4, vs reduced (NaCl), illustrate these gaps, but also show the potential for diagnostic and measurable combinations of geophysical parameters. The low-density rocky core of Enceladus may comprise hydrated minerals, or anydrous minerals with high porosity comparable to Earth's upper mantle. Titan's ocean must be dense, but not necessarily saline, as previously noted, and may have little or no high-pressure ice at its base. Ganymede's silicious interior is deepest among all known ocean worlds, and may contain multiple phases of high-pressure ice, which will become buoyant if the ocean is sufficiently salty. Callisto's likely near-eutectic ocean cannot be adequately modeled using available data. Callisto may also lack high-pressure ices, but this cannot be confirmed due to uncertainty in its moment of inertia.

    ===

    https://www.hou.usra.edu/meetings/lpsc2018/pdf/1519.pdf (paper is very short, fast download)
    The Origin of Callisto's Valhalla Basin: First Results of SPH Impact Simulations and the Search for the Impactor's Origin
    by Winter, P. M.; Maindl, T. I.; Galiazzo, M. A.; Schäfer, C. M.
    49th Lunar and Planetary Science Conference 19-23 March, 2018, held at The Woodlands, Texas; LPI Contribution No. 2083, id.1519 (03/2018)

    QUOTES: We were able to get preliminary results on collisions with Callisto using a novelty GA-approach that allows to cover a much larger parameter space than previous methods. Based on collision velocity and impact angle distributions, we simulate “likely” impacts onto Callisto and are able to roughly reproduce the observed data of the Valhalla basin. We confirmed the necessity of a subsurface ocean for explaining the observed nature of that basin. In the future, we will study possible origins of the impactor that formed Valhalla more closely), considering asteroid families like the Centaurs as possible source.
    Last edited by Roger E. Moore; 2019-Apr-17 at 06:19 PM.

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    The turbine thing might work under Enceladus as well, since the subsurface ocean looks like it is being squeezed (and is therefore mobile) by orbital or tidal pressures, per the news article below on this moon's libration.

    http://www.astronomy.com/news/2015/0...moon-enceladus

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    Most excellent.

    Was thinking myself that it would not hurt to plant the unshielded reactor in a pit of some kind, though the reactor might (depending on its radiation) melt the ice around it. Too expensive to ship lead there. Maybe building surface steam power using solar power (heating from large curved mirrors) would help. I dunno.

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    Perhaps Callisto has a lot of material to be mined and used by a colony. Also implies many craters on Callisto are from ex-moons of Jupiter.

    http://cdsads.u-strasbg.fr/abs/2013Icar..223..775B
    Black rain: The burial of the Galilean satellites in irregular satellite debris
    Bottke, William F.; Vokrouhlický, David; Nesvorný, David; Moore, Jeffrey M.
    Icarus, Volume 223, Issue 2, p. 775-795. (04/2013)

    Irregular satellites are dormant comet-like bodies that reside on distant prograde and retrograde orbits around the giant planets. They are likely to be captured objects. Dynamical modeling work indicates they may have been caught during a violent reshuffling of the giant planets ˜4 Gy ago (Ga) as described by the so-called Nice model. According to this scenario, giant planet migration scattered tens of Earth masses of comet-like bodies throughout the Solar System, with some comets finding themselves near giant planets experiencing mutual encounters. In these cases, gravitational perturbations between the giant planets were often sufficient to capture the comet-like bodies onto irregular satellite-like orbits via three-body reactions. Modeling work suggests these events led to the capture of on the order of ˜0.001 lunar masses of comet-like objects on isotropic orbits around the giant planets. Roughly half of the population was readily lost by interactions with the Kozai resonance. The remaining half found themselves on orbits consistent with the known irregular satellites. From there, the bodies experienced substantial collisional evolution, enough to grind themselves down to their current low-mass states. Here we explore the fate of the putative irregular satellite debris in the Jupiter system. Pulverized by collisions, we hypothesize that the carbonaceous chondrite-like material was beaten into small enough particles that it could be driven toward Jupiter by Poynting-Robertson (P-R) drag forces. Assuming its mass distribution was dominated by D > 50 mum particles, we find that >40% ended up striking the Galilean satellites. The majority were swept up by Callisto, with a factor of 3-4 and 20-30 fewer particles reaching Ganymede and Europa/Io, respectively. Collision evolution models indicate most of this material arrived about 4 Ga, but some is still arriving today. We predict that Callisto, Ganymede, Europa, and Io were buried about 4 Ga by ˜120-140 m, 25-30 m, 7-15 m, and 7-8 m of dark debris, respectively. The first two values are consistent with observations of the deepest dark lag deposits found on the most ancient terrains of Callisto and Ganymede. The rest of the debris was likely worked into the crusts of these worlds by geologic and impact processes. This suggests the debris is a plausible source of the dark lag material found in Europa's low-lying crevices. More speculatively, it is conceivable that the accreted dark particles were a significant source of organic material to Europa's subsurface ocean.

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    Two references of use to anyone also mulling over the exploration and settlement of Callisto. I think robots will end up settling it permanently, humans only now and then as necessary.

    https://nssdc.gsfc.nasa.gov/planetar...act_table.html
    REM: "Solar System Small Worlds Fact Sheet" table showing major statistics for the largest natural satellites in the Solar System, plus Mercury, Ceres, and Earth for comparison. It is interesting that these worlds have very similar gravities, leading one to speculate whether humans adapted to the gravity of the Moon early in the colonization of the Solar System might permanently settle those other worlds with similar gravities (Galilean moons, Titan, Triton, etc.).

    https://web.archive.org/web/20190403...age/Categories
    REM: How locations on Callisto (and other worlds here) are named. Callisto gets all the Far North names from the Vikings, Inuit, etc. I guess this means the first spacecraft to land on Callisto should be called Eric the Red after the guy who settled Greenland.

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    Raises the question of whether radio transmissions on Callisto could be reflected around that world by its ionosphere, saving the trouble of putting up orbiting communications spacecraft.

    http://cdsads.u-strasbg.fr/abs/2017JGRA..12211677H

    Induction signals from Callisto's ionosphere and their implications on a possible subsurface ocean
    Hartkorn, Oliver; Saur, Joachim (11/2017)
    Journal of Geophysical Research: Space Physics, Volume 122, Issue 11, pp. 11,677-11,697 (JGRA Homepage)

    We investigate whether induction within Callisto's electrically conductive ionosphere can explain observed magnetic fields which have previously been interpreted as evidence of induction in a saline, electrically conductive subsurface ocean. Callisto's ionosphere is subject to the flow of time-periodic magnetized plasma of Jupiter's magnetosphere, which induces electric fields and electric currents in Callisto's electrically conductive ionosphere. We develop a simple analytic model for a first quantitative understanding of the effects of induction in Callisto's ionosphere caused by the interaction with a time-variable magnetic field environment. With this model, we also investigate how the associated ionospheric currents close in the ambient magnetospheric plasma. Based on our model, we find that the anisotropic nature of Callisto's ionospheric conductivity generates an enhancement effect on ionospheric loop currents which are driven by the time-variable magnetic field. This effect is similar to the Cowling channel effect known from Earth's ionosphere. Subsequently, we numerically calculate the expected induced magnetic fields due to Jupiter's time-variable magnetic field in an anisotropic conductive ionosphere and compare our results with the Galileo C-3 and C-9 flybys. We find that induction within Callisto's ionosphere is responsible for a significant part of the observed magnetic fields. Ionospheric induction creates induced magnetic fields to some extent similar as expected from a subsurface water ocean. Depending on currently unknown properties such as Callisto's nightside ionosphere, the existence of layers of "dirty ice" and the details of the plasma interaction, a water ocean might be located much deeper than previously thought or might not exist at all.

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    A base on Callisto might prove useful in monitoring the progress of spacecraft performing a gravity-assisted maneuver around Jupiter, i.e. a slingshot maneuver, and using radar to detect nearby asteroids and debris in the paths of spacecraft.

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

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    In addition, the thermal conductivity of gases at low temperatures is very low. A habitat or temporary shelter could be made with a double-hulled dome, the space between the domes filled with a gas that won't freeze out at Callisto's low surface temperature (whether during day or night, or eclipse).

    https://www.researchgate.net/post/Wh...uids_and_gases

    https://www.engineersedge.com/heat_t...vity-gases.htm

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    A pamphlet-sized article on colonizing the four largest Jovian moons. Interesting idea given on seeding the world with gene-engineered plants that can grow in the cold.

    https://environmental-safety.webs.co...aS_Journal.pdf
    Colonizing Jupiter’s Moons: An Assessment of Our Options and Alternatives
    Thomas B. Kerwick
    The Lifeboat Foundation / CEVA, Inc. (Winter 2012)

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    Wonder if it would be possible to gene-engineer mosses and lichens to live on Callisto and build up a thicker carbon dioxide atmosphere.

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    Quote Originally Posted by Roger E. Moore View Post
    Wonder if it would be possible to gene-engineer mosses and lichens to live on Callisto and build up a thicker carbon dioxide atmosphere.
    Currently its atmosphere is little more than vacuum. Dyson Trees?
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

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    Quote Originally Posted by Noclevername View Post
    Currently its atmosphere is little more than vacuum. Dyson Trees?
    Mulling this over. I like it.

    Was also mulling over why bother to give the world an atmosphere. Short answer was, it helps astronauts see better by scattering light all around. Also makes the world seem a bit more Earthlike, helps psychologically. If no one is landing there, no need for atmosphere. Too cold to take off spacesuit, no way to make atmosphere nonpoisonous, but surely looking around at lit ground under a blue sky can't hurt. Works for Mars, right?

    Callisto sounds like a good place to set up observatories, but really, we've been doing great setting up observatories in space orbiting the Earth or Sun. Why bother putting them on a world unless a maintenance crew could fix it? The HST does its best work flying around Earth being serviced occasionally by spacecraft.

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    Quote Originally Posted by Roger E. Moore View Post

    Was also mulling over why bother to give the world an atmosphere. Short answer was, it helps astronauts see better by scattering light all around.
    Don't change the object, change the astronauts! Add a little thermal to their visible spectrum. (Or just put it in their suits' visors, whatever works best.)
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

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    Quote Originally Posted by Noclevername View Post
    Don't change the object, change the astronauts! Add a little thermal to their visible spectrum. (Or just put it in their suits' visors, whatever works best.)
    I read about that a few years ago while writing a science-fiction/fantasy magazine article about infrared vision. The trouble is that the viewer's own body heat messes up the heat vision. Otherwise a fine idea. Maybe a little starlight vision would not hurt, though.

  25. #25
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    It might be good to follow the path of any potential impactor on the way to any ice moon--so that a probe can follow it and splash down before everything freezes over again.
    Last edited by publiusr; 2019-May-01 at 07:21 PM.

  26. #26
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    Quote Originally Posted by publiusr View Post
    It might be good to follow the path of any potential impator on the way to any ice moon--so that a probe can follow it and splash down before everything freezes over again.
    I like this!

  27. #27
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    The article I wrote was "Sight in the Darkness", which used real-world infrared vision data. It can be found in this PDF.

    https://annarchive.com/files/Drmg211.pdf

  28. #28
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    It occurs to me, somewhat late, that the giant unsafe radiation-spilling nuclear reactor that NASA proposed sending along with the HOPE astronauts would be awesome at creating an atmosphere on Callisto. The heat from it would melt the ices around it. Throw an insulating blanket over the reactor, and the heat is directed straight down. If some of the radiation emitted is in alpha and beta particles, you'll have a new crater and maybe a shaft downward in no time. Hope there's nothing alive below the reactor in the underground ocean. Oh, right, will have to keep getting extension cords from Earth, too.

  29. #29
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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.

  30. #30
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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.

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