Mars again

Discussion in 'Fred's House of Pancakes' started by tochatihu, Oct 2, 2016.

  1. tochatihu

    tochatihu Senior Member

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    Elon Musk describes Mars colonization in substantial detail. It is big - individually (100-person carriers launched with 42 large oxygen/methane engines) and collectively (about 100 such carriers eventually shuttling, along with much other equipment). Obviously it would be expensive, requiring much more money than Musk has. Still, much less than global GDP. If there are no fundamental engineering flaws, it is feasible in principle.

    One essential aspect is synthesizing fuel on Mars for all (many) return flights. Until somebody puts a ‘robotic factory ship’ on Mar’s surface and starts working (using energy from solar panels), the entire process will be limited to ‘in principle’. Anyway, a few more people may take interest in Sabatier reactions. Yay chemistry.

    Mars has the first-time exploration cachet (many feel Moon lacks this). It is correct to say that humans won’t become interplanetary while still within range of help from home (Moon and Mars differ). But this would be first major such effort and would rely on complex systems and techniques. Shoot this at Mars without testing many systems first on Moon (1/100 distance) – This is Elon Musk’s way.

    Not my way. If all this is a good idea, it will be a good idea to trial it first on the moon. Moon has more than a few colonization and space-science merits of its own. Not only not my way. Engineering proceeds intentionally, stepwise and cumulatively. Seems to me that all disruptive technologies of Silicon Valley have been engineered in that way. They ‘leapt’ by redefining what constitutes a valuable product or service. So, for Mars to be a disruption that Moon is not, seems to get engineering and marketing confused.

    ‘Shoot the Moon’ used to mean trying what might be impossible, by untested means. It remained so until conquered by incremental engineering steps (rushed, but incremental). Now, the Moon is totally doable, and in a very large (useful) way if Musk-like mega rackets were involved.

    Seems this term could be replaced by ‘Shoot the Mars’.
     
  2. ETC(SS)

    ETC(SS) The other One Percenter.....

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    I tend to agree with the 'Moon first' approach, since the toughest part tends to be the first 6 inches.
    There's water in them thair lunar hills, which means that we can stage there and not have to loft water into LEO.
    When I was punching holes in the Atlantic we used to do "fast cruises" which is a simulated underway period of 1-2 days while tied fast to the pier. A rather silly idea....until you've ever gotten past the 100 fathom curve only to discover that you've forgotten something essential.

    OTOH, there's merit in Elon's approach, since we can spend decades dithering about on the rock next door.
     
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  3. Trollbait

    Trollbait It's a D&D thing

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    Once established on the moon, the cost of launching vessels from there for Mars becomes cheaper.
     
  4. wjtracy

    wjtracy Senior Member

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    Wonder if there is any oil up there? Come to think of if, that would be proof of past life on the red planet. No oil , no prior life forms.
     
  5. Trollbait

    Trollbait It's a D&D thing

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    not if you subscribe to the abiotic petroleum hypothesis
     
  6. tochatihu

    tochatihu Senior Member

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    A new reason why biologicals may suffer from being outside the Earth's magnetosphere:

    https://www.sciencedaily.com/releases/2016/10/161010052832.htm

    Gives another opportunity for Moon-first cheerleaders :). How to best shield against high-energy charged particles out there? Experimentation seems appropriate. Y'all may know that Earth's magnetosphere is not symmetrical; far extended on the 'away from sun' side. Every month as Moon orbits Earth, it is within magnetosphere during 'away' periods. Cosmic rays thus are switched off and on, on the Moon. Very helpful for experimentation I'd say, and not readily found elsewhere.
     
  7. tochatihu

    tochatihu Senior Member

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    As a Moon-first proponent, must report that Moon is receiving impacts at a rate higher than previously supposed:

    Small impacts are reworking the moon's soil faster than scientists thought | ASU Now: Access, Excellence, Impact

    For meter-scale, very fast incoming, I can't imagine a tough enough surface structure to survive. This is a concern :eek:

    At the same time, there is no particular reason to suppose impact rates on Mars surface are lower. It is simply not yet as well imaged for detection purposes. Things are tough all over.

    But we gotta go, right? Being explorers. Gonna need more duct tape...
     
  8. ETC(SS)

    ETC(SS) The other One Percenter.....

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    How many people died on the Oregon trail before we tumbled onto the right combination of wagon type, animal, route, time of year, and basic equipment load?

    Then....
    How many families died ANYWAY from just plain old bad luck?

    Nobody ever said that exploration is easy......just that it's worth it.
    Necessary, even.
     
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  9. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    Muscle atrophy due to lower gravity?

    Millennia in earth's gravity has made us what we are. This would be a big step, heck: bigger than iPhone's OS10. :)
     
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  10. fuzzy1

    fuzzy1 Senior Member

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    For those newly reported craters -- 2 meters and up in the report I saw yesterday -- structure protection almost certainly means deep burial, or underground mining.

    A long ago rule of thumb placed the impactor size at very crudely one-tenth the diameter of the crater. That would suggest that those two-meter craters came from rocks about 8 inches across. I thought that was still in the range where the Earth's upper atmosphere, less massive & dense than Mars' total atmosphere, burns up or fragments most of this debris. So, unlike the Moon, structures on Mars still ought to be well protected by the atmosphere against the typical sand and gravel strikes that we commonly witness as 'shooting stars' in our upper atmosphere. Only the larger rocks, such as those creating the larger newly detected fresh lunar craters, ought to be an issue on Mars.

    But my understanding of meteors here is severely dated, so it is time to go find some refreshers.
     
    #10 fuzzy1, Oct 14, 2016
    Last edited: Oct 14, 2016
  11. tochatihu

    tochatihu Senior Member

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    European Mars lander Schiaparelli is unresponsive and may have hit too hard.

    +++

    What size of meteor is required to get to the bottom of Mars' atmosphere? Seems a good question Seems that millimeter-sized things do not. Centimeter? Maybe. Meter, probably so.
     
  12. tochatihu

    tochatihu Senior Member

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    Rovers on Mars have found meteorites on surface in 20 to 80 cm size range. They would have been larger before hitting the atmosphere. How much? do not know. But probably moving pretty fast at surface contact. Small impact craters do not survive long there because of windblown dust.
     
  13. fuzzy1

    fuzzy1 Senior Member

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    I am not a professional here, just an amateur astronomer speaking well beyond my expertise.

    Taking what I think I've understood about meteors in Earth's atmosphere, then adjusting for Mars' atmosphere, my swag (stupid wild-a**ed guess) is that the centimeter-sized things won't survive Mars either. Somewhere in the decimeter range is where they should start making it, though slowed drastically.
    If they can still see the actual rock after impact, it wasn't moving very fast. Cosmic speeds will leave craters.

    Checking around the web, I see an indication that on Earth, rocks under 8 tons (after ablation??) have pretty much slowed to terminal velocity before hitting the ground. I don't yet see a figure for Mars.
     
    #13 fuzzy1, Oct 20, 2016
    Last edited: Oct 20, 2016
  14. The Electric Me

    The Electric Me Go Speed Go!

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    I cannot in good conscious become a proponent of the "Moon First" movement having watched, Space 1999, as a kid.

    I can't really remember anything about the series, except that The Moon goes hurtling away from the earth.

    Also I think General Zod and his evil friends arrived on earths moon first, killing two astronauts before heading to earth to further their conquest before being thwarted by Superman.

    In short, fiction seems to suggest spending too much time on The Moon is a diminishing return scenario.

    Of course Mars hasn't faired much better....but I think if you are going to dream? Dream Big.
     
  15. tochatihu

    tochatihu Senior Member

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    Mars exploration 'success ratio' is about one for three, and the latest splash has not helped. It may be that SpacEx or others will attempt to go big to Mars, without first practicing on the Moon. I'd not.
     
  16. tochatihu

    tochatihu Senior Member

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    Saturn’s Moon Titan as a colonization target. Advantages presented here:

    Let's Colonize Titan - Scientific American Blog Network

    Two major related disadvantages: So far from Sun that one can forget photovoltaic power. It is 3000 to 4000 times further from earth than is moon, depending on planetary positions. So, if Mars is more challenging than moon for being 200 times more distant, well, crank that up a bit.

    As always I am not arguing against human’s explorer spirits. But technology is needed to match lofty goals. Earth’s oceans were navigated long ago, but not with mask, snorkel and swim fins.

    We don’t have the necessary interplanetary technology yet. Enough for colonizing the moon; that can be perceived as perhaps not so very far off. But it makes sense to solve problems (small and large) at that scale before jumping 200 times further. Or 3000 times further.

    Meanwhile, robotic exploration of Titan’s atmosphere seems like a dandy goal.
     
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  17. wjtracy

    wjtracy Senior Member

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    Well, we now know Steven Hawking is only giving us 1000 years until we must leave the planet for Titan or other home. So better start working it.
     
  18. tochatihu

    tochatihu Senior Member

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  19. bwilson4web

    bwilson4web i3 and Prime

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  20. RCO

    RCO Senior Member

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    I got the problem. Just a different cause, (inactivity)!
     
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