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Least cost to get a self-sustaining space infrastructure

  1. Jul 27, 2018 #1

    Al_

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    I was looking at NASA saying they might not have enough funds to put humans on Mars by 2040. OK, zoom forward maybe 200 years and the cost might be, maybe, just buy a ticket. Or people might already be working there; they will be paid to go there. So, here's the question. What is the least cost method to to get a self-sustaining space infrastructure? To the point where it doesn't matter what the cost of launch from Earth is?
    I think it might involve robots on the Moon that can be controlled from Earth and use materials they find there, so we don't have to send so much stuff up from Earth. What do you think?
     
  2. jcsd
  3. Jul 27, 2018 #2

    anorlunda

    Staff: Mentor

    Obviously, least cost implies no people.
     
  4. Jul 27, 2018 #3

    russ_watters

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    Staff: Mentor

    I don't understand: why would being self-sustaining mean it doesn't matter what the launch cost is?

    In either case, given that 100 years ago we could barely fly, it is pretty tough to imagine what our technology might look like in 200 years.
     
  5. Jul 30, 2018 #4

    Al_

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    Yes, unless there are some jobs that robots find really hard. Probably, if the infrastructure grows to a certain size, there will be.
    I mean, not that it wouldn't matter, but that it would be trivial compared to the billions we are talking about now. It would be an everyday expense.
     
  6. Jul 30, 2018 #5

    russ_watters

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    Staff: Mentor

    No such technology exists or is on the horizon.
     
  7. Jul 31, 2018 #6
    Their are two costs to space infrastructure. The first is getting the infrastructure to its destination, whether its Low Earth Orbit, the moon, or Mars.

    Once you have the infrastructure in place the cost is maintaining it. Lets look at the ISS as an example for maintenance. Every few months large shipment of supplies have to be launched into orbit to maintain the crew and habitat. That included large amounts of food, small amounts of water (most gets recycled but their is always some loss), Air (also gets recycled but some is lost and it takes supplies to filter air). Then you have replacement crew since it is medically impossible to live in 0g for long periods of time. And finally you have replacement parts for equipment that needs preventative maintenance or replacement. The ISS also needs to keep enough supplies on hand so that if a launch fails, they have enough food, water, and air to last them until the next launch. Otherwise they would have to evacuate if they cant get resupplied.

    Similar problems exist for any potential colony. Although some materials can be found locally (processing aluminum-oxide on the moon for oxygen and building materials or Iron-oxide on Mars for the same reason) other resources would require constant resupply. It would be hard for any colony to grow enough food varieties to completely sustain itself indefinitely. Growing food just takes up too much space to be viable in the long term. Then you have the need for finished goods to use in equipment. While basic materials can be found on the moon and mars for construction, finding rare resources (copper, tin, titanium, silver, gold... all the things you need to make complex parts and electronics) could take decades on other planets. Once you are lucky enough to find a resource, then you have to transport it across a hostile environment with no roads to the colony. Consider that some rare earth elements used in almost all electronic devices are transported thousands of miles on earth before they get to the factory. And that is on a planet with roads, railways and oceans to make transport fast and cheap.

    I think that any true self sustaining colony would have to start out entirely robotic (either autonomous or remotely controlled). They would have to go in and find the resources and build the preliminary infrastructure on their own. Then roughly process the materials as well so that building supplies would be available to colonists when they arrive. Current day robotic vehicles could easily perform the following activities: survey the land to locate resources on or near the surface, flatten the ground for future buildings or gravel roads, mine surface resources, process resources into ingots or basic shapes, and transport resources over long distances. Over the course of many years or decades, enough processed material could be amassed so that a small permanent self sustaining colony could be created.

    It would take many thousands of tons of machinery though to do this. And few countries or companies would be willing pay the money to put that much weight on another planet (the ISS alone is only 450 tons and every country has already pulled funding or is planning on pulling the funding for it because of the high cost of maintaining it).
     
  8. Jul 31, 2018 #7

    Tom.G

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    Science Advisor

    The Mars rovers are a start. Think about how they would need to be scaled up, vis-a-vis supplying life support for humans.

    For more background, several years ago there was a project near Tuscon, Arizona, USA (Biosphere 2) that attempted a one year closed living environment. It has an interesting history.

    Cheers,
    Tom
     
  9. Aug 2, 2018 #8
    I really don't like putting too much into this faraway kind of thing, but as I see there might be two directions what worth pondering about.
    - get a list of things of the usual ISS supply missions and start to 'invent' something to replace them one by one with local products. This might end in some direct gain as - for example - the water recycling system there started on this line already.
    - what would be the minimal size of a self sustaining colony (at some advanced/available technology level) on Earth? Self sustaining in this context means that they would be able to build themselves anew from raw materials => so they have nothing what they can't build themselves.
     
    Last edited: Aug 2, 2018
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