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Aerospace Obama's Mars Proposal, and beyond? Lets brainstorm details.

  1. Apr 17, 2010 #1
    To Mars

    Obama just proposed having astronauts orbiting Mars in the mid-2030s. I already know that in 2035 we'll have a fairly close approach to Mars. However, this time frame is interesting for another reason. Sending a vehicle in orbit around Mars is all we really need to do to set the stage for a space elevator mission sometime afterwards. Even though proponents of the project say it can be operational in 20 years, unforeseen problems might arise. The idea here is not to build a space elevator for earth, but to build one that might land on Mars five to ten years after we get a crew orbiting it more permanently.

    Mars's day is only 39 minutes longer than our own, and it has 1/3rd of the gravity. That means that it will be far easier to engineer a space elevator for Mars. The next advantage of building one on Mars as opposed to the earth is that a giant tether wrapping around the earth is a major risk for people on the ground, but it hardly matters if one wraps around Mars.

    Phobos

    Phobos has very low surface gravity and has a lot of useable materials for sustained existence near Mars. Because its escape velocity is only 40 m/s, it might be easiest just to get close to the tiny moon and send astronauts or robots with jet packs to explore and utilize the resources of that tiny moon.

    The University of Arizona recently approved funding for a mission to an asteroid to learn to extract its resources. It's not certain if we'll be learning to do this stuff on Phobos in that initial mission, but we will eventually if we begin sending things farther into outer space.
     
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  3. Apr 18, 2010 #2

    LURCH

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    I think Phobos is the main obsticle to a space elevator on Mars.
     
  4. Apr 18, 2010 #3
    And Deimos. However, there are ways to get around this problem. For instance, you can angle the elevator from a slightly higher latitude and move it out of the way whenever or if either of the moons do happen to pass. Compared to the other engineering challenges, it's not hard to move the tether 20 miles to avoid a big rock.
     
  5. Apr 18, 2010 #4

    DaveC426913

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    The space elevator will be an engineering effort larger than any in the history of mankind. And that's here on Earth.

    What kind of additional effort would be involved in transporting and then establishing the whole infrastructure on Mars to build it??

    And why?? It's tantamount to building a high-speed maglev train in Ethiopia.
     
  6. Apr 18, 2010 #5
    How are you under the impression that it is a century away? Building one on earth is similar in difficulty and cost to the likely to be cancelled constellation program. We just need the nanotubes, climbing and beaming system, and then we're in shape to approve proposals for a space elevator.

    The cost of launching a rolled up one into low earth orbit and shrunken in size would be worth the cost. Mars' low gravity would make the tether much shorter and it would require a much lower tensile strength.

    I am also talking more like 40 years down the line from now, even though most space elevator advocates are talking 15-20 years down the line for one on earth and one on Mars would be easier to build.

    Shipping people to Mars is much more difficult than shipping objects, especially when they don't have to land on the surface. I think it is possible that we could have a space elevator running on Mars for a price under 8 billion if we use low energy, high specific impulse rocketry like ion drives or plasma drives in a spacecraft set for Mars and the cost of the elevator is considered as an extra on whatever vehicle we send humans over there with for missions that come after the initial mission to orbit Mars and maybe land on Phobos.

    To get humans to Mars, we need to build vehicles in space. We can't possibly send people in tiny capsules like we did with the Apollo missions, so a space elevator on Mars will be more proportional to the cost of the project than it would otherwise. Plus, you can leave the thing up for future missions to the surface, or perhaps roll the thing up. Other than Phobos, there are no satellites in the way of an elevator.

    Honestly, I think the first step in securing our place on Mars is getting a base on Phobos. Maybe in 2050 we'll have the robotic technology to continuously dig a base with power collected from solar panels. Maybe in 2050 we'll have a space elevator on earth.

    When you get out to the timescales I'm talking about there are a lot more variables involved in predictions than in predictions that are even 10 or 20 years earlier.

    EDIT: I forgot to address the why. Why? So that astronauts don't go through the seven minutes of terror that destroys a large percentage of the things that land on Mars!
     
  7. Apr 21, 2010 #6
    Yes. That's like saying we just need the entry material, propulsion system, and control systems and we could launch a manned space flight!--in 1850.

    That is not to say it's impossible per se, but the Earth elevator requires materials with tensile strengths that are on the upper limit of what we think can theoretically be made with compounds we know of, dealing with the inevitable oscillations that will arise in a 35,000 km long ribbon or cable, wireless power transmission that is extremely light, compact, and efficient, and climbing techniques and equipment that can deal with going several hundred kilometers per hour for several days while transitioning from the atmosphere to vacuum and passing through a number of rather hazardous areas. In short, it's hard. Really hard.
     
  8. Apr 21, 2010 #7
    More like saying it in 1920. Goddard said it at the beggining of the 20th century. It's hard but doable. I'd rather ride an elevator to space than a bomb.
     
  9. Apr 22, 2010 #8
    I'm more pessimistic than that. Also, did I mention the need to somehow develop extremely light-weight radiation shielding so that you can get rad-sensitive payloads (like people or computers) through the Van Allen belts without getting cooked? Because I really should have.
     
  10. Apr 22, 2010 #9
    Happy Earth Day! Boo Mars
     
  11. Apr 22, 2010 #10
    I know about the radiation. I know that it's a factor and that you have to be ready at all times in case of solar winds that might reach the craft before there is any warning.

    Radiation is quite possibly the biggest obstacle. It's worth putting an extra few billion dollars into launching and development costs, considering it costed around 170 billion for the Apollo missions if converted to today's money.
     
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