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Unorthodox "space" elevator idea

  1. Oct 31, 2014 #1
    Would it be possible, instead of building a 22 thousand mile long space elevator, to make a large floating platform 15-20 miles high which would be supported by gigantic hydrogen balloons. You would then take off horizontally and travel into space from there since most of the energy costs are the first 10 miles . A lightweight cable would be connected from the ground to the platform and carts could move up and down in order to transport whatever. Would this be a more cost effective approach to a space elevator, or is the amount of hydrogen and balloons required simply unfeasible economically?

    The platform would be constructed on the ground at first, and then materials would be gradually transported up the cable, as the platform ascends, to produce additional hydrogen gas via some chemical reaction. Perhaps the cable could be hollow and hydrogen gas could be generated on the ground and then pumped up to the platform. It would probably take a couple years to reach the ideal height and becomes exponentially more difficult the higher in the atmosphere one goes . Some point would need to be calculated to determine the most cost effective altitude.

    Additionally, you could also glide from one of these platforms to some arbitrary location and cut fuel costs immensely while saving the environment. Is this a terrible idea? If so please explain the economic reasons.
  2. jcsd
  3. Nov 2, 2014 #2
    "since most of the energy costs are the first 10 miles"

    The statement is incorrect. Air resistance, yes, most of that is gone rather quickly, but the gravitational well is much deeper than 10 miles. (Theoretically) lifting something straight up from the surface of the planet it won't stay in place until the height is equal to geostationary orbit...
  4. Nov 2, 2014 #3


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    Most fuel is needed for the horizontal velocity of about 8km/s. Getting up to ~400km is about 10% of this, and getting up to 20km is 5% of this 10%. All you would save is some air resistance.
    Are spaceports built on high mountains? No. The logistics effort is worse than the additional fuel needed to start close to sea level (Cape Canaveral and French-Guiana at the coast, Baikonur just at 100m above sea level, ...).
  5. Nov 2, 2014 #4


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    Some confusion might come from the fact that a lot of small rockets are launched from helium balloons in or near the stratosphere. While I'm not sure, I suspect that such is done to avoid the cost and complexity of using multiple stages rather than simply the amount of fuel required.
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