Next Floor: Geosynchronous Satellites, Orbiting Laboratories

On Star Trek, if you want to go from one deck to another, you enter a “turbolift” and tell it where you want to go. However, many people have speculated that one day you’ll ride an elevator to orbit instead of using a relatively crude rocket. The idea is simple. If you had a tether anchored on the Earth with the other end connected to a satellite, you could simply move up and down the tether. Sound simple, so what’s the problem? The tether has to withstand enormous forces, and we don’t know how to make anything practical that could survive it. However, a team at the International Space Elevator Consortium could have the answer: graphene ribbons.

The concept is not new, but the hope of any practical material able to hold up to the strain has been scant. [Arthur C. Clarke] summed it up in 1979:

How close are we to achieving this with known materials? Not very. The best steel wire could manage only a miserable 31 mi (50 km) or so of vertical suspension before it snapped under its own weight. The trouble with metals is that, though they are strong, they are also heavy; we want something that is both strong and light. This suggests that we should look at modern synthetic and composite materials. Kevlar… for example, could sustain a vertical length of 124 mi (200 km) before snapping – impressive, but still totally inadequate compared with the 3,100 (5,000 km) needed.

While researchers have previously noted that carbon nanotubes may have the required strength, they suffer from two problems. First, we don’t know how to make very long nanotubes. In addition, under stress they may fray. However, new work suggests that graphene may be the answer.

Technology exists to make very large graphene fibers, although perhaps not to the scale needed yet — but fibers on the order of 1 km in length are now possible. These fibers aren’t exactly the right topology of graphene, but it shows that it is possible to work with the material at scale and with a tensile strength 200 times greater than steel (according to the post), it could be suitable for use in an orbital tether.

The space elevator idea keeps popping up. In “Ad Astra” (see below) the International Space Antenna appears to be tethered to the ground. China says they are actively building an elevator they expect to have completed by 2045.

We’ve been watching this story for a long time. We also think we may see a moon elevator before we get an Earth-based one.

40 thoughts on “Next Floor: Geosynchronous Satellites, Orbiting Laboratories

  1. Yeah once all the auxiliary structures are included, even the atomic forces inside atoms aren’t strong enough. Nobody will ever build this. And if you somehow did and it ever had a slight hiccup, it would snap, fall, and wrap around the equator with the equivalent kinetic energy of a global thermonuclear war. It’s a nice BDO for science fiction.

    1. I wonder about this. The primary characteristic of the ribbon is its ultra low density. Sure it’d way a zillion tons, but it would be like having a 30,000 mile long leaf fall on you, only far less dense than a leaf. It would be a huge hassle to clean up, but as far as damage? I don’t think you’d even feel it if part fell on you. It can’t build up the kinetic energy in falling because its air resistance is so great compared to its weight.

      1. Weigh. Stupid autocarrot.
        The climbers that go up it: those would be dangerous, as presumably they’d weigh a couple of tons. But unless someone has come up with some really interesting design, you can only effectively have one climber on a ribbon at a time.

    1. They have, I’ve read the research papers, and the conclusion is that climbing the cable has to be done extremely slowly or else the whole thing will bend like a bowstring and pull the cable down.

  2. The space elevator can only be a practical solution if there’s a huge volume of applications for Earth orbiting satellites. In practice, that volume probably isn’t so big. The current supply of launch providers is already bigger than the demand. The price difference for the space elevator isn’t going to be huge, since a large amount of total cost is in the satellite itself, plus the associated ground support for its operation, therefore a lower cost launch isn’t likely to suddenly open up a huge pent-up demand.

  3. Wasn’t there some mention of the idea that the cable needn’t come all the way to the ground? Might have been a piece of sci-fi I read once. Anyway the idea was a rotating tether that at its lowest reach would skim through the upper atmosphere, just within reach of aircraft technology, and you’d just fly up, rendezvous with the cable end as it came past, and get hauled up.

    Yeah, that must have been sci-fi; it might not require an unobtainium cable, but it’d be a nightmare to keep positioned, probably a colossal pain to put up in the first place, and also just as susceptible to orbiting debris as the grounded static tether.

      1. We routinely air-caught dropped photographic reels from satellites for a while, with quite high success rates, long before we had the capability of putting GPS units and transmitters in the falling cargo.

      2. I think the idea is that the tether moves in the opposite direction to cancel out the Earth’s rotation. So from the point of view of an observer hovering in a balloon (eg), the end of the cable would move down from the east, slowing down until it’s practically stationary for a moment, before moving up and to the west.
        I’m not sure that rendezvousing an aircraft with a (very-briefly) stationary point in the upper atmosphere would be any easier though.

    1. Probably from something by Robert Forward, who developed the ideas of rotating whips for all kinds of uses. On the Moon it can touch down vertically like a point on a wheel.

    2. Robert Forward’s company was about tethers. I’m sure it appeared in his fiction too, but I can’t recall which one. Clarke of course used them. An Niven. More recently, Neal Stephenson used the fly-up-to-an-orbitting-whip concept in Seveneves.

  4. lasers! use an ultra strong laser to shoot a beam into space and use the laser as the tether. Then, all you have to figure out is how to build an elevator car that attach itself to and power itself by the said laser beam.

  5. The real problem may be the “Firmament” that you can’t break through.
    And you must know the space station is just CGI, right?
    Do watch out for the ice over on the edge. It’s the real danger.

    1. Never underestimate human stupidity, eventually someone will breach the “Firmament”.

      We’ll then have the twin problems of massive chunks of firmament material falling from a very great height and all the air escaping…

    2. Is this religious mockery? Are you suggesting that Jews, Muslims, and Christians (who believe in Genesis) are all idiots or non-critical thinkers? Why don’t you be specific so we can know who you’re denigrating?

      1. Also, not for nothing, but I believe in God and Jesus Christ, and much of the bible, but I (like many people of faith) have a science background and can accept that a document written thousands of years ago isn’t going to exactly match our modern interpretation of science. Anyways, the firmament Genesis refers to was broken up and fell to the earth in rain when it flooded, so you’re not even accurate with your shade.

    1. Interesting note on that type of device. The function created to “Beam Up Or Down” from space (Star Trek) was the result of bean counters having “no budget”. Originally, a shuttles was to be used. No budget to build a shuttle, so they decided to beam them everywhere.

      1. Now that is a piece of Star Trek trivia I didn’t know. Thanks….

        Only thing going for this elevator concept is it causes scientists to ‘think’ about the hard problem … what is involved in trying to make it happen, and possibly new usable materials (for one thing) could come out if it even if idea doesn’t become reality. Man needs impossible things to think about to advance technologies that can be used elsewhere. In a way it is like the saying “Necessity is the mother of invention” .

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