A new climber?

Once a Space Elevator goes into operation, there will be lifters traveling both up and down the ribbon.  If we don’t want to have them travel in an asynchronous manner, we’ll have to figure out some way to have lifters pass each other (one going up and the other going down) while both are on the ribbon.  Lifters designed now cannot do this – they clamp to the ribbon, enveloping both sides of it (or all four sides of it, if you want to count the ribbon edges).  I’ve toyed with the idea of suggesting this as one of the challenges to be met in future Space Elevator games; i.e. you have to have two lifters on the tether simultaneously, one going up and one going down, and they have to be able to pass each other without causing problems.

Today I came across a video of another kind of climber, one that could, perhaps, crawl up on just one side of the ribbon.  You can find a video of it in action here.  It’s battery powered (I think), and doesn’t seem to be designed to carry anything, but it’s a step in the right direction.  Funding for this is being provided by DARPA.

9 thoughts on “A new climber?

  1. Bob Munck

    Until we have a great many SEs up and they’ve gotten very cheap, it’ll be better economics to throw away used climbers at the top and build new ones at the bottom than to use SE capacity bringing them back down. Parts of the climbers — photovoltaics, cooling systems, structure — will be reusable at GEO and more valuable there than they would be back on the ground since you’ve already paid to get them up.

    Finally, there will be cheaper ways to get things down from GEO than using an SE, such as using a rotovator to deorbit a vehicle containing whatever parts of climbers aren’t reusable up there. A big, cheap reentry shield for it could be built from lunar materials brought to GEO by an Moon-to-L1 SE.

  2. vincent lopresti

    this design would be too slow for the space elevator contest. minimum speed requirement is 1m/s avg.

    at 250mph, it would take a few days to reach the top of the REAL 62,000 mile space elevator. i doubt very seriously that anything could run that fast safely and securely.

    disposable climbers would not be feasable. however, i like the idea of detaching at the top to fly back down to Earth 🙂

  3. Leonard Porche

    Two climbers on a ribbon may never be able to pass each other but that does not mean their payload can’t. It is entirely possible that two lifters that meet each other can transfer their payload to the other. That way they never have to cross, just meet, exchange payload and change direction. This method may have its advantages. The lifter in the higher atmosphere may be more suited to solar power whereas the lifter starting from ground level may benefit from a beamed power source. A lifters first mission may be to get its twin into orbit.

  4. Brian

    I can see some disadvantages as well. The 2nd stage lifter spends it’s service life on a ribbon, far far from anywhere. That makes it expensive to build and operate but that’s not my real beef.

    The real problem comes when you need it to come back to the barn for service. It’s got to come allll the way home before it’s replacement can head up. Your ribbon is out of service for the duration of that cycle. Which isn’t a big deal from a technical POV but when it’s not in service it’s not producing revenue which makes it kinda tricky to pay back the note on the loan.

    If you gotta do it that way then you can plan around it. But it might come down to ‘cheap one-shot’ lifter vs. expensive and long lived two stage system. The data is not yet in but generally the way to bet is on cheap over expensive, always.

  5. Ted Semon Post author

    Why not do both? As Bob Munck pointed out in an earlier comment, climbers will be, for a long time, an expendable commodity – either thrown away or used to add to the counterweight. So, when the “upper-half climber” is at the end of its useful life, it goes to the GEO graveyard in the sky – and a new one is sent up the ribbon.

  6. Brian

    A valid idea, Ted, and a good reason why a) I’m not an engineer and b) many eyeballs are a good idea.

    Why didn’t I think of it? Because I tend to be a binary sort of guy. It’s either A OR B but ‘both’ as an answer never occurs to me.

  7. JonD

    I suspect that as designs are refined there will be branching of the ribbon above the atmosphere… it provides further redundancy in a fashion similar to the hoyt tether design and there is no reason as the amount of material is doubled by the taper that it has to remain monolithic… think of tree branches.

Comments are closed.