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And so what about the downsides? The ultimate target for terrorists. If that comes down and it wraps itself around the Earth, it'll be devastating.

falcor84 4y ago
My understanding is that it would be under tension and orbiting at beyond escape velocity, such that if it got cut off, it would fly away from Earth. Still bad, but not catastrophically. Maybe we could even recover it.
- RandallBrown 4y ago
  But what happens to the tether it breaks away from? That won't stay up on its own. I'm sure you could build it in a way that it would break apart into lots of smaller pieces, but even then it seems like it could be dangerous.
- hammyhavoc 4y ago
  That all assumes that it got loose at the base and not part way up within the atmosphere. If 9/11 can happen, this can happen. All that cable and kinetic energy has to go somewhere.
  - londons_explore 4y ago
    If a tether breaks high up, then only a few kilometers of the tether hit the ground. Anything higher burns up on the way down (since it is very thin, so surface plasma heating doesn't take long to destroy it)
  - midasuni 4y ago
    If your bad guys can get high enough to sever your cable, they can get high enough to do a kinetic or powered bombardment and cause magnitudes more damage.
    - red-iron-pine 4y ago
      ¿Por qué no los dos? Plus accidents are more likely than you think. A rocket just exploded this morning, and read up on rates of railroad or shipping screwups. A train full of apples and pallets of kleenex going over ain't a big deal but the same containers falling out of the sky will certainly cause more damage.
    - jutrewag 4y ago
      A bomb on wheels that rides the cable before exploding.
      - midasuni 4y ago
        I can’t take a tube of toothpaste on a plane. How am I going to pack a bomb large enough to cause that much damage. Why don’t people blow up planes with that method today?
  - concordDance 4y ago
    They're probably better off just flying into a building again.
Balero 4y ago
The structure wouldn't be able to passively stay together. If it was to be destroyed then it would burn up in the atmosphere like anything else. It is not made of a magic non-existent material that is infinitely strong. Of course if you had a massive dense asteroid attached that would not, so it makes sense to be careful with what is around it. But the orbital ring itself would break up and be no more dangerous than a bunch of satellites of similar mass. Also it would not be an "Ultimate target" for "terrorists". Terrorists are violent political activists, not super villains that want to destroy the world. I doubt, for example, that the new-IRA would get a united Ireland by destroying orbital infrastructure.
- PaulDavisThe1st 4y ago
  To the extent that an elevator would represent both the power and interests of whatever rich entity had managed to construct it, it would be a target for those who want to reduce the power and harm the interests of that entity.
- midoridensha 4y ago
  >I doubt, for example, that the new-IRA would get a united Ireland by destroying orbital infrastructure. The most effective way for the new-IRA to unite Ireland would be to help the UK keep shooting itself in the foot, so that the Northern Ireland citizens get sick of regular Ireland being better off economically, and vote to join it.
- hammyhavoc 4y ago
  I'm more concerned about what's already within our atmosphere and isn't going to burn up. That's a lot of kinetic energy, and nobody says it's going to destroy the Earth, I said it would be devastating. You're forgetting religious extremists and countless suicide bombers.
  - ta1243 4y ago
    It would be cheaper to drop an equivalent massed object out of a plane. Or just use the plane as the weapon. You break a space elevator at the ground, it floats upwards. You break it at 30,000 foot then everything above the break floats away upwards, everything below "crashes" down, at a relatively low terminal velocity and thus with pretty low amounts of energy. An elevator isn't a tower, it's a rope handing from a counterweight in orbit which is kept taut by a centrifugal force. It's anchored at the ground to stop the rock floating away, but if you break that anchor everything above will swing away from Earth If you have the ability to break the cable at say 100km above the ground, you have the ability to drop objects from that height anyway, don't have to deal with no-fly-zones, and can target somewhere not on the equator. Want to cause chaos? Get a bunch of heavy dense cheap bits of metal, put them in a high altitude balloon, then drop them over a city. You'll cause more damage to the people on the ground than anything you could do to a space elevator (short of the financial impact of having to resplice it) If you can damage the elevator at the counterweight end, then you have the ability to drop a "rod from god" and cause more damage that way.

falcor84 4y ago

My understanding is that it would be under tension and orbiting at beyond escape velocity, such that if it got cut off, it would fly away from Earth. Still bad, but not catastrophically. Maybe we could even recover it.

RandallBrown 4y ago
But what happens to the tether it breaks away from? That won't stay up on its own. I'm sure you could build it in a way that it would break apart into lots of smaller pieces, but even then it seems like it could be dangerous.
hammyhavoc 4y ago
That all assumes that it got loose at the base and not part way up within the atmosphere. If 9/11 can happen, this can happen. All that cable and kinetic energy has to go somewhere.
- londons_explore 4y ago
  If a tether breaks high up, then only a few kilometers of the tether hit the ground. Anything higher burns up on the way down (since it is very thin, so surface plasma heating doesn't take long to destroy it)
- midasuni 4y ago
  If your bad guys can get high enough to sever your cable, they can get high enough to do a kinetic or powered bombardment and cause magnitudes more damage.
  - red-iron-pine 4y ago
    ¿Por qué no los dos? Plus accidents are more likely than you think. A rocket just exploded this morning, and read up on rates of railroad or shipping screwups. A train full of apples and pallets of kleenex going over ain't a big deal but the same containers falling out of the sky will certainly cause more damage.
  - jutrewag 4y ago
    A bomb on wheels that rides the cable before exploding.
    - midasuni 4y ago
      I can’t take a tube of toothpaste on a plane. How am I going to pack a bomb large enough to cause that much damage. Why don’t people blow up planes with that method today?
- concordDance 4y ago
  They're probably better off just flying into a building again.

Balero 4y ago

The structure wouldn't be able to passively stay together. If it was to be destroyed then it would burn up in the atmosphere like anything else. It is not made of a magic non-existent material that is infinitely strong. Of course if you had a massive dense asteroid attached that would not, so it makes sense to be careful with what is around it. But the orbital ring itself would break up and be no more dangerous than a bunch of satellites of similar mass. Also it would not be an "Ultimate target" for "terrorists". Terrorists are violent political activists, not super villains that want to destroy the world. I doubt, for example, that the new-IRA would get a united Ireland by destroying orbital infrastructure.

PaulDavisThe1st 4y ago
To the extent that an elevator would represent both the power and interests of whatever rich entity had managed to construct it, it would be a target for those who want to reduce the power and harm the interests of that entity.
midoridensha 4y ago
>I doubt, for example, that the new-IRA would get a united Ireland by destroying orbital infrastructure. The most effective way for the new-IRA to unite Ireland would be to help the UK keep shooting itself in the foot, so that the Northern Ireland citizens get sick of regular Ireland being better off economically, and vote to join it.
hammyhavoc 4y ago
I'm more concerned about what's already within our atmosphere and isn't going to burn up. That's a lot of kinetic energy, and nobody says it's going to destroy the Earth, I said it would be devastating. You're forgetting religious extremists and countless suicide bombers.
- ta1243 4y ago
  It would be cheaper to drop an equivalent massed object out of a plane. Or just use the plane as the weapon. You break a space elevator at the ground, it floats upwards. You break it at 30,000 foot then everything above the break floats away upwards, everything below "crashes" down, at a relatively low terminal velocity and thus with pretty low amounts of energy. An elevator isn't a tower, it's a rope handing from a counterweight in orbit which is kept taut by a centrifugal force. It's anchored at the ground to stop the rock floating away, but if you break that anchor everything above will swing away from Earth If you have the ability to break the cable at say 100km above the ground, you have the ability to drop objects from that height anyway, don't have to deal with no-fly-zones, and can target somewhere not on the equator. Want to cause chaos? Get a bunch of heavy dense cheap bits of metal, put them in a high altitude balloon, then drop them over a city. You'll cause more damage to the people on the ground than anything you could do to a space elevator (short of the financial impact of having to resplice it) If you can damage the elevator at the counterweight end, then you have the ability to drop a "rod from god" and cause more damage that way.