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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.
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.
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At that point gravity will act slower though, so it might be enough to take up a small liquid fuel craft too. Rockets will have abandoned solid fuel boosters long before then.
If you take a lift to a distance of 100 km and drop it, it will fall immediately reaching the ground in less than 10 minutes. Gravity remains strong. Satellites and space stations are always in free fall. The thing that keeps them in "space" is the velocity with which they were originally launched to orbit the Earth as centripetal force becomes the weight of the satellite, which slows down such falling process. Seein…
It would be more clear to say that what keeps them in space is that they're moving sideways so fast.
Velocity, not acceleration, is the right term here.
At 74km/h you would reach space (100km karman line) in an hour and a half but you would need to keep going for another 20 days at that speed reach geostationary orbit in order to not fall back to earth when you exit the space elevator.
but do you need to reach geostationary? couldn't you just switch to a rocket at this stage? Maybe a small one to bridge the gap? I would have thought that the first kilometres are the ones where you have to invest the most work so if you just bridge them using the space elevator it would be still an improvement. Maybe for cargo the 20 days are not really important
80% of the energy in a rocket goes to adding sideways motion.
An elevator upto GEO adds enough energy (taken from the earths rotational energy) to your payload to get it into orbit. If you let go lower down you need to add sideways velocity.
In LEO you on an elevator would be travelling about 1,400mph and need to get to 18,000 to get into orbit. Sure there’s no atmosphere to work against but it’s still a lot of fuel to use in a rocket.
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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.
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…
Space elevators are inherently create a new safety risk as cutting them at geosynchronous orbit only takes compromising some security and building a modest bomb. Both of which are achievable by terrorist organizations.
Earlier quoted context omitted.
If you take a lift to a distance of 100 km and drop it, it will fall immediately reaching the ground in less than 10 minutes. Gravity remains strong. Satellites and space stations are always in free fall. The thing that keeps them in "space" is the velocity with which they were originally launched to orbit the Earth as centripetal force becomes the weight of the satellite, which slows down such falling process. Seein…
> The thing that keeps them in "space" is the acceleration with which they were originally launched to orbit the Earth, which slows down such falling process. It would be more clear to say that what keeps them in space is that they're moving sideways so fast. Velocity, not acceleration, is the right term here.
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That is mostly because the international space community works with metric, so the Karman line is at 100km above earth, and converting to imperial units would be forced. Remember, there are only three countries that use imperial units; two third-world counties, and a global superpower.
That’s not entirely true. The UK and Australia use Imperial measurements quite frequently, especially for speed.
Road distance is miles, running its metres. Except for the marathon. Beer is pints, my milk is litres but you can get pints. The lamb in the fridge for the weekend is 2.3kg, I’m 5’11 and way a little over 14 stone as I’m far, probably because of the 200g of Brie I am thinking about eating tonight. I was looking at a floor plan the other day, the room was 6.5m x 3.8m
Earlier quoted context omitted.
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.
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.
Earlier quoted context omitted.
A space elevator on Mars is probably totally feasible. But of course the benefits would be much larger on Earth. The problem is: the benefit of a space elevator is bigger the deeper your gravity well is, but it's also much harder to impossible to make one there. But I've also been wondering: wouldn't it be possible to have a tapering space elevator? Reduce the weight by making the parts that have to carry less weight…
Yes, it absolutely has to taper, with an exponential curve, to keep stress constant over the length of the cable. The taper ratio (in terms of cross-sectional area) for the best currently available engineering materials for an Earth space elevator would be in the tens to hundreds of millions, but a carbon nanotube cable might only require a taper ratio of around ten. (A steel cable would need a taper ratio on the ord…
A steel cable would be 1mm thick at the bottom and several light years* thick at the top.
*hyperbole. Maybe.