3 ms·

I'm a bit confused the ISS is only 408km from the earth's surface so why would it take 8 days at 200kph? Unless they are including the speed of orbit in which c

I'm a bit confused the ISS is only 408km from the earth's surface so why would it take 8 days at 200kph? Unless they are including the speed of orbit in which case the earth is already rotating at 1600 kph. What am I missing here?

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sigmaprimus 8y ago
My bad, missed the explanation below, go synchronization requires a much further distance than the iss. So I guess they will also have to make a new station or shuttle system to get to the iss.
- bencompanion 8y ago
  Getting from GEO back down to LEO would require pretty serious energy to reduce your altitude. You could possibly get off the elevator early, but you would need to then get up to orbital speed for whatever altitude you're at, which would be non-trivial for LEO. The ISS will almost certainly be decommissioned by 2030 anyway, and we're not going to have a space elevator by then. There'll still be other stuff in LEO that we want to get to though.
mojomark 8y ago
They said the tetger would be 36,000 km. 36,000/200kph = 180 hrs... 180hrs/24hrs/day = 7.5 days. Why the tether needs to be 36,000km long wasn't mentioned.
- chriswarbo 8y ago
  In terms of angular speed (e.g. revolutions per minute), lower orbits are faster, higher orbits are slower (think of a Mercury year versus a Neptune year). The ISS circles the Earth every 92 minutes. If we dropped a cable from the ISS (or another satellite at the same height), the anchoring point (e.g. something like a floating oil platform) would also have to circle the Earth roughly every 92 minutes. That's not feasible. Satellites at 36,000km circle the Earth every 24 hours, which is the same speed that the Earth rotates. If the satellite is orbiting around the equator, going the same direction as the Earth's rotation, then we would not have to move the anchor (the Earth's rotation would do it for us)
- leetcrew 8y ago
  it's the height above earth's surface for a geostationary orbit.

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sigmaprimus 8y ago

My bad, missed the explanation below, go synchronization requires a much further distance than the iss. So I guess they will also have to make a new station or shuttle system to get to the iss.

bencompanion 8y ago
Getting from GEO back down to LEO would require pretty serious energy to reduce your altitude. You could possibly get off the elevator early, but you would need to then get up to orbital speed for whatever altitude you're at, which would be non-trivial for LEO. The ISS will almost certainly be decommissioned by 2030 anyway, and we're not going to have a space elevator by then. There'll still be other stuff in LEO that we want to get to though.

mojomark 8y ago

They said the tetger would be 36,000 km. 36,000/200kph = 180 hrs... 180hrs/24hrs/day = 7.5 days. Why the tether needs to be 36,000km long wasn't mentioned.

chriswarbo 8y ago
In terms of angular speed (e.g. revolutions per minute), lower orbits are faster, higher orbits are slower (think of a Mercury year versus a Neptune year). The ISS circles the Earth every 92 minutes. If we dropped a cable from the ISS (or another satellite at the same height), the anchoring point (e.g. something like a floating oil platform) would also have to circle the Earth roughly every 92 minutes. That's not feasible. Satellites at 36,000km circle the Earth every 24 hours, which is the same speed that the Earth rotates. If the satellite is orbiting around the equator, going the same direction as the Earth's rotation, then we would not have to move the anchor (the Earth's rotation would do it for us)
leetcrew 8y ago
it's the height above earth's surface for a geostationary orbit.