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Comment by aredox | Hacker News Reader

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aredox·

Wouldn't the ISS make a nice station for Lagrange Points 4 or 5?

Hell, why can't we use it as the Lunar Gateway?

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No and no.

* At the time its decommissioned it will be over 30 years old, well past it's original planned lifespan.

* It was never designed for orbital maneuvers with that much delta-v.

* Due to how adjusting orbits works, it would require about as much energy to move it into such a different orbit as it would to just ship a new one from Earth. This is even more true when you consider we would have to ship all the fuel into orbit to perform the orbit shift.

No one ever understands how far (in energy) different places (orbits, its all orbits) in space are and what that implies about moving stuff from one to the other.

I understand this conceptually, at least that moving from one orbit to another is very costly in energy. But what mental model can I use to get a rough idea of which things require more energy vs less? Or maybe what contributes to that energy requirement?

Play Kerbal Space Program?

https://commons.wikimedia.org/wiki/File:Solar_system_delta_v...

The component of your velocity that isn't coplanar with the orbit you want to end up in is velocity you have to get rid of.

I don't get the delta-v argument: now that it is in orbit outside the atmosphere, we can accelerate it as progressively as we want, e.g. with ion thrusters or solar sails, to raise its kinetic energy until it reaches a higher orbit, no?

I concede that I was assuming a traditional chemical rocket to generate the force. A more gentle force would put less strain on the structure.

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