[mrfusion]

Have you heard of the idea of running a current through a long wire to propel a spacecraft against the earth's magnetic field?

I remember reading about it somewhere, but I can never find it again.

[TheLoneWolfling]

Yep. It's called an electrodynamic tether. Proposed for stationkeeping for everything from space stations to skyhooks, among other things.

[mrfusion]

Might be too late to follow up. (I wish HN had the response alerts like Reddit does)

But how can you have a current in a single wire without a loop?