Technically, all Unreal Estate is mobile - if it wasn't, it would still be on Earth (or Luna, or Mars). However, once they're Up, "station-keeping" and "permanent Hohmann orbit" don't really count... at least, not IMHO.
--
Rob Kelk
"Governments have no right to question the loyalty of those who oppose
them. Adversaries remain citizens of the same state, common subjects of
the same sovereign, servants of the same law."
- Michael Ignatieff, addressing Stanford University in 2012
--
Rob Kelk
"Governments have no right to question the loyalty of those who oppose
them. Adversaries remain citizens of the same state, common subjects of
the same sovereign, servants of the same law."
- Michael Ignatieff, addressing Stanford University in 2012