A bunch of space companies are planning to service existing and future satellites (see, https://spacenews.com/orbital-atk-ssl-and-others-are-gearing-up-to-make-house-calls-to-ailing-satellites/ ). What they need is a dedicated vehicle that stays in orbit. Some call this an Orbital Transfer Vehicle (OTV). I call it a Space Ferry. Why have it? A ferry can visit dozens of satellites in a particular range of orbits. Yes, once in a while, a rocket or orbital airship (see, JPAerospace.com) would need to service the ferrycraft. Yes, we need more than one ferrycraft. I love Space Ferries (or is it, Space Fairies? because I’m part Irish). The ulterior motive here is that ferry development can support asteroid mining. For miners or barges returning from drilling into Apollo asteroids in earth’s orbit around the sun, a ferry meeting them and taking the ore could spur economic interest in building a refinery in orbit, using a rotating station called a spinship. If you think this is spinship, political, scientific and financial, you are correct. We have a station in space, the ISS. Let’s get a permanent spaceship in orbit and start getting things done! I love it! – L Paul Turner, http://www.TheSpaceTrade.com.