[pavel_lishin]

> Where did the water come from?

Good question! His story "The Martian Way" addresses this. I don't really want to spoil it from you, but basically: where you'd expect.

> Surely they weren't storing it as H20 on the ship?

Why not? It's stable, it's useful for other reasons, and when you've got free energy and easy propulsion, there's no reason not to. (There probably would be some issues with sloshing, actually, but he didn't get into it. Asimov wrote a lot of stories that could be considered Hard Science, but I don't think he'd consider himself an engineer.)

[nkrisc]

Fair enough, it is just fiction after all. I was thinking that storing it as H20 would be a challenge as storing all the water you might need would take a large amount of space. But I suppose if it was for a craft that would never enter an atmosphere the volume wouldn't really be an issue.