What is it like inside Columbus?

BBC News science correspondent David Shukman visits a replica of the Columbus module at the EADS Astrium plant at Bremen, Germany.

This is only a theory - it certainly isn't rocket science - but my first impression on stepping into the brightly-lit module is that it's so surprisingly large that it may even offer enough room to orbit a cat.

I had imagined braining myself and smashing my elbows on the same kind of sharp angles and awkward features you find in the bowels of a cramped submarine.

But Columbus, Europe's first and biggest research outpost in space, is actually roomier and better-designed than many labs you find in some universities on European soil.

Down each side are the racks of instruments and experimental stations - BioLab and the Fluids lab among them - with two more fixed in the ceiling, which for an Earth-bound visitor like me causes a mild pain in the neck to look at.

Apparently one of the lessons from the pioneering days of the Russian space station Mir is that astronauts do need to have a sense of "up" and "down" - so Columbus' layout is quite conventional.

But for someone prone to knock into things by accident, every surface is festooned with switches, and I can't help wondering how many will be inadvertently flicked by a weightless astronaut gliding by a high speed.

On a television screen, a video is playing showing spacesuited gravity-free characters drifting along on previous expeditions and, if I watch for long enough, I start to wonder why my own feet aren't levitating from the metal floor.

But then the PR man says it's time for lunch and we step outside, not into low Earth orbit, but into a foggy car park in the German winter.