[dogscoff]

Lot's of complex things with many moving parts required. And we aren't talking just years here, but centuries. Not just the moving parts either. Computers and other electronics will constantly need replacing.

Nah, it could be done. Just because your average modern family car is carefully designed to fall apart 2 days after the warranty runs out doesnn't mean we are incapable of building things that Last longer.

I remember seeing a program about the railways in India- they had this enormous steam engine running. It had been in service for over a hundred years...

Now obviously a spaceship is more complicated than a steam engine, but with proper, solid, simple-as-possible design and manufacture, a healthy supply of spares and engineering talent I'm sure we could (eventually) build a spaceship capable of a century's travel.