[srl]

I suspect they'll repeat in a few years with a capsule in orbit. If you're in orbit for 520 days, something's almost guaranteed to go wrong, so it'll be a good bit more realistic.

(I'm actually pretty sure I read about plans to do this around 2018 in orbit, but I can't find the article now. Anyone?)

[maaku]

Uhh.. how is that different than the ISS?

[srl]

No single crew has been in the ISS, without other non-radio human contact, for 520 days. In fact, no single person has been in space for that long, period. The record at the ISS is 198 days; at MIR, 437[1].

http://en.wikipedia.org/wiki/List_of_spaceflight_records#Ten...

[rprospero]

The differences between an orbital mars voyage simulation and the ISS would be that the ISS gets resupply shipments and isn't on a 26 minute radio response delay with ground control.