As you say it works both ways.
Knowing if things go bad, shit will certainly hit the fan is a stressor.
On the other hand, knowing that if YOU cause things to go bad and shit hits the fan is very good motivator for YOU to behave properly in the first place.
Wouldn’t a lot of it depend on the crew accomodations? If it is some cramped one compartment Apollo-style capsule, sure, stir crazy they shall be in short order. But if there’s several compartments, perhaps including private sleeping berths which also allow for reading and perusing the internet and such in isolation, perhaps it wouldn’t be so bad.
You got a very long ping from Mars orbit. 
If Pauly Shore and the stoner Baldwin can do it…
Humans are social animals but not that social. I voted someone will go batshit. I guess it could be different if they knew they were really going to Mars. It’s just too easy for someone to bail out knowing that it’s not real.
Its kind of pointless… These are 6 average men, who are NOT partaking in one of the grandest adventures mankind has ever undertook, but rather, are lab rats chimping for the whitecoats.
A not so subtle difference, i think, and will heavily affect the participants mindsets.
Also, whatever ‘work’ they find for these guys to do will probably be quite pointless makework, which will also have a negative impact. Unless they are smart and made the thing a(mostly) self contained mockup that they have to maintain and repair, but the illusion can only go so far.
They should also, I feel, have a ‘vacation’ room, a respectably large(luxuriously so) room on the ship with some really nice things in it, wall to wall LCD monitors to show nice landscape scenes, maybe a nice hot bathtube, and importantly, a lock on the door. Because that much time spent on the ship together… you’re really going to need alone time.
I disagree with the premise, but not the conclusion. Learning how people react in this situation will create valuable data about what sort of living space we could need, what time windows we have to operate in, what to screen for, what sort of entertainment to include, etc. It’s valuable research.
But the fact that everyone will know it’s a simulation will affect their reactions. I could see this going either way though - people knowing that safety is on the other side of a hatch might actually be soothed to continue, whereas being stuck millions of miles from home with no recourse could be stressing. On the other hand, people might be able to suck it up and deal with any adversity knowing the greatness of their mission during the real deal.
Heh. I was watching a video about it on the ESA site and the cameras onboard, if I can believe the video, look just like HAL from 2001.
I think it’s going to be like any other social experiment or reality TV show. Everyone gets along great at the start, then slowly things deteriorate. Someone will eventually become annoying to the others and they will all pounce on him like wolves to a fresh kill. Then someone else will cross a line and they’re next, and so on, until they’re all ready to kill one another.
I don’t think it’s possible to spend 24 hours a day for 520 days with anyone whether it’s ona mission to mars or otherwise.
Wouldn’t work so well during the real thing, though.
Haven’t there been 8 month space missions already? If you can handle 8 months, ~2 years doesn’t seem too bad.
And you are basing this on what?
“Driving ambition” pretty much goes out the airlock around the middle of Day 4, and then you realize that you’re just a part of the machine. The ability to survive long duration confinement and the constant threat of hazard is innate mental stability combined with extensive training and conditioning to cope with any foreseeable emergency and contingency.
As for the Mars 500 experiment, I suspect it will fail, although not perhaps for psychological conflicts between the crew but instead out of sheer boredom and depression. One of the many major challenges of long term space habitation is how to keep people happy and functional when they can’t see blue sky, swim in a lake, step out for a beer, or get more than a few dozen meters from their fellow crew. The need for novel stimulation exists in all intelligent animals, and for people suitable for manning a spacecraft and operating sophisticated equipment it is as strong a compulsion as any ambition. The excessive familiarity with the limited environment and other crew members places a heavy toll on psychological stability.
That, and the smell. Submariners will know what I’m talking about.
Stranger
Are they going to be dosed with sex-drive suppressants? If not, this is going to endup as The Beeftrain to Mars.
Or people who’ve used a major metropolitan underground mass transit system 
Why did they make this experiment a sausagefest, again?
I dunno— I was thinking that the part of a real Mars mission that can’t be simulated might be the part that makes the difference in the end. That being-- on a real mission you know you have to get through it. There IS no out.
With the simulation, no matter how much you try to bury it away in your mind, you always know you can get out if you want to. And rather than making it easier to stay in the whole time, I think in a weird way, it actually makes it more difficult.
That one does not to me, but this experiment reminds me of a different story: Going to Mars was routine, but there were special provisions. Upon returning to Earth, each member of the crew was assigned residence in geographically separate regions and they were not allowed ever to leave that region. The reason? The brass found out the hard way that without that provision, there was a chance one astronaut might bump into another on the street - the result is one would inevitably kill the other. Having been couped up so long with one another, every little gesture became annoying to each other - every toss of the hair, distictive sound when swallowing would drive each crazy (the only reason they didn’t kill each other sooner was the realization they all needed each other to survive).
Does THAT one ring a bell? Can anyone remind me the author or the name of the story?
Oh, and here’s hoping nothing like that happens to our earthbound crew!
I voted that someone would go nuts and have to be removed, but I give the experiment about 40% probability of success.
I would REALLY like to see multiple experiments run on this with various mixtures of ages, sexes, nationalities, and so on. No matter whether we go to Mars this decade or next century, the study of human interaction will need to be much better developed prior to the mission(s).
I assume that this is not a biosphere type of experiment and that the life support systems will be the standard rebreathers without some fancy hydroponics.
Come to think of it, I would really like to know more about this before commenting further.
ETA:
BTW the record stay in space is 437 days, by a Russian aboard Mir.
Wasn’t locking people in vaults for long periods of time to perform experiments on them the premise of the Fallout video games?
Channel 4 in the UK ran a reality TV show called Space Cadets where the contestants were tricked into thinking they had gone to Russia to train for a space trip and if I remember correctly they were tricked into thinking they had gone into low-earth orbit.
They never actually left the UK.