NASAs astronaut training program works in such a way that the crews spendquite a bit of time together leading up to launch. This training includesmission simulations in mockups of the vehicle. With Mars missions it must beassumed that the crew would be larger than the 3 astronauts used the last timewe sent men outside LEO. The training would very likely include more than onelong stint in a vehicle simulation to train adapt and develope the teams. Think about ISS. The crew stays aboard for a mission of 6 months. You do nothear about drama on the crew but that does not mean it does not happen.