If Dr. Robert Zubrin could take a trip to Mars, he would be sure to pack a bread maker in his suitcase. Not just because bread is a pretty reliable expeditionary food, but because the act of cooking, according to Zubrin, seems to help people get along with each other, especially when they are in slightly dire, less than luxurious and more than stressful circumstances. And Zubrin would know, too. He has, after all, led almost a half-dozen mock Mars missions on barren Arctic ice fields and scorching Utah deserts with volunteer teams made up of students, scientists, journalists and anyone else willing to wear fake spacesuits and live in tiny tin-can-like habitation modules for days on end. The simulated expeditions were made, in part, to research ways to live and work on the Red Planet. But they also revealed something else: what personality types might best be suited to make the 35 million-mile journey and who would be better off watching from Mission Control. “Some of these crews have worked out very well,” said Zubrin, president of the Mars Society, a 7,000-member multinational group determined to reach what it calls the New World. “Others were at each other’s throats.”