The first operational crew rotation of the Mars Society’s Mars Desert Research Station (MDRS) has been successfully completed. The MDRS went operational on Feb 7 with a crew of 6. For the past two weeks, the station’s crew has been conducting a systematic program of exploration of the surrounding desert, while operating under many of the same constraints as an actual Mars crew. For example, as on Mars, anyone leaving the station to do field research needs to wear a simulated spacesuit, that limits the mobility, agility, dexterity, and sensory abilities of the wearer much as a real spacesuit would, and communication between EVA team members separated by more than a few feet has to be done by suit radio. While in the station, crew members also do laboratory analysis of samples brought in from the field, repair equipment, write reports (which are exchanged with Mars Society’s Mission Support group via a satellite link that imposes a Mars-like delay on communications), and engage in the chores of daily life living together as a team. The purpose of conducting such simulated operations is to gain essential knowledge of Mars exploration tactics, human factors issues, and engineering requirements – in short, to start learning how to explore Mars.