In February 2013, the MARS2013 Mission was conducted by the Austrian Space Forum in partnership with the Ibn Battuta Center in Marrakesh. MARS2013 was an integrated Mars analogue field simulation during which a small field crew conducted various experiments in the Moroccan desert directed by a Mission Support Centre in Austria. It served as a platform to test a planning strategy that was developed to cope with the characteristics of the mission, such as the duration of 28 days, about 20 experiments, each with its own scientific operational constraints and a 10 minutes time delay in the communication in order to simulate the long distance between Mars and Earth. On future Mars missions, time and resources will be even more limited. In order to ensure the maximum scientific research within the operational limits and experimental constraints, detailed and well-thought-through Mission and Activity Planning is of significant importance. Developing a method for how to properly plan all the necessary and desired activities in advance and how to react to inevitable changes due to contingencies and complications is a necessity. Here we would like to present the theory behind this so-called “3-Days-in-Advance-Planning” strategy, its evolution during the mission, and the results gained regarding the efficiency of this method.