Welcome to the Space Fortress training study. In this experiment we use the game “Space Fortress” to find out how you preserve your gaming skills after periods of non-use. The results will be used for developing a model for optimising refresher training for professionals, meaning that training will be provided just in time: not too early, not too late. As Space Fortress is a difficult game, you will receive a series of training sessions to learn the game and to bring your skills to a reasonable level. This study is performed by the NLR (Royal Netherlands Aerospace Centre). Below, you see a link to a demo of the game. This gives you a quick impression of Space Fortress. More information on the study can be found on the Space Fortress web site. Looking forward to your participation. Goodluck! The NLR Space Fortress research team