"Voyager" is an educational card game involving scientific satellites, developed for use in schools with children aged 9 to 13 years. The idea of the game is to improve pupils' knowledge about the large number of scientific satellites there are in space in a fun way, while also practising numeracy skills. Several copies of the game were produced using funding obtained from the Particle Physics and Astronomy Research Council (PPARC) as a Public Understanding of Science (PUS) award. These initial "trial" versions of the game were taken to three different schools where feedback obtained from both pupils and staff was used to produce a final copy of the game that can be distributed to other schools along with a set of companion notes to form the basis of a science lesson. This article reports the findings of the school trials and indicates possible future developments of other scientific card games that could be beneficial to the classroom. (Contains 2 figures and 2 tables.)