Abstract: Neutron stars are incredible playgrounds for theoretical physicists and observational astrophysicists, featuring the most intense concentrations of all four known force-fields of nature. In this talk, I will highlight a peculiar effect that leads to a prediction of an electromagnetic rocket force. I will explain how recent Gaia observations allow us to probe this force. I will show an exact computation of the rocket force in Force-Free Electrodynamics, which is a good theory describing magnetospheres of many, but not all neutron stars (no knowledge of plasma physics will be assumed). Gaia's neutron stars may well have to be described by a different theory.