1. A method for determining flight direction of a spacecraft, comprising: providing at least one imaging detector associated with a spacecraft; imaging at least a portion of a celestial body onto the at least one imaging detector; acquiring, by the at least one imaging detector, sequential images of at least a portion of the celestial body; and determining the spacecraft flight direction relative to the celestial body based at least in part on processing the sequential images, wherein the processing is performed by one or more computer processors.