You must first minor in physics or astronomy, or get a joint degree in government and physical science. I think that there could be some jobs in public policy, and in areas dealing with how government supports science. In Washington, D.C. you might look for jobs as a congressional staff member specializing in space science matters. I do not know about specific careers that mix government with space science. With all the government donwsizing going on, your best bet might be to get into a 'think tank' or an academic position, but this requires an advanced degree and actual hands-on experience in the government arena. Why not talk to the 'government faculty' at your institution, or write your Congressman or a state representative for advice?