For the last four years, two robot rovers operated from the Jet Propulsion Laboratory in La Canada Flintridge have been moving across the surface of Mars, taking photographs and collecting information. It's an epic event in the history of exploration, one of many for which JPL's 7,000 civilian scientists and engineers are responsible -- when they're not fending off the U.S. government's attempts to conduct an intimidating and probably illegal inquisition into the intimate details of their lives. The problem began -- as so many have -- in the security mania that gripped the Bush administration after 9/11. Presidential Directive No. 12, issued by the Department of Homeland Security, directed federal agencies to adopt a uniform badge that could be used by employees and contractors to gain access to government facilities. NASA Administrator Michael Griffin ... directed Caltech, which has a contract to run JPL for NASA, to make sure all of the lab's employees complied. The government demanded that the scientists, in order to get the badges, fill out questionnaires on their personal lives and waive the privacy of their financial, medical and psychiatric records. The government also wanted permission to gather information about them by interviewing third parties. Twenty-eight of JPL's senior scientists sued in federal court to stop the government and Caltech from forcing them to agree to the background checks as the price of keeping their jobs. They point out that Griffin is one of those who remain skeptical that human actions contribute to global warming, and that some of JPL's near-Earth science has played a critical role in establishing the empirical case to the contrary. They see the background checks as the first step toward establishing a system of intimidation that might be used to silence inconvenient science.