For the past three years, Robert Nelson has been juggling two lives.
He's a senior research scientist at the NASA Jet Propulsion Laboratory by day, attempting to determine whether Saturn's giant moon Titan is volcanically active. When he's not exploring the cosmos, he's leading a legal fight to prevent his employer from asking private details about his life.
"It's almost like having a second job," Nelson said. "It takes you away from something you'd rather be doing."
Since Nelson and two dozen other JPL scientists and engineers sued the government in 2007, the case has crawled through the court system. The U.S. Supreme Court will hear arguments Tuesday.
At issue is whether the government has the right to probe the personal lives of low-risk contractors with access to federal facilities. The lab employees objected to the background checks, saying they were intrusive and violated their privacy.
A federal judge who allowed the security checks to go forward was overturned by the 9th U.S. Circuit Court of Appeals, which said the investigations threaten the constitutional rights of workers. NASA appealed to the Supreme Court, which agreed to referee the dispute.
JPL is NASA's premier robotics lab, famous for sending unmanned spacecraft to Mars and the outer solar system. Unlike other NASA research centers, it's run by the California Institute of Technology. Lab scientists, engineers and staff are Caltech employees, but the 177-acre campus about 15 miles east of downtown Los Angeles and its buildings are owned by NASA.
In 2007, NASA extended background checks for federal employees to its contract workers in response to a presidential directive that ordered government agencies to beef up security at facilities and computer systems by issuing new identification badges for millions of civil servants and contractors.
None of the JPL workers who sued work on classified projects or have security clearances, though several are involved in high-profile missions including the twin Mars rovers and the Cassini spacecraft studying Saturn and its moons.
The plaintiffs don't deny that the government has the right to confirm a person's identity and education for employment. But requiring background checks of low-risk employees, which includes probes into medical records, finances and drug history, is an invasion of privacy, they say.
The Justice Department, which is representing NASA, declined to comment. In court filings, it countered that the background investigations were "minimally intrusive."
"There is no support for respondents' speculation that the government will use the background-check process to pry into their private lives," it said.
NASA has been backed by companies that perform screenings for the government and private employers such as landlords. They argued that open-ended questions during background checks are routine and necessary.
Since filing the lawsuit, the lab researchers have rallied for public support. They wrote to their congressmen and senators and encouraged colleagues to do the same. They handed out leaflets to cars coming onto campus about their case and some have worn T-shirts proclaiming their opposition to the background checks.
The Union of Concerned Scientists, which filed an amicus brief on behalf of the lab workers, worried that NASA may lose its scientific edge.
"If the government succeeds in this attempt to delve into the private lives of scientists doing unclassified research on its behalf, it will harm its ability to attract high-caliber researchers," co-founder Kurt Gottfried said in a statement.
Nelson the JPL scientist has been dividing time his time between researcher and plaintiff for the past three years. His day begins at 5 a.m. and before he hits the gym, he usually answers e-mails from his lawyers or fellow plaintiffs. After working a full day, he spends many nights and weekends on the case.
The payoff, Nelson said, is seeing support from colleagues, managers and strangers.
"It's touched a nerve," he said. "I thought maybe people might ignore us, but just the opposite has happened.
