A federal judge blocked the government from conducting background checks of low-risk employees at NASA's Jet Propulsion Laboratory after an appeals court said the investigations threatened the constitutional rights of workers.
U.S. District Judge Otis Wright issued the injunction Friday after the U.S. 9th Circuit Court of Appeals reversed his earlier ruling and issued a sharp rebuke to the judge.
The higher court said the 28 scientists and engineers who refused to submit to the background checks faced "a stark choice -- either violation of their constitutional rights or loss of their jobs."
The workers sued the federal government, claiming that the U.S. space agency was invading their privacy by requiring the investigations, which included probes into medical records and questioning of friends about everything from their finances to their sex lives.
If they didn't agree to the checks, they were to be barred from the JPL campus in La Canada Flintridge and fired.
"We're ecstatic," workers' attorney Dan Stormer said. "This represents a vindication of constitutional protections that all of us are entitled to. It prevents the government from conducting needless searches into backgrounds."
NASA has argued that requiring employees to submit to the investigations was not intrusive and that the directive followed a Bush administration policy applying to millions of civil servants and contractors.
The plaintiffs have worked for years at the labs that are run for NASA by Caltech.
Veronica McGregor, a spokeswoman for Caltech and JPL, said Friday afternoon, "We are going to abide by any decisions made by the court."
None of the plaintiffs work on top-secret projects at JPL, which employs about 5,000 workers, but several are involved in high-profile missions, such as the Galileo probe to Jupiter and the Cassini spacecraft to Saturn.