LOS ANGELES, Jan. 11 (Xinhua) -- A federal appellate court ruled on Friday that scientists at NASA's Jet Propulsion Laboratory (JPL) will not have to undergo federal background checks until a judge rules on their constitutionality.

    The preliminary injunction granted by the 9th Circuit U.S. Court of Appeals reversed a lower court ruling which dismissed the scientists' lawsuit against NASA and the California Institute of Technology (Caltech).

    In a decision written by Judge Kim Wardlaw, the court ruled that the JPL employees "demonstrated serious questions as to certain of their claims on which they are likely to succeed on the merits and the balance of hardships tip sharply in their favor."

    The court decided that U.S. District Judge Otis Wright erred when he ruled on Thursday that the JPL employees were unlikely to suffer harm from not agreeing to the checks. Wright said in the ruling that the scientists failed to show any constitutional violations on the part of the California Institute of Technology in Pasadena, Los Angeles because it is a private -- not a government -- entity.

    At issue is a 2004 executive order signed by President George W. Bush requiring federal agencies and facilities to institute an identification badge system.

    The 28 plaintiffs -- all long-term Caltech employees -- allege the Bush administration is requiring them to consent to broad written waivers permitting investigators to obtain records from their past employment files.

    Investigators would also be allowed to question the employees' friends and associates about their emotional and financial well-being, as well as their sexual histories, the plaintiffs claim.

    In Friday's decision, Wardlaw wrote that the plaintiffs "face a stark choice -- either violation of their constitutional rights or loss of their jobs."

    Wardlaw said there was a sufficient relationship between the university and the federal government to warrant that CalTech remain a defendant in the case.

    Caltech manages JPL for NASA, the nation's space agency.

    JPL spokeswoman Veronica McGregor noted that although JPL and CalTech were dismissed as defendants by Wright, "We intend to abide by the (appellate) courts' decisions in this matter".

    Dan Stormer, an attorney for the JPL employees, hailed the court 's decision.

    "It is a complete victory for us," he said. ``We couldn't be happier."

    Stormer also accused the Bush administration of "using the word ‘terrorism' as this talisman that could override constitutional protections."

    Charles Miller, a spokesman for the U.S. Department of Justice, which is handling the case for the Commerce Department, which is also a defendant, said their attorneys were reviewing the court's decision.

    Representatives for NASA, which is the third defendant, were not immediately available for comment.