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Congressional candidate Jose Hernandez has flown into space, but a Sacramento, Calif., law firm is challenging his title as an "astronaut" on the June ballot.

The Fresno Bell reported that the firm of Bell, McAndrews & Hiltachk filed a lawsuit against Hernandez last week asking a judge to block the Democratic candidate from describing himself as an "astronaut/scientist/engineer" on the ballot, on the grounds that the candidate has not been affiliated with NASA since early 2011. The lawsuit adds that "astronaut is not a title one carries for life," and the profession listed on the ballot must be a current occupation.

Hernandez, 49,  flew on the space shuttle Discovery in 2009, and his life story has come to be a central narrative of his campaign as he challenges Republican opponent Rep. Jeff Denham for California's 10th congressional seat. Since announcing his candidacy in October, the candidate has touted campaign slogans aiming to market his background as an astronaut, such as  "From Farmworker to NASA Astronaut" and "From Plowshares to the Stars."

The French Camp native criticized the lawsuit Friday, saying it is a distraction from the race's more pressing issues. He took to Twitter Monday to defend the title:

@Astro_Jose: I launched into space and earned the title astronaut. Now, Republicans are trying to take that away: https://www.facebook.com/notes/jose-hernandez/were-going-to-court/280266702048095 #p2 #ca10 #cadem

The Hernandez campaign also issued a written statement Monday defending the decision to list "astronaut" next to the candidate's name on the ballot. The case will be presented in court Thursday.

"I always thought the hardest part of being an astronaut would be the training," Hernandez said. "I didn't realize it was going to be proving it in court."

Both of the lawyers filing the lawsuit against Hernandez have a history of connections to the Republican Party, according to the firm's website. Attorney Charles Bell Jr. is the immediate past president of the Republican National Lawyers Association, and is general counsel to the California Republican Party. The other attorney named on the case, Brian Hildreth, has previously served in the administration of former California Gov. Pete Wilson.

"This is a meritorious lawsuit and I expect the judge to act fairly quickly," Hildreth said. "Jose Hernandez has spent more time in the last two years in a business suit than in a space suit."