(Reuters) - Rocket maker SpaceX on Tuesday will appear before a U.S. labor board judge to face claims that it fired eight engineers for criticizing CEO Elon Musk and accusing him of sexist conduct in a letter to company executives.

The case before National Labor Relations Board Administrative Law Judge Sharon Steckler in Los Angeles prompted SpaceX to file a lawsuit in January seeking to block it from going forward by claiming the board's in-house enforcement proceedings violate the U.S. Constitution.