Did anyone sue NASA after the Challenger disaster?

Yes, families of the Challenger crew did sue NASA and its contractors after the Challenger disaster on January 28, 1986, which killed seven astronauts. The families of the astronauts filed lawsuits against NASA, Morton Thiokol which made the solid rocket boosters with the faulty O-ring, and Rockwell International which made the orbiter. The lawsuits alleged negligence, failure to address known safety issues with O-rings in cold weather, and poor decision making in launching despite warnings from engineers. Most lawsuits were settled out of court with confidential settlements. The family of Christa McAuliffe, the teacher in space, and other families received settlements reportedly in the range of several million dollars each from Morton Thiokol and other contractors, though exact amounts were not publicly disclosed due to confidentiality agreements. The Rogers Commission investigation found that NASA's decision-making process was flawed and that Morton Thiokol and NASA management ignored warnings about O-ring failure in cold temperatures. In addition to lawsuits, there were congressional hearings and reforms to NASA's safety culture. NASA itself as a government agency has sovereign immunity, but its contractors were liable. So yes, there were lawsuits after Challenger, and they resulted in settlements that acknowledged responsibility without a full public trial.