An expensive, highly classified U.S. spy satellite is presumed to be a total loss after it failed to reach orbit atop a Space Exploration Technologies Corp. rocket on Sunday, according to industry and government officials.

Lawmakers and congressional staffers from the Senate and the House have been briefed about the botched mission, some of the officials said. The secret payload—code-named Zuma and launched from Florida on board a Falcon 9 rocket—is believed to have plummeted back into the atmosphere, they said, because it...