Bloomberg News and the Wall Street Journal report that the Northrop Grumman-produced payload did not achieve success, citing unnamed officials.
The government has not disclosed whether the project was overseen by the Defense Department or one of the intelligence agencies. When asked about the status of the billion-dollar project that may have disappeared for good, a Pentagon spokesman refused to comment, leading to a combative back-and-forth at the Pentagon's press room.
"I'd have to refer you to SpaceX, who conducted the launch," DoD spokeswoman Dana White said Thursday in response to a question about whether the project succeeded or failed, according to Military.com's account of the event.
"This is a billion-dollar satellite. It's been four days. Was it a success or failure, and what's the fate of the satellite?" inquired Bloomberg's Tony Capaccio.
"We're not going to give you any more information," US Marine Corps Lt. Gen. Kenneth McKenzie replied.
"Accountability is one of your keystones here. [Defense] secretary [James] Mattis said this repeatedly. I'm asking you from an accountability standpoint. Can you give us a sense of whether you consider it a success or a failure as a mission?" the Bloomberg reporter continued.
The Pentagon again told reporters to ask SpaceX about the project, but Capaccio wasn't satisfied.
"But you're the government. You paid for it. You're the overseers. And you're asking us to go to the company who may have been partially responsible for the problem? That doesn't make any sense," he said.
For its part, SpaceX denied all culpability in the mission's possible failure.
"Falcon 9 did everything correctly on Sunday night. If we or others find otherwise based on further review, we will report it immediately," a statement from the private space company reads.
"Information published that is contrary to this statement is categorically false. Due to the classified nature of the payload, no further comment is possible," SpaceX said.
Northrop Grumman also evaded attempts to get some answers. "This is a classified mission. We cannot comment on classified missions," a Northrop spokesperson said in a statement to the Verge January 9.