SpaceX’s January 7th launch of a Falcon 9 rocket carrying a classified government payload estimated to cost in the neighborhood of one billion dollars was reported a failure by unnamed government officials at the time, but what really happened to the mission, named “Zuma,” remains a mystery lawmakers sought to resolve on Wednesday.

The Zuma payload seemed to deploy from the SpaceX rocket and, depending on the source, may have completed one full orbit of the earth before disappearing from the public tracking apparatus for orbital bodies. According to statements from officials under the condition of anonymity, the payload failed to separate from the second stage of the Falcon 9 rocket, causing them both to tumble back into the earth’s atmosphere, burning up in the process.

However, in the days since, the Department of Defense has been unwilling to comment on the final disposition of the Northrop Grumman constructed secret satellite payload, referring questions instead to SpaceX. For their part, SpaceX has maintained that there was no failure in their Falcon 9 platform, and while they won’t comment on the payload itself, they have been clear that if something were to have gone wrong, SpaceX was not to blame.

In Wednesday’s hearing before the House Space Subcommittee, intended to gauge the progress of SpaceX and NASA’s commercial crew program, lawmakers immediately brought up the Zuma mission, associating the potential loss of a billion dollar defense asset with concerns about the safety of a manned mission on the same rocket platform.

Recent press reports indicated that a U.S. government mission named Zuma may have either failed in orbit or the launch could have been unsuccessful,” Rep. Brian Babin, a Republican out of Texas, said. “I do not want to discuss anything classified in an open session, [but] the circumstances surrounding this mission do have a direct impact on NASA and this committee’s jurisdiction and oversight responsibilities.”

In Babin’s eyes, this failure casts concerns about upcoming SpaceX launches with high-dollar payloads, as well as planned missions that could see a crew put at risk if there’s an issue with the platform. In March, SpaceX will be launching a large exoplanet survey telescope, and the company is expected to begin shuttling astronauts to and from the International Space Station in the not too distant future. Further, if the fault was on Northrop Grumman, who reportedly built the payload adapter that secured the Zuma payload to the Falcon 9’s second stage, it would also be a matter of concern. Among a litany of government contracts, Northrop is also working on the $9 billion James Webb Space Telescope project.

I want to point out, on the Zuma mission, that we relayed the information that Falcon 9 … performed very well as specified, and that we are picking up the launches by the end of the month as we planned all the time,” Hans Koenigsmann, the vice president of build and flight reliability at SpaceX, told the committee. “Regarding a briefing, we will go through the proper channels, and follow the protocol — as you pointed out, we can’t talk any details in this particular setting.”

SpaceX Falcon 9 underway with Zuma payload on board on January 7th.

NASA’s associate administrator of the Human Exploration and Operations Directorate, William Gertenmaier, seemed to insinuate that there hadn’t been a failure in the Zuma launch at all. When asked about what happened on January 7th, Gertenmaier suggested that NASA would be involved in the investigation if and when the mission is formally declared a failure – indicating that internally, it has not been thus far.