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.