One of China’s most used rockets, the Long March 7A, exploded a little more than a minute after lifting off on Monday evening from Wenchang Space Launch Site. The medium-lift rocket’s payload was classified but believed to be a military communications satellite.

The liftoff appeared nominal, yet publicly captured videos showed that the rocket’s first stage exploded about 1 minute and 20 seconds into flight. Developed by China Aerospace Science and Technology Corporation, the Long March 7A is operated by the state’s space agency. As of Monday night in China, no official comments have been made regarding the explosion.

Given that the rocket failed during its first stage, it likely occurred around the time of maximum dynamic pressure as the vehicle accelerated through the lower atmosphere. There's a possibility that the flight was ended by an on-board ordnance known as a “flight termination system,” which ignites when the vehicle veers off course.

China’s state-operated launch industry has seen considerable success in the last half-decade, growing its annual launch total to 50 or more flights per year. However, despite this growth, it has only suffered a handful of launch failures. The significance of Monday's failure is uncertain given the closed nature of China’s state-operated space program; it may never be clear what caused the rocket to explode.