Based on the telemetry from the broadcast it seems that there was a failure at 13km that resulted in both telemetry and engine loss. When telemetry connection came back vertical speed has already doubled and it kept going up until spacecraft hit the ground. Engine was probably never restarted.
Edit1:
Telemetry came back at 10k. For the next minute and a half there was uncertainty about the main engine even though telemetry clearly showed vertical speed going up fast. More then a minute later, at 5k a reset request was made.
Edit2: A minute goes by and at about 500m controller asked if there is a confirmation to send rest to JPL, another, announced that engine is on. Crash happens at that moment. 149m, 134.3ms vertical.
From the NY Times story “We are resetting the spacecraft to try to enable the engine.”
I can't tell from that if normally an engine outage would automatically restart but didn't or if the condition would always require manual intervention. I hope we get more details soon. The moon seems close enough (a few seconds), but accidents always happen closest to your destination. More automation is more complexity but it will be valuable for longer trips.
Edit1: Telemetry came back at 10k. For the next minute and a half there was uncertainty about the main engine even though telemetry clearly showed vertical speed going up fast. More then a minute later, at 5k a reset request was made.
Edit2: A minute goes by and at about 500m controller asked if there is a confirmation to send rest to JPL, another, announced that engine is on. Crash happens at that moment. 149m, 134.3ms vertical.