It also has powerfulcoresealingcapacity, dragcoefficient was greater than 32, residualresistancefactor was greater than 20 and pluggingrate wasgreater than 95%.
The engine constantly throttles up and down, not only to counter the drag on the satellite from residual air molecules in near space but also to smooth the flight of the vehicle to minimise the noise in the gravity measurements.
Residual air molecules more than 200km above the planet will generate drag on the probe and pull it down faster and faster - although it could be some weeks yet before there is an impact.
It was pushed to this height recently to take it clear of residual air molecules at the top of the atmosphere that tend to drag it downwards over time.