Raptor engines began flight testing on the Starhopper prototype in July 2019 and became the first full-flow staged combustion rocket engine ever flown.[1] As of January Raptor also produces the highest combustion chamber pressure ever reached by an operational rocket engine, at 330 bar (33,000 kilopascals), surpassing the record held by the RD-701 rocket engine at 300 bars.[19][20]