Vinci is an expander cycle rocket engine fed with liquid hydrogen and liquid oxygen. Its biggest improvement from its predecessor, the HM-7B (which powers the ESC-A), is the capability of restarting up to five times. It is also the first European expander cycle engine, removing the need for a gas generator to drive the fuel and oxidizer pumps. The engine features a carbon ceramicextendable nozzle in order to have a large, 2.15 m diameter nozzle extension with minimum length: the retracted nozzle part is deployed only after the upper stage separates from the rest of the rocket; after extension, the engine's overall length increases from 2.3 m to 4.2 m.
Although the ESC-B development was put on hold in 2003, the Vinci project has not been cancelled: at a lower pace, the engine is still being developed. On 22 December 2006, Snecma announced a new ESA contract for Vinci rocket engine long-duration and re-ignition testing. In late April 2010 the German Aerospace Center DLR announced the start of a six month test campaign for the Vinci engine at its Lampoldshausen facility. The first successful test firing of this campaign took place on 27 May 2010. The first flight test of the Vinci engine is not expected until 2016 or 2017.