"We put our trust in the thrusters and they have not let us down." - Günther Hasinger, ESA Director of Science.
“Electric propulsion technology is very novel and extremely delicate.” - Elsa Montagnon, Spacecraft Operations Manager for BepiColombo.
“To see the thrusters working for the first time in space was an exciting moment and a big relief." - Paolo Ferri, ESA’s Head of Operations.
Sources:
ESA Press Release: BepiColombo Now Firing On All Cylinders
ESA Science: Getting to Mercury
Wikipedia Entry: BepiColombo
QinetiQ Press Release: Pioneering QinetiQ Solar Electric Propulsion System (SEPS) to power ESA's BepiColombo mission to Mercury
The Conversation: Falcon Heavy: SpaceX stages an amazing launch – but what about the environmental impact?
Wikipedia Entry: Ion Thruster