Every time the RAF's Typhoon fighters are scrambled on a quick reaction alert (QRA) mission, a Voyager scrambles, too.
The Voyager provides the Typhoon Force with range and endurance, allowing them to fly further and stay in the air longer, a capability so critical to air defence.
Carrying up to 109 tonnes of fuel, and burning just seven tonnes per hour itself, Voyager can keep the Typhoons airborne for a very long time.
Operating from RAF Brize Norton in Oxfordshire, Voyager crews maintain a constant readiness, 24 hours a day, 365 days a year. One aircraft is always on standby, refuelled and ready to act.
Part 1 of our video explains more about what Voyager is, and how it supports UK defence.