4 billion miles: One tank of fuel

If the fuel had run out before the probe reached the comet, the navigational thrusters would not have been able to make the numerous course corrections needed to rendezvous with the comet and then establish a stable orbit from which to launch the Philae landing module. Throughout the long journey, Kistler pressure sensors monitored the fuel consumption continuously to ensure that Rosetta arrived at its destination with enough fuel to make the final corrections necessary to put the probe into orbit.

The Rosetta mission was one of the most ambitious projects executed by the ESA and two Kistler piezoresistive sensors played a small but valuable part in the success of the project. The key selection criteria for these sensors included their proven longevity and total reliability despite high levels of vibration at lift-off and years of zero gravity conditions.

Rosetta's cargo includes what is known as the Rosetta Disk – a nickel alloy disk with information etched onto it in image form. The disk contains about 13,000 pages of text in 1200 different languages, and it should still be readable after 10,000 years: durable though they are, even Kistler's sensors are unlikely to be functioning after such a lengthy period.