The ESTEC Test Centre’s Hydra – short for Hydraulic Multi-axis Shaker – is the most powerful and most precisely-controllable of several such shaker tables at the site. 
Hydra serves to simulate the extreme vibration experienced during the first few minutes of a rocket launch, to ensure that satellites and their component parts will not be shaken to pieces during their actual flight to orbit. 
The facility can shake test items weighing up to 23 tonnes, generating accelerations of 0.02 – 5 Earth gravity. Overall, Hydra is capable of generating vibrations equivalent to upwards of a Magnitude 7 earthquake. 
Installed in 1996 and refurbished in 2011, Hydra has served many of Europe’s largest space missions, including Envisat – at eight tonnes the largest ever civilian Earth observation satellite – Herschel and the ATV, which weighed 22 tonnes with its propellant tanks full.’