BepiColombo structural and thermal model undergoing horizontal-axis vibration testing at ESTEC, ESA’s space research and technology centre in Noordwijk, the Netherlands. From top to bottom are the sunshield, which conceals the Mercury Magnetospheric Orbiter, with the Mercury Planetary Orbiter below. Underneath is the Mercury Transfer Module, which will deliver the stack of two scientific satellites into orbit around the planet. The stack is about six metres high. During the 2.5 minute vibration test, the spacecraft was subjected to vibrations at frequencies from 3 Hz to 100 Hz, mimicking conditions it will experience when it lifts off on an Ariane 5 launch vehicle in 2015.