Sensing a rocket's 'heartbeat'

The rumblings of a rocket on the launch pad are picked up by instrumentation destined for Mars. Imperial College London has designed small seismometers to detect tremors on the Red Planet. These devices, which have been fitted to the InSight lander, are so sensitive they will even detect the imperceptible (to our ears) vibrations of the static launch vehicle. The signal is converted here to a sound file that has been sped up 20 times to make it audible.