Illustration of the IXPE (Imaging X-Ray Polarimetry Explorer) space observatory in orbit around the Earth. The observatory, launched on 9th December 2021, is a joint mission between NASA and the Italian Space Agency (ASI). It carries three identical telescopes to measure the polarisation of cosmic X-rays, such as those coming from supernova remnants, black holes and pulsars. Measuring the polarisation will give information about the extreme high-energy phenomena that produce the X-rays.