Passenger of STS-134 Endeavour to be launched this 19 April, AMS, the Alpha Magnetic Spectrometer, is hoped to bring new discoveries. Developped in Europe at CERN, near Geneva, AMS will be attached to the International Space Station and from this orbital outpost will observe antimatter and dark matter. This unique cosmic ray detector will be ISS' largest scientific instrument. AMS could bring a revolution in our understanding of the physics of the universe.