What is AMS?

The Alpha Magnetic Spectrometer Experiment

AMS is a particle detector for the International Space Station. A group of high-energy physicists are taking their experimental expertise - acquired in thirty years of experience at particle accelerators - into orbit. Space is full of high-energy particles of many types (collectively called "cosmic rays"), many of them originating in supernova explosions in distant galaxies. AMS detects them using a huge superconducting magnet and six highly specialized, ultra-precise detectors. It will sit on the ISS main truss - far above the obscuring atmosphere, and making full use of the ISS's irreplaceable support systems - and gather data for three years.

AMS is a major cosmology experiment. AMS will observe the properties of electrons, positrons, protons, antiprotons, and nuclei in high-energy radiation from space. These observations may answer important questions about the Big Bang, including "Why did the Big Bang make so little antimatter"? and "What makes up the Universe's invisible mass?"

AMS is a major particle-physics experiment. Some types of particles - predicted by theorists, and searched for in collider experiments - may be present already in cosmic rays. AMS may observe them, thus learning about the particles themselves as well as their distant astrophysical sources.

AMS is a manifestly international, cooperative project. Like the Space Station itself, AMS is possible only due to the hard work and expertise of many people and many nations. The AMS collaboration involves over 200 people from 31 institutions and 15 countries, in addition to invaluable subcontractors and suppliers all over the world. Scientifically, AMS builds on the collective knowledge and experience of dozens of excellent cosmic-ray experiments - on balloons, on spacecraft, and on the ground - of the past thirty years.

Read on to learn more about AMS's detector, science goals, and launch! If you do not see the nav bar on the left, please click here. If your browser does not support frames, click here