Credits: NASA/RASA The Alpha Magnetic Spectrometer (AMS) is a high-energy particle detector. AMS will detect electrons, positrons, protons, antiprotons, and nuclei in cosmic radiation. AMS is a cooperative project that involved more than 200 scientists from 31 institutions and 15 countries. The data gathered by AMS during its three-year mission will help scientists answer important questions about antimatter and invisible mass in the Universe. AMS could detect many types of particles predicted by theorists and determine their astrophysical sources.

AMS could reveal to scientists unusual astrophysical objects like antimatter galaxies, dark matter, strangelets, microquasars, and primordial black holes. AMS actually refers to two particle experiments: AMS-01 and AMS-02. AMS-01 flew in low Earth orbit (LEO) with Space Shuttle Discovery STS-91 in June 1998. AMS-01 was an AMS prototype (a simplified version of the spectrometer) and was used to test particle physics technology in LEO. AMS-02 is the Alpha Magnetic Spectrometer designed to be mounted and operated on the ISS.

Credits: NASA AMS-02 is a cube-shaped structure with a mass of 6,731 kg. The spectrometer consists of a huge superconducting magnet and six specialized detectors, and requires 2,000 watts of power. The experiment has a 10Gb/sec internal data pipeline and will have a dedicated 2MB/sec connection to ground stations. AMS-02 will gather approximately 200 TB of scientific data during its mission. Four 750 MHz PowerPC computers running Linux will provide the computing power. The spectrometer also contains two star tracker cameras, which detect the orientation in space, and a thermal control system that will control the temperature of the whole experiment. The thermal control system is quite complex. Heat is collected from the detectors and the magnet, and then pushed through conductors to the radiators mounted on the outside of the AMS and radiated into space.

AMS-02 has a little bit of history associated with it … due to the Space Shuttle accidents, which reduced the number of orbiters available, and the decision to retire the Space Shuttle fleet, AMS-02 faced cancellation (a long list of elements meant to be part of the ISS were cancelled for the same reasons). Because an additional shuttle flight was added to the launch manifest, most likely AMS-02 will make it to the space station. The plan for AMS-02 is that it will be attached to the zenith side of the S3 section of the Integrated Truss Structure on the ISS. A Payload Attachment System will be used to keep the spectrometer in place on the truss segment.

Credits: NASA According to the missions schedule, AMS-02 will be installed on ISS as part of the Space Shuttle Discovery STS-134 mission, together with the last ExPRESS Logistics Carrier (ELC-4), in late 2010. STS-134 will be the last Space Shuttle flight before the deadline set to end Space Shuttle operations on September 30, 2010.