After the flight of the prototype, Ting began the development of a full research system designated AMS-02. This development effort involved the work of 500 scientists from 56 institutions and 16 countries organized under United States Department of Energy (DOE) sponsorship.
The instrument which eventually resulted from a long evolutionary process is "the most sophisticated particle detector ever sent into space", rivaling very large detectors used at major particle accelerators, and it has cost four times as much as any of its ground-based counterparts. Its goals have also evolved and been refined over time. As built it is a more comprehensive detector, which has (among other goals) a better chance of discovering evidence of dark matter.
The power requirements for AMS-02 were thought to be too great for a practical independent spacecraft. So AMS-02 was designed to be installed as an external module on the International Space Station and use power from the ISS. The post-Space Shuttle Columbia plan was to deliver AMS-02 to the ISS by space shuttle in 2005 on station assembly mission UF4.1, but technical difficulties and shuttle scheduling issues added more delays.
AMS-02 successfully completed final integration and operational testing at CERN in Geneva, Switzerland which included exposure to powerful nuclear particle beams generated by the CERN particle accelerators. AMS-02 was then shipped to ESA's European Space Research and Technology Centre (ESTEC) facility in the Netherlands where it arrived 16 February 2010. Here it underwent thermal vacuum, electromagnetic compatibility and electromagnetic interference testing. AMS-02 was scheduled for delivery to the Kennedy Space Center in Florida, U.S.A. in late May 2010. This was however postponed to August 26, as AMS-02 underwent final alignment beam testing at CERN.
A cryogenic, superconducting magnet system was developed for the AMS-02. This was a critical technology, enabling a high sensitivity needed to achieve mission objectives. Late in its development, poorly understood anomalous heating in the cryogenic magnet system was discovered. The anomalous heating would place additional demand on the cryogenic cooling. This characteristic significantly reduced the original system design lifetime and contributed to a decision to abandon the cryogenic system in favor of a previously developed but less capable permanent magnet system.
With Obama administration plans to extend International Space Station operations beyond 2015, the decision has been made by AMS management to exchange the original AMS-02 superconducting magnet for the non-superconducting magnet previously flown on AMS-01. Although the non-superconducting magnet has a weaker field strength, its on-orbit operational time at ISS is expected to be 10 to 18 years versus only 3 years for the superconducting version. This additional data gathering time has been deemed more important than higher experiment sensitivity, despite the fact that the abandoned cryogenic system was originally described as critical technology to mission success. Whether the ISS will operate long enough for AMS to take full advantage of its extended lifetime is also unclear.
Read more about this topic: Alpha Magnetic Spectrometer, History