Over the past weekend, a significant development took place at the Aachen RWTH I. Physikalisches Institute in Germany, as the permanent magnet was installed inside the “flight spare” vacuum chamber. This cylindrical Neodymium-Iron-Boron alloy, standing one meter tall with a one-meter diameter, boasts a magnetic field intensity 3000 times greater than Earth’s magnetic field. Having previously embarked on the STS91 mission in 1998, it carries the badge of a seasoned space veteran.

Weighing in at 1.9 tons, which increases to 2.9 tons once the vacuum chamber and interface structures are factored in, the permanent magnet is marginally lighter than its superconducting counterpart. However, both magnets have been meticulously designed to accommodate the same silicon tracker, ensuring identical interfaces between the magnet and other subsystems of the spectrometer. Encased within their vacuum chambers, they appear as indistinguishable twins.

Constructed by the NASA JSC team during integration activities in early 2009, the two vacuum chambers are identical in build. One currently houses the superconducting magnet and is installed in the AMS experiment, while the other now hosts the permanent magnet. Upon arrival at CERN, the latter will undergo preparations for a swap with its counterpart, scheduled for the first half of June.

In a matter of days, the permanent magnet will journey to CERN, where the AMS team has commenced the process of deintegrating various detector subsystems. The ensuing month will be dedicated to the exchange of the two identical vacuum chambers, after which the final detector integration will resume, targeting completion by mid-August. By September 1st, the experiment is slated to depart from Geneva to its ultimate destination: the Kennedy Space Center in Florida, USA.