On Friday 15 November, European Space Agency (ESA) astronaut Luca Parmitano and NASA astronaut Andrew Morgan will begin the first of a series of complex spacewalks to service the Alpha Magnetic Spectrometer (AMS-02). The spacewalk will be streamed live via ESA Web TV from 12.50 p.m. CET and will include commentaries from CERN and ESA.
This series of spacewalks is expected to be the most challenging since those to repair the Hubble Space Telescope. AMS was originally intended to run for three years, after its installation on the International Space Station in 2011, and was not designed to be maintained in orbit. However, the success of its results to date have meant that its mission has been extended.
AMS-02 is a particle-physics detector that uses the unique environment of space to study the universe and its origin. It searches for antimatter and dark matter while precisely measuring cosmic-ray particles – more than 140 billion particles to date. The detector, which measures 60 cubic metres and weighs 7.5 tonnes, was assembled by an international team at CERN, and researchers, astronauts and operations teams have had to develop new procedures and more than 20 custom tools to extend the instrument’s life.
A key task for the astronauts is to replace the AMS-02 cooling system and to fix a coolant leak, and the pair have trained extensively for this intricate operation on the ground. It will involve cutting and splicing eight cooling tubes, connecting them to the new system and reconnecting a myriad of power and data cables. It is the first time that astronauts will cut and reconnect cooling lines in orbit.
The first AMS spacewalk on Friday is expected to last about six hours and sets the scene for at least three more. It will be streamed live on ESA Web TV and the first two hours will feature commentary from scientists at the AMS Payload Operations Control Centre (POCC) at CERN as well as astronaut and operation experts at ESA’s astronaut centre in Germany.
CERN’s contributions will include a tour of the POCC by AMS Experiment and Operations Coordinator Mike Capell, from Massachusetts Institute of Technology (MIT). Here, AMS physicists take 24-hour shifts to operate and control the various components of AMS from the ground. Zhan Zhang, also from MIT, is the lead engineer of the Upgraded Tracker Thermal System, which is being installed during the spacewalks. She will show the laboratory at CERN where an identical spare of the system is kept in space conditions and will explain how the system works and what the astronauts will have to do to install it on the AMS detector in space. AMS scientists Mercedes Paniccia from the University of Geneva, Alberto Oliva from INFN Bologna and Andrei Kounine, from MIT, will explain the science of AMS as the spacewalk takes place and can answer your questions.