Italian astronaut Luca Parmitano, the current commander of the International Space Station (ISS), was leading one of the most challenging spacewalks ever on Friday. The spacewalk is the first of a series of at least four needed to service the cosmic-particle-hunting Alpha Magnetic Spectrometer (AMS-02).

It is considered be toughest spacewalk series since work to repair the Hubble Space Telescope. Parmitano and his spacewalking partner, NASA astronaut Andrew Morgan, went outside the ISS at around 13:00 Italian time. They have to get to a hard-to-reach area on top of the Station's S3 Truss structure between a pair of solar arrays and radiators.