The Launcher of Optical Modules – or LOM for short – is a KM3NeT customized system that works fully mechanically. The 700 m long detection unit consists of 18 pressure resistant glass spheres with the photosensors inside supported by two parallel ropes firmly connected to the anchor at the seabed and held vertical with a synthetic buoy at the top. At regular distances synthetic horizontal spacers keep the two ropes parallel. An electro-optical cable runs the full length of the unit from the optical module at the top to the base module at the anchor changing from the one rope to the other at the occasion of a spacer. The full system is coiled around a spherical aluminium frame. The ropes and the cable run in the cable trays on the frame. With empty glass spheres integrated, the frame is made buoyant with empty glass spheres integrated in the frame of the launcher. The optical modules are stowed inside the frame. The frame is kept firmly in position at the anchor of the detection unit with thick ropes running through the frame from the top to the anchor. At the top the thick ropes are connected to a crown of empty glass spheres. After touch down at the seabed and connection of the detection unit to the seabed infrastructure, the crown is released followed by a release of the launching vehicle that will float to the sea surface while uncoiling the detection unit to its full length.


(Video impression of the test and use of the LOM in our YouTube playlist ‘KM3NeT sea operations‘.)