These functions include triggering efficiency, the accuracy of intrinsic luminosity measurements, and the reconstructed pointing direction accuracy. GLS units will generate benchmark optical signatures in the atmosphere with similar characteristics to the optical signals of cosmic ray EASs. The lasers will generate tracks and the flashers will generate point flashes. But unlike air showers, the number, energy, precise time, direction (lasers) can be specified. The ""laser test beams" technique, builds on experience of the Mines group, and has used extensively at ground based cosmic ray observatories including the High Resolution Fly's Eye, the Telescope Array, and the Pierre Auger Observatory. JEM-EUSO will reconstruct the pointing directions of the lasers and the energy of the lasers and flash lamps to monitor the detector’s triggers, and accuracy of energy and direction reconstruction.
12 GLS units are planned for deployment at selected sites around the globe. The JEM-EUSO footprint will pass over a GLS unit on average once per (near) moonless night under clear conditions for appropriately selected sites. Evaluation of potential sites is in progress. The 12 units will be supplemented by campaign style measurements with an airborne unit that will be flown over the open ocean at selected altitudes under JEM-EUSO.
A GLS prototype in an airplane will support the EUSO-BALLOON pathfinder mission. A high-altitude balloon flight of a proto-type JEM-EUSO telescope was flown the night of August 24/25 2014 from Timmins Ontario.