Warning: contains spoilers for Star Wars #35!Star Wars just officially revealed the first time Luke Skywalker used Force Projection – the technique he would later use to battle Kylo Ren and ensure the survival of the Resistance in Star Wars: The Last Jedi. Force Projection allows a Force-wielder to broadcast their image across the galaxy, appearing in incredibly distant places as if they were physically present. In the movies, Luke only demonstrated this ability late in his life, but it turns out he began using it far, far earlier.
Charles Soule, Madibek Musabekov, Rachelle Rosenberg, and Clayton Cowles' Star Wars #35 sees Luke on a quest to construct his green lightsaber. On Christophsis, he requests the aid of the amoral Dr. Cuata – one of the last remaining experts in Kyber crystals following Palpatine's purge of the academic field. Cuata agrees to help, but also asks Luke to undertake a series of experiments, using the Force to interact with various Kyber crystals. It's during this process that Luke first harnesses Force Projection – though he doesn't actually realize what he's achieved.