Since the start of the Russian invasion four years ago, Musk has played an outsize role in determining the course of the war. His high-speed internet service, Starlink, uses portable satellite dishes to create a Wi-Fi connection anywhere in the world, and it has allowed both the Russian and Ukrainian militaries to stay online in the war zone, coordinate troop movements, and navigate drones. No other system can match the reach and reliability of Starlink, which runs on the world’s largest constellation of satellites. Musk has occasionally used that system in ways that have helped one side of the war or the other.