Later this evening, SpaceX is expected to launch its massive Falcon Heavy rocket on its third and most complicated mission from Kennedy Space Center in Florida. Previous Falcon Heavy launches each carried a single large payload—a Tesla roadster and an Arab telecommunication satellite—but this launch will carry two dozen satellites into Earth orbit. The entire mission will last over six hours due to the fact that the rocket’s upper stage must deliver its payloads to three different orbits. The four-hour launch window will open at 11:30 pm ET, and you can watch starting about 20 minutes before liftoff at the livestream below.
The satellites onboard the Falcon Heavy will be used to demonstrate new technologies and collect a wealth of scientific data. This includes testing an atomic clock for deep space navigation and a new ultrasafe green satellite fuel, studying radiation and space weather, and demonstrating WiFi communication between cubesats and GPS signals for weather forecasts. But arguably the star of the show is the Planetary Society’s LightSail 2, which will navigate its orbit using pressure from light particles hitting the sail.