SpaceX's Falcon Heavy rocket just launched for the third time, lofting 24 payloads for the Air Force, NASA, NOAA and a variety of universities to orbit as part of a rocket ride share.

Why it matters: Ahead of the launch from Cape Canaveral, Florida, SpaceX founder Elon Musk said in a tweet that this Falcon Heavy launch would be the "most difficult launch ever." If those stakes weren't high enough, this also marked the first time the Air Force has flown its wares to space aboard a Falcon Heavy.

The Falcon Heavy’s 2 side boosters — which have both been flown on a previous Falcon Heavy launch — landed back on land, while the core booster just missed a waiting drone ship off the Florida coast in the Atlantic Ocean.

Details: The two-dozen spacecraft loaded into the Falcon Heavy were designed for a number of technology demonstrations and experiments. Some of the more notable spacecraft include:

The Planetary Society's LightSail 2, which will be unfurled in July and, if all goes according to plan, should use its light sail to maneuver through space on the force of the Sun's photons.

COSMIC-2, a clutch of six spacecraft that, once up and running, are expected to improve weather prediction computer models on short time scales, making hurricane and extreme weather prediction more accurate.

NASA's Deep Space Atomic Clock, a technology demonstration which is designed to prove out tech that could one day be used to help astronauts navigate on Mars.

DSX, operated the Air Force, is designed to gather data about the space environment in its orbit, helping researchers figure out how to best protect future spacecraft from space weather.

Background: This was a big launch for SpaceX not only because of the payloads flying to space, but due to the implications of the flight on Earth.