Artemis II, the historic test flight taking four astronauts on a flyby around the Moon, has liftoff after months of preparation.

NASA's Artemis II mission is shaping up to be more than just the next step in returning humans to the moon — it is a key test of whether the agency's traditional contractor-built systems can remain viable in a rapidly ​shifting space industry.

NASA’s Space Launch System rocket is the only vehicle in the current U.S. fleet designed to send astronauts beyond low Earth orbit, and that singular capability makes it the load-bearing element of the Artemis II mission.

The Space Launch System rocket is the only vehicle capable of delivering the Orion spacecraft, humans, and cargo to the Moon in a single launch.

NASA's Space Launch System rocket, with the Orion spacecraft atop, launched at 6:35 p.m. ET on Wednesday, kicking off the first mission to send astronauts to the Moon in over 50 years.

NASA’s Artemis II SLS rocket is on its Florida launch pad, and visitors can see it from several Titusville parks or at the Kennedy Space Center Visitor Complex before the mission around the moon.

NASA's Space Launch System rocket developed for the agency's Artemis lunar program is among the tallest in the world. Here's how it stack up.

NASA's Artemis II rocket has rolled out to the launch pad after repairs, preparing for a historic moon mission in April.

Double rainbow over NASA Artemis II, countdown clock before launch day or SLS rocket on the pad at Kennedy Space Center? Best Instagram moments.