NASA's mammoth Pegasus barge arrived Friday with the longest item it's ever shipped. It paves the way for NASA's Artemis 1 moon mission.
On board the Space Launch System rocket's 212-foot tall, 228,000 pound core stage pathfinder is a large steel mock-up that houses the cryogenic liquid hydrogen and liquid oxygen tanks that will feed four large rocket engines.
The core also contains the rocket's avionics and flight computer.