While it may look like a futuristic tunnel to another world, it's actually the inside of the nearly complete fuel tank for NASA's Space Launch System (SLS) rocket, which will allow humans to explore deep space.

At over 300 feet tall and 5.75 million pounds at liftoff, the SLS needs plenty of fuel to leave Earth. Once a final dome is added to the liquid hydrogen rocket fuel tank, it will come in at 27.5 feet in diameter and over 130 feet long, making it the largest major part of the SLS core stage.

The core stage forms the rocket's backbone and has five major parts, all of which are being manufactured at NASA's Michoud Assembly Facility in New Orleans. Core stage tanks carry all the cryogenic liquid hydrogen and liquid oxygen combusted in four RS-25 engines to produce 2 million pounds of thrust.

The tank holds 537,000 gallons of chilled liquid hydrogen that is completely combusted in the engines in the short 8.5 minutes it takes to send the SLS and Orion crew vehicle into orbit.

When it is finished, a barge will carry the tank to NASA's Marshall Space Flight Center in Huntsville, AL. While the qualification tank won't actually fly, it will be tested at Marshall in a stand that simulates launch and ascent forces. Traveling to deep space requires a large vehicle that can carry huge payloads, and SLS will have the power and payload capacity needed to carry crew and cargo needed for exploration missions to deep space, including Mars.