A team prepares a robot – the yellow machine attached to the liquid hydrogen tank for the Space Launch System rocket -- for friction plug welding at NASA's Michoud Assembly Facility in New Orleans. Friction plug welding is a technique developed by engineers at NASA's Marshall Space Flight Center in Huntsville, Alabama. It uses a robot to fill holes left after the tank goes through assembly in a larger robotic welder. The liquid hydrogen tank is more than 130 feet long and is the largest part of the rocket's core stage -- the backbone of the rocket. The liquid hydrogen tank, along with a liquid oxygen tank, will provide 733,000 gallons of fuel for the first integrated mission of SLS with NASA's Orion spacecraft in 2018. SLS will be the world's most powerful rocket and take astronauts in Orion to deep space, including on the Journey to Mars. Image Credit: NASA/Michoud/Steve Seipel
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