NASA's Mega Rocket

NASA's SLS is the most powerful rocket ever built, capable of sending astronauts to Mars and beyond. The first un-crewed mission around the Moon, in March 2022, will be a giant leap forward for human deep-space exploration, if all goes to plan. Construction has been beset with difficulties, delays and cost over-runs. Featuring interviews with the trailblazers behind the project, archive and nail-biting on-location sequences, it's a unique record of space history in the making.