 The Space Launch System Dress Rehearsals are complete. The next time we see it at the pad, it should be gearing up for its maiden flight. Years in the making. Here is the story of Artemis I, the first launch of NASA's next-generation rocket. The final space shuttle launched on July 8th, 2011. It was the last flight of a 30-year space program. Watching the shuttle era come to an end was a bittersweet moment for me. I was born in 1978 and shuttle was all I ever knew. It's what I grew up with. When I heard NASA was retiring the space shuttle, I thought it odd that such an iconic and beautiful vehicle would no longer be flying. I'd never known a time when space shuttle wasn't flying. Iconic as it was, the space shuttle was not without its shortcomings. Between the side-mounted design of the orbiter, the inability to separate human crew from payload, and a myriad of other issues, shuttle was starting to show its age. Thirty years on, it was time for something new. So NASA selected the most famous, prestigious, and quite frankly best orbital for that final mission, OV-104 Atlantis. I look forward to your comments. NASA realized a new program would be needed to replace shuttle, and so the constellation program was born as a plan to complete the International Space Station and return humans to the moon by 2020. Constellation addressed many of the issues shuttle had. Human crew was no longer required to fly with the payload. They could go up on separate rockets. NASA returned to a top-mounted design, removing the possibility of foam or liberated materials striking a side-mounted spacecraft. The system would consist of two rockets, the Ares-1, which would be for humans, and the Ares-5, which was a super-heavy lift rocket to bring up vast amounts of cargo. And we even got a demo flight. Kinda. On October 28, 2009, the Ares-1X launched. This was a demonstration of what the new five-segment solid rocket vehicle would be capable of. The only thing is, instead of that new five-segment solid motor for the first stage, they used the old shuttle four-segment one. And the upper stage, that was just a mass simulator and it didn't really work. The Ares-1X, they weren't complete, so they just used the system from the Atlas V. For all of those flight test compromises, this experiment did show that their vibe models were correct, which back in the day was a big concern. Turns out humans could indeed launch atop a giant solid rocket motor and not turn to soup. Now I'll let you debate in the comments whether you would want to fly atop a giant solid rocket motor. That, by the way, once lit cannot be easily shut down at all. While NASA was working on the Ares-1X demo flight, constellation as a whole was on thin ice. Many of us spectators thought that the demo flight was really just a last-ditch effort to save the program. Something to show the public they were making progress. But then on April 16, 2010, President Obama dropped this bomb show. By buying the services of space transportation rather than the vehicles themselves, we can continue to ensure rigorous safety standards are met, but we will also accelerate the pace of innovations as companies from young startups to established leaders compete to design and build and launch new means of carrying people and materials out of our atmosphere. At this point, constellation is very over budget and very behind schedule. Its mission of sending humanity to the moon, Mars and beyond looks to have failed. It isn't making much sense to the U.S. leadership anymore. But it's bad politics to eliminate jobs and NASA is something that most U.S. citizens take great pride in. So risking the whole U.S. based program on an as of yet unproven private enterprise approach is, well, kind of unwise. It's late 2010 now and constellation is officially canceled. But we still want something to replace space shuttle, which is about to retire. NASA needed a new mission. Now many studies were performed to determine the best path forward as you can see from this absolutely potato quality image. And the design winner of that was what we call today the space launch system. The key lesson of constellation was that space launch system would need to be done faster than anything before, done better than anything before, and done cheaper than anything before. To make all of those things happen, the system would be derived of old shuttle parts. The Aries 5 diameter had been 10 meters, whereas SLS would be 8.4, same as the shuttle. Aries 5 had five brand new RS68B engines, which had never been flown before. SLS on the other hand had four RS25D engines, the exact same ones used on the space shuttle. The solid motors on the side would be carried over from shuttle as well, although moving from four segments to five since a lot of that work was already well underway and tested under constellation. Space launch system was indeed shaping up to be faster, better, and cheaper than any plan that came before it. And best of all, the architecture was designed to evolve over time. Well, on paper at least. Here's how the timelines actually played out. To start, President Obama signed the NASA Authorization Act of 2010 into law, and with that, the space launch system was officially born. Now, NASA had to take the idea of SLS and get to work. A year later, Senator Bill Nelson revealed the initial design of space launch system to the world. It would fly by 2017 with a projected development cost of $18 billion. After years of refinement, the final design for SLS was approved in the fall of 2014, and it was greenlit to begin construction. At this point, the first launch of SLS was already beginning to slip towards late 2018. That December, however, saw the first launch of Orion, SLS's new crew capsule, atop a Delta IV heavy on an uncrewed mission to test its heat shield. After Orion, NASA and its contractors had set to work building the equipment needed for a space launch system, and work proceeded quickly, if not a bit silently, for several years with very little fanfare. That is, until the spring of 2017, when a tornado tore through the Mishu assembly facility in New Orleans. Facilities were pretty seriously damaged, which could mean only one thing. Delays. By the summer, it had been announced that the first flight would slip to 2019 at the earliest. As you know, 2019 came and went without a launch, but the program got a boost when it was announced that space launch system would become the backbone of the new Artemis program, America's sustainable return to the moon. To back this up, Administrator Jim Bridenstine authorized the purchase and production of up to 10 more SLS rockets, proving NASA was committed and in it for the long haul. With this new found vision and support, by 2021, NASA started to get SLS back on track. With the course segment now built and moved into Stennis Space Center, after a few tries, they were able to do a full 8-minute, 20-second static fire of the stage, proving it was nearly ready to fly. And from there, things began to move faster. By April of 2021, the course stage had completed its testing in Stennis and had been moved to the Kennedy Space Center in Florida for integration with the rest of the rocket. By October, the whole vehicle had been stacked in the vehicle assembly building and it was glorious, not since Apollo had a rocket that tall stood in that building. A few minor delays later, in April of this year, SLS rolled out to the pad for its wet dress rehearsal. This is where they fully fueled the vehicle in its flight configuration. The wet dress encountered a few expected issues, as this was the first time the rocket had been fully attached to all of the ground support equipment in an actual flight config. But by June, the vehicle had passed enough tests to be considered ready for flight. And now, here we are, July 12, 2022. And what's left to get Space Launch System from where it's at right now to actually flying to space? Well, first, NASA will need to correct the issues they uncovered during wet dress, specifically some ground support issues, valves, and leaks. Once NASA is happy with the vehicle and ground support equipment, they'll need to officially arm the flight termination system on the vehicle itself. From there, the final step should be to roll the rocket back to the pad from the vehicle assembly building, and, well, launch! After all of this time, SLS is nearing its maiden flight. The current launch window opens August 23rd and extends through September 6th. But this is a brand new rocket, and so some final delays are not just possible, but very likely. Twelve years in the making, through three different presidential administrations, a tornado, a pandemic, budget overruns, massive delays, SLS has seen a lot. But this is where the story of one of the most powerful rockets humanity has ever built will finally, truly, start to get interesting.