The SLS is Outdated. Why Does it Exist?

I'd like to point out that when you make a solid rocket motor longer, you increase its power, not its burn time. burn time is a function of the diameter and geometry of the fuel. thrust is determined by length because it increases the internal surface area of the exposed propellant. yes, it has 25% more fuel, but due to its geometry, it gives more power than duration. In the case of SLS, the motors are lit from the top, and the fire burns down through a central hole. instead of being round, it's star shape I believe, because it has more surface area to burn. if you lit it from the bottom, you would only have the area of a 12' ish circle. by lighting it down the center, you can get infinitely more surface area (if you had a never-ending tube) Fun fact, the SLS boosters have a geometry where they actually "throttle down" and start producing less power as they burn (I'm assuming they either change internal geometry or fuel composition) but this is so that they don't keep pushing harder and harder as they get lighter, leading to extremely excessive maximum aerodynamic loads. they are way more complicated than an end-burning motor like in fireworks also, the reason they, along with so, so much else that is built in this country, are 12 feet wide, is because that is the largest thing you can move on the highways without needing special routing to clear bridges and such. the central core of SLS needs to be moved down the Mississippi river by barge, and around the tip of Florida because it just won't fit on our infrastructure. Edit, if you want to see what an SRB can look like inside, google "solid rocket propellant grain geometry" and you will see plenty of diagrams alongside thrust profile graphs

It makes me quite sad to see the shuttle engines being throw away. Yes, for a fantastic purpose, but sad to see them going away.

I remember being really excited about the Orion Program and the SLS during the Orion test flight in 2012 and completely forgot all about it for the next 10 years. A couple months ago I was like “wait they STILL haven’t launched yet???”

The reason the SRBs are not being recovered, is because this does not save much cost for SRBs, where the main cost is putting the fuel in in the correct manner. To recover them, you would need to clean the casing etc., which is basically just a steel tube where the only fancy part is the nozzle. If I recall correctly, recovering the SRBs was approximately as costly as making new ones for Shuttle, though I'm not sure on the exact numbers.

"Could the SLS money have been better spent elsewhere? Absolutely." "Would NASA have been given that money if it went elsewhere? Probably not."" That second part is what people miss when they say "SLS money could have funded X commercial launches."

I worked at Rocketdyne when it was still part of Rockwell, and several years after it was bought by Boeing. Then it was sold to Pratt and Whitney, and then sold again to Aerojet. All that should really tell you something. It was the worst companies I've ever worked for, with the lowest average skill level among the engineers, the lowest rate of innovation, and the most incompetent management I've ever seen. So how have they stayed in business so long? Lobbying, and a bunch of stupid stunts to please congress. I remember once, soon after someone in congress complained about the lack of innovation, they made me get up in front of a crowd to accept an award for some stupid invention I had never heard of until I read it off the plaque they gave me. I was completely blind sighted by this. And they gave out plaques to a lot of people that day. Then there was another time when they forced all employees to buy US savings bonds to appease some other member of congress.

The fact the SLS is ready to go and it’s checks notes one and only competitor is not ready to go definitionally demonstrates SLS is not out of date. SLS might not be the future, but is absolutely the present.

Its weird - from the stories I've heard about Apollo, it was this major event world wide. By the time of Apollo 11, you had tv series, stuff in newspapers etc...but for Artemis, the first I head of it was news that Artemis 1 was being launched in the local news. And its not like I'm some space pillock - I watched launch and landing of STS-135 live, I've followed SpaceX developing their landing tech, watched the end of Cassini and the landing of Curiosity...how did this program fly under the radar so much? I heard more about the JWST before it launched than Artemis. The other thing that shocks me is I remember the Orion program being cancelled, but, from you're saying, politics basically revived it, and we ended up with another lunar program...by accident??? (If this is correct, it's gotta be one of the most epic accidents ever...)

I was 10 years old when Armstrong walked on the moon. The real difference, compared to learning about it later, is that when it is live you do not know how it will turn out. Would the ascent stage of the Lunar Module engine fire properly? Would they be stuck on the moon and die there? It was not just an exciting time, but also very tense. During Apollo 13, we did not know if the astronauts would survive. But if you missed it, hopefully you will watch us go to Mars.

Loving the recent space related themes. Would love to see some infrastructure related in the future.

SLS exists because there is no other vehicle flying today that can do what it does. Once that changes, we can talk about whether SLS should exist.

Yes, the technology is outdated. But guess what? It's the only rocket capable of going to the moon and mars currently.

In high school, we went on a field trip to watch one of the shuttle's boosters being tested. (Sideways, strapped to the hill, probably the same hill as in this video). I don't remember the exact noise, but it was certainly an experience I'll never forget.

I'm surprised this video didn't mention the mobile launch tower fiasco. IIRC it was made by a ton of subcontractors that didn't really communicate with one another, cost a fortune, and won't fit the upcoming more powerful version of SLS so we won't even get much use of it.

it exists because its flying now when starship still hasn't. sometimes good enough tech is good enough. We'll get to use starship when its ready but it won't be soon.

that was the most emotional transition to an ad I have seen yet

There are several legitimate staring points for Artemis. The concept for a heavy lift vehicle based on Shuttle components dates back before the first Shuttle flight, the concept was being evolved in the 1980s and looked pretty similar to the various legacy programs, without any hardware being flown. In the 1980s such a vehicle would have made perfect sense. By the end of the 1990s software was developed to allow for fly back boosters to be a possibility. By 2000s the shuttle derived heavy lift vehicle concept was essentially redundant, old tech.

As one of the folks who lost his job when Constellation was cancelled and finally got it back 8 years later to work on SLS, I appreciate the delicacy with which you handled the subject. Yes, it's a jobs program, but it's also a fantastic rocket. I have to give Jim Bridenstine credit for the name Artemis and for focusing the SLS AND commercial partners on working toward a moon base and a deep space station in NRHO. I'm now working habitation design for both, which is the exciting future we have in store!

I’m so excited that Artemis has fully come to fruition (potentially speaking) as I’m completing my aerospace degree. The fact I could some day work on projects that are for direct purposes on the lunar surface is so exciting. I hope the next president doesn’t cancel Artemis because it is doing critical work that no private industry would do: setting up infrastructure to invite more companies to do business. That is what the public sector should be for. This is space being done right.

During the USA manned space flight days, Lockheed was blacklisted after the agena failure. Then came Hubble, what a mess. Lockheed has alway had some crippling flaws in their products. Now Orion sits on top, made by Lockheed who has never built a manned capsule, what could go wrong.