The SLS is Outdated. Why Does it Exist?

Links to everything I do:

Credits:
Writer/Narrator: Brian McManus
Editor: Dylan Hennessy
Animator: Mike Ridolfi
Animator: Eli Prenten
Sound: Graham Haerther
Thumbnail: Simon Buckmaster

References:

[1]
SLS Reference Guide 2022 - NASA

Select imagery/video supplied by Getty Images
Thank you to AP Archive for access to their archival footage.

Thank you to my patreon supporters: Adam Flohr, Henning Basma, Hank Green, William Leu, Tristan Edwards, Ian Dundore, John & Becki Johnston. Nevin Spoljaric, Jason Clark, Thomas Barth, Johnny MacDonald, Stephen Foland, Alfred Holzheu, Abdulrahman Abdulaziz Binghaith, Brent Higgins, Dexter Appleberry, Alex Pavek, Marko Hirsch, Mikkel Johansen, Hibiyi Mori. Viktor Józsa, Ron Hochsprung

[seldoon_nemar]

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

[onthewater]

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.

[steverobbins]

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.

[mluby]

"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."

[SteveandLizDonaldson]

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.

[Hydrargyrum]

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

[limiv]

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.

[davidgifford]

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.

[labboc]

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.

[jonathanstensberg]

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.

[cubefox]

Here is an interesting comment on the history of SLS, explaining that it wasn't just politics that lead to SLS. It was posted as a comment to the piece "The SLS rocket is the worst thing to happen to NASA—but maybe also the best?" which was written by Eric Berger for Ars Technica. Here it goes:

Good article. I think Eric somewhat oversells the angle that Congress and the defense contractors imposed SLS/Orion on NASA. This was very much a two-way street, and although Boeing doesn't deserve any sympathy from anybody, at least one of the other defense contractors had the right idea.

It's really important to the history of Ares/SLS to note that the Crew Exploration Vehicle (CEV) program came before any of that. Sean O'Keefe was NASA Administrator, and he called for a fly-off competition in which multiple providers would fly an LEO demonstration mission before selecting a single winner. This precluded the use of launch vehicles that didn't exist.

Lockheed Martin's CEV proposal was far more innovative than the Northrop/Boeing proposal. They called for a reusable lifting body reentry vehicle with a captive abort system that could be launched on Atlas V. This was their LEO solution. For exploration missions, a pressurized mission module and a long-duration cryogenic propulsion stage (ACES) would be launched on two Atlas V or Delta IV rockets before the crew launch, and the three modules would dock in LEO prior to departure.

Wonderful! That's exactly what we should have done! How did it go wrong? Well, Michael Griffin was appointed NASA Administrator, and he thought the fly-off competition was silly. He also didn't like either of proposals because they were different from what he proposed in a whitepaper he authored a year before his appointment. So he canceled the fly-off, declared Lockheed the winner, and issued a gigantic change request transforming their proposal into the Apollo On Steroids we know as Orion.

Michael Griffin was the originator of the "1.5-launch architecture" in which a super-heavy Shuttle-derived rocket (Ares V) launches the lunar lander and a medium Shuttle-derived rocket (Ares I) launches the crew vehicle. Griffin argued that ULA's rockets suffered from a lack of commercial demand which would make them more expensive than if NASA developed their own rockets -- if you can believe that. This became NASA's official position as part of the Exploration Systems Architecture Study (ESAS) he commissioned. And the ESAS report made it easy to cultivate the support of Richard Shelby, Bill Nelson, Kay Bailey Hutchison, and others in Congress.

ULA was advocating for distributed launch of commercial vehicles and even using the verboten D-word through 2009, when they published this gem that is still proudly hosted on their website:


This was around the time that Richard Shelby flipped out and said he'd pull the funding if ULA or its parents kept talking about propellant depots. NASA sold Congress on the expensive approach, and when big bad industry suggested there's a better way, Congress told them to shut their filthy mouths. Not long after, SLS was enshrined as the spiritual successor to Ares V, and at that point Boeing really started to dig in their heels to protect their cash cow from potential competition.

We could have had Lockheed's modular CEV, and we could have had a depot-based distributed launch architecture from ULA. The "dinosaur" industrial base was not opposed to delivering those solutions. There was a period in time when the big defense contractors were reading the tea leaves, and they were basically told to get their eyes checked and fall in line. So they did.

Still doesn't excuse Boeing's poor performance. Nothing does.

[SirDummyThicc]

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???”

[stevk]

The other thing to remember is that many of these parts were already "human rated" whereas ships such as Starship is not and won't be for a while still.

[RedWolf]

I think you’re missing some very very key aspects regarding the Constellation and Artemis programs, like the fact that even though Artemis (rather sls) has gone 2x over budget at roughly $23B it’s still 10x less than constellation... who’s budget was $230B. On top of that there’s still some political aspects that ‘helped’ shut down constellation and actually helped Artemis.

[ptrkmr]

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.

[anthonycorso]

Completely agree with your take. I made a similar argument yesterday while discussing SLS/Artemis with a coworker. I'm obviously extremely excited to see the return of super heavy launch vehicles and moon missions, but it is very disappointing as full expendability seems like such a step backwards technologically.

[TheRealMikeSheahan]

One of my earliest memories is watching the Apollo 11 crew step onto the moon. I was 2 years old, and the image of my family sitting around the dinner table, and watching that event on our black and white TV, is stuck in my head forever.

[dtgs]

Don't get sentimental about the shuttle. That was a disaster in itself that should be left behind. The Saturn V is objectively better if there were no commercial options.

[ambiguate]

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.

[EnergiaRocket]

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.