The Real Reason NASA Developed The RS-25 Engine!

[@emmyfreudenrich4646]

One note at 8:30 is oxygen rich preburners do *not* cause extreme heat. They are actually significantly cooler than stoichiometric combustion in the preburner. The real danger is that gaseous pure oxygen at these temperatures will chemically react to the engine, not thermally. This is one reason the Soviet NK-9 engines that were supposed to be used on the lunar N1 were so amazing, they used oxygen rich preburners.

[@techwizard8214]

how did the soviet overcome the problem??

[@javant6993]

@@techwizard8214 they probably electroplated the preburners, oxygen injectors and plumbing in between the preburners and injectors with something like ruthenium or platinum or another platinum group metal. That would probably be the simplest (also really expensive) solution, because good luck getting PGMs to react with anything (except bleach). Or they used a super special unreactive alloy

[@volderhamer]

@@techwizard8214 They didn't, the N1 failed four times, most likely because of its engines

[@saturazzi]

The Soviet/Russian Energomash RD-170/RD-180/RD-190 family of rocket engines burns oxygen rich. These engines have been used in several rockets, both Soviet (Energia), Russian/Ukrainian (Zenit 2, Zenit 3SL), and American (Atlas 3, Atlas 5, Antares 200). Energomash developed new alloys to handle the hot oxygen gas problem, something that was considered impossible by U.S rocket engineers.

[@dandeprop]

@@techwizard8214 The LOX-rich situation in the NK-33 (actually the NK-15 in the N1 first stage) was dealt with in 2 ways: 1st, the preburner gas temperature was kept quite low, like only about 700 deg F. A household oven gets almost that hot. Second, thermal coatings (primarily Zirconium Oxide) were used in several places. Since then, some new materials (and coatings) have been developed to allow a turbine gas temperature increase.

[@Yaivenov]

F-1 didnt dump the preburner exhaust, it was trunked into the skirt and served for film cooling and insulating the wall as well as adding back a little bit of thrust and efficiency.

[@ednitsche8188]

An engine designed to be serviceable half a century ago, to be used now in an expendable way, does not sound like progress.

[@davebooth5608]

Fun fact, the movie, “Superman 2”, they have a scene on the moon with the 3 villains and the code name for the astronauts was “Artemis!” Just thought I’d throw that out there. Great movie too!

[@AppleLauda_destroyer99942]

movie predicted the spacecraft

[@JustMe-dc6ks]

Artemis is the Greek goddess of the moon and twin sister of Apollo. It’s not exactly a wild guess.

[@genius1a]

Thank you for finally answering the question I already had back in 1988: Why build such an sophisticated shuttle with amazing reusable rocket engines and then strap it to a basic looking expendeable tank with two solid fuel burning fireworks rockets. It looked more like a proof of concept prototype than a finished rapid reusable Space Transport System. I'd assume, If they had been funded to add better and reusable adjacent components in the first decade and added a remote controlled pure cargo Version, the Space Shuttle STS would still fly today and the upgraded system would have saved Billions in comparison through the centuries. What a waste of Innovative and motivated personell.

[@malachy7986]

the whole sts program was basically a prototype forced to fly. After sts 4 the development and test flights ended and that meant no real design overhauls could be made to the program since the budget for the development got cut.

[@T.E.S.S.]

I mean yeah, it was literally a prototype

[@vinny142]

" If they had been funded to add better and reusable adjacent components in the first decade and added a remote controlled pure cargo Version, the Space Shuttle STS would still fly today " ...and do what exactly? That's the crux of the whole re-use nonsense: there is nothing to do up there that justifies the cost of making stuff re-usable. yes, making stuff re-usable is much more expensive and you have to make that money back by using the system a *lot*. SpaceShuttle was re-usable because they wanted to take an entire science lab into space and back down, or take a satellite up there and take another back down. Today there is no use for a spaceshuttle, we simply have no usecase for such a heavy lift system. Can you name a single actual existing payload for Starship that is not a SpaceX project? No, and neither can they. There seems to be this bizar notion that there is a huge space industry that is just sitting there waiting for launches to become cheaper. This is nonsense. Launching is not the expensive part. Building the satellite is the expensive bit, that thing needs to survive the launch and operate without problems for ten years. THAT costs hundreds and hundreds of millions. Even if the launch is 200mln that is still peanuts compared to what the satellite costs. Want proof: sure: falcon-9 can lift 4mT for $90mln. That's right in the ballpark of what commercial satellites weigh, and the cost is peanuts, yet Falcon-9 mostly does nothing at akll because *the market is too small*. So what if SpaceX can reduce the cost of a launch by 25% through re-use? That's great, but it saves only 50mln at an increased risk that the mission will fail. 50mln is not nothing but again: compared to the budget for the satellite and the added risk it's allmost irrelevant.

[@genius1a]

@@vinny142 You have a strong opinion and I respect that. As a Science Fiction Fan starting back in my youth, I would love to see humans spreading among our solar system. Why? Most things we do in life are pointless. Why do we watch films and videos? Because it earns us more money than going out for a walk? Why are there people buying an expensive sailing yacht to cross the oceans? For fun and social life. Do you think back in the day, when they sent up the first rockets, they thought of GPS and Iridum satellites that would earn money to cover the rocket costs after the first few test launches? No - the idea was not even born yet. Today 60 of the 280 Falcon 9 launches were paid by private companies - most of them for GPS satellites. If Starship succeeds (and so far it looks pretty good) , it will be able to send up 150 tons per flight into Earth Orbit. Send up 10 of them and you can build a massive station capable of a first zero gravity production. Another 10 and you can build a moon rocket capable of transporting a permanent space station into moon orbit. Another 10 and you can transport fuel and a reusable moon lander, capable of multiple landings and departures. "30 heavy lift rockets?" you might ask. In the last years Space X has launched more than 50 Falcon 9 rockets per year - and if Starship works as planned, that number could soon be the same, without reaching a theoretical limit. Of course not in 2024. But I see a good possibility of reaching huge production numbers till 2026 and 100 launches per year in 2028. Call me lunatic, that's what I think has a big chance to be realized.

[@JonathanMensah-h3n]

I noted the RS25 is an engine meant for Shuttle but problematic so SSME 650kN was developed in its place. The tech that was used on Apollo J2X is what you find too in RS25, and RS68 superb engines. AS-V1X needs the "beast", AF-1X that could spue 30mn ea unit. Circular aeropike holds promise for RLV vehicles.

[@rktmn1]

@1130: 16 SSME (@ four per flight) is 4 missions...not 8. NASA is burning thru 16 of the Solid boosters, at 2 per flight, and that will go thru Flight 8.

[@Astronetics]

Just came across your channel and glad I did. This video was really well done. Good work!

[@Checkpoint274]

Hi to everyone:)

[@jenniferjuniper12]

Great video explainer! Thanks 😊

[@nnefer8774]

Why is no one talking about the fact that if space X and Sierra space would work together, then they would have turned out with completely reusable crew dragon version, using falcon 9 or falcon heavy (if you need transport to moon station 💀) and dream chaser (current crew dragon got 2 stage and some parts non-reusable and much less cargo capacity)

[@genius1a]

I think Elon Musk wants to achieve rapid reusability as soon as possible - of the likes we use commercial airplanes today. Falcon 9 needs extensive engine overhaul after each flight. They can do it fast, but he wants more. I think he would rather favor a Falcon 9 sized transport system with 4 Raptor engines for such a collaboration. But its obvoius the massive Starship System has top development priority until it works and is designed to be a person, fuel or cargo transporter to LEO as well.

[@vinny142]

"Why is no one talking about the fact that if space X and Sierra space would work together, then they would have turned out with completely reusable crew dragon version" Because as this video mentions also: re-usability is not the huge advantage that people think it is. First, there will never be a rocket engine that requires no checks at all between flights. Things like the turbopumps, fuel injectors, seals etc *must* be checked between flights because if they have even the smallest imperfection the entire rocket blows up, taking your payload with it. Second, as it stands SpaceX can save a max of 20% on re-used parts and it is highly questionable if those numbers are even real. Musk lies all the time, full stop. So do you want to risk your very expensive payload on a re-used system if it only shaves 20% off the launch costs? The rest of your operation remains hellishly expensive, do you reall want to introduce a risk for a 20% saving on the cheapest part of the whole thing?

[@svendrastrupandersen5866]

Nice and reliable, non biased info. I like it!

[@luiul1]

there are about five seconds between the 49 second and 50 second mark, yes, that is what i said, that i could watch on a loop for about an hour. SRB & rs-25 have come to full thrust and the shuttle is being held down, then begins to rock to and fro, all the while as if screaming, "LET ME GO"!!!!!

[@cricket5044]

Not sure the RS-25 will find that long life of use you are talking about. Raptor and other newer engines (BE4?) are so much cheaper to make and use. Just being under government contract for its lifeblood of cash/sales has the RS-25 on shaky ground to live long or prosper.

[@คมไผ่แข็งแรง]

Very cool big power

[@StandingUpForBetter]

Awesome!

[@Secssl128g]

RS-25 vs Raptor 2? - that would be a fun comparison.....

[@w9gb]

SpaceX has now moved on, Raptor 3.

[@jamescobban857]

The RS-25 is bigger and heavier than the Raptor 2 but has very similar thrust. Each RS-25 costs $250M and only two can be built in a year. Raptor 2 costs $250K. Yes. SpaceX can build ONE THOUSAND Raptor 2s for the same cost as ONE RS-25. And SpaceX can build 350 Raptors a year from one assembly line. When demand picks up SpaceX can just start another assembly line. The thrust of RS-25 is primarily limited by limits to pumping the extremely light liquid hydrogen. The low thrust of the RS-25 is why massive solid rocket boosters are needed on both Shuttle and SLS just to get it off the ground. The alternative would be mounting at least 25 RS-25s and a fuel tank that is four times the volume. While the Raptor has about the same thrust its fuel pump does need to pump as much volume of liquid methane, which is four times as dense. I therefore suspect that once Starship is operational Spacex will invest in a new engine based on Raptor but with about three times the thrust, about the same as the F1, which will permit replacing the 33 engines of the current booster with 12 engines whose total mass will be less than half the mass of the current Raptors. The RS-25 is an amazing engine, a triumph of engineering. However its objectives are flawed, based upon the dream of building a single stage to orbit SSTO spacecraft. "If something is *not* worth doing, it is *not* worth doing well."

[@Breezely]

@@jamescobban857 I'm not sure, but I suspect that $250K for a Raptor is an Elonian projection, not a current reality. But I bet they will still be a LOT cheaper than RS-25. Hey! I just did a Google search and I think I might have coined a useful new term: "Elonian projection". 🙂

[@jamescobban857]

@@Breezely So you believe your gut impression over the informed opinion of a professional mechanical engineer with enormous experience in reducing the manufacturing cost of dozens of products? In particular unlike you and me Musk knows EXACTLY how a Raptor is built: the cost of every component, the operating costs of the robot assembly equipment, the salaries of the human supervisors, the leasing cost of the factory, and how much tax the factory spends. Musk does make mistakes. He was absolutely convinced that the first Raptor 3 would blow up on the test stand. Instead it ran the full duration of the test, simulating a booster running to MECO, and the telemetry indicated it was much more stable than the first Raptor 2 full duration test.

[@glenkeating7333]

@@jamescobban857 . I read somewhere recently that they are building the RS25 engined for 40 million each. Not sure if that's true or not. I also read that each Raptor 3 engine will cost 1 million dollars. Whatever the truth is, the Raptor engine is a helluva lot cheaper. I like your comment.

[@KyleandPrieteni]

The reason why they lost interest is that the war was on their mind, today we have the internet and more and more people are against war. That's why we lost interest back then.

[@glenkeating7333]

Fun fact. Jeff Bezos had an expedition go out on the Atlantic Ocean and recovered some of the F1 engines from one of the Saturn rockets that dropped into the ocean.

[@Blue_Monkey]

2 big critiques about this video: 1. Use metrics! The whole science is in metrics, including all the terms etc. 2. Another important reason for the RS-25 is politics. The companies wanted to keep their sweet (overpriced) contracts and lobbied to use the same companies and as many parts as they could. It is one of the reasons why the SLS is so insanely expensive regarding costs per launch.

[@jamskinner]

Not everyone uses metric.

[@la1m1e]

Scientists do ​@@jamskinner

[@Yaivenov]

What would an RS-25 converted to methalox look performance wise?

[@Breezely]

Probably pretty poor, since it was designed from top to bottom to work with hydrogen. My wife's ailing old Camry would put out more power than a non-functioning rocket engine.

[@jurdharbinger]

The real reason.... 😅

[@Hoopaball]

A lunar space elevator, connecting from either the north or south poles to L2, could be made from a spool of 3/8" dia AMSTEEL Blue dyneema. Only problem is your anchor line has to be 62k miles long. Weight = ~ 400mt

[@TheNheg66]

You're clueless

[@cyph3r.427]

Such a shame these incredible engines are now just being thrown away needlessly.

[@comp20B]

Ask the starship? Please.

[@NicholasNerios]

Cool

[@bobsilly4174]

boom boom

[@Jam-In-With-Ben]

hi

[@AndreaRomanelli-i4p]

Magnus Werner von Braun Elementare Base and then learn alone!

[@onlyblaze_1052]

hi :)

[@devlinhartman1223]

Tec is so amazing now & we will soon be going to Mars & beyond, with Elon Misk as Captain Kirk with his intelligence . I don’t even think he went to Uni so shows how anyone can do it. I’m following him & doing a course on journalism & Woodwork , I’m also good at cooking although I’m on takeaways at the moment as my oven door fell off

[@mikemccormick6128]

He actually did graduate from the University of Pennsylvania but no Masters or PhD so I take your point.

[@Breezely]

He is pretty intelligent, but I think his overwhelming drive is the biggest factor in his success. Most people with such high IQs tend to get lazy in school and that attitude carries with them throughout life. I know it happened to me: very high measured IQ, but too lazy to build a rocket company. 🙂

[@alexandercarson527]

No one will be going space until 2054 I tell you now takes twenty years the build a space which can withstand the orbit levels and NASA destroyed it ❤😂😮

[@goldgamercommenting2990]

Dude…… we’re already in space since 2020 Knock it off!!!!!!

[@hilwaamanamankiyar-pp5bf]

WAS

[@Breezely]

I find it unlikely that the RS-25 will survive for long. I know, everyone likes to talk about Starship as if it is a reality - and it isn't yet. But it sure looks likely and it will outcompete the older NASA style of politically financed, cobbled together mish-mash very easily. No matter how awesome that mish-mash is. (And it was awesome to watch SLS take off.) Unless some corporate-owned senator decides to keep pumping ridiculous amounts of money (yours and mine) into these pork barrels, I give the RS-25 about eight years, not a century. I think it's time for NASA to return their focus to science and innovation, and let private enterprise take over conventional rocketry and make it efficient. (Yes, I know this is not a new idea I just had.) And I'd add another function: regulation and infrastructure. After all, the last two letters in their acronymic name stand for Space Administration. Earth orbit is becoming a place for people to live and work and vie and litter and experience accidents and so on. Like our highways are now. Almost all roads and highways are built and maintained by governments. Governments regulate how they can be used for the safety of all users and for the continued longevity of the roadbed, itself. Etc. I think we need an international regulating agency for Earth orbits. And an adjunct to that would be maintenance: developing and deploying equipment to clean up the space above the mesosphere. This would require the development of some amazing tech because things in orbit are moving fast and this equipment would either be able to divert small space debris with force fields or absorb the impacts without damage. These technologies would probably then eventually find their way into longer range and higher speed space craft - those heading to Mars or Alpha Centauri. That's the kind of thing that we taxpayers fund NASA for: dreaming up great new things, implementing them, and then spinning them off into the world.

[@silverbemr]

SLS is such a waste of money. Invest it in reusable rockets like the Starship. Anything else is crazy to me.

[@trickeruniverse1979]

It’s not. It’s going to be very important for the Artemis program. The plans for Artemis was already laid out before Starship even existed. And starship is still under development. So SLS will have to make due. And who knows ,maybe 10 years from now they’ll start working on making it somewhat reusable. Regardless , No other country in the world has an operational heavy lift rocket that can enable manned missions to the Moon for now. Orion too is also proven and reliable, and so are all the parts of SLS. It is Proven tech and that’s the best advantage of it

[@silverbemr]

@@trickeruniverse1979 how much per launch?

[@_mikolaj_]

How much is starship per succesful launch? Will you treat it like other rockets and divide budget/launches? Hm, suddenly number goes infinately high...

[@silverbemr]

@@_mikolaj_ for now but the goal is just like the F9. Rapid reusability. How much is SLS going to be per launch?

[@_mikolaj_]

How long is this for now? 5 years? Decade? 2? This thing is supposed to be ready to carry humans to the lunar surface in 1 and half years. Yeah over my dead body. As for the SLS, how many you buy is the question that will give you an answer. SLS 'launch cost' isnt a thing. There is only annual program cost that always is ~2.5B per year, no matter how many launch. Which, tbh, from taxpayers perspective thats dirty cheap

[@michaelwilliams8297]

The rs NEVER FAILED in 30 years, SpaceX just sent its second ship up without a failure across 33 engines.....we are about to reach the inner planets. It's such a great time to be a sci-fi fan.

[@KD10Conqueror]

Nah.

[@airsoftagentbauer]

No matter what... refurbishment of RS25s still going to be more costly than putting a single SRB back in action... 🥱🥱🥱 Enter Raptors 2 and 3. 😌

[@KD10Conqueror]

It still is one of the best engines ever made.