Falcon Heavy, one of the best launchers of all time goes up today.(and other Space News)

[Uttamattamakin]

This may not have been a SUCCESS SUCCESS

 

6 hours ago, manikyath said:

they have made it work just as many times as sls, there is no reason to suspect SLS is now a proven known value while in the same breath you would suspect starship to turn out deeply flawed.

 

SLS is built on the technology of the Space shuttle not to mention that most rockets in operation have gone with the relatively few larger engines approach. 

 

You might want to watch this video by Space X fans.  It speaks about the failure of the re-lighting of the engines.  This is still an issue of the greater complexity of a system of many many engines.  More parts more problems.   

 

This is not a matter of what rocket one is a fan of or whatever.  I want a successful Artemis mission.  If SLS was not ready to go and Starship was I'd be critical of SLS. 

 

Here is another BIG fan of Space X who seems to say the test was not succesful ENOUGH for Artemis.  Since the test did not go perfectly by FAA standards it is a mishap. 

 

 

[manikyath]

1 hour ago, Uttamattamakin said:

 

most rockets in operation have gone with the relatively few larger engines approach. 

most rockets in operation? name them.

 

i'll name some "many engine" rockets:

- rocketlab electron uses 9 *tiny* engines on the first stage. like actually "you could put one on your desk" tiny.

- SpaceX falcon 9 uses, as the name implies, 9 merlin engines on the first stage.

- SpaceX falcon heavy uses 9x3 merlin engines, for a total of 27 engines.

- debatable if soyuz counts, they have quite an exotic design, see sidenote below.

 

as for upcoming stuff:

- rocketlab's upcoming "neutron" design currently also has 9 engines on the first stage

- SpaceX's upcoming "Starship" has 33 raptor engines on the super heavy booster.

 

now.. all of these have a pretty major design choice they all share: no solid rocket boosters.

it's almost as if some things are related here.. maybe SLS can get away with 4 liquid fuel thrusters because the SRB's carry over 75% of it's thrust on the pad (that's on NASA's fact sheet). that means that each of the 4 engines on SLS provide less than 6% of the total thrust on the pad.

 

sidenote.. what the heck is soyuz even.. on paper they're 5 engines with 4 combustion chambers each.. and a collection of 12 smaller thrusters for steering.

but really.. depending on how you count, we're looking at somewhere between 17 and 32 thrusters here.. and soyuz is pretty much *the* most proven launch vehicle on the market.

 

and all of this is completely irrelevant because.. news flash..

 

many thrusters isnt a problem, superheavy booster has made it up to hot staging twice with zero issues, the uphill portion hasnt been an issue since that one time they rapidly disassembled the launch pad. and the downhill portion is of no effect to artemis. big rocket go up is the goal, big rocket come down is a cost cutting bonus.

 

1 hour ago, Uttamattamakin said:

If SLS was not ready to go and Starship was I'd be critical of SLS. 

is this the place where i remind you that SLS is 6 years late, and work on starship didnt begin until after that 6 year delay in SLS's first launch?

 

as NSF has talked about before (and no, i'm not gonna delve into their hours upon hours of artemis ramblings) atemis's reliance on starship is NASA's "fault", SLS is way late, SLS cant provide all of the launch capabilities they want, SLS cant reach the budget goals they want. if you really delve into the time scale of "NASA returning humans to the moon" the most obvious answer is that using a launch partner is almost an "afterthought" because it eventually occurred to them that given the budget and timeframe they had no other option.

 

just to remind you; SLS is quoted to cost about 4 billion per launch, which is more than the 2.9 billion they awarded to SpaceX for the entire HLS programme.

 

oh, and while researching i found this statement, that nicely explains what these IFT flights are:

(hint: "T" stands for "Test")

Quote

NASA Office of Inspector General noted that SpaceX's philosophy involves extensively testing and flying their vehicles as early as possible—made possible by rapid in-house manufacturing capabilities that provide a steady stream of hardware—to aggressively reduce risks and acquire flight data.

[Uttamattamakin]

20 hours ago, manikyath said:

most rockets in operation? name them.

 

Pretty much every rocket except the ones you named.  Especially the man-rated ones.  Soyuz and Falcon 9 being exceptional.  

Also note Soyuz does something I said that Starship should consider instead of one big complex system of plumbing for all the engines, break it down in to smaller complexes of engines to get the best of both worlds without the cost of complexity.  

[wanderingfool2]

1 hour ago, Uttamattamakin said:

Pretty much every rocket except the ones you named.  Especially the man-rated ones.  Soyuz and Falcon 9 being exceptional.  

Also note Soyuz does something I said that Starship should consider instead of one big complex system of plumbing for all the engines, break it down in to smaller complexes of engines to get the best of both worlds without the cost of complexity.  

Starship's plumbing isn't really all that complex.  It's essentially a giant manifold attached with a few pipes [effectively].  Soyuz on the other hand has to essentially flair out its butt to make it all work out.

 

Starship actually has a pretty simple design if you think about what it's intended to do, i.e. have enough maneuverability to hover and do a controlled land...and honestly that's what adds the most complexity to the Starship.

 

The maneuverability is what has effectively cost them on the first 2 IFT's.  1st one hydraulic fire and loss of gimble; 2nd likely a hydraulic fire that's a result of the oxygen dump.

 

 

 

The issue I have is you have been shouting to anyone who would listen that many engines = bad, and acting like everyone does it.  The simple fact is the 2 most successful rockets in history have been ones with many engines.

 

 

Even if you want to compare it to others.  Shuttle, which effectively had 5 when you include the SRB's, actually had plumbing that failed that cost the life of Astronauts.  Saturn V [actually Apollo 6 had an engine failure which is a good example why many engines is good]; but Saturn V still had 5 on the lower stage.

One reason why they went with bigger engines is because manufacturing engines at that time was a major issue (they effectively electroplated to the final size).  SpaceX has chosen the manufacturing side first, that's what SpaceX is engineering effectively...how to manufacture it cheaply and to reuse the product.  The engines back then would literally take many months, no matter how many you built and a failure in one would mean months of waiting.

 

You seem to also forget you can only get so much performance/scaling with an engine, and a single larger engine makes it nearly impossible to do what they intend to do (i.e. land it, and reuse it).  Smaller engines are capable of throttling down to a lower amount [and even then Falcon 9 with 9 engines has an issue].  Seriously Falcon 9 has to do a suicide burn because they can't throttle down the engines enough to do a hover maneuver...a few large engines would make what SpaceX wants to do impossible.

 

Small engines also means quicker prototyping and development (back to not taking months to complete).  As a result we are entering into Raptor 3 revision soon, which is only 3x less power than the engines used on the Saturn V while achieving a thrust to weight ratio of like triple...i.e. more payload carrying capabilities

 

 

Your whole argument of many engines being bad effectively doesn't hold up when you look at it.  Yes the "plumbing" is simpler with 3 engines, but I could make that same argument to reduce it from 3 down to a single one.  If your whole idea of less engines is viable then why didn't they make just one...after all they had to fine tune each engine on the shuttle and others to not create a harmonic which would amplify the oscillations leading the destruction of the vehicle

[manikyath]

2 hours ago, Uttamattamakin said:

Pretty much every rocket except the ones you named.  Especially the man-rated ones.  Soyuz and Falcon 9 being exceptional.  

name them, because between SpaceX, rocketlab, and soyuz, i'm pretty sure i caught the great majority of launches in the past 5 years.

2 hours ago, Uttamattamakin said:

Also note Soyuz does something I said that Starship should consider instead of one big complex system of plumbing for all the engines, break it down in to smaller complexes of engines to get the best of both worlds without the cost of complexity.  

souyz is also a 60 year old design, the treshold of "cost of complexity" has changed A LOT in that timeframe.

besides the obvious technological advances made over the past 60 years, soyuz is also essentially an ICBM adapted for human and freight transport. it was *a* solution that worked, and has been extremely reliable in any weather, as you'd expect from an ICBM.. but that doesnt mean plumbing all those engines into a single thank then cant also be a viable option..

 

which.. i'm gonna reiterate again:

22 hours ago, manikyath said:

many thrusters isnt a problem, superheavy booster has made it up to hot staging twice with zero issues, the uphill portion hasnt been an issue since that one time they rapidly disassembled the launch pad. and the downhill portion is of no effect to artemis. big rocket go up is the goal, big rocket come down is a cost cutting bonus.

 

and likewise.. i'm gonna suggest you look into N1, because it really appears that the number of engines had nothing to do with the problems it had.

 

you can keep shouting nonsense, but if i can come with examples and you cant, i'll just have to assume that what you're shouting is in fact nonsense.

 

and just to make sure you dont accuse me of talking nonsense:

in 2023:

- 96 falcon 9 family launches

- 9 electron launhes

- 2 ariane 5 launches

- i'll count the one SLS launch in november of 2022, because otherwise NASA isnt on this list at all.

- 17 souyz launches

- 3 "long march" launches (that's china)

- 9 ISRO launches, on a variety of solid rocket booster configurations.

- 2 JAXA launches

 

fact of the matter is that every big ticket item on this list is either a 9 engine cluster design, pure SRB's, or the undecided quantity that is souyz.

 

while a cluster of 9 engines to a cluster of 33 engines is a big jump, SpaceX has clearly proven that the plumbing into a single tank isnt an issue, because for all 3 test flights none of the problems were caused by said plumbing. - in fact.. all i can find about N1's plumbing is the engine manufacturer blaming the plumbing for their engines blowng up.

 

as for the complexity of many rocket engines.. let's talk about the simplicity of many rocket engines.. or as someone responded to this photo below:

Quote

That’s three spaceX raptor engines, on a regular ass flatbed trailer, being towed around by a ford.

 

forget your special transports for spacecraft parts, having the engines this size and none bigger means you can actually deliver them "by the truckload".

[Uttamattamakin]

23 hours ago, wanderingfool2 said:

Starship's plumbing isn't really all that complex.  It's essentially a giant manifold attached with a few pipes [effectively].  Soyuz on the other hand has to essentially flair out its butt to make it all work out.

 

 

Your whole argument of many engines being bad effectively doesn't hold up when you look at it.  Yes the "plumbing" is simpler with 3 engines, but I could make that same argument to reduce it from 3 down to a single one.  If your whole idea of less engines is viable then why didn't they make just one...after all they had to fine tune each engine on the shuttle and others to not create a harmonic which would amplify the oscillations leading the destruction of the vehicle

I could write a reply to this... but I decided to farm it out to Microsofts CoPilot GPT-4.  Interestingly the cold unfeeling robot agrees with me on the essential issue of complexity.  Space X has their reasons for using many engines but there are SERIOUS drawbacks to it.  

Quote

Copilot

The debate over the number of engines in rocket design is indeed a complex one, with valid points on both sides. Historically, rockets have tended to use fewer, larger engines for several reasons:

1. Manufacturing Complexity: Larger engines were historically difficult to manufacture due to the technology available at the time. Fewer engines meant fewer parts to produce and assemble, which simplified the manufacturing process¹.

2. Reliability: Fewer engines can mean fewer points of failure. The Space Shuttle’s main engines, while fewer in number, were highly sophisticated and provided the necessary thrust without the need for a large number of engines².

3. Thrust-to-Weight Ratio: Larger engines have often provided a better thrust-to-weight ratio, which is crucial for the initial stages of launch where overcoming Earth’s gravity is critical³.

4. Combustion Stability: Larger engines have historically faced challenges with combustion stability, but once these were overcome, they provided a reliable source of thrust without the complexity of managing multiple engines².

However, advancements in technology and manufacturing have allowed for new approaches. SpaceX’s use of multiple smaller engines, for example, offers advantages such as redundancy, where the rocket can still perform its mission even if some engines fail. This approach also allows for more precise control during landing maneuvers, which is essential for SpaceX’s goal of reusability³.

It’s important to note that each design philosophy has its trade-offs and the choice often depends on the specific mission requirements and technological capabilities at the time of development. The success of SpaceX’s approach with the Falcon 9 and Starship suggests that multiple smaller engines can be highly effective when designed and implemented with modern engineering practices.

Those are just facts.  Yes all these systems have their issues.  Many many engines means more complex plumbing.  More parts means more points of failure. 

 

 

[Uttamattamakin]

23 hours ago, manikyath said:

name them, because between SpaceX, rocketlab, and soyuz, i'm pretty sure i caught the great majority of launches in the past 5 years.

I decided to respond to you with Copilot.  It is a robot and can be wrong but not biased.  I have struck out anything that is clearly wrong. 

 

Quote

Here’s a list of some notable orbital space rockets currently in use that have less than nine engines:

• Atlas V: Utilizes a single RD-180 engine for its first stage and can have up to five solid rocket boosters¹.
• Delta IV Heavy: Employs three RS-68A engines in its first stage².
• Falcon 9: Equipped with nine Merlin engines in its first stage³.
• Ariane 5: Features two solid rocket boosters and a single Vulcain 2 engine in the core stage².
• H-IIA and H-IIB: Both rockets use a single LE-7A engine in their first stage and a single LE-5B engine in their second stage³.
• Soyuz: The Soyuz rocket’s first stage has four RD-107A engines and the second stage has a single RD-108A engine².
• Electron: Rocket Lab’s Electron rocket has nine Rutherford engines on its first stage³.

These rockets are designed with a focus on reliability, efficiency, and specific mission requirements, which can influence the number of engines used. The choice to use fewer engines often involves trade-offs in design complexity, manufacturing, and performance characteristics.

It left out the very relevant to this discussion SLS.   4 SSME's and two boosters.  

Assuming we are only counting the first stages. 

 

23 hours ago, manikyath said:

...

I have come up with examples and given Space X credit where it is due for what they do right.  I am just not a fanboy for Space X.    I am a fan of rockets that are on time and don't blow up. 

[manikyath]

2 hours ago, Uttamattamakin said:

I decided to respond to you with Copilot.  It is a robot and can be wrong but not biased.  I have struck out anything that is clearly wrong. 

let's go trough the rest then:

- Atlas V: it has flown 99 times, has 17 more scheduled flights, and ULA is not selling any more flights.. it is therefore just barely "still in operation". it is also HUGELY aided by SRB's, supporting my previous notion that the number of engines might be more related to wether they want to rely on SRB's or not.

- Delta IV heavy: has flown 15 times, with one more flight scheduled before it's announced retirement. so.. again, just barely "still in operation".

- H-II is JAXA's (japan) SRB-only first stage rocket, i'm willing to debate if this should even be considered a "few engines" rocket, because it's basicly an advanced firework. cool tech, but irrelevant in the debate of number of engines, because clearly "no plumbing at all" hugely reduces the chance of plumbing issues.

 

this is also both less in number, and SIGNIFICANTLY less in number of launches than the "many engines" rockets.. do you want to correct your hilareously poor autopilopt response, or should i just assume that many engine cluters are 'at least just as viable' as few engines aided by SRB's?

 

2 hours ago, Uttamattamakin said:

Assuming we are only counting the first stages. 

as far as i'm aware, past the first stage just about everything is one or two engines.. aside from starship, which is unique in this regard because they are hoping to develop soft landing capabilities.

2 hours ago, Uttamattamakin said:

I am a fan of rockets that are on time

so, not a fan of SLS then? because you must have missed the previous douzen times i've mentioned that Artemis 1 launched 6 years late. i know you're just ignoring this fact for the benefit of your own argument, but i'm not. so whatever the case is, if the NASA contract says "moon by 2026", they have until 2032 before they're later than Artemis 1. i'm not saying this is a "free pass" on a 6 year delay, but if you are criticizing the chance for delays on starship, you cant then use SLS as an example of being on time.

 

2 hours ago, Uttamattamakin said:

I am just not a fanboy for Space X

that makes two of us.. i just happen to enjoy rockets that happen, i'm in it to watch cool technology happen, preferably more than once every few years. i like SpaceX because they launch a lot, and their development is very "visible" which really vibes with my engineer mindset. watching artemis 1 fly was cool.. but it was one flight. likewise i really enjoy rocketlab for their "style" of rocketry. their broadcasts are almost like they're playing KSP in real life, down to the gaming chairs and sponsored by logitech headsets.

[Uttamattamakin]

It is interesting how critical so many creators are of IFT 3 .  Having starship get to orbit, for all practical purposes ... and not blow up is great.  Getting superheavy most of the way back to a soft water landing was great.    This raises the bar and we need to see more complete success.   
 

Notice they mention the issues around fuel slosh and the complexity of the multi multi engine system that this is.  Re-lighting the engines is a problem.  They have to engineer around these fundamental physical issues. 

 

 

I am not ignoring what you have written.  The thing is you're just misssing my points.  I am talking about using ...as smart every day said... the playbook that Apollo left for us for how to get to the Moon.  So much about starships system for this purpose doesn't really make sense.  Firing a minimum of 7 of these to get 1 to the Moon... even if everything works perfectly ... by 2025 or  20206  forget it.  Never happen.  I WANT TO BE WRONG ABOUT THAT.  I HOPE I AM.  

7 minutes ago, manikyath said:

that makes two of us.. i just happen to enjoy rockets that happen, i'm in it to watch cool technology happen, preferably more than once every few years. i like SpaceX because they launch a lot, and their development is very "visible" which really vibes with my engineer mindset. watching artemis 1 fly was cool.. but it was one flight. likewise i really enjoy rocketlab for their "style" of rocketry. their broadcasts are almost like they're playing KSP in real life, down to the gaming chairs and sponsored by logitech headsets.

I can agree with this Space X flies a lot.  They are a great company that has accomplished many things.  I am a fan of Artemis and any company involved which does not keep up the pace for a Moon landing I am going to be critical of.  

They may work out all the kinks with Starship given enough time and enough money.    Meanwhile the PRC will be calming a "safety zone" around Shackleton crater (the closest thing in law to owning real estate on a celestial body.)   Without that ice and the insitu resources it will be a lot harder to build a real base on the Moon.  

[wanderingfool2]

2 hours ago, Uttamattamakin said:

I have come up with examples and given Space X credit where it is due for what they do right.  I am just not a fanboy for Space X.    I am a fan of rockets that are on time and don't blow up. 

Except you have been stating things that show you are being ignorant of what ACTUALLY is occurring, and misconstruing "facts". [And it really does bother me that in 15 pages you still choose to spell SpaceX wrong]

 

Name one rocket that was "on time".  Here's a hint, no modern rocket or really NASA funded endeavors have been on time.  So by your logic you aren't a fan of any rockets.

 

The simple fact again is that blowing up isn't a devastating issue, the newest private Japanese rocket blew up but I don't consider it a failure.

 

2 hours ago, Uttamattamakin said:

I decided to respond to you with Copilot.  It is a robot and can be wrong but not biased.  I have struck out anything that is clearly wrong. 

Have you not followed a thing in regards to LLM and their outputs.  They are 100% biased and can get many things wrong.

 

You are also "moving the goal posts" so to speak, as you have clearly emphasized as though no one else does lots of engines etc...and yet even in your list from copilot you struck out nearly half of them because they have above your 9 engine threshold.

 

Atlas V had 1 single engine, but there were 5 boosters that could attach to it to be capable of carrying larger payloads less than a Falcon 9.  You would need close to 8 SRB's to match the same payload as Falcon 9...actually you might need closer to 9 SRB, but that's a hypothetical because Atlas V can only handle 5 SRBs anyways.  So to get the same payload you would need over 9 engines.

 

Delta IV, yes it uses only 3 engines...but in Starship v3 expendable mode it will cost the same to fly if lets say SpaceX wanted a $100m profit on expendable launch [IFT-2 shows that it would be successful in an expendable mode mission already], and would carry close to 15 - 20x the capacity.  So while yes it has 3 engines it also is quite different states of existing.

 

IIB - Same kind of deal as Atlas V...requires SRB's and multiple (up to 4) to carry less mass to orbit.  If you wanted it to carry the same mass as a Falcon 9 could,  you would have to add in additional SRB's which would total closer to 9 total.

[manikyath]

3 hours ago, Uttamattamakin said:

Interestingly the cold unfeeling robot agrees with me on the essential issue of complexity. 

let's break down what your cold unfeeling robot has to say...

Quote

Manufacturing Complexity: Larger engines were historically difficult to manufacture due to the technology available at the time. Fewer engines meant fewer parts to produce and assemble, which simplified the manufacturing process.

your AI misquoted their own source.. they're on about how creating an engine with fewer parts simplifies the manufacturing process.

 

Quote

Reliability: Fewer engines can mean fewer points of failure. The Space Shuttle’s main engines, while fewer in number, were highly sophisticated and provided the necessary thrust without the need for a large number of engines.

again.. a misquoted source, it's a stackexchange discution (of all places to pull data from...) about the pros and cons of both sides, and the reasons to choose one or another. it's a shame your AI misquoted it because it's a pretty good read.

 

Quote

Thrust-to-Weight Ratio: Larger engines have often provided a better thrust-to-weight ratio, which is crucial for the initial stages of launch where overcoming Earth’s gravity is critical.

my job is safe, AI will not replace me.. because nothing in the quoted source evn talks about TWR, instead it talks about the reliability benefit of having more engines, and how modern computer technology allows us to control more complex rockets more accurately.

also - kinda funny.. the source YOU are quoting here.. is elon musk.

 

Quote

Combustion Stability: Larger engines have historically faced challenges with combustion stability, but once these were overcome, they provided a reliable source of thrust without the complexity of managing multiple engines.

same source as 2, same misquoting.. the only reference to combustion stability is a reference to car engines.

 

Quote

However, advancements in technology and manufacturing have allowed for new approaches. SpaceX’s use of multiple smaller engines, for example, offers advantages such as redundancy, where the rocket can still perform its mission even if some engines fail. This approach also allows for more precise control during landing maneuvers, which is essential for SpaceX’s goal of reusability3.

It’s important to note that each design philosophy has its trade-offs and the choice often depends on the specific mission requirements and technological capabilities at the time of development. The success of SpaceX’s approach with the Falcon 9 and Starship suggests that multiple smaller engines can be highly effective when designed and implemented with modern engineering practices.

this is exactly what we have been telling you.. and you now blatantly use it to somehow try and prove your own point? have you any idea how ridiculous this makes you look? have you not proof-read this at all?

 

45 minutes ago, Uttamattamakin said:

I am a fan of Artemis and any company involved which does not keep up the pace for a Moon landing I am going to be critical of.  

so.. NASA then? because the artemis contracts are historically tight timing-wise, presumably because of the 6-year delay from

 

NASA's own internal dealings.

 

45 minutes ago, Uttamattamakin said:

It is interesting how critical so many creators are of IFT 3 .

i think you mistake "being cautious with optimism" for being critical. now, i've only watched the final thoughts of the video you linked.. but i dont think they sounded critical at all.

45 minutes ago, Uttamattamakin said:

the playbook that Apollo left for us for how to get to the Moon.  So much about starships system for this purpose doesn't really make sense.  Firing a minimum of 7 of these to get 1 to the Moon... even if everything works perfectly ... by 2025 or  20206  forget it.  Never happen.  I WANT TO BE WRONG ABOUT THAT.  I HOPE I AM.  

apollo essentially got a bunch of "test subjects" to the moon and back in a tin can, as a physics person you ofcourse understand that if you want to get more than "just another tin can" to the moon, you'll need more energy. the goal of artemis isnt "put human on moon", the goal is to put ACTUAL science down on the moon, and be a pathfinder for further human spacetravel.

or to put it in a vaguely quoted clarkson quote from earler in the thread:

Quote

We've been to the north pole, now let's try to get to the north pole comfortably.

 

45 minutes ago, Uttamattamakin said:

They may work out all the kinks with Starship given enough time and enough money.    Meanwhile the PRC will be calming a "safety zone" around Shackleton crater (the closest thing in law to owning real estate on a celestial body.)   Without that ice and the insitu resources it will be a lot harder to build a real base on the Moon.  

enough time and money.. should i bring up the cost difference between starship and SLS again? and why do you think NASA isnt flying the whole party with SLS?

BECAUSE THEY CANT AFFORD IT.

 

wether you, or anyone else at NASA likes it or not, fact of the matter is that any chance the US has got at winning the modern era space race has to include their commercial launch partners, because they simply cannot do it on their own dime. NASA is too slow, too expensive, and too complicated of an entity to do revolutionary things. the reason why SpaceX is actively blowing up starship prototypes is because it's cheaper and faster to develop that way. two things NASA sorely needs, but cant do themselves for political reasons.

[wanderingfool2]

23 hours ago, manikyath said:

your AI misquoted their own source.. they're on about how creating an engine with fewer parts simplifies the manufacturing process.

As I also mentioned earlier, it's maybe not even about simplifying the manufacturing process but rather the practicality of the manufacturing process.

 

The cooling channels in the rocket main combustion chamber were effectively electroplated on.  The old school method was to create the inner portion, then use wax to fill up the channels and then electroplate to build up like a CM of metal surrounding it.

 

This wasn't used on the Saturn V however, but was used later on on things like the shuttle.

 

The Saturn V though, it used pipes to do it iirc, and at that stage it's about the validation required for each engine would take an inordinate amount of time if it was used...since to create 1 large engine it would be overall simpler to do the process a single time [and the benefit that the more volume gave a better weight to thrust ratio]...either way though both of these methods are obsolete with the advent of modern manufacturing process.

 

On 3/18/2024 at 11:29 AM, Uttamattamakin said:

I am talking about using ...as smart every day said... the playbook that Apollo left for us for how to get to the Moon

SmarterEveryDay's method lacks the awareness of modern rocketry, falls prey to hindsight, and is just as unrealistic as the current timeline is.

 

e.g. The SLS was one of those "playbooks" that congress ate up.  It was meant to be old proven technology that would save money and only cost $10 billion to make, be ready by 2015 and cost $500 million to launch.  It has cost over $23 billion, didn't launch until late 2022, and estimated at maybe upwards of $5 billion per launch [but probably at least $1 billion].

 

As I stated before as well, some of the documents he pointed to would have been classified at the time. There are mission updates, but the public isn't privvy to listening and seeing them.  They already have the testing underway for the starship to Orion dock being tested [and a prototype built]

 

Apollo also existed in the time when the peak budget was ~5%, which today no one would accept that kind of budget today.  Do you know why we stopped going to the moon?  Because it was too expensive to keep the Saturn V running and operating missions.  NASA is setting to accomplish this without breaking the bank, so no the "playbook" is not the same playbook.  The playbook this time is a sustainable mission to the moon.

 

If the Starship isn't ready for Artemis it won't be the fault of SpaceX, but instead it's the pencil pushers who decided to set a public target date that is unrealistic with the actual mission objectives.  It's the whole, don't start a bidding processing on something with only 3 years lead time.

 

Again, the SLS is the prime example of this kind of mentality, it was supposed to have missions by 2015 but didn't.  The Orion capsule was supposed to be in service in 2015 but wasn't.  The old playbook has failed.

 

On 3/18/2024 at 11:29 AM, Uttamattamakin said:

Meanwhile the PRC will be calming a "safety zone" around Shackleton crater (the closest thing in law to owning real estate on a celestial body.)   Without that ice and the insitu resources it will be a lot harder to build a real base on the Moon.  

No need to try making this into a discussion on politics.  The moon is an international body, and the whole combativeness of this country that country etc only leads to additional conflicts.  Space should not be an us vs them mentality, which is what you seem to be pushing

[Uttamattamakin]

2 hours ago, wanderingfool2 said:

SmarterEveryDay's method lacks the awareness of modern rocketry, falls prey to hindsight, and is just as unrealistic as the current timeline is.

The person who is an engineer invited to speak to Engineers at NASA knows less about rocketry than you.   

 

I mean me I'm just a humble theoretical astrophysicist working on a NASA space probe.  So, what do I know.  oki then. 

 

Ok smart guy Wandering.  You know everything about everything but never state any sort of credential to back it up.  Not even a claim of one.  Why should anyone believe anything you have said other than ... Gee whiz it would be nice if this was true because that means a world with really cool technology really soon. 

 

Don't get me wrong I sorely wish your optimism motivated reasoning was sound. 

 

[manikyath]

1 minute ago, Uttamattamakin said:

The person who is an engineer invited to speak to Engineers at NASA knows less about rocketry than you.  oki then. 

to be fair, the little of that speech i could bear to watch didnt really present as a man deeply involved with the intricacies of modern day rocket design. he might be an engineer, he might be knowledgable, but that doesnt make him an authority on the difference between NASA's design philosophy and SpaceX's design philosophy.

 

also - he's a youtuber, a guest speaker.. if he truly was an authority on the matter, why is he a guest speaker instead of an engineer at NASA? to me this felt like a cross-marketing opportunity for both parties. successful, a brilliant idea, a perfect person to light some fire under NASA's butts, but it doesnt make him an authority on the details of an incredibly complicated field. it's obvious to laymen like us, it should be obvious to you.

[wanderingfool2]

37 minutes ago, Uttamattamakin said:

The person who is an engineer invited to speak to Engineers at NASA knows less about rocketry than you.   

I mean me I'm just a humble theoretical astrophysicist working on a NASA space probe.  So, what do I know.  oki then. 

Seriously, learn to read and have an ounce of comprehension and honestly the way you proclaim your education you are much like ThunderF00t ego stroking.

 

I know master level computer science major who worked at Google who I talked to about Waymo before...his response to it was talking about the trolley problem and he seriously was considering that that was an important part of programming it [in the literal sense he had no knowledge of how self driving technology actually worked]

I had a prof who was pretty much illiterate when it came to using a computer, but he taught algorithm design.

I know CCNA's who deployed networks, and I had to come in and correct them on their mistakes [in one case having to show a POC that I wrote proving their setup didn't match the specifications].

 

General education, or even education in a field DOES NOT mean they are knowledgeable in aspects of the field...actually it can be worse in that you could have a very narrow field of focus.

 

Again, I said "lacks the AWARENESS of modern rocketry".  He didn't follow the rocketry and missions up to the point where he was asked to talk with them.

 

He pretty much admits it himself, that he wasn't even aware that it would require in-space refueling.  You can tell that his calculations on burn off are also off, more likely using early numbers of what Starship might have required to launch...because while the statement was 6, he talked about 12 (just still hinted he thought it was more).  Even at a boil off of 20%, the v3 Starship will hypothetically need a max of 6 ships.  Assuming 12 ships would assume a boil-off of roughly 50%.

 

The issue like above is exactly why someone who can have a higher educational background can be wrong when they lack the awareness of their current subject.  Again he's pulling papers and looking at things with hindsight knowledge of the inner workings of Apollo.

 

1 hour ago, Uttamattamakin said:

You know everything about everything but never state any sort of credential to back it up.  Not even a claim of one.  Why should anyone believe anything you have said other than

Degrees and "credentials" in the form of education don't mean anything you ignorant person.

 

It's logic 101, I've made claims, claims that are verifiable that can be tested against; I've made guesses of outcomes that are closer to what turned out to reality than you.

 

But hey you are the one who is to thick to realize your education doesn't mean a thing when you make stupid statements like [fuel slosh is why they never made orbit] and your stupid bits where you somehow think you are better than the people WHO WORK AT SPACEX..

 

To only rely on education merits as a standard is just stupid.

[Uttamattamakin]

16 hours ago, wanderingfool2 said:

Seriously, learn to read and have an ounce of comprehension and honestly the way you proclaim your education you are much like ThunderF00t ego stroking.

 

To only rely on education merits as a standard is just stupid.

Yet you idolize people who work at Space X.  I think this is as Sabine Hoseenfelder put it in a recent video.  People who think in an engineering sort of way have no real respect for theory development.  IF they can't put hands on it, or understand it after taking at most the initial three course sequence of physics they don't believe it.  

It's like how GREAT electrical engineers think gravity is fake, nuclear physics is fake,  and that everything in the universe can be explained by electricity.  

 

Much respect to SpaceX for what they have done with Dragon, Falcon 9, Starlink, and so forth.  Kudos for making a very hard to do system work more than it has before.   In fact I think that most of them would agree with me.  THEY ARE DOING SOMETHING REALLY HARD TO DO... so it is likely that it won't work BUT WILL BE GREAT IF IT DOES.  That using 9 larger engines, as on Falcon might be an easier solution. 

 

Just to check I asked Copilot to figure out how many Saturn V F1 engines would give the same thrust as superheavy.  It would take 11.  Just 11 engines.  So far fewer points of failure to contend with.  https://sl.bing.net/iAHzhJfvnYO  

 

It's only the fans of SpaceX that give me problems.  Never actual people who work with and for NASA who I deal with on a weekly basis.  Actual scientists never doubt that I know science when I speak to them. I wonder why that is.  (Yes I do somewhat relish and luxuriate in how that riles some people.  As if I didn't work really hard to get what little I have. ) 

Many of you talk about innovation and doing something really new and never done before.  That to me would be if SpaceX built a real practical Aerospike engine for this system.  Since these have the advantage of working at any atmospheric pressure or even in vacuum.
 

 

[wanderingfool2]

8 minutes ago, Uttamattamakin said:

Yet you idolize people who work at Space X.  I think this is as Sabine Hoseenfelder put it in a recent video.  People who think in an engineering sort of way have no real respect for theory development.  IF they can't put hands on it, or understand it after taking at most the initial three course sequence of physics they don't believe it.  

I don't idolize SpaceX people, but I'm calling YOU an ignorant person for making statements COUNTER to the SpaceX engineers with the truly crazy statement that you somehow know better than what was in the press release.  And the fact YOU are slagging profession.  We get it you are a theoretical person, your previous statements are still stupid theories that run counter to all the information that has been presented.  Your theory is equivalent of someone stating that the air is 99% oxygen, and people pointing to the nitrogen concentrations and you still stating that they are wrong and just a fanboy of the labs that ran the test.

 

You want to know the type of person Sabine is though, she's the type who lacks AWARENESS in the computer science field, presents the information anyways, and lacks integrity to correct her mistake.  Case in point, she confuses petabit with petabyte [literally in her thumbnail and title she uses the word byte instead of bits], for the first few days the video existed the top comments were all about her usage of bits and bytes almost interchangeably; and still no correction.  Talks about encryption on AI, yet is ignorant of the fact the way LLM's work [and similar advanced AI networks] mostly require non-encrypted information because it's not just simple transforms on encrypted data...the data itself needs to effectively almost "fit" a certain pattern and reasoning basis off the data it sees [I'm not going more into this because I'll start running up against a NDA, but processing on encrypted data would yield worse results and a whole lot less useful insights]

 

The point is stop holding up Sabine as though she is some sort of fixture, she makes mistakes and worse yet when she does make major mistakes in a topic she doesn't readily correct them.

 

After all you are the person making the kind of statement

  

On 2/25/2024 at 3:42 PM, Uttamattamakin said:

I get it you take Elons words and Space X press realeses as gospel.  I am going by what I saw in the data. The line that they almost got to orbit but for not having a payload makes no sense.  NONE.   Surely they would've factored that in. 

So again, your education means nothing if you are conceited enough to believe your word of SpaceX.

 

28 minutes ago, Uttamattamakin said:

THEY ARE DOING SOMETHING REALLY HARD TO DO... so it is likely that it won't work.  That using 9 larger engines, as on Falcon might be an easier solution. 

Please at least THINK before you try responding with something like this; because I'm getting tired of having to point out flaws in your silly theories

 

Falcon 9 uses smaller engines compared to Starship.

 

Falcon 9 has to use a suicide burn because it can't perform a hover maneuver.  In fact, if they don't light it/shutoff at the correct time it will either crash land or if it lands and doesn't shut off in time it will actually start flying again.

 

Again, if you read anything at all and actually comprehended what was said you will notice that the landing burn required would be a lot harder with large engines (because you won't be able to get the control needed AND you will be generating too much power).

 

You say it's an easier solution, but do you understand.  What evidence do you present because so far the engines you keep going on about weren't the root cause of the failure.  A lot of the failures have stemmed from the fact that the Starship is the largest thing ever to take flight and with that comes a learning curve...but again the engines weren't the problem.

 

IFT-1, actually would have been a scrub (as 4 engines weren't available at launch time, but they decided to fly anyways).  Had it been larger engines it would have been a scrub, and we would have had to wait longer.  Engines going out on IFT-1 and it was still able to fly for a longer period of time. [Actually larger engines would have resulted in less data]...actually had they switched to electronic gimbling [which they were going to switch to anyways] it's very likely we would have seen the flip maneuver occur and starship get to the Karman line.

 

IFT-2 , engines not the fault, "complex" plumbing (which really it's pretty simple plumbing) wasn't the issue, it was a blocked filter in the main tank which has nothing to do with many smaller engines as you still would need a similar design to the tank with a few engines and for the starship it was the oxygen dump (along with the hydraulic fire again).

 

So using larger engines isn't the easier solution.  ESPECIALLY since you can't seem to get it through your mind the GOAL IS NOT GET INTO SPACE.  It's GET INTO SPACE AT A LOW COST.  You are missing a great qualifier to the requirements.  You cannot easily create a large engine at a low cost.  Larger engines means a whole lot more specialized equipment, more road closures, slower replacement times, higher cost of manufacturing, higher minimum thrust [which is bad when trying to land the thing], and greater risk of a SPOF.

 

53 minutes ago, Uttamattamakin said:

It's only the fans of SpaceX that give me problems.  Never actual people who work with and for NASA who I deal with on a weekly basis.  I wonder why that is.  (Yes I do somewhat relish and luxuriate in how that riles some people.  As if I didn't work really hard to get what little I have. ) 

Because you label anyone who gives you a problem as SpaceX fans...seriously, go to all the people you work with and ask them to come here and back you up then in your assessment.  Or perhaps, just perhaps stop making asinine statements that are false.

 

1 hour ago, Uttamattamakin said:

Many of you talk about innovation and doing something really new and never done before.  That to me would be if SpaceX built a real practical Aerospike engine for this system.  Since these have the advantage of working at any atmospheric pressure or even in vacuum.

They are doing something new and never done before.  They literally brought ~5000 TONNES of mass into space.  Starship is also only the second methalox ship ever to fly into orbit.  The simple fact is it is attempting to do things never done before.  Starship created the largest mach diamonds ever as well [with the 33 engines all combining together to create giant mach diamonds]

 

Your video you posted about Aerospike, did you ever even watch it?  Here's a hint, Tory Bruno (ULA) talked about heat issues and such, Musk talked about not getting enough performance increase vs optimizing (keeping a simpler design), RocketLabs talking about the pricings and added complexity in engineering, and Vector Aerospace talked about the added weight/parts needed to do it pretty much offset the benefits.  So ultimately you have 4 companies that looked into it, and they all came to similar conclusions that it's not worth pursuing at the moment because the benefits don't outweigh the risks.

[manikyath]

1 hour ago, Uttamattamakin said:

Yet you idolize people who work at Space X. 

idolize < = > assume they know what they are doing better than some outsider with a degree and an opinion.

1 hour ago, Uttamattamakin said:

People who think in an engineering sort of way have no real respect for theory development.  IF they can't put hands on it, or understand it after taking at most the initial three course sequence of physics they don't believe it.  

likewise, people who think in a very theoretical way have no real respect for the difficulties of executing ideas in practisce. if they cant pinpoint it as a variable, it simply doesnt exist. (sidenote, this is referred to as "an unknown unknown", and it's what the majority of engineering time tends to go to.)

THIS point drives home very well why you're getting so much headwind here, to not realise there's two equal and opposite sides to that argument is a perfect example of how shallow your own thinking is.

 

1 hour ago, Uttamattamakin said:

It's like how GREAT electrical engineers think gravity is fake, nuclear physics is fake,  and that everything in the universe can be explained by electricity.  

ellaborate, provide example, please support this statement with anything other than a james may-esque "i dont believe in magnetism" joke, from anyone who has any credibility to be quoted. it might not have occurred to you - but engineers love to joke about everything.

at my place of work we have very in-depth theories about how the colour of a PCB affects the reliability.. which is ofcourse utter nonsense, it's just that not all manufacturers have the same quality standards, but it's funny to blame the colour.

 

1 hour ago, Uttamattamakin said:

In fact I think that most of them would agree with me.  THEY ARE DOING SOMETHING REALLY HARD TO DO..

up until here i'm following you with that thought...

1 hour ago, Uttamattamakin said:

so it is likely that it won't work BUT WILL BE GREAT IF IT DOES.

here you're just falling into your theory pit again.. they're engineers, if the current iteration doesnt work, they will iterate until it works - "iterative design" and "rapid prototyping". go look that up, it might make sense to you one day.

also - i dont think anyone with a key role in the Starship thinks it's likely it wont work.. since it essentially already works "as a rocket", it's just the landing portion and the payload portion to add on top of that to finish it off.. and by my calculations they still have 6 years before they're more delayed than SLS

 

1 hour ago, Uttamattamakin said:

That using 9 larger engines, as on Falcon might be an easier solution. 

deer lord.. page 4 all over again.. there's a lot of practical, real-world issues with making fewer bigger engines. you wouldnt understand because you're stuck in your theory course, but even just yesterday's point about "these engines fit on a regular-ass flatbed truck" is a major factor for something that will be - for the scope of a rocket - mass produced.

 

1 hour ago, Uttamattamakin said:

Just to check I asked Copilot to figure out how many Saturn V F1 engines would give the same thrust as superheavy.  It would take 11.  Just 11 engines.  So far fewer points of failure to contend with.  https://sl.bing.net/iAHzhJfvnYO  

oh, and copilot did such a great job before.. but i'll entertain your idea..

- less points of failure, but also less redundancy.

- i havent measured this.. but based on images i have a strong feeling 11 of these dont fit under starship. or is that too practical for you?

- it would be more difficult to transport and attach 11 of these than 33 raptors. that's a key part of raptors: they're mass producable and 'easy' to swap out. (all statements relative to the field of rocketry)

- if that engine is relevant to starship, why isnt SLS flying on them?

- you keep shouting 9 engines.. and the best example you could come up with ends up at 11.

 

1 hour ago, Uttamattamakin said:

It's only the fans of SpaceX that give me problems.  Never actual people who work with and for NASA who I deal with on a weekly basis. 

because people you interact with might share your beliefs, and/or dont get called dumb fanboys by you on a daily basis.

1 hour ago, Uttamattamakin said:

Actual scientists never doubt that I know science when I speak to them. I wonder why that is.

because you havent said anything that you could support with any facts along this entire thread. dont make this a sob story now.. we're not attacking you personally because of any trait of yoruself, other than your absolute determination to be incorrect in this thread.

 

1 hour ago, Uttamattamakin said:

As if I didn't work really hard to get what little I have.

none of us here have claimed that, it's not what we're here for, we dont know your situation and we dont care about your situation. we're here to talk about big rocket go up is cool. stop trying to victimize yourself.

 

1 hour ago, Uttamattamakin said:

Many of you talk about innovation and doing something really new and never done before.  That to me would be if SpaceX built a real practical Aerospike engine for this system.  Since these have the advantage of working at any atmospheric pressure or even in vacuum.

aerospikes are also very troublesome in the real world (see, here comes reality again.. pesky reality.), and the efficiency benefit is largely offset by the fact that there's very few usecases where a single engine needs to perform from ground level to space. when we go SSTO perhaps, but not on a multiple stage heavy lifter.

 

afaik last time i saw an aerospike it was on some crew SSTO concept that was deemed too complex to make financial sense at the time.

 

i'd dare make a guess that SpaceX will never develop an aerospike engine, because the upfront investment will most likely not match the profitability compared to making engines with an atmosphere version and a vaccuum version. or should i remind you again - SpaceX is a for profit rocket corporation, not a research facility.

 

besides.. i'd argue that making things orders of magnitude cheaper is quite an innovation.

[wanderingfool2]

1 hour ago, manikyath said:

oh, and copilot did such a great job before.. but i'll entertain your idea..

haha, I know right.

 

Don't forget 11 F-1 engines also would weigh an extra ~40 tonnes...so expected payload to orbit would be reduced by about 40 tonnes.

 

Also F-1 engines minimum thrust  at it's lowest can only be ~65%.  [1 M lbf where you got combustion instability, as per https://www.enginehistory.org/Rockets/RPE08.11/RPE08.11.shtml] Or roughly 4,448 kN.

Now here is just a bit of AI goodness then.

Mass of booster, without fuel is ~3,600,000kg [~* 9.8 to get kN]...to hover you need ~35,280 kN.

With F-1 you need 5.2 engines to match that weight (no acc./dec.).  That means you need to light at minimum 6 engines.

Now what is the max number of engines you can light to hover.  7.9, now the issue is 8 would produce too much thrust [also you wouldn't be running all engines a pure minimum].  So you end up with 7 engines max you could light.  Or 6 - 7 engines needed for a hover maneuver.

 

This is where the issue starts to come into play, which is similar to what Falcon 9 experiences (and why Falcon 9 does a suicide burn).

You could have a range of thrust with those 6 - 7 engines as follows: ~26,688 kN - ~47,390 kN.  Since the weight is 35,280 kN though the min it would be would be 35,280 - 47,390.

 

So you wouldn't want to light the minimum, but rather light the maximum...so lets say you light 7; and 1 fails to light.  You will have an imbalance in thrust from one side, so you need to reduce the power on the other engines (equal to 1 engines worth).  That means failing to light a single engine could cause the loss of vehicle.  Because the range is only 6 - 7 engines you effectively have no wiggle room when it comes to underperforming  or failed relights.

 

So a single engine relight will effectively end your mission (and larger engines have the same if not maybe more changes of failing).

 

Lets look at the Raptor engines now though, lets even assume for the calculation that it had the ~65% pitfall (although raptors can do at worst 50%, but lets assume 65% which is in F-1 argument favor).  That's 1,485 - 2,260 kN 

 

Min engines required, 15.6, so 16 engines.

Max engines possible, 35280 23.7 engines; so rounding down to 23 [remember in actuality, based on the true specs, they could have 30 engines and hover]

That means the min to max range is 16 - 23 engines with a usable range of: 23,760 - 51,980

 

Notice how it allows for an extra of ~4.6 mN of wiggle room.  Also note that you can lose ~7-8 engines of thrust before an issue...going like above that means you could lose 3 - 4 engines [with balancing out the load] and still maintain within acceptable range.

 

So Uta I think the above shows the point everyone is making, that you fail to see, more engines = better resiliency when things go wrong.  The booster is capable of returning with 4 engines failing (over 10% engine loss).  That is something a large engine is unable to do...in-fact large engines makes it worse in the sense that you lose a lot more fine grain control.

[manikyath]

interesting watch, and ironically it happens to compare raptor to F1.. didnt even go to look for this and i just happened upon some sources relevant to the current debate..

i could summarize, but it's just a good watch for the entire 18 minutes.

[Uttamattamakin]

21 hours ago, manikyath said:

interesting watch, and ironically it happens to compare raptor to F1.. didnt even go to look for this and i just happened upon some sources relevant to the current debate..

i could summarize, but it's just a good watch for the entire 18 minutes.

I'll give it a look.  I know F1 is NOT how we'd build an engine now.  

 

I hope Space X's plans pan out it'll be great if they do.  I just don't like so many points of failure which when they fail they explode.   

 

23 hours ago, wanderingfool2 said:

haha, I know right.

 

Don't forget 11 F-1 engines also would weigh an extra ~40 tonnes...so expected payload to orbit would be reduced by about 40 tonnes.

Yeah I know even bringing them up makes me feel like an old senator who wonders why we don't build big gun battleships anymore. 

 

23 hours ago, wanderingfool2 said:

 

Also F-1 engines minimum thrust  at it's lowest can only be ~65%.  [1 M lbf where you got combustion instability, as per https://www.enginehistory.org/Rockets/RPE08.11/RPE08.11.shtml] Or roughly 4,448 kN.

Now here is just a bit of AI goodness then.

Mass of booster, without fuel is ~3,600,000kg [~* 9.8 to get kN]...to hover you need ~35,280 kN.

With F-1 you need 5.2 engines to match that weight (no acc./dec.).  That means you need to light at minimum 6 engines.

Now what is the max number of engines you can light to hover.  7.9, now the issue is 8 would produce too much thrust [also you wouldn't be running all engines a pure minimum].  So you end up with 7 engines max you could light.  Or 6 - 7 engines needed for a hover maneuver.

 

This is where the issue starts to come into play, which is similar to what Falcon 9 experiences (and why Falcon 9 does a suicide burn).

You could have a range of thrust with those 6 - 7 engines as follows: ~26,688 kN - ~47,390 kN.  Since the weight is 35,280 kN though the min it would be would be 35,280 - 47,390.

 

So you wouldn't want to light the minimum, but rather light the maximum...so lets say you light 7; and 1 fails to light.  You will have an imbalance in thrust from one side, so you need to reduce the power on the other engines (equal to 1 engines worth).  That means failing to light a single engine could cause the loss of vehicle.  Because the range is only 6 - 7 engines you effectively have no wiggle room when it comes to underperforming  or failed relights.

 

So a single engine relight will effectively end your mission (and larger engines have the same if not maybe more changes of failing).

 

Lets look at the Raptor engines now though, lets even assume for the calculation that it had the ~65% pitfall (although raptors can do at worst 50%, but lets assume 65% which is in F-1 argument favor).  That's 1,485 - 2,260 kN 

 

Min engines required, 15.6, so 16 engines.

Max engines possible, 35280 23.7 engines; so rounding down to 23 [remember in actuality, based on the true specs, they could have 30 engines and hover]

That means the min to max range is 16 - 23 engines with a usable range of: 23,760 - 51,980

 

Notice how it allows for an extra of ~4.6 mN of wiggle room.  Also note that you can lose ~7-8 engines of thrust before an issue...going like above that means you could lose 3 - 4 engines [with balancing out the load] and still maintain within acceptable range.

The above is all very good and informative. 

 

23 hours ago, wanderingfool2 said:

 

So Uta I think the above shows the point everyone is making, that you fail to see, more engines = better resiliency when things go wrong.  The booster is capable of returning with 4 engines failing (over 10% engine loss).  That is something a large engine is unable to do...in-fact large engines makes it worse in the sense that you lose a lot more fine grain control.

See my point below more engines means more explode things that when they fail... fail HARD and fast.  Given the track record so far Starship has a 2/3 chance of BOOM. 

 

I don't get why it is controversial to point out that Space X has seen a lot of catastrophic failures for a system we are supposed to rely on. 

[manikyath]

2 minutes ago, Uttamattamakin said:

I just don't like so many points of failure which when they fail they explode.   

and when one of SLS's engines fails it probably explodes too.. but if you have the capacity to shut down off-nominal engines before criticality (which starship's booster has) it's a boost for reliability figures... and in fact it's how the airplane industry works.

 

the 'points of failure' argument also only holds if you consider the reliability of the engine itself to be a known value to compare against. just to put some numbers behind this, we've seen two boosters reach the point of hot-staging, at which point we've essentially seen 66 raptor engines perform as expected during the critical part of the mission (landing isnt critical), which is more than the amount of RS-25 engines that were used during the entire lifespan of shuttle.

 

losing one engine (and the opposing pair for balance) also only means a 6-10% decrease in thrust (depending on pairs or triplets), which can be made up for by increasing power level on the rest, because it's been stated they have a quite decent headroom on them. if i recall they have some 30% of headroom that eventually leads into "engine-rich exhaust" (yes, every term here is a meme.. welcome to engineering) where they quite literally sacrifice engines to save the mission.

 

to me it's interesting how some very expensive problems of rocketry are resolved with surprisingly simple concepts. i find rocketlab's electron ditching batteries on it's way up a hilareous solution to the problem of electric fuel pumps.

[Lunar River]

On 3/21/2024 at 2:37 AM, Uttamattamakin said:

 

Just to check I asked Copilot to figure out how many Saturn V F1 engines would give the same thrust as superheav

What is your obsession with bringing AI into your rebuttals?

 

1 hour ago, Uttamattamakin said:

I hope Space X's plans pan out it'll be great if they do

..no, I don't think you do. You keep saying this throughout this thread, but I believe nothing would make you happier than to see spaceX fail.

 

You've already fallen into the "people who disagree with me are spaceX fans"

[wanderingfool2]

1 hour ago, Uttamattamakin said:

I don't get why it is controversial to point out that Space X has seen a lot of catastrophic failures for a system we are supposed to rely on. 

Because you are phrasing and acting as though it's a final product and showing a lack of basic understanding of how SpaceX is engineering the thing.

 

Again it's the whole concept of development.  SpaceX could spend an 5 - 6 years simulating, doing closed door testing, etc to get to the same point they are now...or they can just go out and test it can get enough information to accelerate their development cycle.

 

It's like the whole concept of Waterfall vs Agile development; back in the day the massive firms would insist that Waterfall was the only proper method, and that agile would introduce bugs/shows a lack of understanding.  Lots now in the industry focus more on agile development because it produces the results faster and gets to a finished product so much sooner at less cost.

 

1 hour ago, Uttamattamakin said:

I just don't like so many points of failure which when they fail they explode

1 hour ago, Uttamattamakin said:

See my point below more engines means more explode things that when they fail... fail HARD and fast.  Given the track record so far Starship has a 2/3 chance of BOOM. 

Ignorant statement showing that you don't know what you are talking about.  You want to say that it's because of lots of engines give PROOF of it by an actual rational argument how many engines failed it.  At the moment you just use an explosion as proof which isn't a proper rationalization of what is going on.

 

Here, let me break it down for you AGAIN:

 

IFT-1: Fire in engine bays, likely caused by hydraulic gimble system.  They flew knowing an explosion in the engine bay would take out neighboring engines though [they didn't want to retrofit their solution into it].  They flew the thing with 4 broken engines originally at liftoff.  Notice how those 4 engines didn't cause it to blow up on the pad and didn't abort the launch [although a 5th engine gone and it would have past the tolerance].

Eventually the fire got to the point it disabled the gimble system at which point termination was attempted.  So IFT-1 didn't have to do with more engines, it just had to do with fire prevention and using hydraulic fluid which becomes the fuel source.

 

IFT-2 booster: All engines fired perfectly, failed to properly relight because of fuel filter.  That would occur having single large engines as well.  So again not anything to do with lots of small engines.  More likely to do with the fact it's a 3600 ton mass where extreme forces are applied during a flip maneuver.

IFT-2 ship: Oxygen dump, which likely caused a fire in the hydraulic system again.  

 

 

They are exploding because they are trying to do things that really hasn't been done before and they are pushing their vehicles to the limits and at the same time flying hardware they know has faults but still flies it to gather more data about how it's flying [so they can make changes to future vehicles].

 

 

The chances of an engine exploding doesn't scale linearly with the number of engines when in relation to size.  Smaller engines are able to be produced more and tested/swapped out more when errors are present leading to a decreased chance of them exploding compared to a larger engine.  You get this benefit because they are able to manufacture like 360 engines in a year and test them all at extremes beyond what they will operate at and reject any that isn't performing right (or that fails).  If you can only make a few large engines though you don't have the luxury of testing them to the point where you might lose a few.  It is why Raptors will fail, but will fail in a less energetic fashion because they have already been pushed to an extreme that will not be met during flight.

 

Actually larger engines would mean you have larger pipes going to them, so when you shutdown the engine you get more of a liquid hammer than you would when you can shut-off smaller engines overtime.

 

Larger engines means more SPOF.  It's that simple.  If you want to keep claiming lots of engines = bad for Starship them actually try doing proper reasoning on WHY that amount of engines amounted to their failures...because again look above, notice how the reason for failures doesn't have to do with multiple engines.  In fact the IFT-2 ship and IFT-1 could likely be attributed directly to having a hydraulic controlled gimble. [IFT-3 had both systems electronic]

 

Again, like what I mentioning before, SpaceX is capable of over 10% of their engines during relight to fail and it will still be within it's capabilities.  If you use larger engines you knock the amount of engine failures down to 0% failures.

[manikyath]

2 hours ago, Uttamattamakin said:

Given the track record so far Starship has a 2/3 chance of BOOM. 

i missed this earlier.. but let's turn it on you...

 

Given the track record, SLS has a 100% chance of a 6 year delay.