SpaceX SN9 Explodes on Landing(twitter.com)
twitter.com
SpaceX SN9 Explodes on Landing
https://twitter.com/SpaceX/status/1356699321840721920
292 comments
SN10, wenplop?
The debris does not seem to come from next to the failing rocket engine but from the outer wall next to the engine that was not used in the landing attempt. It appears first shortly before the clock shows 6:21.
The debris does not seem to come from next to the failing rocket engine but from the outer wall next to the engine that was not used in the landing attempt. It appears first shortly before the clock shows 6:21.
> SN10 is standing by. Somewhat uncomfortably close by
That was my immediate comment at the end. Pretty confident they are.
That was my immediate comment at the end. Pretty confident they are.
This was my thought even before launch. SN9 could explode on the pad.
I though they pump it with fuel shortly before start?
Not sure why you got downvoted. When talking about 'explode on the pad' it usually refers a rocket blowing up right when the engines lights up before it lifts off.
Or alternatively during fuelling, SpaceX had that issue during Amos-6.
Or alternatively during fuelling, SpaceX had that issue during Amos-6.
Oh! I thought SN9 referred to the other rocket and imagined something like a chain explosion after the 'landing'... Thanks!
They're definitely going to need to inspect it for damage, but it does seem odd not to be THAT close
Here is my favorite footage so far, by Cosmic Perspective: https://www.youtube.com/watch?v=Ep8XJanoFgw
This is 4k slow motion and it is gorgeous. The giant sheets of stainless steel floating down at the end are noteworthy, among other details.
Michael Bay has nothing on Cosmic Perspective + SpaceX.
This is 4k slow motion and it is gorgeous. The giant sheets of stainless steel floating down at the end are noteworthy, among other details.
Michael Bay has nothing on Cosmic Perspective + SpaceX.
I love that small pressurized tank flying around after the RUD like it's trying to find the rest of the booster...
The sheets of stainless steel appear to have separated at the joints. This says the sheets are stronger than the joints, meaning they're overweight :-)
They're experimenting with 3mm steel instead of 4mm steel. A test tank they've built already passed an initial pressure test on 26 Jan.
One Starship requires 15 rings, a nosecone, a bottom and tanks. If they would all move from 4mm to 3mm then that would save a lot of weight. About 7-10 tonnes according to [1].
[1]: https://forum.nasaspaceflight.com/index.php?topic=52701.160
One Starship requires 15 rings, a nosecone, a bottom and tanks. If they would all move from 4mm to 3mm then that would save a lot of weight. About 7-10 tonnes according to [1].
[1]: https://forum.nasaspaceflight.com/index.php?topic=52701.160
Wow, that could be a really big deal in terms of maximum payload.
I was thinking something similar myself (more on weld quality, "welds should be as strong as the rest of the material"), but then I realized that this doesn't matter, and having an unoptimized test vehicle a week earlier is always going to be the better option for SpaceX.
1. Is it light enough to fly?
2. Is it strong enough to not cause a failure?
#shipit
1. Is it light enough to fly?
2. Is it strong enough to not cause a failure?
#shipit
A static weld is usually stronger than the base metal under static conditions (i.e. not undergoing dynamic shock loading). Welds are created at 3000 degrees C with 50-100C metal right next to it. By the time a weld cools there are always captive stresses, meaning during a failure the weld is the most brittle part. This can be alleviated with pre and post weld heat treatment, but there are always stresses built into a weld.
wouldn't it be common to rip right next to stiffer the joints if they where the hardest part too?
Love seeing these tests for two reasons:
1.) Experiencing history in the making, especially knowing that the SpaceX team will eventually get it right. 2.) Realizing that even the best of the best have repeated failures and need to rely on iteration to get "there."
1.) Experiencing history in the making, especially knowing that the SpaceX team will eventually get it right. 2.) Realizing that even the best of the best have repeated failures and need to rely on iteration to get "there."
On the 'repeated failures' piece, that's somewhat new for aerospace. Traditionally, things would be over-engineered, and losing a test vessel would be considered a bad thing. SpaceX seems very content to blow up a bunch of rockets on their way towards not blowing up rockets.
This seems to have caused at least part of their recent issues with the FAA, who seem to be less ok with explosions. It will be very interesting to see if this iterative approach leads to more reliable rockets down the line!
This seems to have caused at least part of their recent issues with the FAA, who seem to be less ok with explosions. It will be very interesting to see if this iterative approach leads to more reliable rockets down the line!
It’s really a throwback to the old days of aerospace. From the 1930s to the early 1960s, the standard method was to iterate rapidly with relatively cheap hardware, to learn and fix problems as quickly as possible. The von Braun and Korolev teams operated this way, among others. They all blew up a ton of rockets. What changed was the necessity of completing Saturn V and landing on the Moon by the end of the 1960s. Apollo program head George Mueller recognized that, with the planned number of iterative tests, they were going to be too late. He made the gutsy decision to launch “all-up”: spend a ton of money up front to overengineer the crap out of the vehicle and cut out most of the iteration. It worked!
But alas, the aerospace world overlearned the lesson and has been cargo-culting it ever since. Mueller’s decision was purely a matter of expediency to meet Kennedy’s goal and beat the Russians. It wasn’t a statement that this was the best way to do engineering, absent those constraints. To make matters worse, all-up only works under the funding conditions of Apollo: a massive spike in funding to cover the up-front cost. Without that spike, the costly development phase has to be stretched out, and the whole thing ends up taking longer than iteration. In other words, you can save time this way when money is absolutely no object, but otherwise you lose time. See Boeing’s SLS: basically 15 years of development and they just static-fired it for the first time. Launch is maybe a year away.
We’ve all gotten used to the all-up style of development, and SpaceX’s rediscovery of rapid iteration makes it seem like a new and untested way of doing things. But I think the dominant narrative—that all-up is prudent and conservative while iterative is risky—is completely backward. All-up carries a massive amount of risk that fundamental design issues won’t become apparent until the tremendously costly development phase is done. Iteration allows assumptions to be tested and modified as quickly as possible. Most of SpaceX’s early ideas about reusability turned out to be wrong. If they had committed all the money and time to those early concepts before flight-testing, they would have never accomplished it. The early rocketry pioneers operated this way, and it’s why they accomplished the things they did. Maybe SpaceX will finally free the space industry from perpetually repeating what worked for Apollo, which after all operated under unique political conditions.
But alas, the aerospace world overlearned the lesson and has been cargo-culting it ever since. Mueller’s decision was purely a matter of expediency to meet Kennedy’s goal and beat the Russians. It wasn’t a statement that this was the best way to do engineering, absent those constraints. To make matters worse, all-up only works under the funding conditions of Apollo: a massive spike in funding to cover the up-front cost. Without that spike, the costly development phase has to be stretched out, and the whole thing ends up taking longer than iteration. In other words, you can save time this way when money is absolutely no object, but otherwise you lose time. See Boeing’s SLS: basically 15 years of development and they just static-fired it for the first time. Launch is maybe a year away.
We’ve all gotten used to the all-up style of development, and SpaceX’s rediscovery of rapid iteration makes it seem like a new and untested way of doing things. But I think the dominant narrative—that all-up is prudent and conservative while iterative is risky—is completely backward. All-up carries a massive amount of risk that fundamental design issues won’t become apparent until the tremendously costly development phase is done. Iteration allows assumptions to be tested and modified as quickly as possible. Most of SpaceX’s early ideas about reusability turned out to be wrong. If they had committed all the money and time to those early concepts before flight-testing, they would have never accomplished it. The early rocketry pioneers operated this way, and it’s why they accomplished the things they did. Maybe SpaceX will finally free the space industry from perpetually repeating what worked for Apollo, which after all operated under unique political conditions.
I’m not sure 3200 full scale tests of Saturn V’s F-1 engine, 2000 in an iterative trial-and-error scramble to suppress combustion instabilities is what I would call “overengineered to cut out iteration” during Apollo
http://www.yang.gatech.edu/publications/Journal/JPP%20(1993,...
There was of course a ton of testing at the component level, and iteration when necessary. This worked for Saturn V because it could be done for each component in parallel, due to the huge mid-sixties spike in funding. But at the level of the integrated system, most of the testing—and nearly all of the iteration—was cut out, since it would have to be done in series for the entire rocket (or its stages). Thus the design had to be set in stone before the vehicle ever flew. The first and second stages of Saturn V flew just twice before crewed flight began. This was the right process for Apollo’s unique set of requirements and resources, but it is a bad idea when you A) don’t have a hard deadline forcing you to forego system-level iteration and B) don’t have a spike in funding to accelerate the up-front development, which otherwise takes forever. Hence SLS.
Granted, I am biased towards propulsion, but we are not talking about some bolt or bearing as a 'single component'. The propulsion system is a complex thermodynamic cycle, with tanks, turbopumps, preburner, regenerative cooling, injection, engine, nozzle, etc. Seems to be a rather involved 'component'.
That's just one engine - much less than a 5-engine stage even on a test stand, not to say about flying.
And combustion instabilities they were fighting were rather novel at the time, the engineers basically had no other options than to test a lot of variants - and invent debugging techniques with "bombs in the chamber" along the way. Fortunately it worked - low pressure of F-1 helped to mitigate problems of size.
And combustion instabilities they were fighting were rather novel at the time, the engineers basically had no other options than to test a lot of variants - and invent debugging techniques with "bombs in the chamber" along the way. Fortunately it worked - low pressure of F-1 helped to mitigate problems of size.
I don’t understand your first paragraph - is this related to the F-1 development having strong iterative components?
Also, Combustion instabilities date back to at least the A4/V2, not quite new, and largely the same engineers.
Also, Combustion instabilities date back to at least the A4/V2, not quite new, and largely the same engineers.
The F1 is a bigger (!!) version of the same engine. It's got the same crucial features:
1. turbo-pumps
2. the nozzle is cooled and the fuel warmed by making the nozzle out of tubes through which the fuel passed
3. holes drilled in the tubes so fuel leaked into the combustion chamber to provide boundary layer cooling
I think the pogo-ing was solved the same way, too - putting baffles in in various places.
1. turbo-pumps
2. the nozzle is cooled and the fuel warmed by making the nozzle out of tubes through which the fuel passed
3. holes drilled in the tubes so fuel leaked into the combustion chamber to provide boundary layer cooling
I think the pogo-ing was solved the same way, too - putting baffles in in various places.
By that logic essentially all cryogenic engines are “the same”.
In a similar vein, all modern jet engines can trace their core features back to the Ohain engine (not the Whittle engine).
I agree that Apollo set the stage for a lot of things in aerospace. It's worth noting that the death of the entire Apollo 1 crew actually led to less iteration in the late stages of the program.
The acceleration of aerospace development costs started long before the Apollo program.
That is definitely true. I do think Apollo was the turning point when rocketry changed from a development process focused on rapid iteration (seen as late as Redstone-Jupiter-Juno) to one focused on a lengthy design phase (and component testing) with late and limited integrated testing. The roots of the shift are probably in the ICBM world, but Apollo was when civilian rocketry (over)learned the lesson.
The FAA seems to be concerned with exploded bits falling on innocent people. You are welcome to blow up your rockets all day long if you aren't putting other people at risk.
The SpaceX rockets don't fly anywhere near people. Nobody is underneath any part of their flight path or within any possible destruction radii.
The early days of the Soviet space program were similar - fast construction and iterative improvements with each successive test.
Soviet rocketry was developed in the artillery department. There iterations are normal. US rocketry was developed under Air Force - here more experienced pilots, lots of training...
Plenty of American rockets failed, especially early on! https://www.youtube.com/watch?v=13qeX98tAS8
And SpaceX has blown up ten Falcons on landing attempts.
After accomplishing their primary mission, which is a key distinction. If you blow up on landing that just means you lose your reuse discount on a future flight.
That's no good for Starship, which is meant to land with passengers and hardware on board.
Yeah, which is why they're making Starship better than the Falcon 9 in being able to land safely even when things go wrong (i.e. Starship can throttle down enough to hover). They're still in the early prototyping stages. You can't judge potential long-term reliability based solely on what we've seen so far.
*While building the first space rockets in the world, literally making it up as they went.
That's not quite the same situation SpaceX is in right now.
That's not quite the same situation SpaceX is in right now.
Actually it is the same situation. The launch was fine. What blew it up is something nobody has attempted before.
It's totally different because only the government is allowed second chances! Everyone else has to get it right the first time. Especially if they're competing with <insert defense/aerospace contractors here>!
[deleted]
Never attempted what? Relight an engine? Engines are routinely re-lit, especially on upper stages, yet Space-X gets it wrong with regularity. The Russians and Arianespace do it just fine.
I'm sorry, what? SpaceX are the undisputed champions of re-lighting engines. They've landed orbital rockets 73+ times, each of which involves multiple engine re-lights while falling through the atmosphere. Let alone gets it wrong "with regularity" — the Falcon 9 Block 5 is a remarkably reliable rocket.
Anyway, landing Starship involves a bunch of things never before attempted: landing a fully-reusable second stage, landing a vehicle of this size, relighting and running engines during the belly-flop-and-flip maneuver, and flying and relighting full-flow staged-combustion engines. Probably some other firsts too.
Anyway, landing Starship involves a bunch of things never before attempted: landing a fully-reusable second stage, landing a vehicle of this size, relighting and running engines during the belly-flop-and-flip maneuver, and flying and relighting full-flow staged-combustion engines. Probably some other firsts too.
Today's crash was due to failure of one engine to restart. Briz and Fregat Russian upper stages are routinely restarted, with ~ 98 % success, same with Ariane EPS and Chinese Yuanzheng. It's doable, just not for Space-X.
You realize the Raptor engine is different from the Merlin used in Falcon rockets, right?
You're comparing a prototype against decades-old, non-reusable rockets.
Briz and Fregat start much smaller - 20 kN - engines with no time constraints, while Starship re-lights 2200 kN engine and rocket immediately does rotation by 90+ degrees, and time is of essence.
Where do thrust and chamber pressure even come into the equation? It's not that the engine exploded, the thing failed to ignite.
> Where do thrust and chamber pressure even come into the equation?
Thrust given to show difference in engine scale. Pressure isn't shown - what do you mean? :)
The point is that re-light of Briz and Fregat is very different and so hard to compare.
Thrust given to show difference in engine scale. Pressure isn't shown - what do you mean? :)
The point is that re-light of Briz and Fregat is very different and so hard to compare.
Saying SpaceX gets it wrong regularly is LITERALLY false. SpaceX Falcon 9 is fully qualified for all DoD Orbits and has reached highest qualification for NASA Scientific Missions and Human mission for. All require demonstration of reliably relight with incredibly high reliability.
In fact, in over 100 flights, SpaceX did not have a single failure of a Second Stage engine not starting or not re-lighting. This is unlike Arianespace who just had a failure when they tried to start an engine on one of their upper stages.
Outside of that Merlin is easily the engine that can be re-lit more then any other on the planet and its not close.
This however is a non-commercial prototype, where they are testing new technologies. Its a completely new engine of a type that has never flown before and is not finished developing. The vehicle has been newly designed and it does things no other vehicle has done before in a way no other vehicle has done before.
You honestly just sound like an incredibly petty hater. I can grantee you that Russia and Europe have plenty of issues with engine starting on their development engine.
In fact, in over 100 flights, SpaceX did not have a single failure of a Second Stage engine not starting or not re-lighting. This is unlike Arianespace who just had a failure when they tried to start an engine on one of their upper stages.
Outside of that Merlin is easily the engine that can be re-lit more then any other on the planet and its not close.
This however is a non-commercial prototype, where they are testing new technologies. Its a completely new engine of a type that has never flown before and is not finished developing. The vehicle has been newly designed and it does things no other vehicle has done before in a way no other vehicle has done before.
You honestly just sound like an incredibly petty hater. I can grantee you that Russia and Europe have plenty of issues with engine starting on their development engine.
Why is SpaceX making the same mistakes 70 years later?
I don't recall NASA ever doing a rocket landing so I'm not sure which mistakes you are seeing repeated.
I was surprised to learn recently that NASA did do some rocket landings in the 90s: https://en.wikipedia.org/wiki/McDonnell_Douglas_DC-X
Ok, so which mistakes is SpaceX making that NASA also made?
NASA and the USSR did many powered rocket landings, actually. NASA even had a program for reusable first stages via powered landings that was scrapped because automatic guidance wasn't feasible yet.
Ok, so which mistakes is SpaceX making that NASA also made?
Failing to restart an engine in a retrograde trajectory. A difficult task that both the Soviets and NASA (and Arianespace and the Chinese) had issues with, but worked out.
It's very difficult because of the turbulent airflow in an engine bell pointed against the airspeed vector. Despite this, many rocket engines can do it reliably.
It's very difficult because of the turbulent airflow in an engine bell pointed against the airspeed vector. Despite this, many rocket engines can do it reliably.
> Failing to restart an engine in a retrograde trajectory
That's not a failure, that's the effect of some upstream failure.
What failure are they repeating? Pumps sized too small? Improper torquing? You talk like you know the details, so share them.
That's not a failure, that's the effect of some upstream failure.
What failure are they repeating? Pumps sized too small? Improper torquing? You talk like you know the details, so share them.
There are a lot of reasons for which an engine would fail to start in such a scenario. They all boil down to the turbulent airflow and high pressure in the nozzle inhibiting the ignition process.
How exactly you decide to fix it depends on many things. It's impossible to tell. But they are all downstream of the same failure, which is overcoming the high pressure and turbulent flow.
How exactly you decide to fix it depends on many things. It's impossible to tell. But they are all downstream of the same failure, which is overcoming the high pressure and turbulent flow.
NASA did rocket landings on another planet with 1970s technology: https://en.wikipedia.org/wiki/Viking_program#Entry,_Descent_...
>At an altitude of about 1.5 kilometers (5,000 feet), the lander activated its three retro-engines and was released from the parachute. The lander then immediately used retrorockets to slow and control its descent, with a soft landing on the surface of Mars.
>At an altitude of about 1.5 kilometers (5,000 feet), the lander activated its three retro-engines and was released from the parachute. The lander then immediately used retrorockets to slow and control its descent, with a soft landing on the surface of Mars.
Ok, so which mistakes is SpaceX making that NASA also made?
The same outcome does not require the same cause.
>> On the 'repeated failures' piece, that's somewhat new for aerospace
Unless you go back to the early pre-Mercury program days of NASA - they had lots of failures, and that was just trying to go up without re-usability, not land and reuse. There's all kinds of fun failure reels (e.g., [1]) and lists (e.g., [2])
[1] https://www.youtube.com/watch?v=g79K-R7xTFo [2] https://en.wikipedia.org/wiki/List_of_spaceflight-related_ac...
Unless you go back to the early pre-Mercury program days of NASA - they had lots of failures, and that was just trying to go up without re-usability, not land and reuse. There's all kinds of fun failure reels (e.g., [1]) and lists (e.g., [2])
[1] https://www.youtube.com/watch?v=g79K-R7xTFo [2] https://en.wikipedia.org/wiki/List_of_spaceflight-related_ac...
You're basically watching the CI/CD workflow for the best aerospace organization in the world, live on YouTube.
> that's somewhat new for aerospace
Because NASA does not launch anything anymore. If they were doing hundreds of launches per year you can bet you'd see failures the whole time.
Because NASA does not launch anything anymore. If they were doing hundreds of launches per year you can bet you'd see failures the whole time.
[deleted]
SpaceX themselves made a failure montage for Falcon 9
https://www.youtube.com/watch?v=bvim4rsNHkQ
It's easy to forget how many failures that had, but look how far it has come, at this point I don't think they've had any major failures in 5+ years. Maybe a couple sea drone ship booster landing issues but zero mission failures in a very long time.
https://www.youtube.com/watch?v=bvim4rsNHkQ
It's easy to forget how many failures that had, but look how far it has come, at this point I don't think they've had any major failures in 5+ years. Maybe a couple sea drone ship booster landing issues but zero mission failures in a very long time.
This is one of my favorite videos. On the SN9 explosion today my partner speculated that SpaceX should make one like this for Starship one day. :)
Neat, seems pretty much any mistake results in a fireball.
Scott Manley and daughter have a fun song about other failures, "You will not go to space today", https://www.youtube.com/watch?v=Ayu0GsrvKQA
I'm guessing the title is probably an allusion to this https://xkcd.com/1133/.
Scott Manley and daughter have a fun song about other failures, "You will not go to space today", https://www.youtube.com/watch?v=Ayu0GsrvKQA
I'm guessing the title is probably an allusion to this https://xkcd.com/1133/.
I was half expecting:
"If an O-ring gets a bit too cold, you will not go to space today"
...but I guess that's a bit too dark, eh?
"If an O-ring gets a bit too cold, you will not go to space today"
...but I guess that's a bit too dark, eh?
"If your rocket runs at all engine rich, you will not go to space today..."
And after every crash I have to read this comment.
And that's why you have an assembly line for Starships: https://i.redd.it/dmr9bjhpcee61.jpg (SN9 lacking the RUD symbol in that image of course.)
Also note that BN1 (which is the booster stage) is getting close to completion! I wonder when we'll see one of those fly?
I saw photos a few days ago that the base piece of the BN1, which will need to hold the weight of the entire thing and thrust mounts for the engines has been spotted at boca chica.
This is why we test. (In this case, header tank helium pressurization and more thermal tiles.)
At least they didn't hit SN10!
Summary tomorrow in this week's Orbital Index (https://orbitalindex.com).
At least they didn't hit SN10!
Summary tomorrow in this week's Orbital Index (https://orbitalindex.com).
Well, they popped a bunch of Falcon 9s until they got those right.
Can they relight sooner to improve their odds of landing successfully, or is the window for when they can relight relatively small?
Or does it not matter because a few more seconds won't increase the chances they'll be able to relight?
Or does it not matter because a few more seconds won't increase the chances they'll be able to relight?
Keep in mind that every millilitre of fuel burned has to be carried from the start.
If you want to start burning a few seconds early on landing by policy, you need to lift that fuel, and the fuel to lift that fuel, from the surface to space and then decelerate all of that. Just for those seconds. If you’re doing this from Mars, you also have to accelerate that mass around the Solar System and out of the Martian gravity well.
Not a bad thought. Just wanted to illustrate how energetically leveraged these systems are.
If you want to start burning a few seconds early on landing by policy, you need to lift that fuel, and the fuel to lift that fuel, from the surface to space and then decelerate all of that. Just for those seconds. If you’re doing this from Mars, you also have to accelerate that mass around the Solar System and out of the Martian gravity well.
Not a bad thought. Just wanted to illustrate how energetically leveraged these systems are.
It's just a question of money. Starship will eventually be re-fueled in earth orbit.
That's true for missions beyond LEO, but for routine LEO missions there's no expectation to do refuels for every flight. Also vehicles returning from missions beyond LEO will not be able to refuel before re-entry and landing.
That's a good question actually, given that they had another engine as well. Or maybe light up all three and then shut down the one they decide not to use.
But these are all in the 'why don't they' category, SpaceX has some pretty clever cookies, experts in their field, the chances that anything we can think of has not been thought of by them are nil.
But these are all in the 'why don't they' category, SpaceX has some pretty clever cookies, experts in their field, the chances that anything we can think of has not been thought of by them are nil.
I'm reminded of the story of two economists walking down the street. One sees a dollar bill on the ground, and the other decides "that can't be right; if there was a dollar bill on the ground someone would've picked it up already".
Not saying that a bunch of random folks on HN are seeing dollar bills in this analogy, but I've never quite been satisfied with the "if we're thinking of it then they probably already tried it" explanation :)
Not saying that a bunch of random folks on HN are seeing dollar bills in this analogy, but I've never quite been satisfied with the "if we're thinking of it then they probably already tried it" explanation :)
"Question: Why only light 2 engines for landing? Any engine failure means loss of vehicle, so you have two single points of failure. Why not light all 3, do the flip, then pick the best two and turn off the other?"
"We were too dumb" https://twitter.com/elonmusk/status/1357256507847561217
"We were too dumb" https://twitter.com/elonmusk/status/1357256507847561217
Hm. Ok.
> but I've never quite been satisfied with the "if we're thinking of it then they probably already tried it" explanation :)
Same here :) . I'm still unhappy with their decision to use toxic propellants on Crew Dragon - I'm sure they could use something much more benign.
Same here :) . I'm still unhappy with their decision to use toxic propellants on Crew Dragon - I'm sure they could use something much more benign.
To be fair they selected it quite some time ago now. There's a lot of very promising research now though, so hopefully they will have better options available down the line.
> To be fair they selected it quite some time ago now.
They've had better fuel options from the very beginning. I guess they didn't have space cycles to additionally solve this issue; hope they'll come back to it.
They've had better fuel options from the very beginning. I guess they didn't have space cycles to additionally solve this issue; hope they'll come back to it.
The landing propellant comes from very small header tanks (to reduce slosh), and those tank sizes constrain how long they can run a landing burn. Future iterations may end up with a bigger header: these are still early prototypes.
[deleted]
Illustration how "move fast and break things" in aerospace domain works.
Honestly, my main takeaway from this testing and Falcon 9 dev has been that we should be doing a whole lot more of that than we have been, at least until there are human passengers. The contrast in rate of progress with eg SLS is stunning.
We knew this since watching how much the Russians got done in the time they had for the resources. Put the engineers together with the manufactures, build often, test more.
just don't sit near the launchpad
And if anyone believes wp381640 is joking, this lesson seems to have been learned the hard way: https://en.m.wikipedia.org/wiki/Nedelin_catastrophe
"54–300 deaths (exact number not known)"
Wow, I can't imagine a disaster happening in the United States where we barely even knew the order of magnitude of fatalities.
Wow, I can't imagine a disaster happening in the United States where we barely even knew the order of magnitude of fatalities.
Also keep in mind that it's already doing what pre-F9 rockets did: go up. The RUDs so far are on landing attempts. Landing is a whole lot harder.
There's a key difference though, Starship is intended to carry people. The correct comparison for this isn't landing Falcon 9 boosters, it's landing crew capsules.
Falcon 9 was also intended to carry people.
Starship is a more capable upper stage then Crew Capsule, part of which means that it can launch itself (at least suborbital). They aren't trying to qualify these prototypes as human-rated, they have to finish the design work first!
For this pase of testing it's much more accurate to compare to Falcon 9 than Crew Capsule.
Starship is a more capable upper stage then Crew Capsule, part of which means that it can launch itself (at least suborbital). They aren't trying to qualify these prototypes as human-rated, they have to finish the design work first!
For this pase of testing it's much more accurate to compare to Falcon 9 than Crew Capsule.
Oh come on, the Dragon capsule brings people back to the ground, not the first stage booster and it's landing these things that is the issue so far, not launching them.
All I am saying is that this vehicle, in it's final qualified form, will be landing human beings on the deck back here on Earth. That's the objective, so it's viability and reliability needs to be considered in that context.
For an F9 first stage a failure rate of 1/10 is fine. One out of 20 is outstanding. For Starship, these things are intended to carry a hundred paying passengers or more. The failure rate needs to be lower than 1 in a thousand. Much lower.
All I am saying is that this vehicle, in it's final qualified form, will be landing human beings on the deck back here on Earth. That's the objective, so it's viability and reliability needs to be considered in that context.
For an F9 first stage a failure rate of 1/10 is fine. One out of 20 is outstanding. For Starship, these things are intended to carry a hundred paying passengers or more. The failure rate needs to be lower than 1 in a thousand. Much lower.
I mostly agree with you, but I'm not sure on why you're focusing human passenger safety on this at this early development stage, as if it's somehow a reasonable thing to focus on.
Launching these things IS the issue so far, by far the main objective of these tests. Landing them would be nice, but the primary objectives are to launch the whole thing (in particular including aero surfaces and multiple engines, as compared to previous prototypes) and test the various novel maneauvres that they are attempting. That almost all the objectives are being met in these tests is a testament to how good SpaceX is getting at launching flying water tanks, and how hard the entire flight profile is to achieve (launch, belly flop, landing flip, landing).
In the anticipated human-rated version of Starship safety will be immensely important, but this is nowhere near being that thing! This was only the second prototype that even started to look like 'Starship'. We have no idea what a human-rated version would loook like, and a human-rated Starship is definitely not the objective of these tests.
The Starship prototypes they are testing at the moment are much much much closer to a Falcon 9 than a capsule. Specifically the systems and processes they are testing all have fairly direct parallels in Falcon 9, and almost no correspondence to a capsule. For example, Falcon 9 and Starship both have: super chilled propellent tanks, multiple large rocket engines, active flight control systems, engine relight, active aero surfaces, and powered landing. Starship and the capsule both have... heatshields?
Human passenger safety will be immensely important for Starship, but to focus on it at this stage of development would be immensely premature.
Launching these things IS the issue so far, by far the main objective of these tests. Landing them would be nice, but the primary objectives are to launch the whole thing (in particular including aero surfaces and multiple engines, as compared to previous prototypes) and test the various novel maneauvres that they are attempting. That almost all the objectives are being met in these tests is a testament to how good SpaceX is getting at launching flying water tanks, and how hard the entire flight profile is to achieve (launch, belly flop, landing flip, landing).
In the anticipated human-rated version of Starship safety will be immensely important, but this is nowhere near being that thing! This was only the second prototype that even started to look like 'Starship'. We have no idea what a human-rated version would loook like, and a human-rated Starship is definitely not the objective of these tests.
The Starship prototypes they are testing at the moment are much much much closer to a Falcon 9 than a capsule. Specifically the systems and processes they are testing all have fairly direct parallels in Falcon 9, and almost no correspondence to a capsule. For example, Falcon 9 and Starship both have: super chilled propellent tanks, multiple large rocket engines, active flight control systems, engine relight, active aero surfaces, and powered landing. Starship and the capsule both have... heatshields?
Human passenger safety will be immensely important for Starship, but to focus on it at this stage of development would be immensely premature.
I suppose that’s fair, but I think public perception might be a bit different. The public aren’t used to watching prototype jet airliners crashing in flames on runways, so some people are going to be concerned about it.
Completely agree, and the messaging is really hard to get right.
They are doing these dramatic tests out in the open which sure gets a lot of attention, but there is a real risk of reputation damage or fodder in the hands of their competitors lobbyists.
I don't know a good way to resolve that, but I certainly prefer the current approach and trust that anyone who really cares about the safety will be able to understand what's important about these tests and what isn't.
Even on the crappy morning news here, where they certainly gave a lot of airtime to the fireball, they had an expert on who focused on what the test was aiming to achieve. There certainly was no focus on the idea that Starship is intended to eventually carry passengers (even though they mentioned it alongside stock renders of Starship going to mars and the moon).
They are doing these dramatic tests out in the open which sure gets a lot of attention, but there is a real risk of reputation damage or fodder in the hands of their competitors lobbyists.
I don't know a good way to resolve that, but I certainly prefer the current approach and trust that anyone who really cares about the safety will be able to understand what's important about these tests and what isn't.
Even on the crappy morning news here, where they certainly gave a lot of airtime to the fireball, they had an expert on who focused on what the test was aiming to achieve. There certainly was no focus on the idea that Starship is intended to eventually carry passengers (even though they mentioned it alongside stock renders of Starship going to mars and the moon).
Interesting point, the image of a bunch of these blowing up in testing might loom large in people's minds once it starts carrying people, even if they rationally know it's had a much better safety record since then.
Unfortunately it seems like traditional aerospace now has a very big lever to pull to get SpaceX shut down: public opinion following the reasoning "rocket go boom. go boom bad. rocket bad".
Or actually the other way around - what will be in the news, another successful Atlas V or Ariane 5 or a nice big powerful explosion during a test flight ? That can bring a lot of interest from people not to mention disseminate the news about Starship far and wide.
If that was going to work it would have already. SpaceX has been blowing up rockets for years.
The way to make them more reliable is not to put human passengers while increasing the iteration rate and manufacturing speed.
The two ways I heard to get really reliable products is to get good at manufacturing them reliably at scale or be really slow and really careful in making them one at a time.
The two ways I heard to get really reliable products is to get good at manufacturing them reliably at scale or be really slow and really careful in making them one at a time.
Well. Yes. It appears to be a fully functioning launch vehicle and just as reusable as its predecessors, don’t see much downside in making the landings more “interesting”. When they work out the dynamics of it then they really have something that will revolutionize launches
They landed a lot of falcon 9 first stages without legs on the water, vertically, to test the control system. And a number of attempted barge landings with legs failed, before the first successful landing. Now it's almost a routine thing.
That's probably what FAA was peeved about SN8. They might have been expecting a water landing and didn't like that an unproven rocket was sent back to dry land.
The Falcon landed on land before it landed on a barge. Obviously landing on a moving/swaying barge is harder, however they had to start with water landings because they hadn't proved they could aim at their target. Once they crashed into the barge a few times, the FAA was convinced they'd only blow up the landing pad and not drop it on something else in the launch complex. So they got clearance for landing on land.
The early starhopper/starship flights proved what they needed to that they'd generally land on target.
The early starhopper/starship flights proved what they needed to that they'd generally land on target.
No, it was the last minute engine swap.
Is there a source for that? I've heard tons of speculation & I'd be very interested to know if the mystery has definitively been settled!
‘We may crash, but at least we do it with style!”
Somehow that should be an Elon tweet.
Somehow that should be an Elon tweet.
If you happen not to have seen it, "How Not To Land an Orbital Rocket Booster": https://www.youtube.com/watch?v=bvim4rsNHkQ from SpaceX.
You could also call this TDD.
I think one thing that people fail to appreciate about what SpaceX is doing is their core believe with this project is that the manufacturing system is 10-100x more difficult then the design of the rocket itself, and that their goals can only be achieved if these two things are co-designed.
Their goals are to design a rocket system capable of landing on Earth, Moon, Mars and possibly others. Is must be able to refuel in space. It must be able to rapidly reusable, as in the same day multiple times. It must be cheap to manufacture, and it must be cheap to operate.
Every prototype brings in lots of new changes, none is exactly like that before, every around 5 prototypes there is a major generation upgrade. Every new prototype does not just test the new design, but also the improved manufacturing process.
All the learnings from both the build and the launch flow directly back to the developers and engineers working on it, and the required changes to into the backlog and eventually make it into later prototypes.
What the outcome of this process is, who knows unknown. SpaceX has shown to be incredibly flexible and change to new things quickly and without making a big deal about it. The change from carbon to stainless steel for example is a case where SpaceX had already tested tanks, they had already ordered tools, they had already bought a location. Within one month they dropped that. Iteration speed to slow, material cost to high, performance gain when combined with heat shield not worth it anyway.
Only when you consider cost, heat-shield consideration and iteration speed is it clear that stainless steel beats carbon fiber by a large margin.
The heat shield has been changed multiple times. The fins have been redesigned multiple times. The legs are a hot issue right now. The header tank design has changed over time. And so on and so on.
SpaceX will move forward like that, produce more and more prototypes that are closer and closer to the almost impossible goal. Every prototype is a fully integrated test from materials, design, manufacturing and operations.
Their goals are to design a rocket system capable of landing on Earth, Moon, Mars and possibly others. Is must be able to refuel in space. It must be able to rapidly reusable, as in the same day multiple times. It must be cheap to manufacture, and it must be cheap to operate.
Every prototype brings in lots of new changes, none is exactly like that before, every around 5 prototypes there is a major generation upgrade. Every new prototype does not just test the new design, but also the improved manufacturing process.
All the learnings from both the build and the launch flow directly back to the developers and engineers working on it, and the required changes to into the backlog and eventually make it into later prototypes.
What the outcome of this process is, who knows unknown. SpaceX has shown to be incredibly flexible and change to new things quickly and without making a big deal about it. The change from carbon to stainless steel for example is a case where SpaceX had already tested tanks, they had already ordered tools, they had already bought a location. Within one month they dropped that. Iteration speed to slow, material cost to high, performance gain when combined with heat shield not worth it anyway.
Only when you consider cost, heat-shield consideration and iteration speed is it clear that stainless steel beats carbon fiber by a large margin.
The heat shield has been changed multiple times. The fins have been redesigned multiple times. The legs are a hot issue right now. The header tank design has changed over time. And so on and so on.
SpaceX will move forward like that, produce more and more prototypes that are closer and closer to the almost impossible goal. Every prototype is a fully integrated test from materials, design, manufacturing and operations.
When you look at the history of the space race between Soviets vs USA, one thing that is clear is the approach used by both countries to engineer their craft were very different. The Soviets would do design by testing and blow up many rockets and gather data vs the USA which would be more up-front about it's design and design testing before gong live.
SpaceX clearly took the Soviet's approach to rocket design.
EDIT: This is not a negative thing. Soyuz is pretty darn safe because of the approach they took.
SpaceX clearly took the Soviet's approach to rocket design.
EDIT: This is not a negative thing. Soyuz is pretty darn safe because of the approach they took.
While the US had better tech and improved design they all tested the shit out of things before going live and then ran live tests on unmanned rockets, many of which exploded quick spectacularly. Soyuz might be safe now, but that safety was paid for by many near-misses and in several cases in cosmonaut blood. Your statement regarding US vs Soviet approach to the space race is simply wrong.
> As of 2020, there have been 15 astronaut and 4 cosmonaut fatalities during spaceflight. Astronauts have also died while training for space missions, such as the Apollo 1 launch pad fire which killed an entire crew of three
The numbers don't really seem to support your assertion that NASA is generally much safer than Soviet/Russia
The numbers don't really seem to support your assertion that NASA is generally much safer than Soviet/Russia
At least 126 technicians and cosmonauts were killed by accidents during the Soviet space program. It’s rumored that additional cosmonauts died on missions that the Soviets covered up.
We also lost all three astronauts in a test of the Apollo capsule which doesn’t count as flight but I think we would agree still counts in the buckets of blood both programs have spent.
If you do more tests which kill more people before declaring the system good, you don’t get to not count those people like it’s a different color of money in some bureaucratic dystopia.
If you do more tests which kill more people before declaring the system good, you don’t get to not count those people like it’s a different color of money in some bureaucratic dystopia.
As far as technicians, I've always felt sad for the two Space Shuttle technicians who died in 1981 after entering a nitrogen-filled engine compartment (John Bjornstad and Forrest Cole).
It's very sad but it's not a bad way to go. I was a nuclear plant supervisor for about 20 years. One day the temp started to increase in the control room. The 3 AC units were behind the control room so I headed there to check on things. Another guy said he'd go with me. These things are as big as locomotives. Well while we were in the room a refrigerant relief valve lifted with a huge roar. Turns out, amazingly, the relief was designed to vent into the room. We made it to the card reader to get back into the control room but my card kept being rejected. I felt myself sliding down the wall and next I knew I was sitting in a chair in the control room feeling better and better. If my buddy hadn't decided to come with me I would have died in that room.
There was no panicky brain screaming "we need air" or any feeling of being O2 short. It was just normal breathing. If you're going to end it all that's the way to do it.
I wrote an incident report with the obvious suggestion to vent the reliefs outside. It was modified the next outage.
There was no panicky brain screaming "we need air" or any feeling of being O2 short. It was just normal breathing. If you're going to end it all that's the way to do it.
I wrote an incident report with the obvious suggestion to vent the reliefs outside. It was modified the next outage.
"But what if we vent the toxic gas into the place where you go to see if there's a problem with the toxic gas..."
Three died in that accident. The third lingered for a couple years before passing.
That's likely to include the Nedelin catastrophe ( https://en.wikipedia.org/wiki/Nedelin_catastrophe ) -
"The most recent estimated death toll, released by Roscosmos on the 50th anniversary of the accident and originating with agency engineer Boris Chertok, was that 126 people had died, but the agency qualified the number by saying that the actual number could be anywhere from 60 to 150 dead."
"The most recent estimated death toll, released by Roscosmos on the 50th anniversary of the accident and originating with agency engineer Boris Chertok, was that 126 people had died, but the agency qualified the number by saying that the actual number could be anywhere from 60 to 150 dead."
The Nedelin catastrophe was an ICBM test run of a rocket with hypergolic fuel that exploded on the launch pad; there was the 1980 launch pad explosion of a (military) sattelite launcher that killed 44 people and injured 43. The Russian version of the article says that hydrogen peroxide filters were produced with catalytic materials, this was later fixed after another launch almost failed in the same manner (it doesn't say how that blast was avoided), initially they suspected an action of the ground crew to have causes the blast in 1980. Both blasts were kept secret until Perestroika in 1989. both explosions were on rockets with hypergolic fuel.
The Russian wikipedia article also has a list of 'other failures' - these are fires in an ICBM silo in Russia in 1960 - eight dead; the US had a fire in a Titan II bunker in 1965 that killed 53 and another one in 1980 that killed one man; also Brazil had a fire of a liquid fueled rocket that killed 21, also on start preparations. (and another blast in Plesetsk in 1973 that killed seven http://www.plesetzk.ru/index.php?p=1973&d=doc/disaster - wikipedia doesn't list everything)
Rocket fuel can be very dangerous stuff! At least liquid methane/oxygen aren't hypergolic.
https://en.wikipedia.org/wiki/1980_Plesetsk_launch_pad_disas... https://ru.wikipedia.org/wiki/%D0%9A%D0%B0%D1%82%D0%B0%D1%81...
The Russian wikipedia article also has a list of 'other failures' - these are fires in an ICBM silo in Russia in 1960 - eight dead; the US had a fire in a Titan II bunker in 1965 that killed 53 and another one in 1980 that killed one man; also Brazil had a fire of a liquid fueled rocket that killed 21, also on start preparations. (and another blast in Plesetsk in 1973 that killed seven http://www.plesetzk.ru/index.php?p=1973&d=doc/disaster - wikipedia doesn't list everything)
Rocket fuel can be very dangerous stuff! At least liquid methane/oxygen aren't hypergolic.
https://en.wikipedia.org/wiki/1980_Plesetsk_launch_pad_disas... https://ru.wikipedia.org/wiki/%D0%9A%D0%B0%D1%82%D0%B0%D1%81...
I've always loved Ignition![0] for the perspective it gives on working with the chemistry of this stuff.
[0] https://www.amazon.com/Ignition-Informal-Propellants-Univers...
[0] https://www.amazon.com/Ignition-Informal-Propellants-Univers...
But the U.S. has sent 3x as many citizens into space: https://en.wikipedia.org/wiki/List_of_space_travelers_by_nat...
So combining with your statistic the U.S. has a fatality rate of 4.4% versus Russia's 3.3%. Given the low N it's probably within margin of error.
So combining with your statistic the U.S. has a fatality rate of 4.4% versus Russia's 3.3%. Given the low N it's probably within margin of error.
At least 60 of those Americans were sent up on the Russian Soyuz: https://en.wikipedia.org/wiki/List_of_Russian_human_spacefli...
Also, How are you doing the math to get a 4.4% fatality rate? The numbers are much lower than that.
Soyuz has launched 394 people and killed 4 of them. The most recent fatality was 50 years ago. The Shuttle launched 833 people and killed 14 of them, most recently in 2003 (8 years before the program ended). That gives Soyuz a fatality rate of 1.0% and the Shuttle a fatality rate of 1.7%. In other words: You're 70% more likely to die if you ride the Shuttle instead of Soyuz.
The more you look into the specifics, the safer Soyuz seems. The Soyuz deaths were early in the program while the Shuttle deaths happened when the program was mature. (Soyuz 11 was the last fatality and it was the 10th manned mission. STS-51-L was the 25th Shuttle mission and was considered to be safe enough for a civilian teacher to ride along. Oops.)
Soyuz's design is inherently safer. It has a launch escape system (which saved the crew of Soyuz 7K-ST No.16L).[1] The Shuttle did not. Soyuz's heat shield is much more robust than the Shuttle's. Soyuz's crew section is on top of the rocket, reducing the chance that any falling debris (or shrapnel caused by an explosion) will harm the crew module. Lastly, Soyuz uses liquid fueled rockets that can be shut off at any time. The Shuttle's solid boosters could not be throttled or shut off. All of these design decisions make for a simpler and safer vehicle. If I had to pick one, I'd ride Soyuz for sure.
1. https://en.wikipedia.org/wiki/Soyuz_7K-ST_No.16L
Soyuz has launched 394 people and killed 4 of them. The most recent fatality was 50 years ago. The Shuttle launched 833 people and killed 14 of them, most recently in 2003 (8 years before the program ended). That gives Soyuz a fatality rate of 1.0% and the Shuttle a fatality rate of 1.7%. In other words: You're 70% more likely to die if you ride the Shuttle instead of Soyuz.
The more you look into the specifics, the safer Soyuz seems. The Soyuz deaths were early in the program while the Shuttle deaths happened when the program was mature. (Soyuz 11 was the last fatality and it was the 10th manned mission. STS-51-L was the 25th Shuttle mission and was considered to be safe enough for a civilian teacher to ride along. Oops.)
Soyuz's design is inherently safer. It has a launch escape system (which saved the crew of Soyuz 7K-ST No.16L).[1] The Shuttle did not. Soyuz's heat shield is much more robust than the Shuttle's. Soyuz's crew section is on top of the rocket, reducing the chance that any falling debris (or shrapnel caused by an explosion) will harm the crew module. Lastly, Soyuz uses liquid fueled rockets that can be shut off at any time. The Shuttle's solid boosters could not be throttled or shut off. All of these design decisions make for a simpler and safer vehicle. If I had to pick one, I'd ride Soyuz for sure.
1. https://en.wikipedia.org/wiki/Soyuz_7K-ST_No.16L
Of course proving a simple design and sticking with it is safer! Not going to space and being content with remaining on the ground is safer still! Water is wet! The sky is blue!
We can all see what happened: the soviets stopped spending money on innovation and tried to re-frame their stagnation as operational brilliance. Sure, Soyuz has a reliability niche, and I'd rather ride on it too, but I'd rather fund efforts to advance space exploration, even if they wind up being a clusterfuck like the shuttle.
We can all see what happened: the soviets stopped spending money on innovation and tried to re-frame their stagnation as operational brilliance. Sure, Soyuz has a reliability niche, and I'd rather ride on it too, but I'd rather fund efforts to advance space exploration, even if they wind up being a clusterfuck like the shuttle.
Aren't solid boosters, like those used by the Shuttle, a simpler design than liquid engines?
On top of that, the Raptor engines used in the Starship, which seem to be considered state-of-the-art, are based on a soviet design from the 60s.
On top of that, the Raptor engines used in the Starship, which seem to be considered state-of-the-art, are based on a soviet design from the 60s.
Raptors are state of the art. They are based on a soviet design from the 60s in the same way that they are based on US designs from the 60s.
It's weird that people seem so keen to talk up the soviet part and talk down the US part.
It's weird that people seem so keen to talk up the soviet part and talk down the US part.
I think he is referring to the Soviet https://en.wikipedia.org/wiki/RD-270 full-flow staged combustion engine from the 60s.
The Americans had not been able to preserve the high-pressure hot oxygen from eating the preburner.
I don’t think it makes an enormous difference, but not all of those US citizens flew in US rockets (nor did all Russian ones)
Also, quite a few of those did multiple flights. Looking at that list, I think that moves the needle in favor of US rocket safety.
Also, quite a few of those did multiple flights. Looking at that list, I think that moves the needle in favor of US rocket safety.
Soviet spaceflights were quite long compared to American - Salyut-6 and Salyut-7 both had more expeditions than Skylab, and that's before Mir, while Shuttles were limited to about a month in space per flight. Of course launch and landing are more dangerous phases of flight - Apollo-13 notwithstanding - so it makes harder to pinpoint an objective measure for safety.
Both had two vehicles lost in space/reentry, the shuttles just held more astronauts. In terms of percentage of fatal missions the two were roughly equivalent, with Soviet failures front-loaded into less sophisticated and less safe early vehicles while the US failures were later on an overly-complicated system design.
Challenger? What's your point? That Russia didn't beat the US into space? I thought the west at least accepted that fact. Or do you just have to believe the US is ALWAYS "superior"?
Downvoting again? Rather than articulate a response?
I was confused by "Russia didn't beat US into space" - you probably meant "to the Moon" (manned flights), while USSR had quite a few space firsts.
No, I meant that the above response calling the other user wrong is wrong itself. The USSR, had it not had to fight a cold war against the US, could very well have been a much better system not just for space flight, but for a way to structure and run society in general.
But yet, if I say this, I will be immediately downvoted because if I suggest that anything other than the established order in the US is the best system, the powers that be as well as the indoctrinated individuals that frequent this place would rather just shut that conversation up than to engage it meaningfully.
But yet, if I say this, I will be immediately downvoted because if I suggest that anything other than the established order in the US is the best system, the powers that be as well as the indoctrinated individuals that frequent this place would rather just shut that conversation up than to engage it meaningfully.
> The USSR, had it not had to fight a cold war against the US, could very well have been a much better system not just for space flight, but for a way to structure and run society in general.
What makes you think that? If they had such a wonderful "way to structure and run society in general", why did the USSR and its satellite states have to systematically mass murder people who wanted to leave this wonderful society?
[0] https://en.wikipedia.org/wiki/Emigration_from_the_Eastern_Bl...
[1] https://en.wikipedia.org/wiki/Schie%C3%9Fbefehl
[2] https://en.wikipedia.org/wiki/Mass_graves_from_Soviet_mass_e...
[3] https://en.wikipedia.org/wiki/NKVD_prisoner_massacres
[4] https://en.wikipedia.org/wiki/Holodomor
What makes you think that? If they had such a wonderful "way to structure and run society in general", why did the USSR and its satellite states have to systematically mass murder people who wanted to leave this wonderful society?
[0] https://en.wikipedia.org/wiki/Emigration_from_the_Eastern_Bl...
[1] https://en.wikipedia.org/wiki/Schie%C3%9Fbefehl
[2] https://en.wikipedia.org/wiki/Mass_graves_from_Soviet_mass_e...
[3] https://en.wikipedia.org/wiki/NKVD_prisoner_massacres
[4] https://en.wikipedia.org/wiki/Holodomor
Well, why did the US actively try to harm the USSR? If it was such a bad way of doing things, why did the US actively go out of it's way to sabotage it rather than just ignore it and let it die?
This is moving the goalposts.
It's possible that the USSR would have been a better system, had the cold war not happened, but that's not the world we live in. If you want to make that argument you have to explain why it's reasonable to excuse how the USSR turned out in reality, and why in your hypothetical world it would have turned out differently.
With respect to space advancement, I suspect the main reason for sustained differences in accomplishments come down primarly to the amount of resources each were able to devote to space. The US was able to sustain a high level of investment for a long time, and the USSR was not.
It's possible that the USSR would have been a better system, had the cold war not happened, but that's not the world we live in. If you want to make that argument you have to explain why it's reasonable to excuse how the USSR turned out in reality, and why in your hypothetical world it would have turned out differently.
With respect to space advancement, I suspect the main reason for sustained differences in accomplishments come down primarly to the amount of resources each were able to devote to space. The US was able to sustain a high level of investment for a long time, and the USSR was not.
It's not moving to goalposts to acknowledge that the USSR beat us to space and that a large part of their collapse was due directly to the influence of the US.
Upthread there was a claim by evgen that the way the US vs Soviet approach to the space race had been characterised by mempko was incorrect, and that the current safety of the Soyuz was (at least in part) paid for with the lives of cosmonauts.
You go on to state that Russia beat the US into space (which is a non-sequitur), and later expand that "The USSR, had it not had to fight a cold war against the US, could very well have been a much better system not just for space flight, but for a way to structure and run society in general."
When challenged by alentist, who asked "why did the USSR and its satellite states have to systematically mass murder people who wanted to leave this wonderful society?" you countered with "If it was such a bad way of doing things, why did the US actively go out of it's way to sabotage it" which is moving the goalposts, and starts to slide into whattaboutism.
Specifically you claimed that the USSR "could very well have been" a better way to structure a society, and alentist provided strong evidence that it was not - people were murdered when they tried to leave. Instead of trying to prove your point you deflected, and shifted the goalposts from "this could very well have been a good system" to "the US didn't like it therefore it couldn't have been bad".
You go on to state that Russia beat the US into space (which is a non-sequitur), and later expand that "The USSR, had it not had to fight a cold war against the US, could very well have been a much better system not just for space flight, but for a way to structure and run society in general."
When challenged by alentist, who asked "why did the USSR and its satellite states have to systematically mass murder people who wanted to leave this wonderful society?" you countered with "If it was such a bad way of doing things, why did the US actively go out of it's way to sabotage it" which is moving the goalposts, and starts to slide into whattaboutism.
Specifically you claimed that the USSR "could very well have been" a better way to structure a society, and alentist provided strong evidence that it was not - people were murdered when they tried to leave. Instead of trying to prove your point you deflected, and shifted the goalposts from "this could very well have been a good system" to "the US didn't like it therefore it couldn't have been bad".
Part you aren't answering the question directly. Did the US not persecute communists? Has the US not directly been involved in wars in communist countries that have led to millions of deaths, both military and civilians? You say the USSR killed its people, yet you won't admit those people were leaving because they wanted apparently to go to capitalist societies. What happens if capitalist societies don't exist? Where are those people going to? Or was the USSR killing people just to kill people as you claim?
On the contrary: It was Western technology and capital that propped up the USSR despite its repeated failures and inefficiencies.
https://capx.co/soviet-communism-was-dependent-on-western-te...
https://capx.co/soviet-communism-was-dependent-on-western-te...
Lol, who beat Nazi Germany? Western technology or Soviet tech?
You completely dodged the question and tried to change the subject, so I'll ask it again: If they had such a wonderful society, why did they have to systematically mass murder people who wanted to leave this wonderful society?
Your question, on the other hand, is silly. Substitute the USSR with Nazi Germany.
Your question, on the other hand, is silly. Substitute the USSR with Nazi Germany.
Why did the US have to systemically mass murder Native Americans and enslave Africans Americans and fight over seas wars in Vietnam and North Korea? If you can assert their atrocities, I can so also assert the US's. You are dodging, not me.
You again keep trying to dodge the question and change the subject, so I'll ask it yet again: If the USSR had such a wonderful society, why did they have to systematically mass murder ordinary people who wanted to leave this wonderful society?
If you're saying that slavery is also abhorrent and evil—like the slavery and mass murder that takes place under Communism—then we're in agreement. Now, can you please answer the question?
If you're saying that slavery is also abhorrent and evil—like the slavery and mass murder that takes place under Communism—then we're in agreement. Now, can you please answer the question?
So you agree, capitalism has been responsible for slavery and mass murder?
A significant reason why Stalin was able to successfully rise to power and why the Bolsheviks were able to secure total power is because of foreign violence and interference.
When all major foreign powers say that they wish for the destruction of your country and would openly prefer you to go back to more suffering, support for monsters like Stalin increases.
Equally, when the threat of invasion is as high as it was for the USSR from Britain and the US, a lot of money and power is invested in the military.
It's very possible that if it wasn't for massive foreign interference neither Stalin nor Trotsky would ever have been able to gain much power (both of them got their power from military conflict mainly, Stalin even moreso), the NKVD never would have gotten nearly as much funding, Lavrentiy Beria would probably have been put against the wall, and so on.
When all major foreign powers say that they wish for the destruction of your country and would openly prefer you to go back to more suffering, support for monsters like Stalin increases.
Equally, when the threat of invasion is as high as it was for the USSR from Britain and the US, a lot of money and power is invested in the military.
It's very possible that if it wasn't for massive foreign interference neither Stalin nor Trotsky would ever have been able to gain much power (both of them got their power from military conflict mainly, Stalin even moreso), the NKVD never would have gotten nearly as much funding, Lavrentiy Beria would probably have been put against the wall, and so on.
You completely dodged the question and tried to change the subject, so I'll ask it again: If they had such a wonderful society, why did they have to systematically mass murder people who wanted to leave this wonderful society?
They did not have a wonderful society. It was very deficient in many ways. I didn't argue that point because we agree. The point I'm arguing is whether or not the USSR could have had a better society if it wasn't for US and other foreign intervention, and the answer is an unequivocal yes.
Exactly! They can't even consider the possibility it seems because they don't want to even consider it. Its almost as entrenched as what some might call faith that the US was superior to the USSR and if you even suggest the idea of anything else you are downvoted because you are the bad guy for even considering it.
GP: They did not have a wonderful society. It was very deficient in many ways. I didn't argue that point because we agree.
You: Exactly!
Glad you also agree with my comments, then.
You: Exactly!
Glad you also agree with my comments, then.
It takes a profoundly ignorant view of historical facts to blame Stalin and Trotsky on foreign interference.
It takes a profoundly ignorant view of historical facts to ignore the immense pervasiveness of foreign interference in the Russian Civil War.
The mere presence of the Bolsheviks as a dominant force was due to foreign interference, as the Germans installed him and his friends in an attempt to destabilize the Russian Empire.
Trotsky's growth in authoritarianism, when he was previously a moderating force, started with the opportunistic German attacks at the fleets of the Red Army, and of course his rise to power from a middling figure to a preeminent Bolshevik was only made possible by German incitement of the Bolshevik movement to begin with.
Even Stalin's justification for power was based on (justified) appeals to centrally planned heavy industries, whose main motivation was military power which was necessary to to threats of invasion.
It is clear to anyone that both Stalin and Trotsky would have had much, much less power if they weren't able to justify centralization on the necessity to resist foreign agression, beyond that the consolidation of the Bolsheviks to begin with was a German plot.
The mere presence of the Bolsheviks as a dominant force was due to foreign interference, as the Germans installed him and his friends in an attempt to destabilize the Russian Empire.
Trotsky's growth in authoritarianism, when he was previously a moderating force, started with the opportunistic German attacks at the fleets of the Red Army, and of course his rise to power from a middling figure to a preeminent Bolshevik was only made possible by German incitement of the Bolshevik movement to begin with.
Even Stalin's justification for power was based on (justified) appeals to centrally planned heavy industries, whose main motivation was military power which was necessary to to threats of invasion.
It is clear to anyone that both Stalin and Trotsky would have had much, much less power if they weren't able to justify centralization on the necessity to resist foreign agression, beyond that the consolidation of the Bolsheviks to begin with was a German plot.
To claim all of this was based on foreign interference is revisionism without foundation, ignoring the agency of the Russian people and its tragically flawed and corrupt leadership/aristocracy. The Germans did not create or even influence the conditions that led to the Russian civil war or the various abortive revolutions prior to the one in 1917; beyond helping Lenin get back to Russia from Switzerland there is a shocking lack of evidence of any direct support (just in case you are trying to suggest the "Kaiser's gold" theory, there is no evidence of significant monetary support in either German or Russian records.) Considering the fact that Russia was a participant in WW1 at the time it is naive to assume they as disinterested or uninvolved, but the Germans did not create Lenin or any of the other committees and factions involved.
You cannot just sweep across decades of internal Russian conflict and paint it with such a broad and quite frankly misinformed brush. Every European nation was involved to some extent, but none had the influence you claim nor did any create any of the central characters in this story.
You cannot just sweep across decades of internal Russian conflict and paint it with such a broad and quite frankly misinformed brush. Every European nation was involved to some extent, but none had the influence you claim nor did any create any of the central characters in this story.
So you are saying that foreign powers had no influence whatsoever on the internal political situations in Russia, or that is was a mix of factors? You do admit that they helped Lenin get back to Russia at least. If Lenin never helps get back, does he ever rise to that level of power?
Is your position that the only possible result of the Russian Revolution was Stalin and the Holodomor?
The phenomena of revolutions turning authoritarian because of an outside enemy attempting to destabilize is in no way unique to the USSR. It's a pattern you see all across the world. It's what gets a movement that was opposed to even the concept of a standing army because of the centralization of power and the risk that brings to the largest standing army.
The Germans didn't create Lenin, but they fundamentally changed the course of the Rebellion against the Tsar by sending him back to Russia at that precise time. They had an intent in doing so that was realized.
The phenomena of revolutions turning authoritarian because of an outside enemy attempting to destabilize is in no way unique to the USSR. It's a pattern you see all across the world. It's what gets a movement that was opposed to even the concept of a standing army because of the centralization of power and the risk that brings to the largest standing army.
The Germans didn't create Lenin, but they fundamentally changed the course of the Rebellion against the Tsar by sending him back to Russia at that precise time. They had an intent in doing so that was realized.
The Russians also were fond of “give it more gas”, which SpaceX has also embraced and Elon has called out before. The fuel is a real big piece of the launch cost but it’s far from the largest. If your rocket equation calls for a little extra fuel but in exchange you can use more reliable or at least less exotic parts, just do it.
The fuel isn't even "a real big part" of the launch cost. It's well under 1% even for SpaceX [0]. But rockets are already just about as big as we know how to make them: the expensive thing is not filling the tank 10% fuller, but building a 10% bigger tank.
[0] https://space.stackexchange.com/questions/8330/what-is-the-c...
[0] https://space.stackexchange.com/questions/8330/what-is-the-c...
[deleted]
Does anyone know some good books that explore the space race? I've read Carrying the Fire(which was excellent), but it doesn't touch much on what the Soviets were doing.
This biography of the chief rocket designer of the Soviets, Sergei Korolev, is also a good introduction to the Soviet space program.
https://www.amazon.com/Korolev-Masterminded-Soviet-Drive-Ame...
https://www.amazon.com/Korolev-Masterminded-Soviet-Drive-Ame...
I found "This New Ocean" by William E. Burrows to be a rather good account of the first space race, as it covers both sides in an equal amount of detail.
I'd strongly recommend Boris Chertok's "Rockets and People" - https://www.nasa.gov/connect/ebooks/rockets_people_vol1_deta... . 4-volume first hand account (Chertok's immediate boss was Korolev and then Mishin, of N-1 fame, and Glushko, Energiya-Buran) . Really good memoirs about Soviet side of things.
the-dude(1)
I wonder what's that tiny thing that seems to have broken off some two seconds before it hit the ground?
Indeed, there were two. Two objects broke off from the ship before impact, one just before the first swing of the pendulum and one just after.
Watching it in slow motion, it looks almost like pieces of insulating foil.
Also, there was an unusually large flame at the end of the liftoff. Maybe that already sealed SN9's fate.
At apogee? Pretty sure that final flame is expected.
At T+01:11 with 3 engines still lit (https://youtu.be/_zZ7fIkpBgs?t=397). Not the apogee one at T+04:34.
That’s just a bit of wraparound suction flame, no big deal.
[deleted]
[deleted]
I'm very impressed by how it's coasting on the fins down the atmosphere. I had never even heard that idea discussed before I saw SN8 do it.
Of course, they'll have to land some other way on Mars or the Moon.
Of course, they'll have to land some other way on Mars or the Moon.
it will be coasting on its fins during atmospheric entry for mars EDL. (Old-ish) video simulation here: https://www.youtube.com/watch?v=xDTZEVMArBE
That phase wipes off >99% of the total energy required to get to 0 m/s, which is pretty remarkable because Mars' atmosphere is ~1% of Earth's.
That phase wipes off >99% of the total energy required to get to 0 m/s, which is pretty remarkable because Mars' atmosphere is ~1% of Earth's.
Exactly- IIRC the problem with martian atmosphere is that its too thick to ignore (hello Mars Climate Orbiter) yet not thick enough for landing havy craft with parashutes or aero surfaces only. See the crazy sky crane system the latest Mars rovers use to work around it.
That they (at least on paper) have a solution for this problem good enough for a 60 metrr craft weighting 100+ tons makes the whole thing even mord remarkable! :)
That they (at least on paper) have a solution for this problem good enough for a 60 metrr craft weighting 100+ tons makes the whole thing even mord remarkable! :)
Wow. That's very far from what my intuition would guess.
Good thing we have physics and math :)
Good thing we have physics and math :)
Fortunately the force of gravity is much lower on both these bodies so I imagine the belly flop becomes less important.
On earth it's also about spreading the heat of reentry over a larger area. Fortunately on Mars (I believe that) the heat of reentry is even less of an issue than here on Earth.
On earth it's also about spreading the heat of reentry over a larger area. Fortunately on Mars (I believe that) the heat of reentry is even less of an issue than here on Earth.
Is that right... at orbital velocity I think Mars entry is a problem.
Are they planning on landing starships on earth? with Orbital refuelling couldn't they just land it like a Falcon 9 (I mean I guess that'd be super inefficient)
Are they planning on landing starships on earth? with Orbital refuelling couldn't they just land it like a Falcon 9 (I mean I guess that'd be super inefficient)
Yes, they plan to land "tanker" starships directly back on earth after they have transferred their fuel to another vessel.
They plan to land passenger ballistic re-entry starships which fly without a booster directly to another city on earth in <30 minutes. These are going relatively slowly.
They plan to land orbital starships, which is like landing the dragon capsule. These are going far faster than the falcon booster ever goes. The second stage (on top of the falcon) never lands, it's disposed of every mission. The StarShip (top half) is essentially a reusable second stage.
The Starship mars or moon editions will remain in orbit and never land on Earth again after initial launch. These do not need hardware for an Earth descent and will rely on refuelling. The Moon edition will have no heat-shield tiles (no need for atmospheric entry) and special thrusters half-way up.
You are correct that interplanetry velocities are very high, so yes... a Mars entry at Earth-Mars transfer velocities is likely to be quite ... exciting. I can't remember how exciting though.
They plan to land passenger ballistic re-entry starships which fly without a booster directly to another city on earth in <30 minutes. These are going relatively slowly.
They plan to land orbital starships, which is like landing the dragon capsule. These are going far faster than the falcon booster ever goes. The second stage (on top of the falcon) never lands, it's disposed of every mission. The StarShip (top half) is essentially a reusable second stage.
The Starship mars or moon editions will remain in orbit and never land on Earth again after initial launch. These do not need hardware for an Earth descent and will rely on refuelling. The Moon edition will have no heat-shield tiles (no need for atmospheric entry) and special thrusters half-way up.
You are correct that interplanetry velocities are very high, so yes... a Mars entry at Earth-Mars transfer velocities is likely to be quite ... exciting. I can't remember how exciting though.
The Falcon 9 booster is going relatively slowly, so retro propulsion into the atmosphere (re-entry burn), the grid fins, and the landing burn are sufficient to land it.
Starship is intended to re-enter from orbit, which is a lot faster. Using aero braking requires much less fuel, and avoids the need for a re-entry burn which may not even be feasible.
Starship is intended to re-enter from orbit, which is a lot faster. Using aero braking requires much less fuel, and avoids the need for a re-entry burn which may not even be feasible.
Was it camera angle that made it appear to be so perfectly flat (top and bottom of rocket at same altitude) when it was in free fall or was that actually the target free fall orientation?
I presume it was the target orientation since they held it for so long, had they wanted to actively leave that orientation earlier I assume they would have done so.
Especially subsonic I assume their orientation does not matter a whole lot when just trying to fall with max drag.
Not sure how much energy they'll save doing the flip maneuver earlier though, seems like they want max drag as low as they can go, then flip to powered flight at the last moment possible -- and their problem seems to be keeping the engines lit.
Especially subsonic I assume their orientation does not matter a whole lot when just trying to fall with max drag.
Not sure how much energy they'll save doing the flip maneuver earlier though, seems like they want max drag as low as they can go, then flip to powered flight at the last moment possible -- and their problem seems to be keeping the engines lit.
Yeah, it does a "belly flop" during descent, presenting as much area as possible to the airflow, reducing its terminal velocity.
(1) I think that is a "hard" landing ;) I say it it the mark.
(2) The Question: I ain't no rocket scientist, but even if the engine failure had turned on, did the engines all just turn on quite late?
Just trying here some crazy college physics so not sure if this checks out but, here goes. Again, just for fun. If it takes X: (summation of thrust) to fly that high over x seconds, then it would take the X + some at the very last 4 seconds I saw engines turn on for soft landing.
Are we capable of having enough thrust in the last 4 seconds? Maybe try earlier so there can be more lead way in case of failure?
===
Freefall: 11:06 (all estimates) 12:45 (still free fall, engines off and preparing for vertical) 12:48 (engine on, flipping for vertical) 12:50 (vertical) (4 seconds left to apply thrust) 12:54 (crash landing)
I have about 104 seconds of free fall, and 4 seconds left when engine turned on.
Is 4 seconds enough? Just intuition and genuinely wondering ...
Just for fun - does my physics checkout (at freefall)?
vf = 0 + (1/2) * at^2 vf = 9.8m/s^2 (108s^2) = 57153.6 m/s = 127848.9621 mi/hr (yea, ignoring at moment drag/terminal, physics ;)
===
vf = (1/2) (F/m)t^2, F=ma (vf2m) / t^2 = F (Thrust required)
Again, just for fun. Don't kill me. Physics, it been a long time. If it's right, Elon, are you hiring?
EDIT: SpaceX, Tesla to the -moon- mars!
(2) The Question: I ain't no rocket scientist, but even if the engine failure had turned on, did the engines all just turn on quite late?
Just trying here some crazy college physics so not sure if this checks out but, here goes. Again, just for fun. If it takes X: (summation of thrust) to fly that high over x seconds, then it would take the X + some at the very last 4 seconds I saw engines turn on for soft landing.
Are we capable of having enough thrust in the last 4 seconds? Maybe try earlier so there can be more lead way in case of failure?
===
Freefall: 11:06 (all estimates) 12:45 (still free fall, engines off and preparing for vertical) 12:48 (engine on, flipping for vertical) 12:50 (vertical) (4 seconds left to apply thrust) 12:54 (crash landing)
I have about 104 seconds of free fall, and 4 seconds left when engine turned on.
Is 4 seconds enough? Just intuition and genuinely wondering ...
Just for fun - does my physics checkout (at freefall)?
vf = 0 + (1/2) * at^2 vf = 9.8m/s^2 (108s^2) = 57153.6 m/s = 127848.9621 mi/hr (yea, ignoring at moment drag/terminal, physics ;)
===
vf = (1/2) (F/m)t^2, F=ma (vf2m) / t^2 = F (Thrust required)
Again, just for fun. Don't kill me. Physics, it been a long time. If it's right, Elon, are you hiring?
EDIT: SpaceX, Tesla to the -moon- mars!
Nice analysis. I can answer your question by illuminating two major points you missed.
1. The StarShip reaches a terminal velocity (in "the bellyflop") of about 200 km/h downwards and remains at that velocity until the "flip maneuver" at the end.
That's essentially a free force vector upwards due to drag which is free thrust on descent.
2. The weight of fuel reduces drastically on ascent which is why less engines are required as the StarShip soars higher into the air (they shut down when one reaches the 40% min thrust)
You'll see during the hover at the top that StarShip balanced on one engine for some time without moving. So that is the thrust required for station keeping. What we saw here was a combination of reaching a target location and burning excess fuel.
---
So, landing burn is (supposed to be) done with two fully throttled raptors, which is essentially 4x the hover thrust. Here with SN9 you see what happens when only one of those raptors is actually working.
Here is an Excellent SN8 (not SN9) video with carefully reconstructed telemetry (based on pixel counting video references) and you can see the velocities on descent. Rewind the video for full detail:
https://youtu.be/XJZ7VWzqtJM?t=867 [How to simulate a Starship launch!]
1. The StarShip reaches a terminal velocity (in "the bellyflop") of about 200 km/h downwards and remains at that velocity until the "flip maneuver" at the end.
That's essentially a free force vector upwards due to drag which is free thrust on descent.
2. The weight of fuel reduces drastically on ascent which is why less engines are required as the StarShip soars higher into the air (they shut down when one reaches the 40% min thrust)
You'll see during the hover at the top that StarShip balanced on one engine for some time without moving. So that is the thrust required for station keeping. What we saw here was a combination of reaching a target location and burning excess fuel.
---
So, landing burn is (supposed to be) done with two fully throttled raptors, which is essentially 4x the hover thrust. Here with SN9 you see what happens when only one of those raptors is actually working.
Here is an Excellent SN8 (not SN9) video with carefully reconstructed telemetry (based on pixel counting video references) and you can see the velocities on descent. Rewind the video for full detail:
https://youtu.be/XJZ7VWzqtJM?t=867 [How to simulate a Starship launch!]
I think they are doing it the most efficient way (similar to the Falcon 9) - that is with 0 hover.
The timing doesn't mean much because an entire engine didn't light... so it would have flipped up right faster and slowed down faster. Timing on a failure case doesn't really work.
Also it was only 1 engine compared with two, they could gimbal independently and have one course correcting while the other decelerates
The timing doesn't mean much because an entire engine didn't light... so it would have flipped up right faster and slowed down faster. Timing on a failure case doesn't really work.
Also it was only 1 engine compared with two, they could gimbal independently and have one course correcting while the other decelerates
In your calculations of speed you've forgotten about friction of air that at some point would stop further acceleration (terminal velocity.)
For both SN8 and SN9 my brain is screaming at me "surely they need more than 3 engines?!" Is the ultimate expectation that the engines will never fail, because it sure seems like they can't deal with losing even a single engine. I'm sure this is completely incorrect given that the issue for SN8 was tank pressure.
The issue is that the Raptor engines can only throttle down to 40% which represents a large thrust-to-weight ratio when you have basically just an empty tank.
There is also a startup time for each engine, so if one fails Starship will likely hit the ground before they can light another.
There are enough engines that a failure on ascent can be handled gracefully but landing is another story.
There is also a startup time for each engine, so if one fails Starship will likely hit the ground before they can light another.
There are enough engines that a failure on ascent can be handled gracefully but landing is another story.
Ah ok, this sort of clarifies the issue, which is that you can't really run more engines at lower thrust, and if you deal with the tank pressure issues from S8 then I imagine it should be able to go down on 2 engines alone without catastrophic issues.
With respect to failure on ascent, I imagine in that case they just send up another starship and transfer in orbit (coming down has always been the hard part).
With respect to failure on ascent, I imagine in that case they just send up another starship and transfer in orbit (coming down has always been the hard part).
There could be a delicate dance somewhat similar to what Soviet lunar lander was planned to do at launch: start all engines, and if all is well, shut down those backups. Here with Raptors one could imagine launching two engines, but if one runs well - during the startup sequence - shut the other down mid-sequence.
But this is totally question to Raptor creators. Might be not really feasible or even meaningful.
But this is totally question to Raptor creators. Might be not really feasible or even meaningful.
Maybe they could light them all, then nominate any extras for turnoff and stabilize things out after that?
It's my understanding currently that a 'production' starship will have three central engines optimized for sea level, and additionally three vacuum-optimized engines installed around its inside base perimeter.
Indeed. Those engines are currently missing partially because there's no reason to lose more engines than strictly necessary and also because they only need that much thrust when the fuel tanks are completely full.
If they decide to lift the StarShip from sea level completely full they will need to use only sea level engines (not vacuum optimized) or risk engine damage. Of course in production the booster will put the StarShip (upper stage) well above sea level.
If they decide to lift the StarShip from sea level completely full they will need to use only sea level engines (not vacuum optimized) or risk engine damage. Of course in production the booster will put the StarShip (upper stage) well above sea level.
Building anything that can deal with a catastrophic engine failure at powered landing time is probably out of scope for the foreseeable future.
Caveat: Did I mistake the scope here? I’ve not checked to see at what point in the trajectory the engine actually failed as I am at work.
*deal with - meaning land successfully anyway
Caveat: Did I mistake the scope here? I’ve not checked to see at what point in the trajectory the engine actually failed as I am at work.
*deal with - meaning land successfully anyway
> because it sure seems like they can't deal with losing even a single engine
Define "deal with". This rocket did 100% of what any rocket was ever supposed to do, before SpaceX came along and redefined what a rocket is supposed to do: go up.
Define "deal with". This rocket did 100% of what any rocket was ever supposed to do, before SpaceX came along and redefined what a rocket is supposed to do: go up.
"Deal with" == "Not blow up" == "No RUD" in the event of a single engine failure.
Manned space flight kind of has this kind of important additional requirement that things like ICBMs don't, which is that they can't just "go up" the have to come back down and not end in a ball of fire.
Manned space flight kind of has this kind of important additional requirement that things like ICBMs don't, which is that they can't just "go up" the have to come back down and not end in a ball of fire.
Unless I am much mistaken what what blew up was a first stage, not a manned stage. I do not believe that SpaceX plans on doing suicide burns to retrieve humans from flight.
What blew up is the second stage, the stage that would contain the astronauts. If this landing profile is also the profile they will use for a manned starship is unknown.
It feels to me like there is no backup plan for engine failures, but they can take so many paths here that I don't think anyone knows except people within SpaceX. Example paths:
* Don't launch it with people until it has landed unmanned so frequently that everyone trusts it. * Land cargo versions like this to get max payload, while manned versions light a lot sooner, with possibly more engines, and sacrifice some fuel for increased reliability. * Catch starship just like the booster in case of failure, with a longer travel to support higher speeds and lower G's. * Add a parachute or increase the flap sizes to lower terminal speed so much that it is survivable to land without engines.
The test articles for the first stage are still being built and are expected to land similar to the falcon 9, which the big difference that Elon is talking about them being catched by a tower instead of landing on their own legs. This seems far enough away though that I would not be surprised if that changes radically.
It feels to me like there is no backup plan for engine failures, but they can take so many paths here that I don't think anyone knows except people within SpaceX. Example paths:
* Don't launch it with people until it has landed unmanned so frequently that everyone trusts it. * Land cargo versions like this to get max payload, while manned versions light a lot sooner, with possibly more engines, and sacrifice some fuel for increased reliability. * Catch starship just like the booster in case of failure, with a longer travel to support higher speeds and lower G's. * Add a parachute or increase the flap sizes to lower terminal speed so much that it is survivable to land without engines.
The test articles for the first stage are still being built and are expected to land similar to the falcon 9, which the big difference that Elon is talking about them being catched by a tower instead of landing on their own legs. This seems far enough away though that I would not be surprised if that changes radically.
Falcon 9 lands using only a single engine and it has been a long time since a merlin engine failed to reignite on landing.
It'll be interesting to see what exactly happened with SN9, there's some clear video footage of piece flying off the rocket right as it was doing the flip maneuver.
It'll be interesting to see what exactly happened with SN9, there's some clear video footage of piece flying off the rocket right as it was doing the flip maneuver.
They only need 2 of the 3 engines to perform the landing flip and 1 of the 3 engines to perform the landing. So they do have some redundancy, and the computers were very likely programmed to light the third engine when the second failed. That this didn't happen was either due to debris from the second engine taking out the third during its failure or the failure being in a common area like the downcomers or that the third engine was still too hot -- the third engine was the one that was used to hover at apogee. Or some other reason.
Woops unscheduled disassembly <3
SN10, we're waiting!
SN10, we're waiting!
>Woops unscheduled disassembly <3
The one where the front fell off?
https://www.youtube.com/watch?v=3m5qxZm_JqM
The one where the front fell off?
https://www.youtube.com/watch?v=3m5qxZm_JqM
Here's a better view of the explosion, along with reactions from Everyday Astronaut: https://www.youtube.com/watch?t=16259&v=l4-PwxnJimg
Is this a viable landing strategy in the long run? Both SN8 and SN9 landings have ended in total fatalities.
What happens if the landing happens to occur during a 50 mph wind gust, etc. If this maneuver isn't designed to be 100% fault tolerant maybe they need to be thinking about an emergency eject?
I like the simplicity of the Starship design. How much extra weight would a nosecone eject + parachute add?
What happens if the landing happens to occur during a 50 mph wind gust, etc. If this maneuver isn't designed to be 100% fault tolerant maybe they need to be thinking about an emergency eject?
I like the simplicity of the Starship design. How much extra weight would a nosecone eject + parachute add?
I don't know, but their reusable Falcon rockets went through a similar phase. They killed a lot of rockets before they got the landing right.
It looks like both of these particular failures are engine-related, rather than air turbulence. (SN8: lost fuel pressure, SN9: failed to start one engine for unknown reasons.) These are engineering problems that probably have relatively straightforward solutions.
It is a fair point though, that landing in less-than-ideal weather conditions should perhaps be thoroughly tested. Launches generally can be done when conditions are optimal, but it might not always be possible to defer a re-entry until weather improves.
Ideally the lander would have real-time high-resolution air velocity data in the vicinity of the landing pad and would adjust its maneuvers to compensate.
I wonder what SpaceX's current tolerances are for wind for Falcon 9 landings? I assume anything more than a light breeze and they put it off for another day, but maybe those rockets are heavy enough that the wind doesn't knock them around as much as one would expect. (Droneship landings are especially difficult with wind plus a rocking boat.)
It is a fair point though, that landing in less-than-ideal weather conditions should perhaps be thoroughly tested. Launches generally can be done when conditions are optimal, but it might not always be possible to defer a re-entry until weather improves.
Ideally the lander would have real-time high-resolution air velocity data in the vicinity of the landing pad and would adjust its maneuvers to compensate.
I wonder what SpaceX's current tolerances are for wind for Falcon 9 landings? I assume anything more than a light breeze and they put it off for another day, but maybe those rockets are heavy enough that the wind doesn't knock them around as much as one would expect. (Droneship landings are especially difficult with wind plus a rocking boat.)
[deleted]
> Is this a viable landing strategy in the long run?
I prefer Dream Chaser's approach, but Elon Musk has his own ideas. Together with SpaceX team. Of course to fly to the Moon there are no such options.
I prefer Dream Chaser's approach, but Elon Musk has his own ideas. Together with SpaceX team. Of course to fly to the Moon there are no such options.
Explosion happens just after 12:45... I'm sure they've collected useful data.
I don't see how this could ever be as reliable as an airliner for passenger service as SpaceX has been talking about. An airliner can land safely with no engines and even no landing gear if necessary (and it sometimes is).
It’s total safety that’s important not individual aspects of safety. Clearly there are many disadvantages, but when comparing it to 15 hour flights there are several advantages.
For example shorter flight times mean fewer chances for in flight human errors. Another is in flight medical emergencies can be more quickly reach a hospital. A few aircraft have been shot down which is again much less likely, etc etc.
Initially it’s going to be risky, but give it say 50 years and it might actually end up being the safest option for ultra long distance travel.
For example shorter flight times mean fewer chances for in flight human errors. Another is in flight medical emergencies can be more quickly reach a hospital. A few aircraft have been shot down which is again much less likely, etc etc.
Initially it’s going to be risky, but give it say 50 years and it might actually end up being the safest option for ultra long distance travel.
One aspect can ruin the total safety. It can't be more safe than the least safe part of the trip. Sure, maybe in 50 years we'll figure out something better. But SpaceX is talking about flying long haul Earth to Earth routes with Starship, not a hypothetical future craft.
A 747 built 1970 is very different than a 747 built in 2020. Barring PR issues etc, SpaceX could be using an ever improving version of Starship for a very long time.
man, SN10 was a little close. Maybe they didn't have anywhere else to put it?
They should make a new version of "How Not to Land an Orbital Rocket Booster" for Starship :)
It almost look like they didnt account for the extra weight or size of the rocket.
Feynman on SpaceX’s “Big Bang” design approach. I don’t think he would have been a fan:
The usual way that such engines are designed (for military or civilian aircraft) may be called the component system, or bottom-up design. First it is necessary to thoroughly understand the properties and limitations of the materials to be used (for turbine blades, for example), and tests are begun in experimental rigs to determine those. With this knowledge larger component parts (such as bearings) are designed and tested individually. As deficiencies and design errors are noted they are corrected and verified with further testing. Since one tests only parts at a time these tests and modifications are not overly expensive. Finally one works up to the final design of the entire engine, to the necessary specifications. There is a good chance, by this time that the engine will generally succeed, or that any failures are easily isolated and analyzed because the failure modes, limitations of materials, etc., are so well understood. There is a very good chance that the modifications to the engine to get around the final difficulties are not very hard to make, for most of the serious problems have already been discovered and dealt with in the earlier, less expensive, stages of the process.
The Space Shuttle Main Engine was handled in a different manner, top down, we might say. The engine was designed and put together all at once with relatively little detailed preliminary study of the material and components. Then when troubles are found in the bearings, turbine blades, coolant pipes, etc., it is more expensive and difficult to discover the causes and make changes. For example, cracks have been found in the turbine blades of the high pressure oxygen turbopump. Are they caused by flaws in the material, the effect of the oxygen atmosphere on the properties of the material, the thermal stresses of startup or shutdown, the vibration and stresses of steady running, or mainly at some resonance at certain speeds, etc.? How long can we run from crack initiation to crack failure, and how does this depend on power level? Using the completed engine as a test bed to resolve such questions is extremely expensive. One does not wish to lose an entire engine in order to find out where and how failure occurs. Yet, an accurate knowledge of this information is essential to acquire a confidence in the engine reliability in use. Without detailed understanding, confidence can not be attained.
A further disadvantage of the top-down method is that, if an understanding of a fault is obtained, a simple fix, such as a new shape for the turbine housing, may be impossible to implement without a redesign of the entire engine.
The Space Shuttle Main Engine is a very remarkable machine. It has a greater ratio of thrust to weight than any previous engine. It is built at the edge of, or outside of, previous engineering experience. Therefore, as expected, many different kinds of flaws and difficulties have turned up. Because, unfortunately, it was built in the top-down manner, they are difficult to find and fix. The design aim of a lifetime of 55 missions equivalent firings (27,000 seconds of operation, either in a mission of 500 seconds, or on a test stand) has not been obtained. The engine now requires very frequent maintenance and replacement of important parts, such as turbopumps, bearings, sheet metal housings, etc. The high-pressure fuel turbopump had to be replaced every three or four mission equivalents (although that may have been fixed, now) and the high pressure oxygen turbopump every five or six. This is at most ten percent of the original specification. But our main concern here is the determination of reliability.
The usual way that such engines are designed (for military or civilian aircraft) may be called the component system, or bottom-up design. First it is necessary to thoroughly understand the properties and limitations of the materials to be used (for turbine blades, for example), and tests are begun in experimental rigs to determine those. With this knowledge larger component parts (such as bearings) are designed and tested individually. As deficiencies and design errors are noted they are corrected and verified with further testing. Since one tests only parts at a time these tests and modifications are not overly expensive. Finally one works up to the final design of the entire engine, to the necessary specifications. There is a good chance, by this time that the engine will generally succeed, or that any failures are easily isolated and analyzed because the failure modes, limitations of materials, etc., are so well understood. There is a very good chance that the modifications to the engine to get around the final difficulties are not very hard to make, for most of the serious problems have already been discovered and dealt with in the earlier, less expensive, stages of the process.
The Space Shuttle Main Engine was handled in a different manner, top down, we might say. The engine was designed and put together all at once with relatively little detailed preliminary study of the material and components. Then when troubles are found in the bearings, turbine blades, coolant pipes, etc., it is more expensive and difficult to discover the causes and make changes. For example, cracks have been found in the turbine blades of the high pressure oxygen turbopump. Are they caused by flaws in the material, the effect of the oxygen atmosphere on the properties of the material, the thermal stresses of startup or shutdown, the vibration and stresses of steady running, or mainly at some resonance at certain speeds, etc.? How long can we run from crack initiation to crack failure, and how does this depend on power level? Using the completed engine as a test bed to resolve such questions is extremely expensive. One does not wish to lose an entire engine in order to find out where and how failure occurs. Yet, an accurate knowledge of this information is essential to acquire a confidence in the engine reliability in use. Without detailed understanding, confidence can not be attained.
A further disadvantage of the top-down method is that, if an understanding of a fault is obtained, a simple fix, such as a new shape for the turbine housing, may be impossible to implement without a redesign of the entire engine.
The Space Shuttle Main Engine is a very remarkable machine. It has a greater ratio of thrust to weight than any previous engine. It is built at the edge of, or outside of, previous engineering experience. Therefore, as expected, many different kinds of flaws and difficulties have turned up. Because, unfortunately, it was built in the top-down manner, they are difficult to find and fix. The design aim of a lifetime of 55 missions equivalent firings (27,000 seconds of operation, either in a mission of 500 seconds, or on a test stand) has not been obtained. The engine now requires very frequent maintenance and replacement of important parts, such as turbopumps, bearings, sheet metal housings, etc. The high-pressure fuel turbopump had to be replaced every three or four mission equivalents (although that may have been fixed, now) and the high pressure oxygen turbopump every five or six. This is at most ten percent of the original specification. But our main concern here is the determination of reliability.
> It has a greater ratio of thrust to weight than any previous engine.
SSME thrust-to-weight ratio: 73.1 https://en.wikipedia.org/wiki/Space_Shuttle_Main_Engine
NK-33 thrust-to-weight ratio: 137 https://en.wikipedia.org/wiki/NK-33 (no gimbaling)
RD-270 thrust-to-weight ratio: 189.91 https://en.wikipedia.org/wiki/RD-270
SSME thrust-to-weight ratio: 73.1 https://en.wikipedia.org/wiki/Space_Shuttle_Main_Engine
NK-33 thrust-to-weight ratio: 137 https://en.wikipedia.org/wiki/NK-33 (no gimbaling)
RD-270 thrust-to-weight ratio: 189.91 https://en.wikipedia.org/wiki/RD-270
This is totally wrong. Feynman is correct obviously by you are totally wrong.
The big bang (your words) or the top down (Feynmans words) method is what the SLS is doing. Not spacex.
The big bang (your words) or the top down (Feynmans words) method is what the SLS is doing. Not spacex.
Soon after SN8 Elon tweeted that they knew the problem. So they quickly added Helium to pressurize SN9, which is a bandaid given their deliberate elimination of Helium and the fact there isnt any on Mars. Now we see what looks like even worse relight capability.
I wonder if recent departures are related in some way. They failed plenty before, but this seems different.
I wonder if recent departures are related in some way. They failed plenty before, but this seems different.
That's a lot of speculation. We don't yet know why one of the Raptor engines failed to relight. The Raptor is a very new engine with only a handful of minutes of flight time. Keep in mind they also replaced a couple of the engines before the flight. I imagine SpaceX still be considers them development engines.
You can also see some debris fly off of the bottom of the rocket just as it's performing its flip maneuver.
With SN8 Musk tweeted casually about it, but he's apparently taking a hiatus for a bit.
You can also see some debris fly off of the bottom of the rocket just as it's performing its flip maneuver.
With SN8 Musk tweeted casually about it, but he's apparently taking a hiatus for a bit.
>> That's a lot of speculation.
Yes it is, but I didn't speculate as to how that might be related. It is a bit of a stretch.
Yes it is, but I didn't speculate as to how that might be related. It is a bit of a stretch.
"I bet they needed that."
As others have noted, SN10 is standing by. Somewhat uncomfortably close by: https://i.imgur.com/F9rsBbD.png
It's so exciting to be a spectator of these events.