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.
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.
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].
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.
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.
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!
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.
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.
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.
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.
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...
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.
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.
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>!
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.
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.
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.
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.
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.
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.
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.
>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.
>> 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])
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.
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.
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.
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.
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 :)
"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?"
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.
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.
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.
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.
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.
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.
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).
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.
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.
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.
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.
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.
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
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.
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.
"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.
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.
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.
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.
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"?
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.
> 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?
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?
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".
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?
Of course you're right. USA has been continually at war, grinding the lives of brown people into profits for rich bastards, since before independence from Britain. Lots of Americans moved to USSR, especially non-whites. Truman had four years in which Stalin would have been happy to sign away nuclear weapons forever, but instead he was led by the nose by the armaments manufacturers and kept creating ever-more-deadly nukes. USSR continually tried to rein in communists in other nations in order to try to preserve peace, but was painted as a great instigator by the airtight propaganda that we Americans choke in from our births.
Still, it would have been better not to restrict emigration. That was not humane, and betrayed an antiquated view of how the world works.
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.
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?
The US fought an actual civil war over the right to OWN people. How is capitalism, THE economic system the US has used since it's inception, not responsible for that, as well as the current demand for slave labor that exists today? I will answer your question when you can answer that one honestly.
To our fellow readers: Notice how Layke1123 has dodged my original question no fewer than 4 times (!), all while continuing to launch barrages of new questions in an effort to derail the conversation and avoid having to answer it. This tactic has a long history in Soviet propaganda.
Let's try 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?
I have repeatedly told you. The direct answer is that the US is directly responsible for meddling in the internal affairs of a foreign state repeatedly causing political turmoil and economic disaster. Do you disagree with this statement? I'd love for you to prove the US had no involvement in fighting against the USSR to varying levels of success.
To our fellow readers on HN: notice how alentist himself cannot answer a question asked back, even though I have given him the answer to his question directly multiple times. It is his attempt to save his narrowly constructed world view that he is right, America has never committed atrocities against its own people and others, and you should accept his point of view matter of factly without questioning! Notice how he acts more like the places he criticizes than I do simply for questioning his assertions?
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.
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.
>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.
thus implying disagreements. Since neither of us have contradicted such a statement, either you've been replying hors-sujet or you were just trying to show agreement, right?
Does that also apply when Capitalist policies have inevitably failed and murdered millions? The civil war actually was the bloodiest war in the US's history no? Was that not a failure of capitalism? Was the great depression not a failure of capitalism?
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.
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.
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 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.
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.
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.
It's funny because the Soviets did it right, in that they funded smart people and gave them control. The Nasa's approach was to have people create proposals and get approval for funds.
We have forgotten that the "fund smart people and let them do what they want" is the best approach. Look at Xerox Parc, Bell Labs, etc. Nasa's modern approach with SpaceX and other companies seems to reflect these hard learned lessons.
"fund smart people and let them do what they want" - well, that's not exactly how it worked - for example, while Korolov was mostly able to get the resources he needed in the 1950s, in the early 1940s he did his engineering work on bomber design from a prison labor camp (which is a bit far from "let them do what they want" or "give them control") after losing most of his teeth from malnutrition during forced labor in a gold mine. This probably provided a perspective for him of what the limits of "do what you want" are in reality.
Since Spring 1945, Korolev was much more able to control resources, getting to reconstructing V-2 manufacturing - Soviet version, of course, dubbed R-1 - then upgrades to R-2 and R-3, then even more powerful R-5 - all alcohol-based - and then, starting from 1953, working on R-7.
One interesting piece of history (Chertok wrote about it in his memoirs) - in Spring 1961, just before Gagarin's flight, which, of course, was priority number 1, Korolev managed to worry about upcoming R-9 testing, saying to his people "after Gagarin, they won't allow us to work on R-9 as easily".
Korolev did enjoy significant freedom in how he did things - the Council of Main Designers was created thanks to that freedom, and von Braun's decision to add fifth F-1 to Saturn just because he felt it will be needed - bypassing all bureaucracy - would be quite understood by Korolev and his team, they had similar things done themselves. It was often the case that Korolev went to Kremlin with some space-related offerings, and got green light, after the principal work was already done, and more scaled-up development was all what remained. You have to work your asses off this way of course, but you have full support of your political bosses and you're a hero for everybody.
These smart people did not have any semblance of control in the USSR. The Soviet space program was 95% political, heavily influence by the politburo and Soviet interests. Smart people would not have developed the Buran if all options were on the table
Surely that’s the same with NASA pork barrel politics affecting who gets to build it and therefore the particular companies and manufacturing capabilities the engineers have to work with. The space shuttle wasn’t engineering lead either.
It's interesting to see that during Moon Race, in USSR there were 3 space design teams - Korolev's (later Mishin), Chelomey's and Yangel's - competing for resources, while NASA established centralized planning with everybody doing parts of the common project (with lots of money of course). It seems that "capitalistic" approach in USSR lost to more "communistic", central planning approach in USA.
Sure, but start of the "race" was pretty much the reverse - factions in the USA fighting for who will be allowed to launch the first satellite, resulting in the Vanguard fiasco. They had to bring in Von Braun in the end to do it, starting the centralization.
And in the USSR Glushko also played along initially, designing R-7 engines that are in use till today basically. Only later he stopped and started demanding all future engines to be hypergolic, which didn't go well with Korolev, especially for crewed vehicles.
> Glushko... started demanding all future engines to be hypergolic
I think Glushko owns a big share of Soviet problems with the Moon.
On the other hand, at the time the leading idea in USSR was that hydrogen is a rather advanced fuel (which, by the way, Glushko also supported at a time), and given good existing engines, rocket designers wished to use proven fuels. In general, and to compete with hydrogen in particular, Isp was an important goal, so rocket designers set goals to engine designers - make rocket engines with good Isp. There was created a conflict between high Isp/high pressure engines - as required - and large thrust engines, as was needed for big, Moon rocket. Glushko had the opinion that they won't have enough time to create large thrust high Isp engines with kerosene, only with UDMH/NO2 . Kuznetsov could only create relatively low thrust (1500 kN) high Isp kerosene engines, and those were late.
If Glushko tried, those engines could possibly work. At least Glushko experience with large thrust chamber of RD-270 helped later with large thrust 4-chamber kerosene RD-170.
It's more funny that both primarily used thousands of Germans as their rocket technicians, and both german parties used their german style, based on engineers as heads.
This all changed with Lyndon Johnson taking over, getting rid of the Germans, introducing the well known inefficient NASA/gov-style management style known from the Shuttle era, and moved the technicians out of Alabama to Houston. This was the anti-modern democratic approach.
SpaceX simply went back to the old modern style, which worked well for the US and Russia.
The trick was not using smart people, but experienced engineers in control, and not fresh anti-engineer PM's out of college. Everybody can control a budget, esp. engineers, but only engineers can control engineering problems.
I have watched PMs actively contribute nothing to a project by entering false metrics. It really is either you can build something, or you can't and contribute nothing to the project.
Well, those managers are only there for the hype. You need liars apparently. I can name a couple of popular of software projects who went this route, and were successful because of this. But NASA?
Not always. Some of the software guys just zone out in meetings and don't pay attention while their managers and PMs do the talking. Can confirm, I wasn't paid nearly enough in that job to care about what my manager or PM said.
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! :)
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.
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)
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.
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.
Another amazing test flight! Can't wait for SN10. I understand they have already started the last step of construction which is fitting the Raptor engines to SN10. Should be ready to fly very soon.
No existing rocket has tried to perform either the "belly flop" or the "Landing flip manouver" that SpaceX is trying to do.
The failures are due to complex issues (fuel tanks, valves, engine reliability under complex forces) not simple control system issues (choosing wrong thrust, not able to orient using thrusters, etc)
I don't understand the term belly flop or rapidly reusable. Do You mean that it is becoming horizontal to reduce the falling speed rate to land on its belly?
shuttle was reused and landed on wheels parallel to its belly.
Rapidly reusable means the goal is to have Starship (or at the very least the Super Heavy booster) fly multiple times a day. The Space Shuttle needed a new external fuel tank each flight, and the SRBs required significant refurbishment, to say nothing of the orbiter's own refurbishment.
Also important to note that Starship is going to be an interplanetary vehicle. And that means it needs to be able to land in places with little to no atmosphere on a surface with no runway.
The Space Shuttle was an impressive engineering marvel, especially for the time, but even if it could leave low earth orbit, there was no way it could land anywhere other than Earth.
Rapidly reusable - You can land it directly on (or next to) a launch platform, refuel it and launch it again the same day. Same as a regular aircraft.
The Space shuttle had a disposable tank (which was lost on launch), recovered but basically destroyed solid rocket boosters (ditched into ocean) and finally on landing it had (potentially) damaged heat tiles which all needed inspection and which were all fragile and different.
SpaceX Starship boosters are refueled after they land themselves using a pump.
Shuttle solid rocket boosters have their shells fished out of the ocean by a boat. Then they return to the factory to be broken into sections and filled with a solid propellent.
1. People doing analysis and hoping to check everything through engineering rigor and (hopefully) good assumptions
2. Test early and often, learning along the way until many positive tests have proven the system
I'd prefer 2. Look at systems like SLS to see the schedule results of (1).
No people were put on Falcon launches until almost 100 successful launches. I imagine a similar situation for StarShip. For example NASA is funding in orbit refuelling experiments (unmanned) and also a StarShip moon landing (unmanned) which will help prove the system prior to human flight.
Don't worry, plenty of people will carefully do analysis (1) later on. But the data they will review will include telemetry from real flights rather than just hopeful simulation / analysis results.
Don't get your hopes up. Since it is rotating on an axis while moving and twice, it has a huge degree of freedom for failure.
Even if successfully returns 100 times, any untested change to its payload can change the parameters which are apparently unknown because they have not used any fancy simulation.
Good luck. I will be watching and ready to say I told you so. The staff could be absolute geniuses by they will not be able to foresee all the unexpected results.
The failures so far relate to the pressurization of the header tanks and the engine performance on re-light (hard problems). I imagine these will be well solved after 100 flights.
The assumption that shifting payload is going to boggle the flight computers leading to loss of craft sounds unlikely. Both because the payload will be secured and the flight computers are more dynamic than that.
Finally, the forces on the cargo shift from 1G towards the belly during the belly flop to a mix of gravity and pressure from the engines during the flip. While the view from the window would be "interesting" - the actual forces on the payload will remain a summed ~2G from these two axes (mostly from "down") during landing. This is similar to how the lift vector while rolling in an aircraft keeps you safely stuck to the floor (and not the walls) during jet flight.
Anyone flying an aircraft or space vehicle who doesn't secure their loads is going to experience some shifting of cargo. Of course that's why you have a small cargo compartment which physically restricts the movement of potential cargo. See how 747s secure cargo in large bins within a dedicated cargo hold for reference.
747 can not flip like that; it would stall and crash. The narrow bodied 737s crashed for less. Their fancy flight computer miscalculated because of center of gravity miscalculations. They crashed after 100s of flights.
I like your optimism. Good luck. I mean it. I would not fly in that thing even if they paid me a million.
Big airliners do parabolic arcs - "vomit comet", so it's not a huge problem. 737 MAX crashed for different reasons. E.g. Soyuz capsule returns safely despite different loads and different distributions of mass - control systems, even relatively modest ones, can compensate. It's failures which provide most useful information about shortcomings of the system at some point, so they are welcome during testing - if you think that at this point they shouldn't explode, you'd better bring good arguments. Shuttle had much better aerodynamic shape than Starship, and their landing modes are different.
737-max crashed because they never went through full blown simulation and acceptance procedures for it. They just made the body longer and compensated for differentials in flight control software parameters but they had a blind spot in their assumptions. Those aircrafts have decades of air flight simulation behind them and yet ....
Shuttle is a much finer craft but these guys may have different objectives and that is their prerogative. The fact that there are errors in there that can lead to explosion is troubling to me.
The claim that the explosions will lead towards a better design is an assumption.
737-Max crashed because of the "lets analyse this rather than test it" thinking that you described earlier. That and an overly cosy relationship with the FCC and a culture of silencing cautious engineering voices.
It's seemed cheaper to tack larger engines and new software onto the old air-frame than to redesign the aircraft to be mechanically stable and update the cockpit.
Not surprising that the same company (Boeing) that campaigned for analysis over testing in spaceship design (they claimed SpaceX couldn't do commercial crew) also failed to design a working and stable aircraft.
I'd argue that the bureaucracy involved in "signing off" an new aircraft design contributed to these problems. Designing a aircraft or spacecraft from first principles and then refining through testing does have its advantages.
My point about aircraft was that the lift vector is perpendicular to the wings, even if the aircraft flips (rolls) upside-down there is still a force that pushes you toward the deck if you are inside the plane. In the StarShip there is a similar upwards force from the engines (when lit) towards the nose regardless of which direction the ship is oriented with respect to the Earth.
The reason why flying a plane in clouds is so dangerous is that your sense of up and down in a plane is invalid. You'll always think the deck is down without the aid of either a view of the horizon or the correct use of functioning instrumentation.
The bureaucracy had nothing to do with it. They did not want to spend the money to create a new craft. The long bodies aircraft was not airworthy physically speaking and so the software was designed to limit its pitch to prevent it from stalling.
All aircrafts can stall and some angle of attack but a long+narrow aircraft is way more sensitive.
Design of an aircraft from scratch would have flagged it as poor design right away.
As pointed out in some other comments, SpaceX do extensive simulations, they almost certainly have the best rocket simulations in the world (see some of the published talks on youtube to see the state of their research).
We know that their simulations/calculations were excellent for these last couple of Starship tests because the tests themselves were excellent. There were a number of things being tested, including things like flying multiple Raptor engines, turning those engines off, switching between different fuel tanks for launching and landing, the bellyflop maneauver, the landing flip maneauver, engine relight from the header tank, and finally landing. Almost all of these were perfect, from what information we have.
There have been two failures, and from what we know these were not related to simulations at all - they seem to be system/integration issues, though we don't really know much about the engine failing to relight this test.
On SN8 they had a pressure issue feeding the engines from the header tanks. It may have been possible to anticipate this or test it independently, but it was probably the least important of all the things being tested. Given that they have multiple new (and updated!) test articles rolling off the production line they clearly made the choice to conduct the test without spending years trying to validate every single component. Again, they obviously did a lot of excellent engineering despite not undertaking a long pre-flight validation, as the test was so succesful.
Both you and I agree that aerospace companies should do large scale vehicle simulations, which they do.
In addition SpaceX does complex fluid dynamics simulations to design and test their engines. That's likely part of why they have successfully made the "holy grail" of Full-Flow staged combustion work in the Raptor. [0]
None of the failures so far could have been detected through simulation since they were complex integration issues. At some point the cost of simulation is vastly larger than the cost of just creating a test article.
Components like drogue chutes, explosive bolts, failsafe valves and abort systems are typically validated both analytically (by reviewing designs) and are often hard to fully validate by testing.
Since validating components is so expensive, it leads companies that rely on analyitical validation (like Boeing) to become overly attached to previously analysed and working components because analysis is so time consuming and expensive. You end up with modern rockets built with space-shuttle engines as components (SLS) and old jets with new engines tacked on (747 Max).
When you talk about explosive deconstruction of a test article after something new was learnt you fail to realise the learning (not the landing) was the goal. If SN9 had landed correctly, it is very likely they would have deconstructed it anyway. They just deconstructed SN12, 13 and 14 to make way for SN15 which has a very improved design.
Pedantic trolling noted; I’ll engage just to hone my thoughts.
Every production rocket is fully expendable. Launch, expect discard of 100%* of launch system. Starship is designed for 100% reusable, with same-day fly/land/refuel/repeat. That’s obviously a huge difference.
* - exceptions:
Space Shuttle discarded most of the launch system, acting as glider to return crew/cargo and some engines. Reuse turnaround was months, with extensive repairs expected. Boosters required prolonged recovery and refurbishing, with high likelihood of loss.
Falcon 9 is only one remotely viable for same day return to pad and reuse of first stage. Second stage is discarded.
SN# is a fast-reuse second stage. Landing involves leveraging the terminal velocity physics of a brick (not gentle glide of Shuttle), followed by effectively flipping a 16-story building ~90° in free fall with powered deceleration to 0m/s in less than 2km vertical.
Nothing in the industry resembles the fast launch/fall/relight/reorientate/decelerate/land/refuel/repeat sequence, of SN#. There is no established industry specifications addressing such operation. And as the history of rocketry shows, establishing such specifications practically involves lots of crashes. [cue How Not To Land A Booster]
It’s been a few days and other people above have already put you through the ringer on this, but funny enough the 1960’s work style, of the soviets specifically, is ideal for rapidly advancing rocket tech. Or any tech, for that matter! They iterated and flight tested early and often. The soviets only lost the space race because they ran out of resources, as this is an expensive approach, but SpaceX is back-stopped by Elon + the US gov via contracts + they already have production flight revenue and wildly successful products.
I won’t be able to do the explanation much justice in a paragraph here but Google around about how the Soviet approach to rocketry was far superior than that of the US and you’ll uncover plenty on the topic. SpaceX is executing that same style of engineering development, marrying the ‘move fast and break things’ tech company ethos with aerospace engineering.
That’s why they’re so revolutionary: aero is typically riddled with red tape and risk aversion... they take the Silicon Valley approach of moving fast and breaking things, along with keeping as much engineering in-house as possible to cut down on expenditure, lead time, quality control etc. etc.
Source: used to work on SpaceX’s only commercial crew capsule competitor, Boeing’s Starliner, down at the Kennedy Space Center.
You can choose to develop rockets - especially of such size - this way instead of putting (much) more efforts in calculating how it would behave and prepare for all cases.
Nasa did the calculation with with ancient computers and these guys are speculating and not using proper technology to achieve success. It makes no sense in 2021.
They should not be experimenting. Their simulations should be been solid before this stage.
They're developing this thing in stages; they've developed and tested the engines, they've developed and are testing launching the thing, they've developed and are testing the re-entry flop. They have partially developed the whole "landing" thing and if you're going to be testing the belly flop, you might as well put whatever you have with regards to landing through its paces as well.
By having a small team develop and test individual parts in stages, you avoid needing a giant team, and you avoid needing to have all of the schedules line up to be ready to go all at once. And it's the engineers who develop the rocket that is expensive, not the manufacturing.
IMHO the benefits of having a completely flexible schedule greatly outweigh the expensive of assuming failure.
You are so confident in your opinion and you are so incredibly wrong.
Pretty much every NASA engineer that has worked with SpaceX has been incredibly impressed by their methods. Literally every single one of their competitors, including nation states have started to change their who launch strategy because they saw no other way to compete with Spacex (and they are still failing) all of them have expressed how impressed they are with SpaceX.
You also seem to have a very trivial understanding of what SpaceX is doing and how it is different then what has been done before.
SpaceX is not just developing a the biggest rocket ever (double Satrun V lift-off thrust), or just the most advanced rocket engine ever, or just a new method of landing (very different from Shuttle), or a new type of heat shield (again different from Shuttle or SpaceX Pica), or a method of mass producing rockets. They are fully vertically integrated and they build and work on all of these and many other things at the same time.
Having one prototype explode is fine, because they are not just testing the prototype, they are testing the production of the rocket and optimizing the operations and everything mentioned above. The goal is to have the most advanced rocket of all time by a long margin, and be able to produce it cheaper then a current generation rocket, and operating it as cheaply as a airliner.
You can not simulate or plan anything so complex and get it right the first time. They are constantly learning and improving every single aspect. The engine team uses every test fire for new inputs and adjust their simulation and improve the design, the engine manufacturing team is trying to improve the cost per engine and the production quality, the rocket manufacturing engineers are constantly improving the way the rocket is built and later prototypes have these improvements, the materials team invents new materials and is measuring their performance on the prototypes, the operations team is trying to reduce the amount of work it takes set up a launch and I could go on and on like that.
Literally every prototype coming of the manufacturing line is a incrementally improved and usually cheaper then the one that came before it. The current SN8, SN9, SN10, SN11 are only small differences and with them they want to test the landing. They will be museum pieces once the landing is done, them blowing up generates real world data that can then improve their simulations. One of SpaceX 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. A test of a prototype is not just testing the design but also the manufacturing and quality control.
When you try to design something that has never been done before and is incredibly complex, and you have the requirement that it must be incredibly cheap and incredibly reliable there is no way you can simply design it on a white sheet of paper, simulate it and then simply have a mass production system of that vehicle. That is simply impossible.
And your claim that this is just 'cash burn' for no reason is equally wrong. SpaceX approach to engineering has routinely beat everybody in every single competition and usually by quite a lot. Nobody knows better how to develop something with a small budget compared to SpaceX. The whole Starship program so far, including new revolutionary engines, has cost less half of the much smaller Ariane 6, or less then a single year of the SLS program.
SpaceX is simply universally acknowledged as the most advanced rocket company in the world, and its not close. They are doing it this way for a reason, and they are a lot smarter then you.
I just want to know how you know that "you" are incredibly right in this. You are just speculating like everybody else here. There is no quality or quantitative measurement available here for you to make these absolute statements. The only thing that I can gather from your text is that a lot can go wrong in fact.
Having the prototype that is exploding is NOT fine at this stage and that is "my" opinion. Your opinion is yours alone.
You are basically claiming your analysis is indisputable and that it has to be accepted and your belief in people's intelligence makes it so and I am stupid because you believe that they are smarter.
It is not matter of getting it right the first time and improvements in parts and efficiency. It is about having it never explode after the first round.
I don't care who you believe they are beating in the market place and how magnificent you believe this rocket is.
Good luck if you are associated with this venture. If so you are allowed to pump it.
I know that because that is what Elon Musk and other SpaceX engineers and have said. They have explained this in multiple presentations and interviews over the last 5 years. This is not a mystery. I am not speculating.
There is a whole community that has been following this project since day 1. There are people filming the production site every day. The analyze every part they see and try to figure out what changed. Some people in the community can get questions to Elon Musk and others.
The reason you are getting down-voted is that you seem to have not studied it at all what SpaceX is actually doing, and simply jump into the comments and make strong statements that what SpaceX is doing is wrong.
And your justification for this opinion is totally unconvincing for anybody that has actually studied the problem.
> I don't care who you believe they are beating in the market place and how magnificent you believe this rocket is.
Its really not about believe. Its a simple fact that everybody has acknowledged.
> I just want to know how you know that "you" are incredibly right in this. You are just speculating like everybody else here.
Sure, and the same goes for you. Empirically, though, we know that when the US/NASA throws a ton of money at something and has a good engineering culture, we can get brilliant things like Apollo. When that culture erodes and the appetite for burning cash fades, we get things like the Space Shuttle. Yes, amazing, but mediocre when compared to the achievements of the Apollo program, and ultimately ending in failure and decommissioning.
Empirically, we have SpaceX, which has basically invented the "reusable rocket" category, using a hybrid development method that includes simulations and building and testing prototypes early and often.
Empirically, we (still) have Boeing, which has stuck with the old model, overengineering from the start. What do we have? A development process that is years behind SpaceX's, for a lot more money.
Learning from failure is fine when the only cost is money and materials. SpaceX's progress so far seems to have proven their development model, even before Starship.
I do find it really funny that you start out by deriding everyone for just speculating, but then finish your post loudly denouncing everyone who supports SpaceX as some sort of idiot... which is exactly the same sort of speculation... speculation which is not supported by the facts on the ground.
Simulations of certain things are still a problem today, even though less than it was in 1960-s. For example, trans-sonic aerodynamics is still hard. I'd imagine a good simulation of Raptor's inner flow when Starship does active maneuring can be a problem, especially if you also need to take into account material properties under dynamic loads.
That is where they should spend their cash to produce something of real value that can be reused. Simulation close to perfection is the end game. Not sending something chunky into space.
Falcon 9 now flies and lands with no crashes, especially comparing to expendable rockets. Of course a modification big enough will require changing control parameters, but that's a routine task for engineering.
Some day we'll have good enough models for air flows in all necessary modes and good enough computers to run those models; we aren't there yet. Testing is still required.
Honest question: Have you worked with fluid simulations before?
We cannot fully predict turbulent flow from first principles. I mean, we can, but when constrained by real-world computing hardware, we can only do it in very tiny domains. Turbulence requires way too many orders of magnitude in spatial resolution to fully resolve it in "real world" problems.
Therefore, any practical simulation for engineering purposes involves some way of modelling (read: approximating) turbulent behavior at sub-grid scales. There are tons of these models suitable for all kinds of different applications, domains, flows, etc. - but they are all just models. Part of the engineering effort is finding the right model for the task on hand, and for that you need experimental data.
This of course doesn't apply only to fluid dynamics (but also e.g. the overall dynamic behavior of the entire assembled rocket and rocket engine, which could interact with the fluid flows in a nontrivial manner), but the point is that simulations aren't automatically accurate because you do more of them or throw more money or compute at them (that is also a good way to burn cash) - they are still approximations of unknown accuracy until you actually compare them with data from reality to confirm whatever modeling assumptions you made. The "least cash expenditure" approach will thus involve both simulations and experiments, and you will eventually reach the point where putting money into making rockets (potentially) crash will give you better lessons than running yet another simulation with (unbeknownst to you) subtly flawed assumptions.
SpaceX does do simulations, and tons of it. SN8 and 9 wouldn't have performed that well during the descent stage without amazing guidance software, which could only have been developed through extensive simulations.
Simulations are always going to be "assume a spherical cow in a vacuum" to a degree, as the real world is unbelievably complex, and you have to use models at some point. These models _can_ be wrong, and the only way to test them is through experimentation.
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.
(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 ;)
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:
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
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.
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).
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.
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.
> 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.
"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.
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.
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.
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.
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?
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.)
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.
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.
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.
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.
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.
"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.