[valine]

Altogether, it was a terrific flight and a big step forward for the Starship program. The biggest success was the survival of stage zero, which bodes well for a quick turnaround for the next flight.

Hot staging was the second big success, and Starship got to space.

The flight termination was disappointing, but the actual functioning of the FTS system seems to be fixed. That was a problem with the first flight and should make the FAA very happy.

[mattsan]

The second big success was all 33 engines working reliably all the way up! There were so many nay-sayers saying if the soviets could build those amazing engines but couldn't solve their flameout problem on their N-1 rocket that Superheavy was never going to work

[johnyzee]

Looking at that full set of 33 engines burning almost brought a tear to my eye (and the controlled cutoff). That more than anything else tells me they've made it.

[gavinray]

I don't understand what makes the functioning of all the engines so difficult (I know nothing about rockets).

How is it that you build something so expensive with so many development resources and expect parts to fail?

[saberience]

I'm going to assume you made this comment in good faith.

Most rockets (almost all) use just a few engines. The Saturn V had five engines, and the Space Shuttle had a total of five engines (including the Solid Rocket Boosters). The Atlas V uses one engine, New Glenn seven engines, etc.

Historically, there has only been one rocket that attempted the 'many engine' approach before now: the N1 by the Soviets, which they never managed to get working successfully.

SpaceX is thus attempting something unprecedented. They are not only trying to create a rocket with 33 engines, but they are also building the most powerful rocket ever made. Furthermore, it is the only rocket ever designed with fully reusable first and second stages. In this single machine, SpaceX is innovating in multiple ways that neither the US, the Soviets, nor any other country has managed to achieve.

Additionally, the Raptor engine used by SpaceX is the only full-flow staged combustion rocket engine that has ever flown. This design makes it more efficient and high-performing and has been considered the 'holy grail' of rocket engine design. Until now, no one has managed to build a successful rocket engine using full-flow staged combustion due to its complexity. The Raptor is also, pound for pound, the most powerful and efficient rocket engine ever made.

SpaceX is innovating throughout their space 'stack.' The entirety of the Starship project is immensely innovative in almost every way possible. Many others have tried and failed to achieve even a single aspect of what this project encompasses. The fact that SpaceX managed to have 33 Raptors firing perfectly today is already absolutely phenomenal.

So yes, I expect things to fail because much of what they are doing is literally the first attempt of its kind. It's entirely predictable that some aspects might fail. What you're asking is akin to questioning the pioneers of quantum computing: 'Hey, are you telling me the first quantum chip you built failed? That’s crazy! How can you build something so expensive and expect it to fail?'

[gavinray]

Thanks for the genuine response, it wasn't a troll comment.

[panarky]

I was also genuinely interested in your simple question, "what makes the functioning of all the engines so difficult?"

You received a response with many words but I don't think it contains a real answer, other than "the Soviets couldn't do it".

[Dalewyn]

>Space Shuttle had a total of five engines (including the Solid Rocket Boosters).

Very minor nitpick, but the Space Shuttle had seven engines: Two SRBs, three SSMEs, and two OMS engines.

The SRBs and SSMEs were used for launch, and the two OMS engines were used in orbit.

[saberience]

Yep, you're correct. I was meaning for launch only but I wasn't specific. :)

[bryanlarsen]

Falcon Heavy has 27 engines.

[mattsan]

9 engines times 3 cores. Unlike Superheavy which is 33 x 1

[hinkley]

People genuinely don’t understand how statistics work. Which is part of why Vegas still makes so much money.

When you put together a bunch of equipment with a small error rate, the time between errors climbs very fast. Build a RAID array with 33 disks and you’d better have a vendor picked out for replacements because you’ll be doing replacements fairly often, instead of every four to ten years with a single disk.

And they don’t understand dependent statistics either. Every failing rocket engine can potentially damage its neighbors. Every failing hard drive requires a stressful operation on the remaining disks (resilvering) that may push the next drive to failure.

[panarky]

> Build a RAID array with 33 disks ...

Yes, naturally 33 > 1, so you might expect 33 times as many failures of individual components.

But your analogy between arrays of rocket engines and disks is apt, because both have redundancy to survive the failure of individual components.

For example, in the high-altitude flight test of the Starship prototype in May 2021, three of the 33 Raptor engines powering the first stage failed shortly after liftoff. The vehicle still managed to continue flying, reaching an altitude of 40 kilometers before failing due to a variety of causes.

> People genuinely don’t understand how statistics work

Indeed.

If an individual disk has MTBF of 2 million hours, the probability of it failing in the first year is 0.437%.

But put 33 of those disks in a RAID 6 array, which can tolerate 1 or 2 failures without replacement, and the probability of the entire array failing in the first year drops by a factor of ten to 0.0413%.

The statistics say the array is even more reliable than a single component by itself.

[Ingaz]

The interesting point for me was:

> Every failing hard drive requires a stressful operation on the remaining disks (resilvering) that may push the next drive to failure.

I saw something similar: RAID array with 5 disks and 3 spare disks. One night controller detected failure, ejected one drive and replaced with spare. After rebuild of RAID it ejected another disk and then another. In an hour all spare disks were used and on fourth failure it stopped work

What was probability of such series of failures?

[magicalhippo]

Everyday Astronaut had a couple of (IMHO) great videos which goes into why rocket engines are hard[1] and the Starship many-engine approach[2] specifically.

[1]: https://www.youtube.com/watch?v=bAUVCn_jw5I

[2]: https://www.youtube.com/watch?v=AgqZMK22LEk

[parsimo2010]

It’s literal rocket science. Liquid fueled rockets have to work in basically the most extreme environments we’ve ever made machines work. Extreme cold temperatures through extreme hot and from extreme high pressures through vacuum. You have to have the best metallurgy and amazing machining tolerances. And then on starship they got it to work more than thirty times simultaneously.

[gavinray]

Sure, but if one works, why wouldn't the rest?

It's like saying "we built a car engine, but every 33rd car we make the engine doesn't" work. That's not a very good engine.

Also, not sure why I am getting downvoted for saying I don't understand something and asking other people how it works.

[Redoubts]

Could you imagine more problems if you physically strung 33 cars together and tried to drive them in unison?

[lamontcg]

Things like vibration and Pogo oscillation (https://en.wikipedia.org/wiki/Pogo_oscillation). All the engines collectively have about twice the thrust of a Saturn S-IC first stage (on the Saturn V rocket) and they're all going to be trying to shake the crap out of each other just due to thrust oscillations. If they hit a resonant frequency of the rocket it could shake the rocket apart. So, you can have 33 engines that all individually ignite properly on the pad and are all well-built to tolerances so that they function, but when you put the whole vehicle together and have all 33 of them pushing against the same airframe they could spectacularly fail.

[nvm0n2]

Yes but the reliability of modern car engines is a minor miracle, achieved through over a century of incredible engineering effort. Also remember that production lines always have yield, which means that not everything that rolls off it will actually work and the non-functional components are discarded. For example new chip production fabs very often have low yields, sometimes even the majority of chips don't work.

[NOT_RICK]

Lots of vibration and heat on what is effectively a massive bomb. And more engines means more parts that can potentially break.

[DoesntMatter22]

The early history of rocketry was non stop blowups, I mean hundreds of them. You can watch edits of this on youtube.

Rocket science is hard hence "It's not rocket science", except it is.

Having money and smart people doesn't ensure success. Bezos started his company before Musk did Space X and they still haven't gotten to space.

[fragmede]

And it's science that fails spectacularly. If I utterly fail at a Computer Science, there's no giant explosion.

[MatthewElvey]

Depends. Titan 4 test-stand SRB explosion; simulation missed failure mode (S 16 4)

The limits of simulation (From Henry Spencer) The 27May91 Aviation Week, reporting on the April 1 test-stand failure of an upgraded SRB (Solid Rocket Booster) for the Titan 4: Investigators determined that extensive three-dimensional computer simulations of the [motor's] firing dynamics did not reveal subtle factors that they now believe contributed to motor failure. [Program director] Stifling said the full-scale test was essential precisely because computer analyses cannot accurately predict all nuances of solid rocket motor dynamics. "That's why we test", he said. For those who don't follow the space news, a few seconds into the test the motor pressure rose rapidly and exceeded the limits of the casing, the result being a large, spectacular explosion that destroyed the motor and much of the Edwards AFB test stand.

-ACM SIGSOFT SOFTWARE ENGINEERING NOTES vol 16 no 4 Oct 1991 Page 15

[BackBlast]

If you use auto scaling services and fail to limit a recursive call to a service. You can create a giant explosion aimed at your bank account.

[egberts1]

... yet ... so far.

The more reasons to leave AI out of nuclear launch mechanism.

[brg]

saberience’s reply should be read because it is more complete and insightful, but perhaps there is a simpler intuitive answer. Error rates increase exponentially.

[avhon1]

Say you want to build something new, something that is beyond the bounds of what anyone has ever built before. In this case, a rocket that has more thrust than any built before. The basic mechanics say that it is feasible, so you start to work the details. You find the limit of knowledge in all kinds of directions, and determine which limits you can definitely build the rocket within, and which ones you will need to exceed. As the world's most powerful rocket, perhaps it will exceed current bounds of knowledge about things like material performance and turbulence under extreme temperatures and pressures.

Anything built outside of currently-known parameters might fail, so you design as much of the rocket as possible to operate within the limits of current knowledge.

Some of those limits turn out to be feasible to push in a laboratory. So you build and conduct experiments on those parameters, record the results, and design your rocket accordingly.

But for some parameters, the lab experiments required to test them are incredibly costly. Especially for parameters that vary strongly with scale (like turbulence), a system with the size and energy of the world's largest rocket can only be predicted by an experiment with the size and energy of the world's largest rocket.

Say it costs a billion dollars to build and launch your new rocket, but it will operate with ten unknown parameters, each of which will cost 200 million dollars to individually test on the ground. You could spend two billion dollars on experiments, then one billion dollars on a rocket you're confident will work. This is more-or-less the model that NASA used for developing the Space Launch System: do as much science as necessary, ask Congress for as much extra time and money as the contractors say they need, so they can be extremely confident that their new biggest rocket will work perfectly the first time. NASA doesn't like launching rockets that they don't know will work, because Congress doesn't like when rockets they paid for blow up, and NASA depends on Congress for all of their funding.

However, for the same money, you could build your rocket best-guess within the known unknowns and fly it. It's likely to blow up, because you guessed on ten unknowns. However, if the results of the flight allows you determine some of the parameters with greater confidence than one billion dollars in ground experiments, then it was worth the while, and you re-design your rocket according to the newly-understood parameters. You can do this three times for the cost of building the experiments and flying once. That's a decent chance at learning the parameters, and as a bonus, you get to practice building and flying the rocket, productively employing all of your staff and facilities.

That's more-or-less the model that SpaceX is developing Starship on, and previously Falcon 9. Blowing up prototype rockets only costs SpaceX time and money, and as long as it costs less time and money than running ground experiments (and keeping their production and launch crews on retainer, and maintaining their facilities between rockets), they're saving money by launching rockets they expect to blow up.

[LargeTomato]

> There were so many nay-sayers saying if the soviet

Who are you talking to where many people are saying that? I work in the space industry and no one I've ever spoken to says that.

[Mountain_Skies]

Elon Musk has plenty of people who hate everything he and his companies do, and they are very vocal about doom on everything. Working in the actual space industry, you're exposed to people who are evaluating things based on professional knowledge and experience rather than a social media bubble.

[qiine]

Sad we didn't get any shot from the Starship onboard camera during reentry.

[thelittleone]

Starship didn't do re-entry though right? They lost signal, and what happened after that was not explained. It was at the target height and >24,000km/h when it lost signal. Some coverage suggested SECO happened, they they lost signal.

[datameta]

At the conclusion of the SpaceX stream they confirmed the automated launch abort system triggered with vehicle lost. But so much data gained!

[euroderf]

I hope that future mission commanders will never ever let control forget that someone mistakenly kaboomed an upper stage.

[datameta]

I believe it was automatic based on a potential course deviation that brought it dangerously close to Hawaii?

[euroderf]

Well... that'll teach them pesky nav-bots to threaten populated areas.

[haarts]

SECO = Second stage Engine CutOff.

[MatthewElvey]

Yeah, me too. There were onboard cameras on Starship and Super Heavy. Hopefully they'll release more footage and info over time.

Even the first launch had some. https://www.reddit.com/r/SpaceXLounge/comments/12claay/the_k.... I recall the during the SpaceX audio commentary of this morning's launch (but perhaps EverydayAstronaut's) it was mentioned that onboard cameras on Starship and Super Heavy would be attempting to communicate via Starlink for the first time.

[sertbdfgbnfgsd]

Isn't reentry supposed to be the hard part? How was this a success?

[valine]

The largest rocket ever built just got to space for the first time. Even without re-entry this is a milestone.

They have a production line to build these things. They’ll roll out the next one and try again. It’s not like SLS where everything is expected to work perfectly.

[s1artibartfast]

>They have a production line to build these things. They’ll roll out the next one and try again.

Yep. to be more specific, they have 6 more ships built and 5 under construction. Engines are being produced one per day. The scale of manufacturing is stupefying.

[aidos]

One. Per. Day?? That’s pretty wild.

[s1artibartfast]

They claim to be able to scale up to 4/day with the current factories. Obviously a bold handwavy claim , but people said that 1/Day.

I have to imagine 350 engines/yr is more than enough for now, even if the FAA has permitted up to 20 launches per year.

Like I said, the whole scale is staggering.

[fragmede]

Yes, and not to diminish it in any way, but keep in mind that they need 33 of them per.

[s1artibartfast]

39 if you count starship itself.

[sertbdfgbnfgsd]

Why is the size a milestone? I don't remember ever hearing NASA measure its achievements by the size of its rockets.

[friend_and_foe]

You've never heard the phrase "Saturn V is the largest rocket ever built"?

[gregjor]

I guess that’s one way to define success or a milestone. The Saturn V used for the Apollo program had different criteria, like not blowing up and having all engines ignite.

Now that we have the person who knows more about manufacturing than anyone else alive in charge I’m sure these glitches will get sorted out.

[godzillabrennus]

It’s nice when you have the backing of a super power nation and their blank check to do it vs having shareholders.

[aik]

Amazing the effect competency has when trying to win a blank check away from others.

[deadbeeves]

Doesn't SpaceX receive plenty of money from the US?

[spurgu]

They get money for launching stuff into space, i.e. it's a business.

[ralfd]

It depends on the definition of plenty. At the peak in 1965 NASA/Apollo funding was 5% of government budget. That would be hundreds of billions today.

[avhon1]

Ah yes, because the Apollo program is famous for never having any problems with unscheduled fires or explosions. Completely safe, it was.

Sarcasm aside, NASA has blown up plenty of rockets. It's not a problem to blow up a rocket if it doesn't pose any substantial risk. NASA doesn't much like to blow up rockets anymore because it's contrary to how their operational model works: Congress gives NASA a task, a deadline, and a budget, and NASA is expected to deliver on the task, and can ask for more time or money down the road. Any kind of high-profile public failure is risky to NASA because it looks bad to Congress, who might cancel the project. Asking Congress for more time or money is normal, so the safe strategy with NASA's undertakings (especially high-profile ones like the James Webb Space Telescope and the Space Launch System) is to deliver flawless performance, usually late and over-budget. Congress doesn't need to be paid back, and history mostly remembers program success rather than schedule and budget overruns.

Of SpaceX's current programs, Falcon 9 is operated most similarly to NASA. It's expected to be mature and reliable; it is trusted to fly billion-dollar spy satellites and human crew. Any kind of failure will be heavily scrutinized, so SpaceX is only pushing the envelope of reuse and flight performance with their in-house payload program, Starlink. All of their customer flights get to operate well within the established safe performance envelope of the rocket. With over 200 successful consecutive flights now, SpaceX's Falcon 9 obviously can be depended on.

Starship, on the other hand, is not being depended on by anybody at the moment. No project gets delayed or cancelled when it explodes; no missile complex goes unwatched, no humans get stranded in space, smacked into the ocean, or burned alive. Nobody, least of all SpaceX, needs it to be perfect now. What they need is for it to become good enough to sell, to sell lots once they're selling it, and to not cost too much once they're selling it, all of this ideally sooner rather than later. They have access to lots of money now to make this happen, but investors' money has to be paid back someday.

So the bar for Starship isn't set at "succeed". It's set at "maximize future return on investment".

SpaceX is counting on present failures to save them money in the future by proving exactly what is necessary to succeed, at a time when failure is relatively cheap for them. They've clearly improved from the previous launch. Key milestones were passed. Telemetry was collected, and the flight safety systems executed an authoritative conclusion to the flight. With the investment of only 212 days of time and money since their previous high-profile Starship explosion, SpaceX has gotten demonstrable progress towards future flight success.

[imtringued]

>Starship, on the other hand, is not being depended on by anybody at the moment. No project gets delayed or cancelled when it explodes;

Did you forget the Artemis 2 mission?

Starship appears to be a source of delays, not SLS.

[avhon1]

I did not forget Artemis. Artemis 2 will not require Starship; it's just the Orion capsule going around the moon and back. Starship Human Landing System won't be needed until Artemis 3, which is currently scheduled for December 2025. That is a lot of time use to get Starship in shape to operate beyond Earth, and even if it isn't enough, won't result in the cancellation of the Artemis project.

[bryanlarsen]

The gating factor for Artemis 3 (not 2) appears to be the space suits, not Starship.

[pattmayne]

It was more successful than the last one. These are experimental rockets that are tested, usually to destruction. It's a success to the extent that it gets them further along in their R&D. To call it a failure would be to ignore the fact that this is progress.

But yeah, landings would have been much bigger successes.

[idlewords]

They got through staging this time and it looked like all the engines stayed on during the first stage boost. It's a flight test program, as long as new things are breaking each time you're making progress.

[pixl97]

If they can get stage 2 to a stable orbit then they can start putting payloads up, and this is long before they start recovery of the units. Now stage 2 popping at the (almost) orbital insertion stage is interesting as it just should have shut down for stable flight.

[MPSimmons]

There are multiple goals, up to an including full mission success, and this checked several boxes that hadn't been checked before.

[chpatrick]

All of those are very hard.

[slenk]

I don't understand why people are celebrating failed rocket launches.

Apollo 4, the first time the full Apollo Saturn V rocket stack was assembled, did not blow up on the first attempt to space. That is something to celebrate. Now wasting millions of government dollars from subsidies, which in the end comes from citizens.

We should not be celebrating failure.

[avhon1]

I notice you omitted an earlier, extremely prominently failed, Apollo mission.

Apollo 1 is highly analogous to the current testing of Starship. New spacecraft, highly ambitious, coming together for the first time.

Its conflagration was predictable, and a total waste of the life of the astronauts onboard. Only their deaths forced the whole spacecraft to be redesigned the way it should have been before any astronauts were onboard. Even afterwards, a second electrical fire nearly killed three more astronauts, far from any safety though their shiny new door.

The Space Shuttle ran much the same way. Carrying astronauts on its very first flight, people though it was safe, right up until it spectacularly killed seven astronauts. After that, it was flown much less ambitiously, and then it killed seven more people, and then we still kept flying it because it was all we had, and our bureaucracy was stuck with it.

Starship blowing up today poses no risk to human life, or to any organizational ambition. Rather, its present failures represent progress towards future success. Somebody is trying to do better than has been done in the past. If they learn all the things to not do to their rocket before valuable payloads and people fly on it, all the better.

[fragmede]

Because, even in failure, there's progress. "Genius is one percent inspiration and ninety-nine percent perspiration" is often attributed to Edison, without whom, we wouldn't have the lightbulb. In order to make progress, you need to try. And if you never fail, you're not trying hard enough. Would it be better if it hadn't failed? Absolutely. But better to try and fail than never try.

[slenk]

What bothers me is that they don't even try to succeed. They only want liftoff - they don't seem to care about the ever important orbital aspect

[avhon1]

Why don't you think they're trying to succeed? They got very close to orbit today, much closer than many prototype rockets do. Just earlier this year, Japan's new rocket also failed to achieve orbit. Its second stage just didn't ignite at all. Starship got closer to orbit than that today.

https://arstechnica.com/science/2023/03/the-launch-of-japans...

The Soviet N1 rocket never even got past first stage separation, in 4 launches. They got closer every time, but after the 4th stage blew up during main engine cut-off, they canceled the program, and never flew a cosmonaut beyond low-earth orbit.

[MatthewElvey]

I think most people don't understand the concept of if you want to succeed, fail faster.

It's valid (and explained well and often) but counterintuitive.

(And with mundane tasks, it's less applicable, as with them, it's reasonable to expect that when competent people attempt them, they generally get done correctly.)