"The initial tests completed successfully but the final test resulted in an anomaly on the test stand."
I'm not saying this is spin, but it sounds like how you'd spin something like this. Basically, the tests worked until they didn't. And that one therefore became the final test.
It could also be that the last test they planned to execute resulted in the 'anomaly'.. Not every public communication is subterfuge even though the armchair detectives in the HN comment section always seems to think it is.
No, anomaly means there was an outcome which was not expected. It says nothing about how many tests they were going to execute (if any), what the unexpected outcome was, or what the lead test engineer ate for breakfast that morning.
That's the dictionary definition of "anomaly". But that's not the interesting part, what's tickling us armchair detectives is how it got into the press release: "anomaly" is a bit of an anomaly itself, most people would never use that term unless specifically to play something down. That surely is no proof, enough to inspire speculation.
Speaking of speculation, there could be quite a few speculators in this thread that are invested in SpaceX. The downplaying of the actual event could be their own way to shape the stock price.
Right. It means exactly what it means. Actual test did not match expectation. Thus, there is an anomaly. Sometimes that means "boom" and sometimes that means bad sensor and sometimes it means the result was outside the margin and they need to do a thorough analysis before retest.
It sounds like a good thing: 'we passed so many tests successfully!'
But it also sounds like kind of a bad thing that it's the last test: 'holy cow - that was close - thank god we had the last test in there.'
Without knowing the specifics of what they were testing every time that might be irrelevant, but if it was multiple test fires of the same engine and only the last one caught the problem, that's scary.
It is how you talk about failure when it is another part of your engineering characteristics and not something that causes fear or shame.
Another reminder is why you run tests. They don't scare away failure by existing, they are there to catch failure, doing their jobs exactly as intended.
It will probably result in a delay of any human spaceflight by SpaceX until the source of the source of the problem is removed. (not the particular issue that caused the anomaly but the systematic issue which didn't find it before it happened on the pad)
> It is how you talk about failure when it is another part of your engineering characteristics and not something that causes fear or shame.
That depends on whether this was supposed to be the final test. If it's a post-hoc "final", then that's an obfuscation done out of shame. If it was always supposed to be the final test, then the statement is fine.
It really doesn't matter if it's the final test or not.
Your QA (or dev, or whatever) group has a number of test cases to verify. They verify the ones that they can, and record failures against the ones that they couldn't not. Sometimes in hardware testing, a failed test results in destruction of the hardware and/or peripheral damage to the test environment.
IME, riskier tests are run later, because you want as much test feedback as possible so the tests that aren't likely to break something are run first. However, you can't really draw any conclusions from that unless you know what the test plan was.
'Anomaly' is a polite way to say 'failure', no matter how fine the semantic wrapper. Failures are to be expected and OK and it's good that they happen during testing rather than operation, but there's no value in euphemism here.
It is useful as long as they do not know what happened. NASA once had the problem that the initially suspected problem turned out to be wrong but the news was already out there and it took years to spread the correct one. That's why it these problems are now referred to as anomaly until the real cause is clear.
"Anomaly" or anominal is the antonym (ie opposite) of "nominal". When things are going right, then everything is "nominal".
An anomaly is where things aren't going according to their expected behavior. Anomalies can have differing levels of severity, depending on the impact of the anomaly on the mission plans.
You can have anomalies at any time, that's different to a "defect" or a "failure". Failure implies anomalies so severe that the mission can not complete.
So it's not a euphemism, it's a distinct term of the art in engineering of this sort.
"it's a distinct term of the art in engineering of this sort" - I think the problem might be for people who don't work in that field, that the word anomaly in ordinary English means something that is slightly unusual. In other fields, including software, we would say that something failed even if it is only in initial development. If the term in common use for space craft is anomaly, then everyone in that field knows what it means so it is a good term because they are the only people that matter in dealing with it.
If they have a series of tests to perform, I'd expect them to order the tests so that the ones with the highest chances of anomalies that will make them abort testing come later in the series. It doesn't seem all that unreasonable given that for them to really have the spectacular failure occur on the last scheduled test of the series.
The use of such a vague and overloaded term as "anomaly" is deceptive.
The purpose of communication is to inform the audience, and rather than clarify what happened, this statement obscures the truth to the public.
The test capsule exploded. It means both SpaceX and Boeing have had test failures in the launch abort system for their respective human launch capsules. It will set back the timeline for the US to regain the ability to launch humans into space without paying for seats on the Soyuz.
Instead of discussing the event and its implications, the longest thread is now dedicated to excessive pedantry and incorrecting each other over textbook definitions of the word "anomaly".
It's a vague term because they don't know what exactly happened yet and anomaly is a technical term that those in the industry know.
Explosion has a technical meaning too, and many things that look like an explosion aren't. AMOS-6 for instance was not an explosion, even though it really looked like one to a bystander.
This isn't excessive pedantry, it's jargon meant for an audience that will understand it and not take more away from a statement than they intend to say. Better to use the word that means "something bad happened" rather than a word which means something specific only to have to follow that up with "sorry, we were wrong, it wasn't that, it was..."
As much as I hate seeing setbacks and delays to commercial crew, it's best to have these failures early on in the program before they risk the life of astronauts and personnel.
That’s slightly misleading. Originally they put 1 atmosphere of pure O2 in the Apollo capsule. This proved to be a great environment for fires. After that they pressurized the capsule with 5 psi of pure O2, which is about 1/3 atmospheric pressure.
If you're wondering why there wasn't nitrogen mixed in, it's because the additional systems+tanks for handling nitrogen would've added more weight to the spacecraft.
Interestingly, that's higher than the ppO2 at sea level, which is about 3 psi, or at ~5K feet (standard airliner cabin pressure) where it's 2.5psi, so they were still running at almost double the amount of oxygen available normally.
My understanding is that the initial design was intended to fly in space with a ~5psi pure-oxygen environment for the same reasons that previous spacecraft all did, and that American spacewalks today still do: it reduces complexity, reduces weight, and decreases required hull strength. Fire propagation in that environment isn't actually as bad of an issue as you expect because the pressure is correspondingly lower, so their isn't actually more O2 available in the air.
The problem is that the Apollo 1 test was run with both a pure-oxygen environment and a positive relative pressure to the outside, but was run on the ground. That meant a ~16psi pure oxygen environment, which is a real fire propagation issue, meaning materials which were specced not to burn in the flight environment could burn during the test.
In spaceflight, does 'anomaly' ever refer to something other than an explosive fireball? Because I've heard that term used for rocket explosions and I get that vibe from this announcement, but... But could it be that the computer just tanked and now they're going through a core dump? Would that be an 'anomaly'?
Ideally, computers inside rockets don't crash. The software should be that good when you're letting it handle tons of explosive fuel. Then again, Ariane 5 did happen...
That's the idea. I'm working on flight software for Orion, and there are many levels of redundancy, both in design and process, that are put into the software architecture. It's extremely expensive, but flight software is still a drop in the bucket compared to mechanical, propulsion, and electrical systems. It should have an expected failure rate much lower than the physical systems, and should never be on the critical path. We're not doing fancy stuff, it's just gotta be robust and fault tolerant.
Yeah well, it's definitely not trivial. I just mean that most of the problems we're implementing have been solved decades ago (inverse kinematics, control, comms, etc). When you actually need to get all of those functions working in a hard real-time system, of course there are enormous engineering difficulties. In my limited experience, these mostly manifest as extensive testing and formal verification, to the extent to which that is possible.
Check out NASA Core Flight System if you're curious, it's an in-house framework and abstracted OS layer meant to support hard real-time flight systems.
Definitely will do that, thank you for the pointer. Reliable software design is something I've been interested in for a very long time and it is amazing (to me, at least) how much we already know and yet refuse to put into practice. I think a big part of this is that speed is sexy and reliability is not.
Ariane 5's computers never crashed. At least, not until they hit the ground. They operated flawlessly and ran the software the way they were supposed to.
Yes, but there's a big difference between "the spacecraft blew up in the test harness" and "all of the stack traces were recorded and a CS intern is currently testing a patch and we'll be back in business by Monday". The press-release didn't really indicate how serious of a setback this anomaly is. Although now the article has been updated with "smoke seen for miles" which wasn't the case before.
usually means something rather more mundane than a fireball. basically anything that happened that you didn't want to happen is an anomaly.
10 years ago the folks putting your reaction wheels together botched it, and now they're acting slightly weird? anomaly.
you charged your batteries too hard for years because you thought "max" was a great setting for your battery chargers, and now they're failing? anomaly.
>Anomaly: The unexpected performance of intended function.
Good or bad, major or minor, an anomaly is when reality does not meet engineering design and expectation. It just happens that in spaceflight the most active time is the most dangerous time and most anomalies result in fireballs when your engine is lit as there is not much room at all for error.
I believe the motivation for referring to things as anomalies is to forestall any rush to judgement about an unexpected event. AKA something 'bad' happened.
Old memory from the 80's an engineer mentioned that he went down to the lab and found an unhappy test tech. Guy was testing a new pressure sensor and it wasn't able to make 10,000 full cycles without blowing the diaphragm. Turned out the test setup was shock loading the pressure sensor. He was surprised it was almost passing. The solution was a rate limiting valve in the test setup. There was nothing wrong with the pressure sensor.
There is a great write up from one of the guys that developed the thrusters for the Apollo program. They had problem where you could get layers of frozen oxidizer and fuel in the inside of the nozzle. Which would then go explode and shatter the nozzle. The solution was to operate the thrusters so that didn't happen.
Currently reading On The Shoulders of Titans about the Gemini program. It gets slammed for being very poorly edited & formatted, etc. but it's dirt cheap if you can see past that. Quite a good collection of interesting engineering problems & solutions like that, and some very good lessons on how (and how not) to run major engineering projects (but as the reviews will tell you, it's just a human-readable series of events drawn from memos and calendars, etc - there's little analysis or real commentary). One of my favorites is that the maneuvering & attitude thrusters used ablative cooling, but ablated way too fast. They got incremental improvements by messing with the orientation of the laminated layers and other tweaks, but the real break through was squirting fuel down the inner walls of the cone immediately prior to ignition: got something like 4x the previous engine life and double their target.
In spaceflight, does 'anomaly' ever refer to something other than an explosive fireball?
Strangely enough, yes: the satellite guys use 'anomaly' to describe the (angular) position of a body in its orbit. I've never heard where the term originated in that context.
I was curious about that myself. In astronomy, there is the mean anomaly, and the "true" anomaly. The mean anomaly is relative to a circle with the same period as the actual object, while the true anomaly is relative to an ellipse. A few minutes of Googling suggests that originally, the term anomaly came from the discrepancy between predictions of orbits assuming they were circular and observations, and it was something that was explained by epicycles in the time of Ptolemy, almost 2,000 years ago. So yes, it comes from the same concept of an anomaly.
Incidentally, according to what I was just reading, epicycles in principle can be used to approximate any curve if you pick them appropriately. Choosing them is related to fourier analysis which of course hadn't been developed yet. When you hear about it in grade school, it's presented as this dumb thing that doesn't make sense, but it was really not a terrible solution.
Some thoughts on the initial images from /r/spacex (great community):
1. The orange smoke [1] is the color of Nitrogen Tetroxide, which is the hypergolic fuel that Crew Dragon uses. The normal reaction in the Draco engines in the Crew Dragon is Nitrogen Tetroxide (N2O4) and methyl hydrazine (CH3(NH)NH2) [2]
2. The prior grey smoke might mean the engines were already firing for the test, which would rule out something like a tank loading error or something else with the ground crew.
3. Boeing had a hypergolics + Launch Escape System anomaly and it pushed their program schedule back 6 months. [3]
4. Eric Berger (Reporter for Ars Technica) indicating it may have been a serious incident. [4]
> Boeing had intended to complete the test of its abort system last summer but has yet to reschedule the flight 10 months later, apparently due to complications from this accident.
Yes because they both work for the same customer (nasa) who will determine the type of process needed. When it comes to human spaceflight, nasa decides the pace of the investigation (number/nature of reports etc). They take accidents on the pad exectly as seriously as accidents in flight.
In case it's relevant, here's a 1958 NASA film on the hazards of the propellants (various hydrazines) and the oxidizer (nitrogen tetroxide) that were used at the time. As mentioned in another top-level comment, the Crew Dragon uses nitrogen tetroxide as an oxidizer.
They’ve recently done a second paperback edition so you can even get a physical copy! It’s a great read for anyone, and shows the crazy risks taken in the early rocket programs.
Actually there is an Anomaly Detection Cognitive Service in Azure currently in Preview Mode for whom wants to retry experiments before real buttons push
No, it'll form nitric acid as it reacts with moisture in the air and be neutralized as it reacts with the environment. Nitrogen tetroxide is used as a hypergolic oxidizer because it's very reactive. It'll react with basically most anything that can be oxidized so it's not going to hang around for too long.
There was no or very little monomethylhydrazine released. If there was, it would have reacted with the nitrogen tetroxide. Since it's hypergolic, it doesn't need to be under high temperatures or pressures to react. Just the two substances coming into contact will cause them to react.
Explosions tend to disperse material in uncontrolled ways, so I doubt the two substances got mixed perfectly. Chances are not all monomethylhydrazine reacted with the nitrogen tetroxide.
The complexity of internal combustion engines and their emissions control seems to support the idea that perfectly reacting two substances is very difficult even when all of your machinery is working nominally.
Unfortunately I can't edit the previous comment anymore but you're right. Originally I was under the assumption that the conjecture that the propellant valve failed or started leaking upstream from it was correct. However, it appears that the entire vehicle exploded before the SuperDraco test even started. Since it wasn't just leaking out of a damaged engine, my assumptions about roughly complete mixing were wrong. There's very little chance that there wasn't a decent amount of MMH released as well.
Interesting. The voice in the video is mid countdown when it happens ("Ten, Nine....expletive") which implies the Super Draco engines hadn't fired yet.
If it's something like a pressure issue, it could be similar to what happened to AMOS-6, where there was buckled liner in a COPV [1] tank that caused a liquid oxygen buildup [2]
Someone on reddit captured the frames before and after, it looks like it's originating from just near one of the Super Dracos [3].
AMOS-6 suffered from a problem with a Helium Composite over-wrapped pressured vessel (COPV) that most likely had a liquid oxygen intrusion into the composite layer which due to the cold temperature of the helium created oxygen ice that violently reacted with the composite when friction ignited the combination. (Fun fact: as far as I know a liquid-oxygen drenched cigarette basically explodes when lit).
Afaik there is no Helium COPV on Crew Dragon.
Edit: after checking because of Someones comment, it turned out that cigarettes do not explode when drenched with LOX, they just burn brightly not unlike a flare.
In retrospective, a launch abort tower may hav been better and safer solution, those internal superdracos may make it very hard to get back in the game .....
After the success of the Falcon Heavy a couple days ago, I'm actually surprised there weren't more hiccups in SpaceX activity. They are pushing the limits of spaceflight technology, there are _bound_ to be setbacks like this. A roadmap with no errors like this is highly improbable. Amen for rigorous testing.
There's a line from Bezo's annual shareholder letter a few weeks ago that this brings to mind:
"As a company grows, everything needs to scale, including the size of your failed experiments. If the size of your failures isn't growing, you're not going to be inventing at a size that can actually move the needle."
I think SpaceX is great. But how are they “pushing the limits of spaceflight technology?” The SpaceX Merlin engine uses the same basic RP-1/LOX cycle as the Saturn V’s first stage engine, which is more than half a century old now. Rocketdyne’s engine produced about 7-8 times as much thrust (which is why SpaceX needs 27 engines on three boosters for a Falcon 9 Heavy, versus 5 for a Saturn V.)
(Here is the computing equivalent of what SpaceX is doing: creating a PDP-11 with modern technology, that’s maybe 75% as fast, but at a fifth to a tenth of the cost.)
A more accurate summary is SpaceX is retreading well-worm ground that was trod before many of us reading this article were born, bringing modern materials and manufacturing capabilities to bear improving the same basic designs. That’s cool. But that’s not pushing the boundaries of space flight technology.
Doing things at a Harbor Freight price point that have never been done at that price point before basically always winds up being uncharted engineering territory. Anyone can build something that works when you don't care about cost.
No doubt SpaceX is solving lots of cool engineering problems. But portraying those cost-optimization efforts as “pushing the limits of spaceflight technology” is a triumph of marketing. And it obscures how little real progress has been made in aerospace over the last half century.[1] (Also, your last sentence is obviously not true. The physical sciences are a harsh mistress. Lots of things never work.)
[1] Even with computer aided design, composites, laser sintering, etc., the thrust-to-weight ratio of a Merlin engine is a factor of two better than an RP-1/LOX engine from half a century ago. That’s about the same factor improvement as we achieved in subsonic jet engine performance over that time period. Aerospace technology moves very slowly, there is no reason to be hopeful and optimistic.
You are asking: how are they “pushing the limits of spaceflight technology?”
Let's not go futher, just concentrating at the incident in question. The anomalous test happened on a location named "Landing Zone 1". That's not a thing any other rocket company has. Why? Because they don't land their rockets.
It happened with a space capsule fished out of the brine. No other company reuses their space capsules in such a way.
The detonation very likely will be found to have something to do with the SuperDraco system. Which they originally designed there to enable propulsive landing on dry land. The russians have their kick engines, sure, but that's not really same as hover landing, isn't it? Why did they plan that? For rapid reusability.
So yes, if you ignore all the things they did for reusability, then they indeed are not pushing the limits of spaceflight technology.
> Let's not go futher, just concentrating at the incident in question. The anomalous test happened on a location named "Landing Zone 1". That's not a thing any other rocket company has. Why? Because they don't land their rockets.
Parachute landing a crew pod into the ocean is something we first did the year my dad was born.
> Which they originally designed there to enable propulsive landing on dry land.
We landed an entire orbiter like an airliner three years before I was born.
> Parachute landing a crew pod into the ocean is something we first did the year my dad was born
You're getting confused between the tiny pod that people sit in - which basically does nothing, and the actual rocket, with all the flames and gasses and actually make the pod go somewhere.
Nobody has ever landed and reused the rocket before SpaceX
> landed an entire orbiter like an airliner three years before I was born
Yes, a thing with wings landed using lift from the wings. It did not use rockets for propulsive landing like SpaceX have designed.
I do not believe you do not know that reusing the Space Shuttle Orbiter after landing required disassembling it, which made launching satellites on the reusable STS cost much more than using expendable rockets of the time as opposed to reusing the Falcon 9 booster which does not require disassembly and is cheaper than using a newly built Falcon 9 booster, which itself is cheaper than the competitor's Atlas V, which uses engines built in Russia and has lowered prices significantly in response to Falcon 9 became certified to fly government payloads.
I am mentioning the fact that RD-180 is built in Russia only because the US company got the plans to build them from the Russians but decided that doing that is too expensive while built-in-Russia engines are available, so basically the US did not have the capability to manufacture state-of-the-art engines until SpaceX Raptor, Blue Origin BE-4. If newly built RS-25 happen, I'll count those as state of the art, but so far they're only using old already-flown-on-shuttle engines with extremely expensive computer upgrades.
> The SpaceX Merlin engine uses the same basic RP-1/LOX cycle as the Saturn V’s first stage engine, which is more than half a century old now.
If I build an electric car with the same rubber technology as cars have used for a century, this would not mean I hadn't pushed the limits of technology.
> Rocketdyne’s engine produced about 7-8 times as much thrust (which is why SpaceX needs 27 engines on three boosters for a Falcon 9 Heavy, versus 5 for a Saturn V.)
"Thrust per engine" is a bad metric since, for larger payloads, it can be better to add more engines than make them bigger, and that metric immediately disqualifies that strategy. (For instance, more full independent engines means more redundancy. Which strategy is better is going to depend on the details.) We wouldn't say that 18-wheelers are worse technology than 4-wheeled earth movers because the latter have more weight per wheel. Ultimately, the thing we care about is most mass to highest orbit at lowest risk. But if you want to concentrate on raw engine performance, you probably should look at metrics like ISP (which SpaceX is indeed not pushing the limits).
> A more accurate summary is SpaceX is retreading well-worm ground that was trod before many of us reading this article were born, bringing modern materials and manufacturing capabilities to bear improving the same basic designs. That’s cool. But that’s not pushing the boundaries of space flight technology.
Surely re-useable first stages is the biggest advance by far in spaceflight technology in decades?
It sounds like by "space flight technology" you just mean engines, but chemical rockets are within about a factor of 2 of the maximum efficiency allowed by the laws of physics. So within that paradigm, you're just not going to get revolutionary (multiple-orders-of-magnitude) improvements in the things we care about (mass to orbit) by improving engines as opposed to things like re-usability. So I think by your definition, the only thing that would be really be an improvement would be nuclear rockets, or something else even more extreme.
> If I build an electric car with the same rubber technology as cars have used for a century, this would not mean I hadn't pushed the limits of technology.
That's a misleading comparison, because we're not talking about some ancillary aspect of the design (like rubber tires). This is more like designing a car with the same basic engine technology as a 1969 Impala, except you're using an aluminium engine block and modern crumple zones.
> "Thrust per engine" is a bad metric since, for larger payloads, it can be better to add more engines than make them bigger.
More engines can also mean more chances for failure. (You can make the design resistant to engine-out conditions, but some engine-out conditions are less recoverable than others.) Regardless, the Falcon 9 Heavy also has substantially lower maximum thrust than the Saturn V.
> Surely re-useable first stages is the biggest advance is spaceflight technology in decades? It sounds like by "space flight technology" you just mean engines, but chemical rockets are within about a factor of 2 of the maximum efficiency allowed by the laws of physics. So within that paradigm, you're just not going to get revolutionary (multiple-orders-of-magnitude) improvements in the things we care about (mass to orbit) by improving engines as opposed to things like re-usability. So I think by your definition, the only thing that would be really be an improvement would be nuclear rockets, or something else even more extreme.
I don't even really disagree with that point. Unless there is some groundbreaking advance in rocket engines, you're not going to be "pushing the boundaries of spaceflight technology." It's just like how we don't say Intel is "pushing the boundaries of CPU technology" every time they widen the vector units on the same basic Core architecture they've been using for almost two decades. It's a mature field where revolutionary improvements aren't possible with foreseeable technology. But that doesn't mean you get to relabel incremental improvements as revolutionary.
> That's a misleading comparison, because we're not talking about some ancillary aspect of the design (like rubber tires).
I think within the context of chemical rockets, engines really are sorta ancillary! Not to the same extent as rubber tires (I used that extreme example just to make my point clear), but engines is just not where the large improvements in things we care about will come from.
> More engines can also mean more chances for failure.
Agreed. I wasn't arguing for either strategy since I don't know enough to have an opinion. I just wanted to point out that more engines was a plausible best strategy, depending on engineering details, and we shouldn't choose metrics that immediately disqualify it.
> Regardless, the Falcon 9 Heavy also has substantially lower maximum thrust than the Saturn V.
Agreed, Falcon 9 is not an example of an advance in total lift capacity, and total lift capacity is important. BFR/Starship may exceed Saturn V, but if so it will be a very slight edge which is not impressive after half a century. So I agree that this is not where the advances are happening. But, to pick another extreme example, the even older Spruce Goose was only recently dethroned in total wingspan, but this doesn't mean no dramatic advances in flight technology have occurred.
> But that doesn't mean you get to relabel incremental improvements as revolutionary.
abledon's original comment said "pushed the limits of spaceflight technology". I was the first person to use the vague word "revolutionary", and I immediately clarified what I meant: orders of magnitude improvement in metrics we care about. And I think the SpaceX tech, both completed and under development, really can lower mass-to-orbit prices by a factor of 100.
> I think within the context of chemical rockets, engines really are sorta ancillary! Not to the same extent as rubber tires (I used that extreme example just to make my point clear), but engines is just not where the large improvements in things we care about will come from.
They're not ancillary because propulsion performance metrics really drive the things you can do with the rocket. (Same thing in airplanes.) Acknowledging that "large improvements" will not happen in that area is a concession that we've hit a pretty hard wall on what we can do with this technology.
I don't think lowering mass-to-orbit prices by a factor of 100 is hitting a wall! But at this point I think we're risking a semantics dispute and we agree on many of the substantive points.
(Also, fwiw, I don't think your comments should have been, downvoted since they have been thoughtful, and a good counterpoint to the SpaceX over-enthusiasm in these threads.)
Merlin is also the highest thrust-to-weight engine ever, by a large margin. F-1 could produce a lot of thrust because it was huge, not because it was efficient.
But that's stuff they've already accomplished. You're ignoring what they have in development. The Raptor engine is among the most advanced engines ever made, pushing combustion/metallurgy technology literally to the limits, certainly not well-worn ground. Not to mention Starship/Super Heavy, which is pushing reusability further.
They might not accomplish everything they set out to do, but that's why it's "pushing" rather than "pushed".
> Merlin is also the highest thrust-to-weight engine ever, by a large margin. F-1 could produce a lot of thrust because it was huge, not because it was efficient.
It's about twice the thrust-to-weight ratio of an F-1, which was designed in 1969. With all the advances in materials science since 1969 (composites, etc.), that tells you a lot about the glacial pace of advancement in the field. It's also not clear to me why that even matters--a Saturn V has about 90,000 pounds of engines; a Falcon 9 Heavy has about 27,000 pounds. Both need millions of pounds of fuel. (As to your comment about "pushing" versus "pushed"--that interpretation of OP's comment doesn't match the fact that he's talking about a setback involving SpaceX's current generation of vehicles.)
Mate, not everything in the world moves as fast as the Javascript ecosystem. There are some hard laws at hand, called physics, that limit what you can lit under a rocket and get propulsion. Oxygen needs to be there. A combustible needs to be there as well. This is known since the 19th century. It just turns out that RP-1 is a good choice.
Given the same chemical reaction, improving the engine efficiency state-of-art by 50% in 50 years is astounding. With Raptor they are actually getting close to the theoretical limits.
What other expectations do you have for advancements? New chemicals are hard to get by. Nuclear is beyond contemplation. You can't invent new physics. What do you expect?
I have a degree in aerospace engineering, so I'm quite aware of all these limitations. What irks me about SpaceX is Silicon Valley-style marketing ("pushing the boundaries of spaceflight technology") being imported into what is in reality an extremely mature field where we have hit some pretty hard walls on possible advances. It's also immensely disrespectful to the folks who designed this technology two generations ago (back when it wasn't already proven), to act like you're "pushing the boundaries" when the main thing you're doing is cost-optimizing well-established designs.
However they are pushing the boundaries in terms of cost per pound to LEO, in terms of reusability, and in terms of scale (what classic system launches with 27 engines firing!?!). So while you may not like it, they do all of what they claim.
Through aerospace innovation? Perhaps not as much as you would like. But they do it through materials, manufacturing, automation, computers and operations innovations, which are just as important.
Then I don't know why you brought up Merlin at all because there's no Merlin engines involved in this anomaly. The Crew Dragon is not as revolutionary as other things they're doing, but it does have an integrated abort system that hasn't been done before as far as I know.
Not at all. It is neutrally called anomaly, so that there's no premature explanation out there that would be difficult to correct later if proven wrong. NASA had that problem once and that's why it is done like that today.
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[ 4.0 ms ] story [ 220 ms ] thread1. https://www.bouncycastle.org/java.html
Still have no idea what they were thinking with that one. Apparently it's an anagram of "matchers". Ooooookay.
Netherlands to London in 5 and a half minutes
I'm not saying this is spin, but it sounds like how you'd spin something like this. Basically, the tests worked until they didn't. And that one therefore became the final test.
But it also sounds like kind of a bad thing that it's the last test: 'holy cow - that was close - thank god we had the last test in there.'
Without knowing the specifics of what they were testing every time that might be irrelevant, but if it was multiple test fires of the same engine and only the last one caught the problem, that's scary.
Another reminder is why you run tests. They don't scare away failure by existing, they are there to catch failure, doing their jobs exactly as intended.
It will probably result in a delay of any human spaceflight by SpaceX until the source of the source of the problem is removed. (not the particular issue that caused the anomaly but the systematic issue which didn't find it before it happened on the pad)
That depends on whether this was supposed to be the final test. If it's a post-hoc "final", then that's an obfuscation done out of shame. If it was always supposed to be the final test, then the statement is fine.
Your QA (or dev, or whatever) group has a number of test cases to verify. They verify the ones that they can, and record failures against the ones that they couldn't not. Sometimes in hardware testing, a failed test results in destruction of the hardware and/or peripheral damage to the test environment.
BTDT.
It’s very similar to a cloud provider saying “increased error rates” meaning total outage or 0.001% of users experiencing off-nominal behavior.
Is there nomenclature that’s better?
I prefer "rapid unplanned disassembly".
What video are you referring to?
This looks like a very fast disassembly indeed. I hope they find the cause soon.
An anomaly is where things aren't going according to their expected behavior. Anomalies can have differing levels of severity, depending on the impact of the anomaly on the mission plans.
You can have anomalies at any time, that's different to a "defect" or a "failure". Failure implies anomalies so severe that the mission can not complete.
So it's not a euphemism, it's a distinct term of the art in engineering of this sort.
The purpose of communication is to inform the audience, and rather than clarify what happened, this statement obscures the truth to the public.
The test capsule exploded. It means both SpaceX and Boeing have had test failures in the launch abort system for their respective human launch capsules. It will set back the timeline for the US to regain the ability to launch humans into space without paying for seats on the Soyuz.
Instead of discussing the event and its implications, the longest thread is now dedicated to excessive pedantry and incorrecting each other over textbook definitions of the word "anomaly".
Explosion has a technical meaning too, and many things that look like an explosion aren't. AMOS-6 for instance was not an explosion, even though it really looked like one to a bystander.
This isn't excessive pedantry, it's jargon meant for an audience that will understand it and not take more away from a statement than they intend to say. Better to use the word that means "something bad happened" rather than a word which means something specific only to have to follow that up with "sorry, we were wrong, it wasn't that, it was..."
This video goes in to a bit more detail: https://www.youtube.com/watch?v=FvA7N_j_8os
https://www.popsci.com/why-did-nasa-still-use-pure-oxygen-af...
https://www.space.com/17338-apollo-1.html
The problem is that the Apollo 1 test was run with both a pure-oxygen environment and a positive relative pressure to the outside, but was run on the ground. That meant a ~16psi pure oxygen environment, which is a real fire propagation issue, meaning materials which were specced not to burn in the flight environment could burn during the test.
The effects could be redone in HD, but I think it wasn't even widescreen originally.
https://www.rferl.org/a/soyuz-rocket-anomaly-to-delay-u-s-sa...
The deadpan delivery really does it.
Check out NASA Core Flight System if you're curious, it's an in-house framework and abstracted OS layer meant to support hard real-time flight systems.
10 years ago the folks putting your reaction wheels together botched it, and now they're acting slightly weird? anomaly.
you charged your batteries too hard for years because you thought "max" was a great setting for your battery chargers, and now they're failing? anomaly.
>Anomaly: The unexpected performance of intended function.
Good or bad, major or minor, an anomaly is when reality does not meet engineering design and expectation. It just happens that in spaceflight the most active time is the most dangerous time and most anomalies result in fireballs when your engine is lit as there is not much room at all for error.
Old memory from the 80's an engineer mentioned that he went down to the lab and found an unhappy test tech. Guy was testing a new pressure sensor and it wasn't able to make 10,000 full cycles without blowing the diaphragm. Turned out the test setup was shock loading the pressure sensor. He was surprised it was almost passing. The solution was a rate limiting valve in the test setup. There was nothing wrong with the pressure sensor.
There is a great write up from one of the guys that developed the thrusters for the Apollo program. They had problem where you could get layers of frozen oxidizer and fuel in the inside of the nozzle. Which would then go explode and shatter the nozzle. The solution was to operate the thrusters so that didn't happen.
Strangely enough, yes: the satellite guys use 'anomaly' to describe the (angular) position of a body in its orbit. I've never heard where the term originated in that context.
Incidentally, according to what I was just reading, epicycles in principle can be used to approximate any curve if you pick them appropriately. Choosing them is related to fourier analysis which of course hadn't been developed yet. When you hear about it in grade school, it's presented as this dumb thing that doesn't make sense, but it was really not a terrible solution.
1. The orange smoke [1] is the color of Nitrogen Tetroxide, which is the hypergolic fuel that Crew Dragon uses. The normal reaction in the Draco engines in the Crew Dragon is Nitrogen Tetroxide (N2O4) and methyl hydrazine (CH3(NH)NH2) [2]
2. The prior grey smoke might mean the engines were already firing for the test, which would rule out something like a tank loading error or something else with the ground crew.
3. Boeing had a hypergolics + Launch Escape System anomaly and it pushed their program schedule back 6 months. [3]
4. Eric Berger (Reporter for Ars Technica) indicating it may have been a serious incident. [4]
/r/spacex thread:
https://www.reddit.com/r/spacex/comments/bfhm2c/on_april_20_...
[1] https://pbs.twimg.com/media/D4oMNJmXsAAv_7B.jpg:orig
[2] https://en.wikipedia.org/wiki/Draco_(rocket_engine_family)
[3] https://spacenews.com/boeings-starliner-launch-abort-engine-...
[4] https://twitter.com/SciGuySpace/status/1119730184544976897
> Boeing had intended to complete the test of its abort system last summer but has yet to reschedule the flight 10 months later, apparently due to complications from this accident.
So it's probably more than 6 months
https://www.youtube.com/watch?v=Zha9DyS-PPA
https://azure.microsoft.com/en-us/services/cognitive-service...
Just a small computer glitch or, things firing/smoking when they shouldn't, or something more drastic?
Things firing/smoking when they shouldn't? That's an anomaly too.
Pressure reading slightly out of predicted range? Also anomaly.
Everything went kaboom? That is also an anomaly, as long as that wasn't the plan.
Basically everything where expectation and reality do not meet.
If it's something like a pressure issue, it could be similar to what happened to AMOS-6, where there was buckled liner in a COPV [1] tank that caused a liquid oxygen buildup [2]
Someone on reddit captured the frames before and after, it looks like it's originating from just near one of the Super Dracos [3].
[1] https://en.wikipedia.org/wiki/Composite_overwrapped_pressure...
[2] https://en.wikipedia.org/wiki/Amos-6
[3] https://imgur.com/G0iE6Rr
Afaik there is no Helium COPV on Crew Dragon.
Edit: after checking because of Someones comment, it turned out that cigarettes do not explode when drenched with LOX, they just burn brightly not unlike a flare.
Doesn’t seem to be true. At the least, that’s isn’t guaranteed. https://www.youtube.com/watch?v=t48QWjtoVfw
(Can confirm that this Twitter account is a real person who works at KSC.)
[1] https://en.wikipedia.org/wiki/Apollo_1
Rockets are dangerous esp when you try out new designs , things blew up rather spectacularly during the early days of the space race.
Is this a joke?
"As a company grows, everything needs to scale, including the size of your failed experiments. If the size of your failures isn't growing, you're not going to be inventing at a size that can actually move the needle."
https://www.cnbc.com/2019/04/11/jeff-bezos-annual-shareholde...
(Here is the computing equivalent of what SpaceX is doing: creating a PDP-11 with modern technology, that’s maybe 75% as fast, but at a fifth to a tenth of the cost.)
A more accurate summary is SpaceX is retreading well-worm ground that was trod before many of us reading this article were born, bringing modern materials and manufacturing capabilities to bear improving the same basic designs. That’s cool. But that’s not pushing the boundaries of space flight technology.
[1] Even with computer aided design, composites, laser sintering, etc., the thrust-to-weight ratio of a Merlin engine is a factor of two better than an RP-1/LOX engine from half a century ago. That’s about the same factor improvement as we achieved in subsonic jet engine performance over that time period. Aerospace technology moves very slowly, there is no reason to be hopeful and optimistic.
Let's not go futher, just concentrating at the incident in question. The anomalous test happened on a location named "Landing Zone 1". That's not a thing any other rocket company has. Why? Because they don't land their rockets.
It happened with a space capsule fished out of the brine. No other company reuses their space capsules in such a way.
The detonation very likely will be found to have something to do with the SuperDraco system. Which they originally designed there to enable propulsive landing on dry land. The russians have their kick engines, sure, but that's not really same as hover landing, isn't it? Why did they plan that? For rapid reusability.
So yes, if you ignore all the things they did for reusability, then they indeed are not pushing the limits of spaceflight technology.
Parachute landing a crew pod into the ocean is something we first did the year my dad was born.
> Which they originally designed there to enable propulsive landing on dry land.
We landed an entire orbiter like an airliner three years before I was born.
You're getting confused between the tiny pod that people sit in - which basically does nothing, and the actual rocket, with all the flames and gasses and actually make the pod go somewhere.
Nobody has ever landed and reused the rocket before SpaceX
> landed an entire orbiter like an airliner three years before I was born
Yes, a thing with wings landed using lift from the wings. It did not use rockets for propulsive landing like SpaceX have designed.
I do not believe you do not know that reusing the Space Shuttle Orbiter after landing required disassembling it, which made launching satellites on the reusable STS cost much more than using expendable rockets of the time as opposed to reusing the Falcon 9 booster which does not require disassembly and is cheaper than using a newly built Falcon 9 booster, which itself is cheaper than the competitor's Atlas V, which uses engines built in Russia and has lowered prices significantly in response to Falcon 9 became certified to fly government payloads.
I am mentioning the fact that RD-180 is built in Russia only because the US company got the plans to build them from the Russians but decided that doing that is too expensive while built-in-Russia engines are available, so basically the US did not have the capability to manufacture state-of-the-art engines until SpaceX Raptor, Blue Origin BE-4. If newly built RS-25 happen, I'll count those as state of the art, but so far they're only using old already-flown-on-shuttle engines with extremely expensive computer upgrades.
If I build an electric car with the same rubber technology as cars have used for a century, this would not mean I hadn't pushed the limits of technology.
> Rocketdyne’s engine produced about 7-8 times as much thrust (which is why SpaceX needs 27 engines on three boosters for a Falcon 9 Heavy, versus 5 for a Saturn V.)
"Thrust per engine" is a bad metric since, for larger payloads, it can be better to add more engines than make them bigger, and that metric immediately disqualifies that strategy. (For instance, more full independent engines means more redundancy. Which strategy is better is going to depend on the details.) We wouldn't say that 18-wheelers are worse technology than 4-wheeled earth movers because the latter have more weight per wheel. Ultimately, the thing we care about is most mass to highest orbit at lowest risk. But if you want to concentrate on raw engine performance, you probably should look at metrics like ISP (which SpaceX is indeed not pushing the limits).
> A more accurate summary is SpaceX is retreading well-worm ground that was trod before many of us reading this article were born, bringing modern materials and manufacturing capabilities to bear improving the same basic designs. That’s cool. But that’s not pushing the boundaries of space flight technology.
Surely re-useable first stages is the biggest advance by far in spaceflight technology in decades?
It sounds like by "space flight technology" you just mean engines, but chemical rockets are within about a factor of 2 of the maximum efficiency allowed by the laws of physics. So within that paradigm, you're just not going to get revolutionary (multiple-orders-of-magnitude) improvements in the things we care about (mass to orbit) by improving engines as opposed to things like re-usability. So I think by your definition, the only thing that would be really be an improvement would be nuclear rockets, or something else even more extreme.
That's a misleading comparison, because we're not talking about some ancillary aspect of the design (like rubber tires). This is more like designing a car with the same basic engine technology as a 1969 Impala, except you're using an aluminium engine block and modern crumple zones.
> "Thrust per engine" is a bad metric since, for larger payloads, it can be better to add more engines than make them bigger.
More engines can also mean more chances for failure. (You can make the design resistant to engine-out conditions, but some engine-out conditions are less recoverable than others.) Regardless, the Falcon 9 Heavy also has substantially lower maximum thrust than the Saturn V.
> Surely re-useable first stages is the biggest advance is spaceflight technology in decades? It sounds like by "space flight technology" you just mean engines, but chemical rockets are within about a factor of 2 of the maximum efficiency allowed by the laws of physics. So within that paradigm, you're just not going to get revolutionary (multiple-orders-of-magnitude) improvements in the things we care about (mass to orbit) by improving engines as opposed to things like re-usability. So I think by your definition, the only thing that would be really be an improvement would be nuclear rockets, or something else even more extreme.
I don't even really disagree with that point. Unless there is some groundbreaking advance in rocket engines, you're not going to be "pushing the boundaries of spaceflight technology." It's just like how we don't say Intel is "pushing the boundaries of CPU technology" every time they widen the vector units on the same basic Core architecture they've been using for almost two decades. It's a mature field where revolutionary improvements aren't possible with foreseeable technology. But that doesn't mean you get to relabel incremental improvements as revolutionary.
I think within the context of chemical rockets, engines really are sorta ancillary! Not to the same extent as rubber tires (I used that extreme example just to make my point clear), but engines is just not where the large improvements in things we care about will come from.
> More engines can also mean more chances for failure.
Agreed. I wasn't arguing for either strategy since I don't know enough to have an opinion. I just wanted to point out that more engines was a plausible best strategy, depending on engineering details, and we shouldn't choose metrics that immediately disqualify it.
> Regardless, the Falcon 9 Heavy also has substantially lower maximum thrust than the Saturn V.
Agreed, Falcon 9 is not an example of an advance in total lift capacity, and total lift capacity is important. BFR/Starship may exceed Saturn V, but if so it will be a very slight edge which is not impressive after half a century. So I agree that this is not where the advances are happening. But, to pick another extreme example, the even older Spruce Goose was only recently dethroned in total wingspan, but this doesn't mean no dramatic advances in flight technology have occurred.
> But that doesn't mean you get to relabel incremental improvements as revolutionary.
abledon's original comment said "pushed the limits of spaceflight technology". I was the first person to use the vague word "revolutionary", and I immediately clarified what I meant: orders of magnitude improvement in metrics we care about. And I think the SpaceX tech, both completed and under development, really can lower mass-to-orbit prices by a factor of 100.
They're not ancillary because propulsion performance metrics really drive the things you can do with the rocket. (Same thing in airplanes.) Acknowledging that "large improvements" will not happen in that area is a concession that we've hit a pretty hard wall on what we can do with this technology.
(Also, fwiw, I don't think your comments should have been, downvoted since they have been thoughtful, and a good counterpoint to the SpaceX over-enthusiasm in these threads.)
But that's stuff they've already accomplished. You're ignoring what they have in development. The Raptor engine is among the most advanced engines ever made, pushing combustion/metallurgy technology literally to the limits, certainly not well-worn ground. Not to mention Starship/Super Heavy, which is pushing reusability further.
They might not accomplish everything they set out to do, but that's why it's "pushing" rather than "pushed".
It's about twice the thrust-to-weight ratio of an F-1, which was designed in 1969. With all the advances in materials science since 1969 (composites, etc.), that tells you a lot about the glacial pace of advancement in the field. It's also not clear to me why that even matters--a Saturn V has about 90,000 pounds of engines; a Falcon 9 Heavy has about 27,000 pounds. Both need millions of pounds of fuel. (As to your comment about "pushing" versus "pushed"--that interpretation of OP's comment doesn't match the fact that he's talking about a setback involving SpaceX's current generation of vehicles.)
Given the same chemical reaction, improving the engine efficiency state-of-art by 50% in 50 years is astounding. With Raptor they are actually getting close to the theoretical limits.
What other expectations do you have for advancements? New chemicals are hard to get by. Nuclear is beyond contemplation. You can't invent new physics. What do you expect?
Through aerospace innovation? Perhaps not as much as you would like. But they do it through materials, manufacturing, automation, computers and operations innovations, which are just as important.
Call it "malfunction discovered during testing", could you not?
Edit: Here's an example search (excluding SpaceX): https://www.google.de/search?q=anomaly+rocket+launch+-spacex
Nominal - as expected (no more than nominal deviations from expected parameters)
Anomaly - something unexpected
Not sure which I overheard.