.50calBMG

As for building a test stand for testing that many engines at once, I'b bet buying the land, paying the contractors to clear the land, then building a test stand strong enough to hold up against something with THREE TIMES THE THRUST OF A SATURN V (in the early prototype aka smallest version, no less) for minutes on end, multiple times, will be much more expensive than actually just launching the rocket. The concrete or steel alone just to build that stand probably costs as much if not more than just building the rocket. Then you have to pay for all the licenses to make that much noise for that long, just to get data on how that cluster of engines behaves for maybe the first 5 seconds of a roughly 7 minute flight, and no data on how it behaves with the change in atmospheric pressure, temperature, speed, G forces... Why wouldn't you just fly at that point? That test makes no sense. The only way a static test like that makes sense is doing what SpaceX already does, the short static tests before launch that last 5-10 seconds. After that time, the rocket isn't sitting still anymore, so why bother running the engines longer in an environment that is A: already understood and B: not relevant to any actual flight?

To my knowledge (which I would consider above average), no other rocket has actually been built up and tested like that aside from Falcon 9. Falcon Heavy didn't, but that's a bit of a stretch all things considered. Before you say SLS did, no, they didn't have the boosters on it. Same with shuttle, Saturn V, Titan, Saturn I, any of the Soyuz family, etc. Literally the only rocket that I know of that was given a full duration burn while on the ground in flight configuration was Falcon 9, and I'm sure you can find that video on YouTube. As for Raptor reliability, flight one used the Raptor 1, which in fairness kinda sucked, but it was more just to prove that the idea worked, and is still the first engine of its kind to be flown even with its teething troubles. Nobody says Raptor 1 was the final evolution, it was literally the starting point, which is why it's been replaced. Follow how Merlin evolved, and Raptor 1 was the Merlin 1A. Right now, we are phasing out Raptor 2 (Merlin 1C) and moving to Raptor 3 (Merlin 1D). There have been three versions of Merlin 1D, and now Merlin 1D++ is probably the most reliable rocket engine ever flown. As it currently stands, there have been over a hundred Raptor 2s lit and relit in flight, and only a small percentage of those have failed to relight, which is in all probability not a fault of the engine, more likely fuel slosh, clogged filters, GSE faults, yadda yadda. Raptor isn't perfect, but it's certainly not bad considering how new it still is, and it has plenty of room to grow if you base it off Merlin's history.

They are, Raptor 314. That said, those are still Raptor 2s, and they are about to be replaced by Raptor 3s, and the new Raptors are arguably a new engine with how much different they are from the 2s, so not really much to gain there. Keep trying though

Or maybe it's the liquid oxygen/methane that they flow through the engines to thermally condition them that comes out of the engine bells... The famously flammable oxygen/methane that then gets compressed and superheated in the skirt when the booster comes back at near hypersonic speeds. And the flame that came up the side of the booster during the landing burn was definitely a leak. It couldn't possibly be that it came from the liquid methane vent for the QD on the bottom of the booster where they vent the pressurized flammable gases from... Seriously, you might as well point to an LNG flare stack and say that methane is just leaky and impossible to use.

We're back to fuel leaks again, and here I thought that had been proven not to be the case after the last 2 flights showed no indication of it. If you listen to the video, the engineer says they misconfigured the startup on the engines, not that it was a fuel leak. Also, with the chine cover, the engineer literally says in the video that it was aero forces, not a fire, and there are no scorch marks on the clearly visible copv and internal structure of the chine. You can't just say fuel leak every time something goes off nominal, especially when the people with all of the data say it's something entirely different. Raptor reliability is being proven before our very eyes, both on the test stands and during the flights, and they still haven't shown us any real footage of the further improved Raptor 3s putting in work either. As for the legs, do you really think having to restructure the booster to withstand further compression forces on landing rather than some tension, and that legs tough enough to survive a plasma sheath seconds before supporting a few hundred tons of booster will be lighter than a set of pins?

Well, I guess a certain someone can drop the argument that the engines aren't reliable enough. Not a single engine out on any of the burns. That out of the way, I didn't expect them to get the landing on the first try, but I couldn't be happier I was wrong. What and incredible thing to see.

I seem to remember the press making a big deal about starliner being rated for 45 days of spaceflight during the first two delays "extensions", but aren't we coming up on something like double that pretty soon? Was that 45 days of free flight or spaceflight in general?

So someone who repeatedly uses incorrect data is pushing an article that uses incorrect data... Hm...

A new product that will be even further delayed?

Probably the same place he gets the ideas about raptors' reliability, out of date videos from the same time as when we thought shuttle would be cheap, reliable, and reusable.

I'd have to say I agree with you all as well, going through and reading these forums for updates on spaceflight while also getting a laugh or two (like when @sevenperforce calculated when you could pop some popcorn during an atlas v ascent with air friction) is a highlight of my day. You guys are all pretty awesome.

I think I'm done using logic here, clearly it's not working. So... nuh-uh

And the first set of RL-10s ever launched to space exploded because of something unrelated to the engine back in 1962, so starliner is in grave danger of exploding too... How many times do we have to say that the problems you bring up are from a design that was retired literally years ago, and physically cannot happen anymore? Can this be seen as spam yet?

I would like to see the actual reliability for the actual number of the current raptors that have failed mid flight vs the ones that succeeded, because I bet the reliability is in the ballpark of most engines out there. The closest engine I can think to compare it to complexity wise would be the RS-25s, which may I remind some people still had a test stand premature shutdown on the sls green run tests after flying on the shuttle for how many years? No engine will ever be perfect, but I bet raptor is doing about as well as any other engine at this stage of development. (I feel like I've said this before...) I would also like to point out that the failures during the boostback and landing burns from IFT-3 were fuel starvation, not the engines exploding.

Raptors' fault

Just because they said fully fueled doesn't mean 100% full. There's plenty of rockets that will partially fuel the tanks for certain variants or flight profiles. Fully fueled in this case could just mean "fully fueled for this mission profile"

Starting to think that the crew dragon test that exploded a few years ago may be raptors fault. Also that falcon heavy center core curse... And crs 7...

Just because they are hardware rich doesn't mean they can afford to redo testing. All the requirements to do those tests cost time, money, and add associated risks that occur during any flight. You don't see them testing the hot staging by putting it on the SO pad with a full ship on just the hot staging ring to see if it works. They could, but they would get the same if not better data by actually flying.

Again, I will add emphasis to test data that is A YEAR AND A HALF OLD. How many improvements were made since then? How many hundreds of tests have been done since then to verify that they work? I'm sure raptors reliability has followed the same curve that starship has from ift-1 to today's test, if not exceeds it based purely on the fact that they can and have been testing multiple times a day since the first test

Here, a test from a year and a half ago. Seemed to work fine, and I don't think we've seen any RUDs from these kinds of tests since then. Issue solved

But it does relight successfully. The failures on the last flight were due to the fuel system, not the engines. The failures in this test were attitude control and fuel systems, not the engines. Raptor 1 fixed the fuel leak issues 2 years ago with sn-15. The first one to land landed hard and cracked a tank bulkhead, leading to an explosion, so another fuel system problem. No ship other than ift-1 was lost to engine issues, and that engine design has been retired. The issue you keep bringing up has been fixed.

"something something landing test", those tests were 2-3 years ago, they've had that issue fixed for a minimum of a year and a half. That was two engines ago. I doubt sls will have an engine failure because an rs-25a test failed on the test stand

My best guess is that it's fuel slosh from the booster wobbling and spinning so much. That's solvable with tweaked control algorithms, not a failure of the engines. Seriously, with the number of test firings, I don't understand why you automatically jump to engine failure

I just showed my father the animation for how Starship is supposed to work while sitting in our favorite booth at our favorite pizza place, and he just laughed and shook his head. Seems crazy that almost a decade ago, in the exact same booth, I showed him the animation for Falcon 9, to which he said it would never work... Think they landed their first booster two weeks later...

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