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Ultimate Steve

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  1. The volume of gas that needs to enter the tank is proportional to the number of engines running. Doing everything off of those three means you run into trouble if one of those three fail, and during times when fewer than 33 engines are running you have far more pressurization than needed and need to deal with that somehow. Plus, they really want as few variants of the engine as possible. Granted the header tanks probably have a different pressurization system (in the video, one of the ship (?) header tanks was shown to use COPVs, unsure about super heavy). If I were designing this, it would probably either be its own system (maybe with its own burner) or one per engine. It is definitely possible to do it on just a few engines though. With what I know, I don't believe that would be the best way. Also, very off topic, but I really loved Long Term on Laythe back in the day and I don't think that has ever come up in conversation.
  2. I did the math for another chat somewhere else, at a minimum, assuming I did the math right, you would need 77.5 megawatts just for the phase change on super heavy (assumed super heavy was entirely lox, bc I couldn't be bothered). More for inefficiencies, more if you want the gas to be anything higher than 91 kelvin. And then you have to pump fuel and exhaust through it which is gonna lead to some efficiency losses. More connections, possibly another pump system, something that has to be built into all 33 engines... However I don't really know what a 77.5 megawatt heat exchanger would look like. That sounds like a big number but super heavy is so big that it could be a tiny number. I don't know enough about heat exchangers and raptor to do more than a simple ballpark "how much heat moves through this wall" with guesstimate temperatures and materials and thicknesses. So I really couldn't tell you if it's a bone headed decision or something that was heavy and complex enough that filters looked like (or are) the better option.
  3. And confirmation on injecting several hundred kilos of ice into the tanks.
  4. Presumably if they've been doing their homework, they have come up with an adapter. Although in an emergency situation they would probably just take the risk. All the suits do is protect against depressurization.
  5. Presumably they are at the bottom of the ocean by now. If you can get them, you probably deserve them. There is some precedent for that, Jeff Bezos funded a submarine mission to recover engines from the Saturn V. Unsure what exactly the law is there. Probably classified as some sort of salvage, but ITAR might have something to say about the fiddly bits of the engines. F1 was an obsolete design and Raptor is cutting edge.
  6. I don't suppose you have any information that is shareable regarding the forum's future?
  7. I doubt that the forum is getting shuttered considering KSP 1 is still fairly successful. But I only ask that we get like a month's notice or something. Too many cool things here that aren't backed up anywhere else. I will echo the sentiment. This has been (and will hopefully continue to be for many years) a great place. I do a little sigh of relief every time the page loads after a while of bad gateway errors.
  8. Thankfully, officially confirmed to be a misrouted simulation. https://x.com/Space_Station/status/1801043194253127963
  9. Update, People are saying it was a simulation that was accidentally broadcast.
  10. Possible medical emergency on the ISS. https://x.com/nasaspaceflight/status/1801028546703306765?s=46&t=X_3pYMdCCOx3EH_7dvCogQ
  11. Hello! After watching James May make the longest ever toy train journey for a TV special, it has re-awoken my fascination with steam locomotion and trains in general. I got out my old electric train sets and messed with them for a bit, I learned some amount about the real life Flying Scotsman, and I've attempted to create vaguely locomotive like vehicles in KSP. Originally I wanted to do it with actual pistons and stuff, but the only requirement now is that it must use engine thrust to move mechanically (that engine thrust may not actually be used to move forwards). This is probably going to be a one off. Maybe I'll make a challenge based off of it. My early experiments took the whole "train" thing very literally. The train was to be powered by pistons actuated by toggling twitch engines on and off with an action group. This was incredibly finnicky but I was able to get it working reasonably reliably, although I had to hit "1" repeatedly at the right time. The first issue was that fairings, while they are great at actually rolling, will explode if you go above 7m/s. My next attempts used these Mk 3 to 3.75m adapter parts, as they are the only large circular parts with an impact tolerance above running speed. However, the ride proved incredibly bumpy as the hitbox doesn't have enough sides to make it a good enough cylinder for this purpose. I tried covering the wheels with flags for a more circular wheel, with the knowledge that they made good takeoff gear, but in that application, they were constantly on the ground, not repeatedly impacting the ground. The flags blew up once speed was made. I attempted to automate the piston changing with the KAL controller, as there's no way I was going to be able to stand pressing "1" every few meters for an entire long journey. Once you get it at the right speed (easier said than done), it can keep going that speed more or less, but asking the KAL controller to change speeds, even slowly, led to it desynchronizing and slowing down instead. This inability to change speeds was the downfall of the KAL method. Even if you could slowly change speeds, going up a hill would change the speed more rapidly than it could likely cope with it. The solution would ideally be some mechanical interrupt connected to the wheels that blocked the thrust of the engines at the right time. You wouldn't even need a KAL. But I really did not want to deal with moving parts more than I already had, so, in sadness I abandoned the piston based approach and instead attempted a sort of paddlewheel based approach. While this is a departure from conventional steam locomotives, steam turbine locomotives were also a thing, briefly, so this is technically still reasonably realistic! The early attempts were simply the previous vehicle with one heat shield paddle per wheel. This worked pretty well and I was soon able to surpass my speed record. This is however when I found out that flags didn't like going that fast. I also discovered that the vehicle would just refuse to exist going faster than about 20m/s. This turned out to be because of the common axle on the rear wheels, which wasn't needed any more because I had abandoned pistons (for the time being, at least). The next prototype upped the number of heat shield paddles to 8, 4 per side, and this, unsurprisingly, worked significantly better (and was significantly more fuel efficient). This version tested structural panel paddles and smaller engines, evidently without much success, as I quickly changed back to Thud engines. At this point I should probably say that I was having fun giving the engines increasingly British names. The lineup so far was: L01 Hufflepuff L02 Raleigh Flow L03 Prince Edward L04 Reginald Langley L05 Rupert of Birmingham L06 Bristol Faerie L07 Newcastle Challenger L08 Newcastle Challenger II L09 Spirit of Southampton The L10 Brisbane Challenger (I did not know Brisbane was an Australian city until I looked it up just now haha) was a pretty substantial redesign. While it kept the paddles from the previous locomotive(s?), the wheels were changed to structural panels and grip pads, as they had pretty good impact tolerances. The drive system was two Thud engines, this time moderately angled down so they wouldn't be so low as to be in danger of hitting the ground. They were fueled by just over an entire orange tank of fuel, in anticipation of a long range journey, as fuel economy was significantly better than previous piston based craft. The Brisbane Challenger quickly surpassed the current speed record and was easily on track to break the distance record! However, she quickly ran into a new problem: The vehicle was going so fast that the paddles didn't have time to cool down before hitting the engine again! Thus, the throttle had to be significantly limited. Like the Flying Scotsman becoming the first locomotive to reach 100mph (about 45m/s), I wanted similar glory, so I pushed my luck. After the loss of several paddles, the engine just barely didn't reach that speed (or maybe just barely did, this is the only screenshot I have, it could have gone slightly faster). It attempted to stop before the end of the runway, but in my efforts to make the vehicle realistic, the only brakes were the main wheel bearings with the sliders set low. Thus, the vehicle did not stop in time! The Brisbane Challenger II was slightly changed, removing the grip pads on the wheels, and slightly increasing the paddle and wheel diameter for more torque, which resulted in improved performance. It soared past the end of the runway at nearly 50m/s, and promptly crashed into the water. The Brisbane Challenger III placed heat shields over the paddles for better protection in an attempt to reach a higher top speed. During speed trials, it reached a speed of at least 56.8m/s, but at the cost of destroying nearly the entire paddle system. Jeb had to bail out with his parachute when the locomotive couldn't stop before hitting the water. After another iteration, the Brisbane Challenger IV tested out some stuff, the design was upgraded into the L14 William Tell Overture (which is also not a British song like I thought it was, it is an Italian song for a French opera about a Swiss folk hero). This was not a speedster, it was a long distance vehicle. The initial goal was to reach the end of the runway, but now the goal was to go as far as possible. The craft reached the edge of the space center and encountered a slope for the very first time, which it tackled fairly easily. Throttle was limited to a little bit over 2/3 for most of the journey in accordance with the results observed by the Brisbane Challengers. 40-45m/s was about the safe maximum speed on level ground. Going higher in speed or throttle risked paddle damage. The William Tell Overture made it a whole 21 kilometers before running out of fuel! I decided to sacrifice vibes a little bit and switch to jet engines for their vastly superior efficiency, though rockets kinda seem significantly more steampunk to me. Maybe it is the noise. Maybe the inefficiency is the appeal. Ideally this whole thing would have been rocket pistons, but I wanted to reach the mountains! Initially I powered the vehicle with twin Wheesleys, but the exhaust temperature was too high and it kept melting the paddles. At this time I also started looking at adding more train cars. In this case, just a fuel tank. Partially to test towing capacity, partially to make it as far as possible. However, I had a really hard time keeping it straight and powerful enough to go up hills, especially given that I had to limit the throttle on the Wheesleys. Weirdly enough the Thuds gave me a lot of advance warning before the paddles exploded, but not the Wheesleys. After a lot of research and development trying to get the tender to stay straight and the engines powerful enough (L15 Willaim Shakespeare, L16 William Penrose), I found the solution: Cluster a ton of Junos together. I think I ended up with 8 per wheel. The temperature is not an issue (you can go full throttle), it looks neater than the Wheesleys). To keep the trailer straight, the two rearmost wheels had their friction controls turned up and were canted outwards by 5 degrees to provide some ground friction/drag. To maintain steering control, the friction control on the front pair of wheels was increased to 0.7 and the steering limiter was disabled. Previously all wheels had zero friction control as that helped solve other problems. The main drive wheels are very slippery side to side but very draggy forwards-backwards, at least compared to normal landing gear. The L17 William Tell Overture II set out on a journey to the mountains, modifications in hand. The locomotive made good time, and, at least for the flatter bits, a combination of MechJeb Smart A.S.S. and MechJeb Rover autopilot was able to keep it within 5-10 degrees of where it was supposed to be pointed, at least on the flatter areas. However, a new problem appeared. With a load this large, and going fast over terrain borders, the wheels liked to skip (either due to being momentarily airborne, or just slippery in general). The wheels were also kind of floppy, getting crushed like tires. While this was good for grip, it was not good for longevity, as wheel segments would also have some vertical velocity when slamming into the ground, increasing impact velocity. Ideally the pieces should hit the ground with zero impact velocity each time under normal circumstances, up to any speed, but as we saw with the flags earlier, KSP still considers them to be impacting at least as fast as the vessel is moving for weird KSP reasons. After it became evident that wheel lifetime would be the limiting factor for this mission and not fuel, power and speed was reduced somewhat to extend the life of the wheels (which were already significantly damaged 13 minutes in). At this point only about a quarter of the orange tank had been used up. The rear tank had enough fuel inside to refill the orange tank twice (it was half empty to reduce mass). If treated gently this thing could go very, very far. The train made it to the base of the mountains without much trouble. I believe I slightly reduced throttle after it became apparent the wheel issues weren't one offs. The new goal for the Kerbin Locomotive Works was to make it through the mountain range. Not around, through! This may be not a reasonable goal, and would probably require significant scouting, because I struggle to make it up that mountain range in a normal rover. These dreams were dashed fairly quickly as a 20 degree hill (ish, the locomotive is at a slight angle usually that changes with how fast the wheel is moving because it is stretchy) quickly killed the locomotive's momentum and brought it to a standstill. As it started to roll backwards, fuel was transferred from the tender to the engine, and the tender was cut loose. The L17 William Tell Overture II once again began to accelerate up the hill, an impressive feat for real life locomotives, but probably less than what is required to make it over this mountain range. However, with already missing wheel segments, sharp transitions between terrain tiles, and the high power setting, the wheel slip problem only got worse. The vehicle also slipped to the side and began going back down, the wheels unable to correct. The vehicle came to a stop under a kilometer from where the tender ended up, maybe even lower than when the tender was released, the wheels thoroughly shredded. I nevertheless adjusted the steering wheel settings and turned back towards the mountains. But the trip proved too much for the engine, and the wheels soon gave out, causing the locomotive to flip over and become destroyed. Note the now non existant wheel tread. After a large enough portion fails, the rest will soon follow as the wheel will accelerate a lot without resistance (being in the air because there's no wheel tread in that area). Nevertheless, I loaded a quicksave and tried again. This time, an even steeper slope was chosen, and the locomotive appeared to handle it well, until it crested the top. Its rear wheels became momentarily airborne, and the left wheel was completely shredded. The vehicle tumbled down the hill a little, but came to a stop in remarkably good condition. There was another engine, the L18 Spirit of Luton, which was a test to produce more durable wheels. Unfortunately the modifications (a second layer of plates and autostrut) didn't appear to help much, only managing to limit the vehicle's speed to 35m/s, and a breakthrough in wheel durability would have to happen for me to consider longer journeys. Nevertheless, the concept is likely capable of at least reaching the north pole. The current locomotive is probably good to 500 kilometers. The pole is only 950 (probably more accounting for routing to avoid mountains). I briefly considered making train track, but the part count would be prohibitively high for even 100 meters of track unless I designed it to run in something really weird looking like an open cargo bay (and even then, the cargo bay would probably explode before the wheels do). Kerbal Konstructs may be viable but I would probably have to go through the hassle of installing a 3D modelling program again and actually making the track pieces. There is at least one other person doing Kerbal Konstructs trains right now but from what I know, it will not release for a long time. Part of me wonders if this technology actually has any practical use cases. Assuming the heading control and wheel durability problems can be solved, I think I would rather drive one of these than a solar-electric rover, as they tend to eat power like crazy when encountering even moderately steep slopes. They also tend to want to flip over a lot. Except for not being able to accurately stick to a heading, the L17 was a joy to drive. I never felt in danger of flipping (except when tumbling down a hill), and I didn't have to stop to charge, or pay much attention to how I was driving, as the efficiency curve is significantly flatter for this design compared to rovers. I have not yet attempted to physics warp with this design, though, as I fear it would go poorly. Granted, that is a problem that stock wheels also have, you have to tune them to behave during time warp. Fuel cell electric is probably better than this. I'm not 100% sure, I'd have to do some more tests, but it might not be any better (or it might be significantly worse) than just using 16 Junos for their thrust directly. But it sure looks a lot cooler! And then, of course, their efficiency goes down significantly if you use them on another planet. That concludes my research into mechanical engine driven craft for the time being! I don't intend to do much more research at the current time, but if you have any ideas for making the wheels more durable, or know of any Kerbal Konstructs train track stuff, let me know! If the problems can be fixed I may attempt a run to the north pole.
  12. Probably the video footage of an engine exploding on relight during the IFT-4 Superheavy booster landing burn, a giant mass of fire remaining where the engine was, and chunks flying off.
  13. Good luck to them! I lost one of my intrepid Lego astronauts on a rocket mission that broke up 500 feet above a corn field once, hopefully they make it out alive!
  14. I know I've been in a particularly bone picking mood lately but I saw a Thunderf00t meme and long story short I watched his IFT-4 stream and wow. I knew he had some bad takes, but I assumed he was a couple steps above a conspiracy theorist. It is more like 1-1.5 steps above. Hopefully this will be the last sort of this post I'll be making for a while. I cannot stress this enough, do NOT take your space news or opinions from this channel. I saw someone posting his stuff earlier but as a summary so you know better: Opens stating that this is launch will blow up a billion dollars worth of taxpayer money Says they are burning 2 billion a year and will be bankrupt soon (Starlink revenue alone is over 4 billion a year from just normal users) Says the only technical challenge to solve with reusability is relighting engines and that the real problems are economic So many times he decries something impossible because they haven't reached a certain milestone yet. Decries SpaceX for delays, when delays in space are normal, Starship program isn't even abnormally delayed compared to other ambitious programs (SLS, Dragon, Starliner, JWST). Constant comparisons to different development programs, still in "must work first try" mode "SpaceX has not revolutionized spaceflight" although this does depend on your definition of revolutionize. "Everything SpaceX sells is at a loss" Holds promotional videos up to the standards of a full flight simulation Says the darkness in the engine trail isn't right (To my knowledge has been seen before) "Green flash, bad engine ignition" either camera artefact or the metal in the hot stage ring burning Confused by shutdown venting of engines Mistakes the jettison of the hot stage ring for reaction control thrusters (???) "Clearly the booster is not gonna make it, it is in an uncontrolled descent with not enough oxygen left to light up the engines" with no indication of control loss after a lecture of how inaccurate the fuel gauge can be in zero g "As a general rule I don't like gases escaping from my rocket" "Gases aren't supposed to be leaking out of a rocket" plenty of valid reasons for that, emptying main tanks for landing, RCS, engine purge "We're not gonna see inside the starship because it is a completely empty vessel" Yeah, and? Suggests use of AI for writing postgraduate theses (admittedly only for fluff/introductions) "The bright white flashing is the engines burning" Statements during re-entry: "We've lost attitude control" "And there goes the control" "It's gonna go pop in a second" "It's over" "Send in the clowns" "The feed will go blank in a second" "We've lost aerodynamic control" "It's gone" Thinks it is day during the landing "This is falling way too slow" during landing, insinuating that it is just a piece of debris, that's about how fast it fell on previous tests, actually faster because it is still decelerating Does not realize the ship conducted a landing burn, thinks it hit the ocean Thinks the illumination from the landing burn is the ship on fire Calls the cheering employees morons "This flight has shown that Starship is a complete non starter" "Starship has cost 15 billion in government funding" is only true if it actually cost that much and you assume every single government contract went directly to Starship dev, that's like saying my college education cost $15,000 in government funding because I drove buses for the city and used my wages to pay for school. In fairness, he does have some valid points: Validly debunks lack of orbital refueling on the published Dear Moon flight path (in defense was the possibly the optimistically massed carbon fiber version of Starship, possibly with an expended booster) Valid points about Cybertruck, Roadster V2, supersonic electric jet, hyperloop, and Tesla's business practices City on Mars is something to be skeptical of Launch pads should probably not be as close together as they are in the promotional video Does take it all back (talk about the booster failing) when the booster lands successfully There has been a tide change with respect to public opinion of Elon Gets physics of re-entry correct "The top stage doesn't work and it can't get anything to orbit" is a correct, if lacking context, statement (no payload door) "You can't do rapid iteration with billion dollar vessels" is a valid statement, but if the 30+ vehicles they have made actually did cost a billion they would be bankrupt. "meters per second is the appropriate unit for this" The one thing he said I wholeheartedly agree with. This man is living in another reality.
  15. Another thing I found while reading old parts of the thread (2018-2019) is the general sentiment that New Glenn would come soon and eat Falcon's lunch. Has not come to pass.
  16. There is not and has never been a plan for a ship entry burn unless I've missed something pretty major. There's also currently no entry burn for Super Heavy, unlike Falcon 9. The flap hinges were a known problematic area before the flight (there is a preview clip of the EDA interview showing Elon predicting that if it failed, that would be the failure mode). They have had a redesign in the works for Starship version 2 for a while now. Landing burn happened for sure. Video showed illumination at the same time the engines were supposed to turn on (unclear what the earlier illumination was so could be a fluke I guess). There were callouts for landing burn startup, landing burn in progress, and landing burn shutdown. Telemetry showed the flip, ship slowing down during flip, coming to a standstill, and then falling over as if it was in the water. Video was hard to make out but appeared to show a violent impact at about the same time the telemetry indicated it had fallen over after landing in the water. For it to had not have done a landing burn, the lighting would have to be coincidental, the callouts would have had to be lying, the telemetry would have had to be lying, and there would need to be an alternate explanation for what the video showed. Not impossible but on the edge of impossible. Engine telemetry to the stream did indeed fail. Unless you're specifically referring to the reliability needed for crewed propulsive landings, which would be a different category, I will note that SSME and Merlin are also not at your threshold for crew rated reliability. You're talking 1 failure in 1000 firings. Maybe the RD-107/108 meet that if you measure in a certain timeframe? There are a number of 100% reliable engines, of course, at the sample sizes they have been fired at (nowhere near 1000).
  17. Doing a reliability tally for Raptor in the integrated flight tests. I will generally assume SpaceX is being honest with us and I will not count ignition failures on aborted launch attempts. I will not be going back to the suborbital hops, because that would be a hassle, those were really old Raptors, and the small number of burns wouldn't make much of a dent in the reliability statistics. Attempted burn is defined as the engine being commanded to start. I think it would be silly to say "Raptor failed the landing burn!" when Super Heavy blew up during boostback and the landing burn was never attempted. IFT-1: Three engine ignitions were either not attempted or aborted (likely aborted but wording is kind of unclear). A further 3 engines cut out during the flight. There may have been one engine reignition. It is unclear if this actually happened or if it was a telemetry error. There were discrepancies between the graphic and the camera views, which is consistent with the fact that they lost contact with at least one of the engines fairly early on in flight. The upper stage never got to attempted ignition. Depending on how you count, either 30, 31, 33, or 34 attempted engine burns, and 27 or 28 successful burns (the engine that might have restarted either had 1 success and 1 failure or 1 failure). From a steel man point of view, an additional 12 Raptors failed as thrust vector control was lost. Either the fires (unclear if they originated in the fuel feed system or in Raptor) or the possible hydraulic unit explosion was likely the culprit. Best number: 28/31 successes. Reasonable number: 27/33 successes. Worst number: 15/33 successes. I don't think it is fair to say that the fires, even if Raptor related, equate to each of those engines that the failure took out of commission being unreliable, but there will be those that disagree with me. Numbers equal or near equal for per engine reliability, not per burn reliability, the only ambiguity coming from that one possible engine restart. If I remember right, this was the only full up flight of Raptor 1. I think IFT-2 used Raptor 1s still on the upper stage, but not on Super Heavy. IFT-2: 33 engines lit. 9 of 10 engines relit for boostback. All 13 engines subsequently shut down. Officially, the most likely culprit for this is a clogged LOX filter starving the engines of fuel. This is a problem with the fuel feed system, but I would also accept that one Raptor failed to safely shut down and blew everything up ("SpaceX stated that the most likely root cause was filter blockages where liquid oxygen is supplied to the engines, leading to a loss of inlet pressure in the engines' oxidizer turbopumps that eventually resulted in one engine failing in such a manner that it resulted in the loss of the vehicle") If you want to be that guy, sure, they could be lying to us and all 13 engine shutdowns could be Raptor's fault. Or maybe Raptor should have just coped with no LOX somehow. Of 43 burns, there was only one shutdown that can be definitely said to be Raptor's fault (unless the LOX clog started extremely early). At extreme cope levels, you could say 30/43 successful burns. Upper stage lit successfully. All six engines were shut down by the AFSS after communication was lost with them due to a LOX vent causing a fire. I don't see any justifiable way you can call this a Raptor failure unless you think SpaceX is lying to us, NASA, and the FAA. Best number: 48/49 successful burns. Reasonable number: 48/49 burns. If you count that one Raptor that wasn't its fault, but did kill the vehicle, I would also accept 47/49. Worst number: 36/49. Per engine, the numbers are 38/39, 37/39, and 26/39. IFT-3: 33 engines lit and stayed lit. Ten were relit for the boostback, with six shutting down early, officially likely due to LOX filter issues. This triggered a "benign early boostback shutdown". Taken at its worst, the computer told the other 7 engines to turn off even though there was more burn to be done. The problem should not reside with those seven Raptors. Booster attempted a seven engine landing burn. Two engines ignited, only one was left by the time the booster crashed. No official word on why this failed, I would assume LOX filters again, but it is possible that six Raptors failed for Raptor reasons here. It could also be due to unexpected conditions (reportedly the hot stage ring was ripped off by aero forces, the booster was in the middle of a large shake during engine ignition). All six engines on the upper stage lit and stayed lit. The test de-orbit burn was cancelled due to non Raptor related issues (lack of attitude control). Best number: 56/56 burns (all engine failures have a plausible non Raptor explanation). Reasonable number: 50/56 burns (6 landing burn failures). Worst number: 44/56 burns. Per engine, the numbers are 39/39, 33/39, and 27/39. IFT-4: 32 engines lit and stayed lit. Ten were relit for boostback. 12/13 engines lit for landing. All six engines on the upper stage worked. We don't know how many engines lit for landing because the graphic didn't work. But we have no indication of a failure. I'm gonna call it 2/2, but it could theoretically be 3/3 or 2/3 or even 1/3 or 1/2. Best number: 63/65 (3 engine landing burn). Reasonable number: 62/64 (2 engine landing burn). Worst number: 61/65 (3 engine landing burn, 2 failures). Per engine, the numbers are 37/39, 37/39, and 35/39. This could change if it turns out that an engine failure was due to a clogged filter or something. It can only change in Raptor's favor, though, barring something ridiculous being uncovered. Plugging all of that into a spreadsheet, per burn, Raptor reliability across the Integrated flight tests is 97.0% at its best, 92.1% if we take SpaceX's word, and assume, in the lack of an official statement, that the IFT-3 landing burn failure was Raptor's fault (number is 95.0% if that incident was a filter issue), and 76.8% at its worst. Per engine, the numbers are 95.9%, 89.3%, and 74%. The lower numbers require SpaceX lying to us and attribution of Raptor failures to non Raptor causes and is intended to be an extreme example. If we just tally flights 2, 3, and 4, mostly just counting Raptor 2s, those numbers change to 98.2%, 94.1%, 82.9%, 97.4%, 91.5%, and 82.1%. Raptor is not currently producing 230 tons of thrust (official numbers per flight 3 had it at 7130 tons, or 216 tons per engine). We don't know why this is. Maybe the 230 ton number was a one off, a vacuum number, a future version, or de-rating because Raptor would eat itself otherwise. For all we know, this isn't an issue. 7130 is notably 31*230, so maybe at this stage they assume 2 engine out capability and possibly throttle a little low and throttle up if an engine or two goes out. If it is an issue, though, those reliability numbers are starker, as this is with a gentler environment. In the context of an iteration driven development program where a single engine out (or several) doesn't make or break the mission, and where many engine failures were in unique environments, and where we've only just gotten to flight number 4, I'd say those numbers are not great but acceptable. 98.2% reliability, the best justifiable number I was able to come up with, is not acceptable for humans by traditional standards. The lowest, ridiculously far out number, 74% with derating, is grounds for program cancellation. I cannot find another modern, significant flight history rocket engine reliability number below 98.2%, except for specifically just Vacuum Rutherford, and Delphin on Astra's rocket 3 (there are probably more I wasn't able to find). We don't know how many times it failed, Astra was pretty secretive, but it is at most 97.2% (one definite engine failure out of 7 orbital attempts with 5 engines each). SSME: 99.75% Merlin: Somewhere at around 99.7-99.8%, numbers use different launches, are from different times, unsure if they counted the landing burn failures if there were any, or the first Falcon 1 failure. RD-180: 100% Rutherford (normal and vacuum): 99.38% Vacuum Rutherford: 93.75% Granted, all of those examples have more flight history than Starship in terms of flight count (Raptor probably beats RD-180 in engines flown). If Starship were to work flawlessly on the next 3 flights, maximum reliability for Raptor 2 would increase to 99.2%. Still low. I'm beginning to see where Exoscientist is coming from. I would still argrue that in the context of the Starship program, the current reliability is within the realm of what is expected at this stage. But with conventional thinking, for something that is to power a moon lander, even 98.2%, let alone 94.1%, or 74%, is an absurdly low number. To suddenly see NASA being okay about, and enthusiastic about reliabilities this low under a conventional scenario would be grounds for conspiratorial thinking. Imagine if NASA had wrapped up SSME engine testing with a 90% success rate with ambiguity as to whether or not the engines were derated, and were still touting the shuttle as the future. I'd think there was a conspiracy at that point. The difference is that these are not conventional circumstances. I don't think that Starship should be looked at the same way other rockets are looked at. 98.2% is not acceptable for something carrying humans. 92.1% can be reasoned with for something that is fault tolerant, pushing the envelope, fairly early in development, under significant active development, has to ignite in difficult scenarios nobody had tried before, will not fly an external payload for at least a few more flights, will not fly humans for at least another 2-3 years, and even then, only on the upper stage (which has not had a single engine failure during the full up tests), and is doing hardware rich testing.
  18. Exciting day for spacecraft with "Star" in the name!
  19. If this is not acceptable, feel free to remove it. There was a particularly persistent naysayer on the forums back in the days. Now that we have a semi-successful re-entry, I thought I'd go through his (I'm assuming he/him) Starship related statements and do a tally of sorts. I'll skip most of the Mars-only related ones for the sake of brevity, as basically every other post is saying "There will never be a Mars colony". That remains to be seen. Maybe throw in a few other general spaceflight ones. Will be interesting to see how much has been proven true vs false. I'm going to try to tilt things as much in his favor as I can. True at the time, now there's 2, almost 3 spacecraft (Dragon, Starliner, almost Orion), 5 if you count suborbital. (In response to the suggestion that Starship (at the time BFR) could be developed for less than Apollo) Most of that statement still remains to be seen, and we will probably never know how much Starship cost to develop. Still correct, although the assumption that you would need much money may not be completely valid. Worth noting that there are three people with over 200B, although with inflation since 2018, it probably isn't half anymore, and obviously that isn't all cashable in reasonable timeframes. (And many other similar statements) Nobody ever flew on FH, nobody probably ever will. He was right about that. Mars remains unproven. (And other such statements saying FH's first test flight did not meet expectations) FH center core recovery was mostly abandoned after a few more attempts, so FH did not meet its reuse goals. Does have a similar ring to the current discourse about Raptor. 2022 nor 2024 happened (unsurprisingly to anyone who was paying attention). 30 year horizon statement was wrong, as the vehicle that will theoretically do that is now flying in some capacity 6 years later. A 100+ ton ship (admittedly a broken shell) was just landed on Earth. Martian challenges are obviously different but that's a step. Depending on "anywhere close" or "remotely possible" you can give this one to him. (In response to sending cargo to Mars by early 2030s) Remains to be proven, but looking hopeful. He was right. No 200 ton lander on Mars by 2023, but again, not surprising. Says Starship doesn't land like NASA lands things, which, well, yeah. No real competition just yet, most agencies are trying to capture their domestic home country market, trying to be the redundant second provider, or being the "anyone but SpaceX" option. Accurate on second statement with Artemis. Remains to be seen, but Falcon is in what, the 350 flight range these days? Vulcan has flown once, SMART reuse is a few years off at best, nobody I know seriously expects it to be cheaper than F9. Even if it is, Starship has flown more than Vulcan. This has not conclusively been proven one way or the other, but I don't see a realistic path to him being right about this. He hit the nail on the head here. Red Dragon is gone, Grey Dragon is gone, and now Dear Moon is gone. Starship is still here though. Demo 2 was still two years out at this point in time, so the comment about starting small is accurate. Starship has flown four times. Mars challenges are still huge. We know they did some ISRU work but who knows how much. In orbit refueling still hasn't happened, but they did the header tank test successfully and NASA appears to be behind refilling for Artemis. It is worth noting that this guy is usually just referring to Starship/BFR in the context of a Mars lander and doesn't necessarily think LEO stuff is a pipe dream: Human rated Starship is being built partially because of NASA interest. Even at the time SpaceX was doing supersonic retropropulsion fairly consistently. They've done it hundreds of times now, not on Mars, granted. IDK what the Mars landing velocity is, but at least on Earth, Starship (the upper stage) doesn't even need supersonic retropropulsion as it is subsonic at time of landing. 6 years later, Orion and Starship are both going to the Moon. Starship remains the only remotely serious Mars lander concept. Colonial transporter: Remains to be seen. Earth to Earth: Remains to be seen. Moon transporter: Is happening. Space tourist spacecraft: In progress (Polaris 3 and Dennis Tito's mission are on the cards, though Polaris is kind of in a gray area between space tourism and a professional private space program, so despite what happened with DearMoon (RIP) they are still working towards it). Satellite launch vehicle: Immanent, and Starlink appears to be working reasonably well for them, revenue wise. It remains to be seen whether Starship will cost less than Falcon and be profitable. Cancellation and replacement with something bigger and dumber: Technically correct. Carbon fiber BFR was "cancelled" and replaced with the "dumber" stainless steel Starship, which is either now or will be slightly taller. Replacement with economically profitable: Arguably correct, but arguably just an iteration on what they had. Falcon 9 flyback reliability: We just saw Super Heavy land with an "occasional failure". Obviously reuse would be problematic currently, so it goes both ways. Largely remains to be seen, though Starship is here, in a primitive form. Supersonic retropropulsion has worked well over 200 times in a row by my count on Falcon. 1 in 200 is not good enough for humans. We're getting there, though. Human missions using this are on the books, though far away. Those vehicles do not exist but are soon to exist. Assuming of course that they are serious about Mars. I have no reason to think they aren't. Starship will indeed not reliably land using supersonic retro-propulsion, as it uses subsonic retro-propulsion. One point to him. The booster remains to be seen, but a smaller booster does reliably (for unmanned standards at least) land using supersonic retropropulsion. It is so routine I don't even bother watching 95% of the time. An engine and a composite tank is indeed not a functioning rocket, and they did abandon that. Remains to be seen. Starship is here, and was NASA's favorite Moon lander of the proposals. It is here. Mars remains to be seen. 4 full up flight tests, I want to say at least 8-10 hops depending on how you count? I wanna say it is probably gonna be at least 10 more flights before Artemis 2. Words marked, post recorded. Remains to be seen but looking good. BFR not operational yet, would take a tragedy for it to not become operational soon. Current customers: NASA, Jared, that one company that bought a satellite launch, that one company building gigantic satellite busses (no contract yet but working on it) (does Starlab have a contract yet?), maybe Dennis Tito, I'm probably forgetting stuff. Starship has been successfully funded thus far and has not been cancelled. Retroburning with people remains to be seen. Falcon has proven that it is possible to do semi-reliably. Today has proven that Starship is, at least to a certain extent, a fairly robust and fault tolerant design. Missing tiles, half of a flap melted off, two engine failures, and if people were riding and the landing had been on land, they probably would have survived (no info on exactly how hard the landing was but it appeared nominal). Starship is here. Not much crow to be found. He's right. DearMoon was cancelled. Remains to be proven, but NASA thinks the Moon can happen. SpaceX Starship is now part of CLPS as of November 2019. 2022 and 2024: Absolutely not, again, not a surprise, as pretty much everyone said back then. Ever: Remains to be seen. Booster reusability saving money: By the skeptical proof standard, remains to be seen. They could be lying and they could be doing it as a stunt. 300 times. Just to keep up the lie. I strongly have my doubts but we will likely never have 100% proof, just 99.99%. Booster reuse is now over 20 per booster for the life leaders. SpaceX did indeed fly significantly less in 2019 than in 2018, so he's right. SpaceX and Tesla are still around and not bankrupt. Starlink is at nearly 3 million users (~4 billion a year in revenue), the US government is buying their own custom version for military use, airlines and ship operators are buying it for ocean connectivity, they at least were using it as a demo in Antarctica (unsure what became of that), travel trailers are using it, they are using it for direct to cell with T mobile, it would almost be faster to list who isn't interested in it. Reportedly they have had at least one profitable quarter, so yeah, it is still "one of Musk's money losers" for the time being, but that's kind of how infrastructure buildup works. Tilting this as much in his favor as I can, Starhopper was nothing like a real spaceship and was constructed by a company that makes water towers. Starhopper was as much tech demo as it was PR stunt, as they made it look pretty by coating it with reflective sheets, and built a useless nose cone that they did up with logos and added fake engine bells for a photo op, deceiving investors into thinking they were going for a dual bell nozzle to combine vacuum and sea level into one engine. But it flew and they built 30 more of them, each a little better than the last. Tesla and SpaceX are still here. It has been more than 5 years and if anything there's more dust.
  20. @Exoscientist What would convince you that Raptor has become reliable? We don't know exactly how many engines lit for the landing burn as the indicator didn't work, and who knows, there might have been an engine out there, though I doubt it. There were 2 engine outs, which were compensated for, across 33+10+13+6+2? attempted engine starts, a score of 62/64 plus or minus one, 96.8% reliable on this flight. One of those failures was in a particularly intense environment (landing burn, that thing was going FAST) on the second ever attempt, the first of which was, to my knowledge, foiled by a clogged filter. While that's obviously not amazing, I don't think it is worth doomering about on flight 4 (IIRC flight 3 of Raptor 2). While I don't think it is an amazing comparison, Falcon 9 was 39/40 cumulative through Flight 4, and the J-2 (at least on the Saturn V, I didn't look up Saturn I, or the Merlins on Falcon 1 for that matter) was 23/26 by flight 4 of the Saturn V. I'd have to go back and do a lot more counting for a cumulative Starship number though.
  21. Looks like at least one tile is missing that wasn't missing before. Here goes.
  22. Footage is back, and Starship appears to be not tumbling out of control!
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