Racescort666 Posted January 16, 2020 Share Posted January 16, 2020 On 1/14/2020 at 3:13 PM, mikegarrison said: I really do think this report https://www.nytimes.com/2019/09/18/magazine/boeing-737-max-crashes.html is the best explanation of what really went wrong -- in Boeing, in the airlines, in the FAA, and most importantly in the entire system. This was hands down one of the best articles I’ve read, thanks for sharing. Boeing is certainly not innocent in either of these matters but considering that the first level of management Boeing Defense, Space, and Security has in common with Boeing Commercial Airplanes is David Calhoun, the CEO, I think it’s unfair to wrap the 737MAX issues into the Starliner issues. Quote Link to comment Share on other sites More sharing options...
MinimumSky5 Posted January 21, 2020 Share Posted January 21, 2020 (edited) https://arstechnica.com/science/2020/01/nasa-and-boeing-are-closely-looking-at-starliners-thruster-performance/ Well, this isn't good. Note that this is coming from an anonymous source within NASA, and Boeing is denying everything. Edited January 22, 2020 by MinimumSky5 Quote Link to comment Share on other sites More sharing options...
mikegarrison Posted January 21, 2020 Share Posted January 21, 2020 (edited) 2 hours ago, MinimumSky5 said: https://arstechnica.com/science/2020/01/nasa-and-boeing-are-closely-looking-at-starliners-thruster-performance/ Well, this isn't good. TLDR: due to an unconventional use of the thrusters during the orbit raising manoeuvre on the orbital test flight, there were multiple issues with thrusters later in the mission, which apparently were severe enough that a simulated docking abort manoeuvre was failed. Note that this is coming from an anonymous source within NASA, and Boeing is denying everything. If true, it sounds like they may need to redo the orbital test. I guess we'll see. The article you quoted seems a lot more nuanced than your post about it. I would disagree with your "TLDR" summary. My TLDR summary of this article is: The anomaly event overstressed the thruster system, leading to parts of it being shut down. This later impacted the simulated docking/undocking, leading to the undocking simulation not meeting the delta-v targets. NASA and Boeing are studying whether this was entirely due to the anomaly event or whether it indicated a different system problem that might have to be fixed/retested. Edited January 21, 2020 by mikegarrison Quote Link to comment Share on other sites More sharing options...
sh1pman Posted January 21, 2020 Share Posted January 21, 2020 So, Starliner’s next flight is supposed to be with astronauts, right? That’s going to be scary... Quote Link to comment Share on other sites More sharing options...
mikegarrison Posted January 22, 2020 Share Posted January 22, 2020 19 minutes ago, sh1pman said: So, Starliner’s next flight is supposed to be with astronauts, right? That’s going to be scary... That's not yet been determined. Either it will be with three people (two from NASA, one from Boeing) or they may have to repeat the uncrewed orbital test. I'm not sure how "scary" it would be, since the capsule landed safely even despite the anomaly. But it remains true that docking/undocking has not been successfully demonstrated by an actual flight to the ISS. Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted January 22, 2020 Share Posted January 22, 2020 Spoiler 5 hours ago, sh1pman said: So, Starliner’s next flight is supposed to be with astronauts, right? That’s going to be scary... They may sit on top to quickly jump off if something goes wrong. Spoiler Quote Link to comment Share on other sites More sharing options...
MinimumSky5 Posted January 22, 2020 Share Posted January 22, 2020 11 hours ago, mikegarrison said: If true, it sounds like they may need to redo the orbital test. I guess we'll see. The article you quoted seems a lot more nuanced than your post about it. I would disagree with your "TLDR" summary. My TLDR summary of this article is: The anomaly event overstressed the thruster system, leading to parts of it being shut down. This later impacted the simulated docking/undocking, leading to the undocking simulation not meeting the delta-v targets. NASA and Boeing are studying whether this was entirely due to the anomaly event or whether it indicated a different system problem that might have to be fixed/retested. Well, that'll teach me for trying to sum up an article while running on very little sleep. I can't actually see where i went wrong with my summing up, but that's probably the best reason for me to just post the links. Quote Link to comment Share on other sites More sharing options...
tater Posted January 22, 2020 Share Posted January 22, 2020 I think the one thruster not firing at all is probably the most concerning bit as that's clearly not attributable to overuse. Quote Link to comment Share on other sites More sharing options...
jadebenn Posted January 22, 2020 Share Posted January 22, 2020 30 minutes ago, tater said: I think the one thruster not firing at all is probably the most concerning bit as that's clearly not attributable to overuse. I think a lot of investigation will be going into whether or not that was indicative of some deeper problem, or just an unfortunate coincidence. A single random thruster failure can be tolerated, as the system has redundancy. But if it's indicative of a deeper issue, that's a serious problem. Quote Link to comment Share on other sites More sharing options...
tater Posted January 22, 2020 Share Posted January 22, 2020 6 minutes ago, jadebenn said: I think a lot of investigation will be going into whether or not that was indicative of some deeper problem, or just an unfortunate coincidence. A single random thruster failure can be tolerated, as the system has redundancy. But if it's indicative of a deeper issue, that's a serious problem. Yeah, seems like a lot of testing of the whole thing on the stand is in order... that or going over everything with a fine-tooth comb if their methodology is not to just put it on the stand (CSM together) and test. Quote Link to comment Share on other sites More sharing options...
magnemoe Posted January 22, 2020 Share Posted January 22, 2020 15 minutes ago, tater said: I think the one thruster not firing at all is probably the most concerning bit as that's clearly not attributable to overuse. More because of over heating if it burned for too long i think. As RCS tend to have short burns only they might not be rated for burning for long periods. Quote Link to comment Share on other sites More sharing options...
mikegarrison Posted January 22, 2020 Share Posted January 22, 2020 6 hours ago, MinimumSky5 said: Well, that'll teach me for trying to sum up an article while running on very little sleep. I can't actually see where i went wrong with my summing up, but that's probably the best reason for me to just post the links. Well, not "wrong". I guess I just thought your TLDR was a little bit too abbreviated. I mean yeah, "the simulated docking/undocking failed", but apparently they way that it failed was that they did not get sufficient delta-v right at the end. This detail helps explain why it might actually be reasonable that the crazy thruster use during the anomaly maybe did reasonably explain the failure. (Or maybe it didn't. Still being studied.) I still wonder exactly why the thrusters fired so much during the clock problem portion of the flight. Was it something like the capsule continuously trying to point in a the direction needed to burn to the ISS, but the orbit was curving away around the Earth, so the thrusters kept firing to re-orient it? Quote Link to comment Share on other sites More sharing options...
magnemoe Posted January 22, 2020 Share Posted January 22, 2020 45 minutes ago, mikegarrison said: Well, not "wrong". I guess I just thought your TLDR was a little bit too abbreviated. I mean yeah, "the simulated docking/undocking failed", but apparently they way that it failed was that they did not get sufficient delta-v right at the end. This detail helps explain why it might actually be reasonable that the crazy thruster use during the anomaly maybe did reasonably explain the failure. (Or maybe it didn't. Still being studied.) I still wonder exactly why the thrusters fired so much during the clock problem portion of the flight. Was it something like the capsule continuously trying to point in a the direction needed to burn to the ISS, but the orbit was curving away around the Earth, so the thrusters kept firing to re-orient it? The crazy trust use was explained with the clock being wrong and trying to burn at the wrong time. However unless the capsule had external position data like GPS or other systems the capsule would simply execute its planned circulation burn. In KSP term imagine you do plane your circulation burn at Ap with Ap at 100 and Pe at 50 Km, however burn was triggered too early so you was at 70 km attitude and pointing a bit up as it would be pointing straight forward. This will raise your Ap above 100 wile it might not raise your Pe up to 100, don't bother simulating this now. Option two, it was pointed parallel to earth surface because of star trackers or other systems, this should probably give an better orbit, still no ISS or abnormal truster use. Option three: they uses gps or other position system. In this case the system should notice that the position is wrong. in this case it has some option. It can burn as planned who is 1 or 2 above or wait until radio contact and signal an emergency. Instead something else and weird happened, my guess is that they used the gps position but the errored clock so rater than waiting for maximum attitude or AP to circulate they tried to do an 100 km circulation burn at 70 km Yes that would end well, computers are stupid, programmers tend to be careless. Now the question is how bad the software is. Yes it was not an life threatening fail and an crew would most likely spotted and corrected this bug. However I would do an review of the software. Quote Link to comment Share on other sites More sharing options...
tater Posted January 29, 2020 Share Posted January 29, 2020 (Boeing posted a loss for the first time since 1997) Quote Link to comment Share on other sites More sharing options...
Meecrob Posted February 7, 2020 Share Posted February 7, 2020 Didn't see this posted yet. They found another software bug on Starliner.https://spacenews.com/nasa-safety-panel-calls-for-reviews-after-second-starliner-software-problem/ Quote Link to comment Share on other sites More sharing options...
mikegarrison Posted February 7, 2020 Share Posted February 7, 2020 (edited) Software. Can't live with it; can't live without it. Sounds to me like they should do another test flight, but I still trust the process to decide whether that is necessary or not. Edited February 7, 2020 by mikegarrison Quote Link to comment Share on other sites More sharing options...
DasSkelett Posted February 7, 2020 Share Posted February 7, 2020 38 minutes ago, Meecrob said: Didn't see this posted yet. They found another software bug on Starliner.https://spacenews.com/nasa-safety-panel-calls-for-reviews-after-second-starliner-software-problem/ Quick summary for the lazy: The bug has been found when the did some tests during the OFT, when Starliner was in orbit. They did a quick OTA (no wait, it's OverTheVacuum - OTV) software patch. It is said that it was a critical bug with potential catastrophic outcome for the mission: Quote [...] it would have led to erroneous thruster firings and uncontrolled motion during [service module] separation for deorbit [...] ~ Paul Hill, NASA Aerospace Safety Advisory Panel member Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted February 7, 2020 Share Posted February 7, 2020 1. Why not just use MechJeb? 2. At least, they don't have Kraken. Quote Link to comment Share on other sites More sharing options...
Wjolcz Posted February 7, 2020 Share Posted February 7, 2020 And I thought nothing can be as bad as SAS in KSP. Quote Link to comment Share on other sites More sharing options...
tater Posted February 7, 2020 Share Posted February 7, 2020 Yeah, I’d wanna see a redo of OFT. Maybe they could buy a falcon launch for it for cheap Quote Link to comment Share on other sites More sharing options...
tater Posted February 7, 2020 Share Posted February 7, 2020 Quote Link to comment Share on other sites More sharing options...
tater Posted February 7, 2020 Share Posted February 7, 2020 Quote Link to comment Share on other sites More sharing options...
tater Posted February 7, 2020 Share Posted February 7, 2020 I’ll be really surprised if they fly humans this year on that spacecraft. Quote Link to comment Share on other sites More sharing options...
tater Posted February 26, 2020 Share Posted February 26, 2020 Quote Link to comment Share on other sites More sharing options...
StrandedonEarth Posted February 26, 2020 Share Posted February 26, 2020 Quote Link to comment Share on other sites More sharing options...
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