kerbiloid Posted July 31, 2021 Share Posted July 31, 2021 (edited) And this time- Izmir. The Earth is really under attack. Spoiler Edited July 31, 2021 by kerbiloid Quote Link to comment Share on other sites More sharing options...
DDE Posted July 31, 2021 Share Posted July 31, 2021 2 hours ago, kerbiloid said: The Earth is really under attack. The Armstrongians are getting restless. Spoiler Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted July 31, 2021 Share Posted July 31, 2021 Are these meteors visible from space? From the Moon? Looks like they are adjusting. (Funny, but can't google "пристрелка" in English, even in wiki. I.e. when they are repeatedly shooting at the target, trying to find out correct setting numbers). Quote Link to comment Share on other sites More sharing options...
DDE Posted July 31, 2021 Share Posted July 31, 2021 32 minutes ago, kerbiloid said: (Funny, but can't google "пристрелка" in English, even in wiki. I.e. when they are repeatedly shooting at the target, trying to find out correct setting numbers). https://www.multitran.com/m.exe?l1=1&l2=2&s=пристрелка I've also seen the term "notching". Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted July 31, 2021 Share Posted July 31, 2021 Yes. That's what they are doing. Kyrgyzstan, Norway, Turkey, ... Quote Link to comment Share on other sites More sharing options...
JoeSchmuckatelli Posted July 31, 2021 Share Posted July 31, 2021 6 hours ago, Jacke said: who shoots effectively first wins Yup 1 hour ago, kerbiloid said: Are these meteors visible from space? From the Moon? Looks like they are adjusting. (Funny, but can't google "пристрелка" in English, even in wiki. I.e. when they are repeatedly shooting at the target, trying to find out correct setting numbers). Adjusting works. As does Ranging or "Bracketing" in context - if I understand the term correctly. Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted July 31, 2021 Share Posted July 31, 2021 Or maybe these are dropships, and they are gathering at secret bases... Quote Link to comment Share on other sites More sharing options...
magnemoe Posted July 31, 2021 Share Posted July 31, 2021 6 hours ago, kerbiloid said: And this time- Izmir. The Earth is really under attack. Hide contents It was one in Norway a week ago a lot of them now, they are looking for part of it as it did not break up. Quote Link to comment Share on other sites More sharing options...
Admiral Fluffy Posted July 31, 2021 Share Posted July 31, 2021 How would you use a LES with SRBs. given you can't turn them on and off? Quote Link to comment Share on other sites More sharing options...
DDE Posted July 31, 2021 Share Posted July 31, 2021 52 minutes ago, Admiral Fluffy said: How would you use a LES with SRBs. given you can't turn them on and off? LES doesn't rely on engines shutting down in the first place. Also, an SRB can be shut down on command by blowing up the nozzle. ICBMs do this routinely. Quote Link to comment Share on other sites More sharing options...
Jacke Posted August 1, 2021 Share Posted August 1, 2021 2 hours ago, DDE said: LES doesn't rely on engines shutting down in the first place. As in the LES has enough thrust to pull its load away from the launch vehicle even under thrust. 2 hours ago, DDE said: Also, an SRB can be shut down on command by blowing up the nozzle. ICBMs do this routinely. SRBs can also have blowout panels at the top to help reduce the net thrust as low as possible. Quote Link to comment Share on other sites More sharing options...
wumpus Posted August 1, 2021 Share Posted August 1, 2021 13 hours ago, Jacke said: As in the LES has enough thrust to pull its load away from the launch vehicle even under thrust. SRBs can also have blowout panels at the top to help reduce the net thrust as low as possible. Blowing up the nozzle would only reduce thrust by a large fraction, I think 50% or so (possibly a lot less, if you also took out the throat and realized that the expansion chamber had grown to near the edge of the fuel). Pretty sure you'd need the top as well. But I think that is overthinking a LES. You just ride it out till it runs out of fuel and then parachute down. You can either design the parachutes to handle the entire range of possible escapes (more or less necessary, as you'd want it to work from the launch pad up to out of the atmosphere) or add the ability to cut the SRBs. I'd guess that cutting the LES doesn't buy you much but plenty more complexity. Remember that parachutes are a lot more complicated than what is shown in KSP. You might want additional retro-rockets for more abort coverage, and I'd expect these to be able to cut the thrust. No idea if Dragon's draco engines can do this role. Quote Link to comment Share on other sites More sharing options...
DDE Posted August 1, 2021 Share Posted August 1, 2021 22 minutes ago, wumpus said: Blowing up the nozzle would only reduce thrust by a large fraction The idea is that the pressure drop would yeet the entire propellant grain out of the nozzle. Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted August 1, 2021 Share Posted August 1, 2021 (edited) If blow out the SRB panels on the Shuttle, this will destroy both tank and shuttle. *** A crew-rated rocket provides 4 g of T/W. A LES tower provides 12..21 g (on various capsule ships). Even the Crew Dragon built-in "LES" provides ~6 g, based on video (rokkit gawdz bless their souls). So, there is no need in anything but detach and ignite, regardless of SRB. Edited August 1, 2021 by kerbiloid Quote Link to comment Share on other sites More sharing options...
wumpus Posted August 1, 2021 Share Posted August 1, 2021 11 minutes ago, kerbiloid said: If blow out the SRB panels on the Shuttle, this will destroy both tank and shuttle. *** A crew-rated rocket provides 4 g of T/W. A LES tower provides 12..21 g (on various capsule ships). Even the Crew Dragon built-in "LES" provides ~6 g, based on video (rokkit gawdz bless their souls). So, there is no need in anything but detach and ignite, regardless of SRB. Quick googling implies that for SLS, the idea is to clear the SRBs without cutting them. Shuttle had plenty of impossible abort modes, but I don't think they even pretended that there was anything they could do in the case of a SRB failure. Even if they could blow the panels, it would have required an ultra-fast reaction to blow the panels to save the Challenger. And then you get to detach the SRBs and try to fly the Shuttle? Quote Link to comment Share on other sites More sharing options...
Jacke Posted August 1, 2021 Share Posted August 1, 2021 (edited) 1 hour ago, kerbiloid said: If blow out the SRB panels on the Shuttle, this will destroy both tank and shuttle. I believe I remember SRB top blow-out panels from Titan III's, which were all uncrewed. Also, it's all part of the abort system. Which means different events can be timed. The Shuttle I believe had no abort modes during SRB thrust, but another crewed spacecraft on a launch vehicle with SRBs could have the LES and SRB nozzle jettison fire at the same time with the top panel blow-out after 1 to 2 seconds. Can't remember if launch vehicle bursting charges are used on crewed missions, but they could be on a longer delay. The point is getting the crew away, but the failing launch vehicle needs to be reduced as a risk as well. Edited August 1, 2021 by Jacke Quote Link to comment Share on other sites More sharing options...
lrd.Helmet Posted August 2, 2021 Share Posted August 2, 2021 On 7/31/2021 at 11:37 PM, Admiral Fluffy said: How would you use a LES with SRBs. given you can't turn them on and off? You don't really want to abort with big srb's nearby. Parachutes don't do well with burning chunks of srb fuel flying around, even the regular srm exhaust is filled with burning stuff and chances are that during an abort the booster stage experiences a critical failure due to aerodynamic stresses and other new forces. So unless you have a soft landing system capable of soft landing your capsule, your chances of survival are pretty slim (better than zero though, so yeah). Quote Link to comment Share on other sites More sharing options...
K^2 Posted August 2, 2021 Share Posted August 2, 2021 17 hours ago, wumpus said: Blowing up the nozzle would only reduce thrust by a large fraction, I think 50% or so Short term, yeah. So in context, it might not matter, but on a slightly longer term, the rate at which SRB fuel burns depends on the internal pressure. As the pressure begins to drop, less fuel will burn, causing the pressure to drop further, causing an even slower burn, etc. In an extreme case of nozzle being completely removed, it can take the process down to a gentle burn with almost no thrust. Nozzle diameter on solids is actually a very delicate matter. There is a range at which pressure is self-stabilizing, but you make the nozzle too large, and pressure drops to nothing. Too small, and it's a runaway to an explosion. So depending on the nature of emergency. blowing out the nozzle can actually be a way to safely shut down the boosters almost completely. But it's not going to be instant. Quote Link to comment Share on other sites More sharing options...
JoeSchmuckatelli Posted August 2, 2021 Share Posted August 2, 2021 Be honest - who else did not know that WD-40 was developed as rocket grease? Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted August 2, 2021 Share Posted August 2, 2021 Me. I thought, it's a hard drive. Quote Link to comment Share on other sites More sharing options...
JoeSchmuckatelli Posted August 2, 2021 Share Posted August 2, 2021 3 minutes ago, kerbiloid said: Me. I thought, it's a hard drive. Y'all don't spray WD-40 on everything when working on bicycles to carburetors? Quote Link to comment Share on other sites More sharing options...
JoeSchmuckatelli Posted August 2, 2021 Share Posted August 2, 2021 On another note: https://phys.org/news/2021-07-apollo-ascent-stage-orbiting-moon.html Quote Link to comment Share on other sites More sharing options...
magnemoe Posted August 2, 2021 Share Posted August 2, 2021 8 hours ago, K^2 said: Short term, yeah. So in context, it might not matter, but on a slightly longer term, the rate at which SRB fuel burns depends on the internal pressure. As the pressure begins to drop, less fuel will burn, causing the pressure to drop further, causing an even slower burn, etc. In an extreme case of nozzle being completely removed, it can take the process down to a gentle burn with almost no thrust. Nozzle diameter on solids is actually a very delicate matter. There is a range at which pressure is self-stabilizing, but you make the nozzle too large, and pressure drops to nothing. Too small, and it's a runaway to an explosion. So depending on the nature of emergency. blowing out the nozzle can actually be a way to safely shut down the boosters almost completely. But it's not going to be instant. Good enough for something like Orion on SLS abort or an manned Ariane I think you are still carrying first and second stage and main engines are shut down. Solid fueled ICBM you want accuracy and you have nothing on your sides anyway so just rip the stage to stop trust. Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted August 2, 2021 Share Posted August 2, 2021 (edited) 59 minutes ago, JoeSchmuckatelli said: Y'all don't spray WD-40 on everything when working on bicycles to carburetors? I said: the drive is hard after the WD-40 spraying on the tyres. It's slick, idk why. Though, maybe it's good if use it as a home reactor coolant. Edited August 2, 2021 by kerbiloid Quote Link to comment Share on other sites More sharing options...
SOXBLOX Posted August 2, 2021 Share Posted August 2, 2021 Huh. F-16s will be able to update their EW systems in flight. This, and the DoD wants AI that can predict and adapt to enemies' moves... Remind anyone of these guys? Quote Link to comment Share on other sites More sharing options...
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