egg changed the topic of #principia to: Logs: https://esper.irclog.whitequark.org/principia | <scott_manley> anyone that doubts the wisdom of retrograde bop needs to get the hell out | https://xkcd.com/323/ | <egg> calculating the influence of lamont on Pluto is a bit silly…
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<queqiao->
⟨nvv⟩ would launching into the plane of the planet you're targeting always be the most optimal way to get to it?
<queqiao->
⟨lpg⟩ I'm not seeing this. tank-fed mode, MJ DV shows 73m/s 12.7s, principia flight plan for 73m/s predicts 12.7s
<queqiao->
⟨test_account⟩ ⟪nvv⟫ would launching into the plane of the […] ⮪ No, use TWP for interplanetary transfers
<queqiao->
⟨test_account⟩ ⟪lpg⟫ I'm not seeing this. tank-fed mode, MJ […] ⮪ Interesting, now I also get correct numbers. The issue must have been because I tried to activate an engine that will work after staging, apparently it doesn't work.
<queqiao->
⟨lpg⟩ activating next-stage engine while previous-stage is attached will give you a plan for the selected engine but the current dry mass
<queqiao->
⟨lpg⟩ principia doesn't acknowledge the idea of staging
<queqiao->
⟨test_account⟩ Now that's a serious complication for LR101 TLI
<queqiao->
⟨test_account⟩ Same issue as with solids
<queqiao->
⟨test_account⟩ * solids, but longer burn time
<queqiao->
⟨lpg⟩ not quite. solids you can't even activate
<queqiao->
⟨test_account⟩ Here I can activate, but it achieves nothing
<queqiao->
⟨lpg⟩ (I'm a dirty cheater and I _can_ activate my solids without igniring them, for just this reason)
<queqiao->
⟨lpg⟩ * igniting
<queqiao->
⟨test_account⟩ OK, but you still have incorrect burn time, so what's the point?
<queqiao->
⟨lpg⟩ I don't do stupid things like unguided moon shots
<queqiao->
⟨test_account⟩ I see, if precision is not important then it will be helpful
<queqiao->
⟨test_account⟩ +to activate next stage engine
<queqiao->
⟨lpg⟩ precision has nothing to do with it. I can point my solids after ditching the lower stage
<queqiao->
⟨test_account⟩ hmm, but you start the burn at a wrong time anyway
<queqiao->
⟨lpg⟩ no?
<queqiao->
⟨lpg⟩ (one advantage unguided solids do have over your lr101 contraption is that a shorter burn is closer to matching instant-impulse plans)
<queqiao->
⟨test_account⟩ Yes, this is true, small errors are tolerable
<queqiao->
⟨test_account⟩ (but not in the case of unguided TLI)
<queqiao->
⟨lpg⟩ I'm saying I can do my solid burn planning while the masses are correct, so the plans are correct
<queqiao->
⟨lpg⟩ +guided
<queqiao->
⟨test_account⟩ ah, yes, now I see, you are planning solids in the current stage
<queqiao->
⟨ماركو⟩ Isnt Lr101 as main engine...a bit cheesy?
<queqiao->
⟨Proton | Mod.ROTanks Protester⟩ You are the 3000th person to think of that.
<queqiao->
⟨Proton | Mod.ROTanks Protester⟩ Good point.
<queqiao->
⟨ماركو⟩ Or does the tank feed mode exist to decheese it?
<queqiao->
⟨test_account⟩ Tank fed mode makes it a legitimate orbital thruster I think
<queqiao->
⟨test_account⟩ Everything is realistic: it requires HP tanks, it has a low ISP, higher variance and residuals (this works weird, but still)
<queqiao->
⟨test_account⟩ -it
<queqiao->
⟨Sumguy⟩ Tbh, the rl version didn’t use hp tanks
<queqiao->
⟨Kirk (He/Him)⟩ Yes it did
<queqiao->
⟨Kirk (He/Him)⟩ When operating in tank-fed mode after main engine cutoff, it drew fuel from the LR105 start tanks, which were pressurized to like 50 atm
<raptop>
I tend to get concerned when discussions of realism come up because real life included multiple rockets that used all-horizontal staging, a design with 9 SRBs, and some upper stages that were stuck on tons of different rockets