<lamont>
yeah that’s where we need the trajectory optimization for the initial gravity turn
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<wb99999999>
btw
<wb99999999>
why does PEG yaw my upper stage so much
<lamont>
depends what you’re trying to do, but that might “leading angle to plane”
<lamont>
(or it might be entirely normal)
<wb99999999>
I think it's just normal
<wb99999999>
it's sticking with the initial inclination too strictly
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<lamont>
PEG on kerbin is much harder
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<ferram4>
I don't know how you use PEG on Kerbin. It's too easy to SSTO without trying.
<ProjectThoth>
Holy crap... SpaceX only has an estimated profit margin of 3%.
<wb99999999>
puff
<wb99999999>
accidental SSTO
<wb99999999>
I think that was the reason I liked RSS
<lamont>
i think the problem is that single-burn-to-orbit in kerbin is hard and non-optimal
<ProjectThoth>
How much did Atlas V cost to develop?
<ProjectThoth>
I'
<ProjectThoth>
I'd assume less than a billion.
<wb99999999>
most of the cost is probably on the CCB
<wb99999999>
I really like how Boeing and Lockheed Martin use multiple Cs and Bs in the acronym for their booster
<wb99999999>
I am never 100% sure I said the right one
<ProjectThoth>
CBBCCBCCB
<ProjectThoth>
Union Of Soviet Socialist Boosters, CCCB.
<wb99999999>
I don't think the Russian uses the word equivalent of "booster" for entire lower stage though
<wb99999999>
this is another silly thing
<wb99999999>
I mean in my language a Atlas rocket is just a rocket
<wb99999999>
and those things you strapped on to the side are boosters
<wb99999999>
but then in English these can all be called boosters
<taniwha>
wb99999999: consider "give me a boost up" when someone is trying to climb something
<wb99999999>
yeah...I guess it makes historical sense
<wb99999999>
it's just a bit of a confusing terminology
<taniwha>
"boost" is essentially "lift"
<wb99999999>
like...dwarf stars
<wb99999999>
you know
<taniwha>
dwarf stars /are/ dwarfs... compared to other stars
<wb99999999>
but they are not...necessarily stars
<wb99999999>
a brown dwarf is not a star
<taniwha>
(although it has since been found that red dwarfs outnumber other stars)
<taniwha>
(or maybe it was brown dwarfs)
<taniwha>
they /are/ stars
<wb99999999>
yeah...red dwarfs are the norms
<wb99999999>
brown dwarfs are not stars, they don't do fusion
<taniwha>
fusion isn't the criterion
<taniwha>
I may be wrong, but I think it's the chemical composition
<wb99999999>
really?
<wb99999999>
need digging
<taniwha>
ie, mainly H2 and He, while gas giants have all sorts
<UmbralRaptor>
Star is weirdly defined, but a 'normal' one is fusion.
<taniwha>
certainly everything bigger than a brown dwarf fuses
<wb99999999>
but then what about post main sequence
<UmbralRaptor>
Something something stellar corpses an protostars,
<wb99999999>
white dwarfs don't fuse anything
<UmbralRaptor>
Jupiter and Saturn are mostly hydrogen an helium, though Uranus and Neptune have a fair amount of ices.
<Starwaster>
*I* am weirdly defined???
<taniwha>
wb99999999: aren't they smaller than even brown dwarfs?
<UmbralRaptor>
wb99999999: yeah. it tends more towards mass.
<taniwha>
Starwaster: aren't you? I know I am
<Starwaster>
yeah fair point
<UmbralRaptor>
taniwha: diameter yes, mass no.
<wb99999999>
oh and back to the starting point of this talk
<wb99999999>
confusing terminologies
<UmbralRaptor>
(Incidentally, brown dwarfs, gas giants, and low mass M stars are all about the same diameter.)
<wb99999999>
in astronomy "metal","gas" and "ice" have very different meanings than we usually think of these words...
<UmbralRaptor>
wb99999999: strapping boosters to stars to make them fuse faster?
<wb99999999>
I am lost
<UmbralRaptor>
heh.
<UmbralRaptor>
I may have mashed together a few different parts of the conversation with that line.
<wb99999999>
yes sir
<wb99999999>
so you see the thing about a booster
<wb99999999>
it can mean 1) a strap-on booster, 2) a lower stage and 3) a launch vehicle
<taniwha>
wb99999999: gas is lighter elements, metal is heavier elements, and ice is frozen anything (my understanding)
<wb99999999>
so you can attach boosters on boosters to make a new booster
<taniwha>
I don't have a problem with the terms
<wb99999999>
I don't really, it's just funny to think about
<wb99999999>
and it is near Christmas and I am cold and boring XD
<taniwha>
ah, well, yeah. the silly season :)
<UmbralRaptor>
silly can be fun.
<taniwha>
(my mom is on her way here to Japan to avoid the silly season)
<taniwha>
(her first christmas after dad's death)
<UmbralRaptor>
=(
<wb99999999>
I feel sorry
<lamont>
kerbin is too damn small
<taniwha>
I'm just glad that the bulk of his suffering lasted only about eight weeks despite being diagnosed with thyroid cancer 19 years earlier
<Starwaster>
crap.... does the current live version of Real Fuels use the MLI code?
<wb99999999>
lamont: use a rescale mod
<wb99999999>
even 2x makes it much better
<wb99999999>
oh wait, are you trying to test if PEG would work in stock...？
<Starwaster>
there's really no reason it couldn't, but the thrust scale of most Kerbin sized rocket would probably confuse it unless you used a design that most would consider sub optimal
<Starwaster>
the real question is how does PEG handle lunar launches
<taniwha>
Starwaster: a lot of my recent rockets would do well with PEG
<taniwha>
9 minute continuous burns from KSC to LKO
<wb99999999>
9 minute???
<taniwha>
wb99999999: yes, 9 minutes, most of which was done by an LV-909
<wb99999999>
but, but the gravity loss
<taniwha>
so?
<wb99999999>
yeah
<wb99999999>
you're right
<Starwaster>
yeah at Kerbin scale you're still going to have a shit ton of fuel
<wb99999999>
my feeling is in stock if you optimize for propellant fraction, you end up accidentally SSTO a lot
<Starwaster>
I accidentally the SSTO.... the whole SSTO.... is this bad?
<Starwaster>
(yeah.... Aztec coin spiders are a thing...)
<Starwaster>
PEG 10.... sounds like a game rating....
<Starwaster>
Lamont: please PLEASE... failed convergence + unguided gravity turn.... please, no. Even if it's just to maintain its current heading or last known good pitch, please no more unguided anything
<wb99999999>
lol
<wb99999999>
Starwaster you sounds very despaired
<wb99999999>
what happened to you, and by extension, your ship?
<Starwaster>
yeah well, I just got into space proper and PEG failed, not sure why. It's easy enough to salvage except that PEG failed means control inputs = DEAD. I can't imagine a real world guidance system doing that. The rocket veers off course wildly
<Starwaster>
slammed into the recently ejected fairing :(
<Starwaster>
tjomgs
<Starwaster>
things went kind of explodey wodey
<awang>
Starwaster: I don't think current RF uses MLI?
<awang>
Thought that was on a 1.2.2-based branch
<taniwha>
what's MLI?
<awang>
MLI?
<awang>
Qboid :(
<awang>
multi-layer insulation, I think?
<taniwha>
ah, ok. I was thinking "modular ?? ??"
<awang>
!acr -add:MLI Multi-Layer Insulation
<Qboid>
awang: I added the explanation for this acronym.
<Starwaster>
awang yeah I just searched through the branches, it's not active yet
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<ProjectThoth>
Has anyone come to a concrete conclusion on how much an RL-10 costs?
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<lamont>
yeah if peg fails it should probably restore the old guidance and fly by that
<wb99999999>
is it possible to let off a audio alarm of some sort when it fails mid-flight?
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<wb99999999>
it still feels surreal looking at the ~360 Isp of Russian upper stage kerosene burners
<wb99999999>
did they used BOTH high pressure chamber and high expansion nozzle on those things?
<ProjectThoth>
yeet
<ProjectThoth>
wb99999999: Soviet engines were crazy shit.
<wb99999999>
sophisticated, too
<wb99999999>
every time I see someone referring Soviet engines as "brute force approach", I can't help but to chuckle
<wb99999999>
they are big bad engines, yes, but they're also reliable and polished
<ProjectThoth>
It's fascinating how differently rockets evolved after WWII.
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<Pamelloes>
Hi! Is there an introduction to engine mechanics in RO somewhere?
<Hypergolic_Skunk>
Pamelloes: you could check youtube for NathanKell's videos.. or just generally search YT for RO RSS vids :)
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<wb99999999>
Ariane 5 core has a burn time of 10 min and 5 sec
<wb99999999>
is there anything longer than that?
<awang>
wb99999999: For a first stage?
<wb99999999>
yeah
<wb99999999>
for a ground-lit stage
<UmbralRaptor>
If stage isn't specified, I'm going to point at NSTAR
<awang>
For ground-lit, gotta be a sustainer-ish stage of some kind
<awang>
idk which one, specifically
<wb99999999>
well ion engines burn for months at a time
<awang>
There's this Space.SE question, but the listed ground-lit engines don't burn longer than Ariane 5 core