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…
_whitelogger has joined #principia
_whitelogger has joined #principia
raptop has quit [Ping timeout: 192 seconds]
raptop has joined #principia
UmbralRaptor has quit [Remote host closed the connection]
Raidernick has quit [Ping timeout: 189 seconds]
<_whitenotifier>
[Principia] pleroy closed pull request #3159: A test to produce a pre-Ζήνων trajectory - https://git.io/J6E1l
<_whitenotifier>
[Principia] pleroy pushed 5 commits to master [+0/-0/±7] https://git.io/J6PLY
<_whitenotifier>
[Principia] pleroy b4eacb2 - A test based on the lpg save to produce a pre-Ζήνων trajectory.
<queqiao-_>
⟨neamesis⟩ what's that formula on the right??
<queqiao-_>
⟨neamesis⟩ it looks super interesting
<queqiao-_>
⟨neamesis⟩ it kinda looks like the lagrange inversion theorem
<UmbralRaptop>
Sums with increasingly high order derivatives and a slight change affecting them like that (converging vs diverging?) feels vaguely cursed
UmbralRaptor has joined #principia
UmbralRaptop has quit [Ping timeout: 189 seconds]
<queqiao-_>
⟨Zeusbeer⟩ Can confirm it's cursed
<queqiao-_>
⟨Zeusbeer⟩ I'd say plop it in wolfram alpha 👺
egg|cell|egg has quit [Ping timeout: 198 seconds]
_whitelogger has joined #principia
<queqiao-_>
⟨Amselfass⟩ I'm very sorry for bringing up the "from the Cape to the moon" question again, which you are probably quite tired of. But I am beginning to wonder whether a lunar flyby from Florida using a solid unguided kickstage is even a realistic option.
<queqiao-_>
⟨Amselfass⟩ While Butcher's script has been very helpful in obtaining the required launch inclination, I find it extremely difficult to plan an intercept using exactly the amount of dv that I have in my kickstage. There is no way to "lock in" the norm of the burn vector and I find myself pulling rather aimlessly at the sliders.
<queqiao-_>
⟨Amselfass⟩ And even if I were to succeed, residuals and the motor's thrust curve make it hard to actually execute the burn.
<queqiao-_>
⟨Amselfass⟩ I guess my question is: Is it, from your experience, possible to reliably achieve this manoeuvre without spending several evenings on it?
<queqiao-_>
⟨Stonesmile⟩ The problem with a solid kick stage is that the transfer time isn't the expected 4 days. I managed to do it once by first doing a sim where I got the transfer time, and then edited the script to use that transfer time.
<queqiao-_>
⟨lpg⟩ reliably? it's a crapshoot, just like IRL
<queqiao-_>
⟨Amselfass⟩ "Managed to do it once" and "it's a crapshoot" is not what I was hoping to hear. 😄
<queqiao-_>
⟨lpg⟩ one way to substantially improve the odds is to go for a very fast transfer; that tends to reduce the effect of inaccuracies
<queqiao-_>
⟨lpg⟩ But it's always going to be "let's try for impact and be happy with a flyby"
* raptop
eyes rangers 3 and 5
<queqiao-_>
⟨Amselfass⟩ I'd be happy with a flyby, but even 5000 km are so tight! From a career perspective, I guess it doesn't make much sense trying it dozens of times. I could rather spend the time with other contracts while I wait for a guided (or at least a liquid) option to become available.
<raptop>
(Granted the Agena used hypergolics)
<queqiao-_>
⟨Rad⟩ hypergolics are based
<raptop>
Looks like the relevant Luna launchers from that period also had hypergolic upper stages
<queqiao-_>
⟨Amselfass⟩ I'm willing to try faster transfer times, although the problem of "fiddle with the sliders until my trajectory hits the moon and I spend exactly x m/s" is still a steep climb for me.
<queqiao-_>
⟨Vlood⟩ i think there was a section for probability of hitting the moon in the pioneer 0/1/2 report, depending on launch date
<queqiao-_>
⟨Vlood⟩ "crapshoot" is putting it mildly
<queqiao-_>
⟨lpg⟩ "fiddling with the sliders" is what principia flight planning always boils down to
<queqiao-_>
⟨pEdro⟩ fiddling with sliders *slowly* for interplanetary stuff
egg|cell|egg has joined #principia
<queqiao-_>
⟨pEdro⟩ fiddling with sliders *slowly* for interplanetary stuff
<queqiao-_>
⟨pEdro⟩ Maybe the rare frame switch to see if you fiddle in the right direction (edited)
<queqiao-_>
⟨Amselfass⟩ Well, you're right about that.
* raptop
wants to say that some early lunar missions had a bunch (15?) course corrections
<queqiao-_>
⟨Damien⟩ > But I am beginning to wonder whether a lunar flyby from Florida using a solid unguided kickstage is even a realistic option.
<queqiao-_>
⟨Damien⟩ there's a reason it didn't work IRL. The Pioneer 0/1 attempts failed due to launch issues, but even those, while having an SRB transfer stage, had the ability to perform mid-coast correction burns
<queqiao-_>
⟨Damien⟩ it's a similar problem to what the russians had trying to do the Luna missions from Baikonur
<queqiao-_>
⟨Damien⟩ and they used a liquid transfer stage
<queqiao-_>
⟨lpg⟩ oh yes, rp-1 has a regrettable lack of tiny SRBs comparable to Pioneer 1
<queqiao-_>
⟨lpg⟩ (and it's unfortunate that this oversight wasn't corrected when the 'rcs h/n' escape hatch was removed)
<queqiao-_>
⟨Paculino (ŝi/ri/she/they)⟩ Isn't there some procedural SRB mod?
egg|laptop|egg_ has joined #principia
egg|laptop|egg has quit [Ping timeout: 189 seconds]
<queqiao-_>
⟨Blothorn⟩ Yes, but it's not balanced for RP1.
<queqiao-_>
⟨Amselfass⟩ Well, I now succeeded with a spacebee, although I'm a bit miffed because I had originally promised myself to not use them. 😄
<raptop>
🐝❓
<queqiao-_>
⟨Paculino (ŝi/ri/she/they)⟩ Real Aerobee, or the early AJ10
egg|laptop|egg has joined #principia
egg|laptop|egg has quit [Remote host closed the connection]
egg|laptop|egg has joined #principia
egg|cell|egg has quit [Remote host closed the connection]