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…
<queqiao-->
<Mmeridian> it resets the flight plan based on your current trajectory
<queqiao-->
<Kaga> how hard is it to do lunar impact with pioneer styled TLI?/ any tips?
<queqiao-->
<Mmeridian> imagine you set up a very precise maneuver, and then you rotate your craft which kicks your rcs on and that rcs thrust slightly alters your current orbit/trajectory. that button resets it so it matches again
<queqiao-->
Reply to "Kaga: how hard is it to do lunar impact with pioneer styled TLI?/ any tips? (no parking orbit b..."
<queqiao-->
<Mmeridian> after seeing your edit, extremely difficult. we dont have the proper tools to plot a direct ascent. I would not recommend that style
<queqiao-->
<Mmeridian> personally, I do impactors with a solid, unguided TLI stage, and a few unguided pioneer solids for adjustment. I don't think they are hard but I have done them many times. principia does make these kinds of craft easier imo
<queqiao-->
<Kaga> welp, parking orbit + solid kick it is then
<queqiao-->
<Kaga> luckily i have castors for that extra oomph
<queqiao-->
<Kaga> what to do if my solids actually overshoot?
<queqiao-->
<ezsnack> every engine overshoots its stated dv, find out by how much with the "MARK" and expended dv functions from mj
<queqiao-->
<ezsnack> also if your burn is eg. 15 seconds you dont fire at t-0s to node, you wanna split your dv half before and half after the node, usually 2/3 is good enough so t-10s
<queqiao-->
<Kaga> is lunar transfer planner still reliable for principia or do i need something different?
<queqiao-->
<Rad - LR-87 fanatic> Is the moon's wobble added by Principia? I just noticed that the Earth sets and rises from a fixed location on the moon, is that stock RSS or is that something Principia does?
paculino_ has joined #principia
paculino has quit [Ping timeout: 190 seconds]
<queqiao-->
Reply to "Rad - LR-87 fanatic: Is the moon's wobble added by Principia? I just noticed that the Earth sets and rises fro..."
<queqiao-->
<Nazfib> It's actually much less pronounced with Principia. In stock, there's a 28° difference between the rotation axis of the Moon and its orbit; with Principia, the difference is more like 5°. This is what causes the Earth to move north/south across the sky as seen from the Moon. Due to the eccentricity of the Moon's orbit, the Earth will move a little east/west as well.
<queqiao-->
<Kaga> if the launch pad inc is too high for the moon, longer day lunar coasting is not possible right?
<queqiao-->
Reply to "Kaga: how hard is it to do lunar impact with pioneer styled TLI?/ any tips? (no parking orbit b..."
<queqiao-->
<Butcher> I have done it. My tip is don't. :p
<queqiao-->
<Butcher> There's no real advantage over parking orbit + TLI, it complicates flight planning a lot and reduces your launch window opportunities a lot too.
<queqiao-->
Reply to "Butcher: I have done it. My tip is don't. :p"
<queqiao-->
<Kaga> so solids are a no go?
<queqiao-->
<Butcher> Solids are fine, no parking orbit is the issue.
<queqiao-->
<Kaga> ah, i already managed to do parking orbit
<queqiao-->
<Tivec> so when creating a burn, i can either select "direct impulse", "active engines", or "RCS". Is there a way to manually say how long a burn is expected to take?
<queqiao-->
<egg> No.
<queqiao-->
<mako> Would be cool if you could
<queqiao-->
<mako> 😛
<queqiao-->
<mako> I ran into an issue with Gemini OAMS in RCS config where “use active RCS” would give an estimated burn time of several days for an intercept to the target vehicle
<queqiao-->
<mako> I fixed it by using two engines in engine configuration and two in RCS configuration, that lets me use the docking autopilot while still having a reasonable burn time with engines for Principia
<queqiao-->
<mako> Is anyone else having problems with precession when spinning up for a solid motor burn?
<queqiao-->
<mako> I seem to have a lot of problems keeping the spacecraft pointed in the right direction for the full duration of the burn.
<queqiao-->
<mako> I’ve basically started to give up on it and just have three-axis control but it feels wrong since I know so many systems are spin-stabilized IRL
<queqiao-->
<Kaga> i keep undershooting my probe TLI by 200dv, i thought that in 3 days the moon wouldve had influence on it but i guess i overestimated it. i suppose its better to have excessive DV to compensate?
<queqiao-->
<mako> Huh, I tend to overshoot instead.
<queqiao-->
<mako> But yes usually you want excess dV IRL, it’s a margin of safety
<queqiao-->
<Kaga> my booster is only capable of 3000dv ish cuz i usually hear about principia was you can do cheaper burns thanks to principia
<queqiao-->
<Butcher> 3150 is my normal target
<queqiao-->
<Butcher> You'll struggle with 3000 especially as a solid.
<queqiao-->
Reply to "Butcher: 3150 is my normal target"
<queqiao-->
<Kaga> based from my sims, the dv i get to be able to get lunar impact is 3200