Ohm is Futile

Good first answer, especially if you like the technical side of things. In practice, people use the information from the tools @George van Doorn told you about to help them create a maneuver node. The maneuver node will give you direct visual feedback of where you will be and where your target will be if you get close enough with your maneuver node (close enough does not need to be close at all).

I think this does a better job of telling me what the issue is with my own project in a single line than the 22 reponses I got. Would you say the less TWR below 0.5g (I assume Kerbin g's) makes it less and less practical, especially with more demanding (dV-wise) transfers?

The capture is something, but I meant that mostly for the ejection burn from Kerbin, actually.

If you are transferring fuel from/to a large tank from/to small tanks, you can click the large tank and alt-click all the smaller ones and either press in or out on the large tank to automatically feed/draw from/to multiple tanks from/to the large one without going through each smaller tank. Does not save pumping time directly, but it does save the trouble of having to go through each tank manually.

As mentioned, Moho goes around Kerbol very fast. For this reason, the transfer window is key. The link provided shows that. I am going to somewhat disagree on using nukes or ions for this though, unless I'm crazy from my own experience at shooting for Dres with low TWR, you're going to have to perform an ejection burn of roughly 2,800 m/s of dV. With low TWR, this can take 20 minutes of burning. Patience is not the issue here, but making your burn precise due to it being spread over a long period of time is going to be difficult and result in a lot of wasted dV in the end. Anyways, hopefully, shedding some light on this may help my own case.

No, I'm using the same maneuver essentially. I'm not doing the "prograde part" of the burn on the first pass and then the "normal part" of the burn on the second. My ship's attitude is in-between prograde and normal for each burn. To be honest, I'm not sure what you're asking. I understand my situation is baffling (at least to me) and so I understand the need to find an anomaly, but the notion of splitting my burns in terms of relative markers would be absolutely nuts (to me). No, my ship's attitude is always the maneuver marker that is created by a maneuver node that takes me to an encounter with Dres. I did delete the original maneuver node after burning 3 times 2 minutes split equally across my periapsis and create a new one to account for my new, significantly different orbit from which I was burning, but that new maneuver led to another encounter that is practically identital to my previous encounter and I still pointed my ship towards the maneuver node for the whole burn. Does that answer your question?

That's exactly what I am not assuming, yet, I will probably test it because it's one of very few variables that are different between my two attempts. Although I'm not sure you typed your example right. You mean you hope I'm not assuming one maneuver with 500 m/s prograde and 500 m/s normal is not equal to two separate maneuvers each of 500 m/s prograde and 500 m/s normal, respectively, especially in different situations (ie orbit around the sun vs orbit around kerbin vs periapsis vs ascending nodes vs did I forget something).

Wow. I know what I did, which is set up a separate stage for the nuke, which is why I said I fudged the staging, because there normally isn't a stage there, I just hit undock instead. What I didn't do is give deliberately false information. I understand your explanation for the discrepancy, however, you can also see in the screenshot that I locked the fuel usage for the lander's tanks. I only show one, but I assure you they are all locked. This works in the VAB, I just tried pushing the "disable crossfeed" button anyways and nothing changed. I did consider the possibility that KER is not exactly sure whether or not it can use the liquid fuel in the top stage. It's still strange to me and if that was the whole problem, KER would display the extra m/s of dV even after the burn as I did not undock the interplanetary stage even after all those burns. I also didn't disable crossfeed by default since I needed to refuel the whole thing, not just a single stage, and the fuel had to flow through all stages given the docking port setup. I tried isolating the top stage and dV readings were alright, although it makes sense that they would if we don't consider the nuke stage at all since the limiting resource for them would be the oxidizer and not the liquid fuel. I suppose they would show up accurately in the VAB since I don't think I enabled crossfeed on the decoupler I put there to clearly isolate stages. Hmm. Still don't think that's the issue though, KER wouldn't "change its mind" about having the extra fuel and pressing the disable crossfeed still didn't change the reading. That was my thought process during the few hours I spent trying to get this thing on course yesterday. Yet, in my tests I managed to get into a near circular orbit around Dres with this very design with a much, much worse attempt efficiency-wise. This is why I came here instead of just testing more, because I just don't know how to interpret these results. I'm not sure how that can even happen. How can a launch window costing 300 m/s more dV, on top of maneuvers done in orbit around the sun add up to the same result as launching from a better launch window and doing all the work at periapsis?! I guess I might try splitting the maneuvers like I did previously, I just can't imagine it working, but I can't think of any other way to be sure, it's the one variable that's different from my test apart from the launch window, which should be better either way.

No, I deliberately fudged the staging in the VAB because I wanted to show the dV readings for all stages and afaik you can't add docking ports to staging (anymore? maybe I'm lazy and it's in the advanced tweakables, anyways) This is rather difficult to pull off given the speeds involved and the fact that I'm basically threading needles at different angles every time I make a new maneuver node and then you need to factor in burn times. 10-15 minutes is more realistic, but again, given the speeds, this means I'm going to be quite far from periapsis at this point. I hadn't seen your reply, but I believe this is a partial answer to it: Tested. It works. It's just that it burns up on re-entry. Minor inconvenience. As for the second part of your reply, I know the theory, at least in terms of concepts if I'm entirely honest. What I'm wondering is between a long but inefficient burn at periapsis around Kerbin due to speed and trajectory issues stemming from the low TWR and not quite burning at my orbital periapsis because I'd leave Kerbin's SOI first but not having to deal with massive differences in my trajectory due to Kerbin's gravity would be better? I am aware the short answer is likely no, but I'm not sure what else I can try to salvage the final re-entry of the mission. I wish, but the nuclear stage is capped with a decoupler and a docking port to refuel prior to departure. If I stage the nuke, I lose the ability to refuel the whole thing. The craziest part about this whole thing is that in my test run, I acually had a worse launch window and I did go for an escape first, then a prograde burn, then an inclination burn and such, and I still managed it. This was actually my salvage plan: get this new, better launch window (the one mentioned here), leaving the interplanetary stage in orbit with the fuel I saved, dock back with it and mostly use the fuel left in there to get an encounter with Kerbin. Then I wanted to get an encounter with the Mun to perform a powered gravity assist and hopefully knock a solid 1km/s off my re-entry speed, minimum... and the result is I'm actually spending more fuel while trying a more efficient burn at a more efficient launch window! I'm just baffled. So this thread is essentially trying to salvage my plan to salvage my original plan.

1st point: 2nd point: thanks, figured as much, but this experience has left me so stumped that I wondered if that would work somehow (like the fact that I'm not performing a fly-by of kerbin or something like that...) I have a save file while my vehicle is still docked to the fuel depot, it might be painful, but it may have enough fuel in it to allow my 3x sparks to raise the whole thing's orbit by a decent margin, hopefully. The fact that VAB KER and In-Flight KER disagrees with itself makes me want to scrap the whole thing and try again though, however painful it feels to throw away hours of engineering away. Lessons were learned though. Anyone else has ideas on how to salvage this or if KER has been known to lie so blatantly about dV values? EDIT: core of the issue is that this dV loss does not compromise the mission as much as the lower fuel values force me to perform Kerbin re-entry at 5 km/s with a long thin capsule and a heat shield that is flush with the fuselage. Even spinning to spread the plasma toasting equally cannot save it from a spectacular sky BBQ.

Well... the name... kinda implies it..? I guess we forgot it did imply that since I'm pretty sure the module predates CommNet. There's a hint in its stats though, I believe it says remote pilot assist and also multiple hops and such in the specs. Nothing about the experiment storage though, but it's cool that it has that option.

I don't. I also don't have any intelligent excuse for it beyond being a minimalist at heart and not *really* needing it.

I like your style and taste in video games @George van Doorn, you just earned yourself another subscriber! ...but I do find you're cutting it close there. Also, welcome to the forums!

Define "if only possible". But oh my... if that works, you've made my... month? Learn something new everyday. I mean, I knew about precision mode, but I didn't think it would help with unbalanced RCS. Would that imply having more than a single set of RCS ports and then the thrust being automatically adjusted across them to account for unbalanced CoM/CoT? That would be simply too good to be true.

I know right!? I did it with large things before, although I don't recall the exact TWR, I never had issues. I suspect it's because half of my burn is actually anti-normal. I'm actually aiming at Dres, albeit during a deliberately suboptimal launch window. Thing is, I'm trying to do this with 140 tons maximum launch pad capacity. This setup already required three launches: a lander/return stage, an interplanetary stage and a refueling run. Thing is, I'm afraid using Terriers, for example, would still result in a heavier payload since they do have only less than half the Isp of nukes. Here is a screenshot of the assembly. I tried to cram as much info into a single picture. While doing that, I noticed that VAB KER and In-Flight KER seem to be in disagreement, which is troubling and may explain most of my issues. Anyways, beyond scrapping the whole design and going with other engines/more individual launches and assembly in orbit, I'm considering the possibility of escaping Kerbin first and planning a transfer in orbit around the Sun. I do realize it's likely to waste some dV also, but then a long 10+ minute burn should be insignificant compared to an orbit that takes more than a year. I have a feeling the end result is going to be similar, but I'm curious as to what some of you math wizards think of that? EDIT: screenshots

Yes, you do. In fact, you can do it very simply: 4-way symmetry of the 4-way RCS blocks on-top of the CoM, not simply near it. You could also do 2 4-way RCS blocks and stick 2 more linears on top of them, but you're not going to have equal amounts of thrust in every direction, although the same could be said for the previous method since you're going to have twice the forward and backward facing RCS ports. Either way uses 4 parts and negligible amounts of mass (unless you're using a tiny probe, I guess). True. Although I find it endlessly annoying when translating induces torque, it's hard to avoid with ships assembled in space and fluctuating fuel stores. I've found that the best way to fight it is to actually turn off RCS and SAS and then tap the SAS again and re-align your attitude after each important maneuver. Of course, planning ahead and minimizing torque in the first place is a good idea, and I suppose this is part of the reason why I dislike using RCS for torque so much. I would probably skip one degree of freedom, put two symmetrical 4-way RCS blocks on top of the CoM and rotate the ship around itself whenever I need to translate the other way. Not too sure what would happen with 3-way symmetry here.

Torque, yes, thrust no. If you only use RCS to translate, then torque doesn't matter. In the case of thrust, all you want is the CoM to be in line with the center of thrust and to do this you care about mass vs. thrust balance, not distance with the CoM. No. That's exactly not it, you could stick your RCS blocks as far away as you can, so long as they are balanced your ship will translate without inducing torque. If you want to use RCS for attitude + translation, then yes, putting it as far away from the CoM as possible is better, it will create more torque. ...but then you don't really need to go further than Kerbin.

I figured as much, although I really wouldn't want to make anyone watch 15 minutes of burning I suspected something like that, but I still feel that the total loss of about 575 m/s is huuuge. I don't know what I could be doing wrong, essentially, I point my ship at the maneuver node very precisely and begin burning and time my burns with both the node timer and the MET at the top for subsequent burns. I also used my periapsis as a reference for when to start the smaller burns, so 1 minute before periapsis until a minute after. For the following burn, I made a new maneuver node as after the 3 previous burns, it was horribly skewed. Then I followed the same process, pointed the ship at the maneuver node and split a bit less than 5 minutes on each side of my periapsis. I was under the impression that, even with low TWR, I could achieve a trajectory close enough so I would only need minor adjustments to get the desired encounter as long as I could get the ballistic trajectories to be parallel (as opposed to perfectly matching the maneuver node, since that's obviously going to be impossible to do). Although I have no idea how I would go about that without a precise reference on my NavBall. Long story short, while I did expect some losses due to precision, I assumed there was a way to aim myself close enough to the target maneuver that the last burn would not cause such losses, especially since I was going at escape velocity by that point. Maybe I oversimplified rocket science again. Beyond my original question, that leaves me wondering what the point of nukes is since if I'm going to waste 26,8% of my dV to compensate for low TWR. Compared to, say Terriers, they're 6 times the mass and a little bit over twice the Isp and exactly the same amount of thrust. So I thought bringing a lot of nukes would essentially nullify any advantage of actually using nukes because of their mass beyond the fact that it's a very kerbal thing to do. But then wasting this much fuel kinda makes me want to try using Terriers as interplanetary stages.

As much as I like Quill, I find he makes strange assumptions and statements for a game like KSP. I'll admit I haven't watched his latest series, but the previous ones made me feel like prying the mouse off his hands and stealing his headset. I much prefer Scott Manley, Marcus House or Mark Thrimm when it comes to KSP. I have to ask, what is it you intend to do to "complete" career mode?

Polar orbits are the only orbits that will guarantee you will cover just about all of a body's surface. As for distance/orbiting body, well, it really depends on how it functions... what kind of field of view does it have? The narrower, the further you can (have to) be, the wider, the closer you want to be if you want a chance to see anything.

All you really need is the prograde/retrograde vector which every level 1 pilot has. Not that hard to find and point to the target marker oneself if need be. And RCS should be close to COM in the x-y planes but not necessarily in the z, if you are using them for attitude control they will be more efficient if you have some radial distance from the center. Actually, I would argue all you really need is attitude hold, period. Prograde/retrograde hold are useful, mind you, but I don't see those being more useful than good old attitude hold. In fact, I could imagine it spinning your ship when you really don't need it to, like if you bump your target just a little off target and the ports don't stick for some reason. That could result in SAS swinging your ship around and hitting your target like a batter striking a home-run. As for RCS ports being close to CoM, that's absolutely, totally false. What they need to be is balanced according to CoM, but distance hardly matters. You are right about the attitude control, though I wouldn't really use RCS for that. As for the OP, happy to see your attitude (haha) towards the game. I am slightly puzzled as to why you'd need 6 nearly full orange tanks anywhere else than on an ascent stage, but it's simply too much of a kerbal thing to do for me to judge.

Ok, so I am rather confused, but first things first, here is the situation: Low TWR (0.21 in LKO when fully fueled) 2-part rocket assembled in space. KER says it has 4,800 m/s dV. TriggerAU's launch window planner's estimate dV for an encounter with my target: 2,399 m/s My maneuver: 2,444 m/s, off the top of my head the game tells me it's supposed to be somewhere between 16 and 19 minutes of burn. Impossible to do in one pass, my periapsis drops within atmosphere, best I managed was to cut roughly 1/3 of the burn before I reach escape velocity I did that in 3 burns of about 2 minutes, one minute before the node and one minute after. New maneuver that takes me to my target: 1,400 m/s with about 3,200 m/s left according to KER (net loss of 200 m/s? due to..?) Performing the remainder of the burn in one pass due to escape velocity: just under 10 minutes, burning 4:45 before the maneuver leaves me with 1,875 m/s (another loss of 375 m/s???) So, I'm not used to low TWR rockets, I usually stick with 0.5 or greater. Is it normal that there is wasted dV due to not performing burns as precisely as one would with greater TWR? Is it KER that's lying to me? Or am I approaching long interplanetary burns wrong? How do you deal with long burns? I have been using physics acceleration, has that been known to fudge things? Because I just don't get why I would end up using about 30% more fuel according to KER compared to what maneuver nodes tell me. That's a rather disconcertingly large margin of error.

Hello and welcome! For your rendez-vous needs, I recorded this video which may prove helpful: https://youtu.be/n1v5gfXe-xU I have also recorded a dedicated docking video, it only needs to be edited and uploaded, which is going to happen in the next two days. Otherwise I suggest heading to the questions sub-forums or the tutorials subsection to find more information. Hope it helps and good luck!

Hello and welcome! I would think this post would be most helpful to you: Otherwise, this section of the forums may appeal to you more: http://forum.kerbalspaceprogram.com/index.php?/forum/44-science-spaceflight/ As for having a good idea of what KSP takes into account, you may want to visit the wiki: http://wiki.kerbalspaceprogram.com/wiki/Main_Page Now, I am not the most science literate guy around, but I can tell you off the top of my head that the physics in KSP are much simpler than real life, although they do a good job of reproducing real hurdles of rocket science. Things you will encounter in KSP: aerodynamics/atmospheric drag and heat effects, Oberth effect, Hohmann transfers and such. Things that are especially unrealistic: clear cut sphere of influences, celestial bodies are fixed on their orbit and don't influence one another, no need to worry about wear and tear (dust, micro-meteorites, etc.) and probably more things I cannot think of at this moment.

Given the sandbox nature of the game and just how much you can tweak the difficulty settings, I don't think anyone can really what is "best" in this game for most part. The fact is that you can technically complete the whole science tree without ever going interplanetary. Money can also be rather abundant depending on your what you set the funds rewards/penalties sliders to. Now, as far as funds per mission efficiency, it's only logical that you should go when you have as many contracts as possible and try to get as much science as possible from every trip. But you don't have to. Also, welcome!