strider3

I'm using a triple asparagus setup to get to 350km Kerbin orbit and I will not have "a lot" of fuel left in the lower half of the central stack (the tanks feeding the Mammoth) once I arrive at the station.

I think I've worked the problem...but we shall see. Putting a Wolfhound on the bottom of the central stack instead of a mammoth caused issues with getting to Kerbin orbit of 350km due to lack of thrust. What I've done is split the central stack into 2 stages with a Mammoth at the bottom to help get me to 350km Kerbin orbit, and added several tanks and a Wolfhound to the top of the central stack, to get me to Moho. So far I will have no problem reaching my Kerbin refueling station at 350KM with both central stages intact. Now the question is...do I just jettison the lower stage with the Mammoth (which still has fuel) and go for Moho or refuel at my station and burn the Mammoth then the Wolfhound for Moho? I'm going to do the later on this first go as I see no reason to dump the lower stage which will still have fuel even before refueling at the station. Might as well use the lower stage DV and arrive at Moho with more fuel/LoX available, I'm thinking.

The problem I ran into is that unless I have an LF only tank connected to the Nuke engine...it will not run? With the Nuke connected to my central stack (which is all LF/Ox tanks), it doesn't run. Unless I'm misunderstanding you?

I'll be leaving Kerbin from 350 km orbit. More importantly, the GNR is apparently not going to work? It wants liquid fuel only tanks and I need both fuel and LoX to refuel my lander at Moho. At this point I guess I'll try the Wolfhound on the central stack and send 3 more refuelers to Moho to complete the Moho science mission.

I don't seem to have a "liquid hydrogen" tank available for the GNR??

Let's see if I understand ( a big "if" ). Say I replace the central mammoth with a GNR 2500 nuke engine and use it only once in Kerbin orbit for the transfer to Moho. I'd keep the 6 mammoth asparagus setup (minus the fuel ducts to the central stack) to get to Kerbin orbit. The GNR 2500 will take a much longer burn to get me on the way to Moho (lower vacuum thrust than a mammoth) but should, if I understand, use much less fuel per second (higher vacuum ISP). The question becomes...does the much longer burn required using the GNR 2500 negate the increased efficiency of it's higher vacuum ISP...making the whole thing "moot"?

I'm still confused on the engine efficiency question? ISP seems to deal with thrust...not "miles per gallon". I would like to know which engines are the most efficient in their use of fuel and which numbers tell you that?

What I need is to get out of the "bigger is better" hole and send some ships to Moho which will have fuel to continue the exploration and get all that info and my 2 Kerbals home. Thank you.

Nope, the scanner was to find biomes only. I am not looking to make fuel at Moho...only to land and get science. My mining operation will be on Dres.

That I have done on Dres...but it doesn't really help on this situation? Or am I misunderstanding your point?

ISRU?

Here's what I have been using to get fuel to various bodies. It's a triple asparagus setup and I do not eject the last 2 outer stacks. It's all Mammoth's. I leave them attached, drag their empty weight to my Kerbin refueling station (350 km orbit) and fill everything up. This has not really worked as it seems to result in very little fuel/Lox left once I have it at my working Moho orbit of 30km. The vacuum ISP tells me thrust...but not really "efficiency"? It doesn't tell me "miles per gallon"?

I am 2/3 of the way through my scientific exploration of Moho. What I have discovered is the tremendous amount of fuel I have expended to keep my science lander fueled and making landings on Moho. I originally sent a scanner, the lander and 3 refueling ships...and the amount of fuel actually available to the lander after the refuelers were in the working orbit was...depressing. I still have 4 landings at biomes to complete and I'm out of available fuel for my lander. I don't know if getting fuel to Moho orbit is always this costly or if it's the UT years I am trying to accomplish this in (11-13). Either way, I may have fallen into the "bigger is better" rabbit hole. I built large refuelers, refueled them from my Kerbin space station and sent them to Moho only to have (comparatively) little fuel left after they were in my Moho working orbit of 30 km. I feel that part of the problem, besides the size of these refuelers, may be the efficiency of the engines I am using to get from Kerbin orbit to Moho orbit. How does one determine the efficiency of an engine (in vacuum)? What numbers do you look at as far as engine performance to determine which engine will be the most fuel efficient in getting to Moho? My "off the cuff" calculations for fuel needed to complete 4 more landings, return to a close to equatorial Moho orbit (I'm at 54* inclination now) and return to Kerbin is about 30,000 fuel. I'm basing this number on my lander's Delta V when full of fuel as it will be the return to Kerbin vehicle (barely!). I realize there is way more to this than I am asking but, at this point, I just want to get my biome landings done and get Ferbin and Arbart back home.

That post was very helpful! Thanks James!

I am speaking more of going from Kerbin orbit to another body. I can leave Kerbin for Moho (for instance) and make my maneuver node to arrive at Moho at 50 km or 500 km. If I want to "work" Moho landings from 50 km, I was curious if I should arrive at Moho at 50 km periapses (my required working orbit) or a higher periapses...and burn down to 50 km from a Moho orbit of 500 km.

Yep...Moho to Kerbin would be...bad! Thanks!!

Is it more Delta V "friendly" to have an orbital insertion periapsis at high altitude, and then reduce to desired orbit or to just go for the desired periapsis from the initial ejection burn (or mid-course correction burn)? As an example: I am heading to Moho from Kerbin, my "working" orbit will be 50 km. Is it more efficient to arrive at 500 km and create an orbit at that height then burn down to my 50 km orbit after...or just shoot for a 50 km periapsis from the git-go and burn to circularize?

Another thing that should be added. If we can land on the moon, we should be able to create landing struts in KSP2 that don't slide down the slightest slope? Even Apollo had spikes protruding from their landing struts, to prevent sliding...can we?

I've actually started using the KJR mod (Kerbal Joint Reinforcement) and it has basically solved all my problems. One important note...if you use this mod...turn off ALL auto-strutting, on both ships, before docking. From my experience with KJR...auto-strutting is no longer needed, and may, in fact, need to be avoided. I'm still trying to determine if I can turn off auto-strutting at launch...for "wobbly" ships. Not quite sure if KJR helps with the "noodles" on launch.

Just one more note...turn off "auto-strutting" of station parts! Although KJR is an immense improvement, there will still be very rare instances of the "shudders" and a part drifting off. AFAICT this is caused by KSP's auto-struts "re-aligning" when docking to the station (even with "Grandparent" mode). I may be wrong, but after months of trying...I'm going with my uninformed conclusions .

Success! After adding the KJR mod, I have been able to complete the last 3 tank sections of the station...with only 1 disconnect of a part, and I'm pretty sure that one anomaly was "self-induced" as I switched to the station from the arriving ship and immediately started rolling the station towards the arriving tanks. It does appear that KJR requires just a bit of patience when switching crafts, to allow it's function to perform, before jumping all over SAS (not sure if I'm making sense, but, it seems the physics "dampening" needs to complete before you get all crazy with moving the craft). At none of the other points mentioned above, including switching crafts without getting all squirrelly on the SAS, did I have any issues. Wish I had found this many moons ago . Thank you, Rocket Witch, for the suggestion! Jeb and Bill and their MK2 are still attached to the last tank stack, waiting for Bill to EVA and connect the portable struts (just in case!). A few "top off" trips with the mobil 1 refueler from Kerbin and...Duna (or Eve), here I come.

It sounds like it might do everything I'm looking for? The only thing I don't see mentioned, below, is docking ports...but it's worth a try. https://github.com/KSP-RO/Kerbal-Joint-Reinforcement-Continued

Yes, I tried that...it didn't help.

It sounds like something I need to try...you all have good things to say about it. One more question...what about existing crafts? Will it help my 75% completed space station?

Thank you, as always, to all of you. It reduces my aggravation level when you all offer help. Does KJR "reinforce" any joint? RE, if you attach a station part using 2 Senior docking ports...does it reinforce that connection? Or does it only work on VAB attached joints? Does anyone know if it will reinforce joints made, in flight, with the Konstruction mod "weldable" construction ports?