March Unto Torment

Beautiful! Unfortunately, it's not loading in 1.0.5 ("data incompatible" or something), so I'm going to wait until Nertea's mods update to 1.1 before I'm able to use it. But that's not a problem, since I'm running the mission in 1.1 anyway (current operations around the mothership look more or less like a slideshow). So I'll probably be taking that, at least as my preliminary Laythe lander. However... This thing is sweet. Massively overkill for my Jool-5 purposes, but given that my mothership will be repurposed as a Low Laythe Orbit space station overseeing operations there, I think I'll be taking that and modifying it some (take away the cabin, add some RCS and more room for internal cargo) for the purposes of supporting my Laythe colonisation efforts. Do you happen to have a .craft file I could borrow?

Full disclosure, Whackjob is basically my Senpai

If I recall, SpaceY actually has something like this; a 1.875m SRB with a 1.25m node at the top. I could be wrong, but I'm pretty sure that it's too small to be a 2.5m booster. I use four of them on my mainline (40t to KEO) launch system. I'd definitely endorse the idea.

Nah, not worth it. If I do decide to do this challenge, I'll probably build a stupidly-giant 400-Kerbal habitation module and send it on its own. It'd only weigh 180 tonnes (a tiny fraction of what my main ship weighs), and I could dock it to the space station that I'm turning my mothership into. Hell, I already need to make a second trip to get another transfer stage, so I may as well send 400 folks along for the ride.

Neat! That thing looks really cool. Mine's still larger, but the most I've ever had on the pad at any given time was about 3,500 tonnes (the 1.0-era aero makes gargantuan, ultra-wide launchers more or less impossible). It's basically been assembled in blocks, and will be fuelled in KEO by a large-scale Minmus mining ship. Mad respect for being ballsy enough to put 26,000 tonnes on the pad, though. And without even using SpaceY! P.S. I'm no longer sure that I take the record for 'in history', although I feel reasonably confident that I'll still be able to claim the title for 1.0-era crafts.

Unfortunately, no screenshots of the launches for the main space station My steam overlay broke for a while (caused weird flickering blocks on-screen - anyone else seen that?), and I've only recently managed to re-enable it (turns out I need to launch through Steam, not through the .exe). I will be providing screenshots of all the launches of the 'mission' components, though (my assorted landers, my enormous transfer stages, etc.), which will presumably verify my ability to put multiple outsize 250-tonne payloads in KEO and dock them. Compared to some of the stuff I'm launching (ever tried to get eighty LV-Ns into orbit in a single launch? Me neither, but I'm about to have to try), the station itself was pretty easy. I'm not using the 3.75m engine for any of my landers, mostly because I don't have any 3.75m landers (although it is used on one of my launchers). But I do believe it's stock-balanced (6t, 525kN vac. thrust, 345 vac. ISP). Mostly, I'm just using the 3.75m command module in one of my habitats and the 2.5m module as the 'bridge' of the ship (it has nice big windows!). Thanks! No nuclear reactors (my entire transfer stage is LV-Ns), and I've never worked out what the capacitors are for, so I have none of those either. Haha! If 550 tonnes is the largest we've ever seen, then make no mistake, this thing will blow it out of the water...

So! I'm going to undertake the challenge soon. And it's going to be, uh, an 'interesting' iteration, mostly because - in terms of sheer tonnage - it most likely dwarfs any Jool-5 attempt in history. However, before I start, I have a few questions that I'd like to ask, which will mostly be for the purpose of determining how 'official' my attempt will be. Is the mod 'Near Future Spacecraft' allowed? It's one of Nerteas, and all it contains (if I recall correctly) is two command pods (an alternate 2.5m module and a 3.75m module) and two low-profile 3.75m engines (comparable to an upscaled Terrier, if you will). How rigid are the rules regarding mods? The core of the mothership is a space station I have in KEO, which (because it wasn't originally designed for Jool-5) has eight (?) Near Future Electrical batteries on it, each containing 800 charge. I can't really see it being a balance issue at all, and I'd be happy to block off electrical flow (the ship gets plenty of power from its forty-odd Gigantor panels, even at Jool), but I wanted to check anyway. Does anyone remember the tonnage record for Jool-5? The largest I'm aware of was Kidonia, which was around 800 tonnes on departure. Does anyone know of any larger missions? I want to know what I'm up against Anyone who can help me out with these would be really helpful! I'm really excited to get started Best regards, - March Unto Torment

Funnily enough, my current Jool mothership is actually in the correct tonnage range for this, although as it's designed for Jool-5 operations and includes a whole bunch of excess stuff (refineries, inter-Jool transfer stages, 100,000 units of spare LF...), it has a capacity of only around a hundred Kerbals and hence won't be used for this challenge. Still, watching this one with excitement!

Hey, everyone! So, thanks to the tireless efforts of this forum, I've managed to reach a point where my main ship is approaching the stage of being 'ready to go' (still need to actually get the propulsion stage orbited and fuelled, but that's a problem for 1.1-era me). I've got two landers built so far; one Tylo/Vall lander and one Bop/Pol lander. That covers four of Jool's moons. However, I'm struggling with devising a fully-functional SSTO for Laythe. The requirements are as follows - Must be capable of descending from a 100x100km Laythe orbit, flying for some fifteen minutes or so within Laythe atmosphere (long enough for me to find dry land), landing, and then ascending back a 100x100km orbit while still having 100m/s or so of dV for rendezvous operations. Must be capable of transporting one Kerbal. Must have a reasonable amount of RCS to allow for docking operations. Must possess one 1.25m docking port (ideally the inline docking port, but I'm not overly picky). Must weigh less than 40 tonnes fully-loaded (although that's an issue with being able to use my mediumweight launcher - it's not like I'm on a tight weight budget for this mission, as anyone from my other thread will know by now). I tried modifying the existing 'Dove' SSTO for this purpose (basically by adding some RCS and an inline docking port in the middle of the craft), but I ended up with something that lacked enough fuel for my requirements and had huge centre-of-mass issues (when empty, the CoM was directly over the CoL, rendering the aircraft effectively uncontrollable). So that option's out. Does anyone have any good tips for designing Laythe SSTOs? The main issue is that I can't really test them, since obviously, dV requirements aren't really linear for spaceplanes. (Oh, and yes, I'd prefer it be a spaceplane, for the aforementioned reason of being able to fly in Laythe's atmosphere.) Best regards, - March Unto Torment

My problem is that (per the above explanation), I'm using multiple manoeuvre nodes in sequence for greater accuracy. However, if I'm remembering right, there's an 'execute all nodes' function on MJ, which basically solves my problem. I'll check tomorrow if I'm right. EDIT: Checking the online manual backed me up - the function exists! Which means, once I finish assembly (and fuelling, which will likely consist of six or seven trips to Minmus and back to mine ore) I'll be able to sit back and get around to watching The Right Stuff.

Perfect! That saves me worrying about overheating, at least. Wondering about other functions, though. Can I tell MechJeb to burn for, say, 30 minutes at full throttle, then cut engines? Or to expend 2,100m/s of dV, then cut?

I've got six of the largest radiators possible, split between 80 LV-Ns; I'm not sure that it's enough, but combined with the sheer mass of the ship, it should be enough to keep me below critical temperature just long enough. Unfortunately, reliable information regarding LV-N heating is hard to come by. Anyway, it sounds like I have just about enough dV to complete the Laythe capture; I may run a little short on Laythe circularisation, but if that's the case, I can fix that up post-mission by shipping out a few (dozen :P) tonnes of spare LF, since a non-circular Laythe orbit doesn't interfere with my mission profile much. And I like your suggestion of letting things run themselves - I might just do that It'll save me some hassle, certainly. I wonder if there's a feature on MechJeb that'll let me tell it to automatically cut engines after a certain time...

MechJeb would make me quit immediately. Playing without it is just too frustrating. I'd also get seriously liquided if Nertea didn't update their mods; Station Parts Expansion is basically a must-have for me, as is Near Future Construction.

So, I think I've settled on the final transfer stage design. It's got a hair over 3,000m/s of dV (since I've broken it up into multiple pieces for the purposes of getting it into KEO, I don't have exact numbers). It's also only about 200 parts total, which is nice, and should keep my final part count at around 1,600. @KerikBalm: I'm not willing to disclose mass - it's a surprise! - but its part count is sitting on 900 right now, and I have yet to attach my refinery (80 parts), my four landers (around 75 parts each), my tug (50 parts) or my return and transfer stages (100 and 200 parts, respectively). I'm not playing the 1.1 prerelease - hence, docking is currently a nightmare, due to my abysmal framerate - but I won't be starting the mission until the full release is out and all my mods (most importantly Near Future Construction) are updated, since 1.1 apparently features massive performance boosts (and I'm already in a good place for performance, seeing as I'm running an i5 4440). EDIT: Did my numbers wrong; I've got 3,415m/s dV total. So, the question becomes - is that enough to get me from KEO to Low Laythe Orbit? That is, without requiring aerobraking or excessive numbers of difficult gravity assists, which (due to the sheer bulk of the ship in question) are difficult in the case of the latter and straight-up impossible in the former.

Huh, interesting. Thanks for testing this! So, looks like they're roughly equal in terms of dV expenditure. However, I'll probably stick with the KEO burn, mostly because it means I can afford longer burns (I can split my main burn into a handful of larger burns instead of requiring numerous smaller burns) without losing too much precision. Also, some alterations to mission objective and profile (long story) mean that I now need to park my mothership in a Laythe orbit. Which means that - ironically - I'm stuck with my original 4,130m/s stage, which has (allowing for some light modifications to pack on some extra fuel) just around enough dV to make the transfer, followed by a transition to Laythe orbit. Does anyone know a more efficient method of getting into Laythe orbit? Swash's dV map is giving me 2,000m/s to transfer from Jool capture to Low Laythe Orbit, but I suspect that I can probably take some of that out with a gravity assist of some description.

More than 880 tonnes. A lot more. I haven't counted the total number of nukes, but, uh... yeah. This thing is mind-blowingly huge. Let's leave it at that. And I've got ISRU on hand, but given the scale of this thing, mining enough ore at Jool to be useful is... impractical. Given any kind of sane timeframe, anyhow. I may end up using Minmus ore to help fuel it, though, once the transfer stage is docked (I feel that Minmus mining would be more practical than trying to lift insane amounts of LF into orbit). (Before anyone asks me if I can downsize, the entire point is to see if I can pull off the highest-tonnage Jool-5 mission in history. But shhhhhh, that's a secret )

Doubling the number of nukes would be... difficult, to say the least. My craft is at the point where I basically can't fit any more nukes onto it. Hell, I probably have so many nukes mounted that the weight of the propulsion units alone outweighs the total tonnage of most Jool-5 missions. Anyway, my mission profile involves parking my mothership, then splitting up the mission; each lander is taken out by a tug, lands, and then is returned to the mothership by the tug, which is then refuelled. After my entire Kerbal team is back at the ship, a secondary propulsion unit with about 4,000m/s of dV is broken off and returns to Kerbin, leaving the mothership in orbit to function as a space station. So where I park the mothership is mostly about which location will cost me the least in dV terms to travel back and forth from.

Transfer stage is still in the design phase, so nothing's set in stone yet.

http://13375.de/KSPDeltaVMap/ I was using this dV map, which was indicating wildly out-of-proportion dV numbers (3,860 for KEO to LJO). Reading everything in this thread, that definitely seemed wrong. So, I tested it out myself with a manoeuvre node and it turns out that to get to Kerbin's SOI edge (KSE from here on out), it only takes me 390m/s from KEO - not the 2,270m/s that my dV map was indicating (for which matter, the love is wrong with that dV map?!). This stands to reason, as it's 660m/s to raise AP to KEO, and 950-660=390. So, from that, I infer from Swash's dV map (which seems much more reliable) that I need 1410 to make the transfer from SOI edge to Jool elliptical, which seems reasonable to me. That brings me up to a round 1,800 for KEO to something resembling an orbit around Jool. From there, I need to make a transfer to... an orbit around Jool. I'm keeping the mothership in orbit around Jool while using a separate tug to move my landers around the system for operations, but I'm not sure where would be the most dV-efficient place to put my mothership (I'm thinking around 20,000km, putting me just inside Laythe orbit; it's staying there indefinitely and won't be making the return to Kerbin, due to my 'unusual' mission profile). Anyone else have any other suggestions for where to plant the mothership? And does anyone have any idea how much dV it would take to get from Jool capture to that orbit? EDIT: The forum autocorrect to 'love' is hilarious Also, I'm not quite sure what you're saying about orbital velocity - exactly how much dV do I lose by starting with my PE at KEO?

Well, now this changes everything. I've actually more or less cut my fuel weight by 2/3 (not sure why it scales so linearly, although it's probably because - even when fully-fuelled - the craft was only originally less than 50% fuel), and I still have 2,000m/s left, which gives me plenty for correction burns once on a transfer trajectory. In doing this, I've increased my TWR to around the 0.1 end of the spectrum - still not fantastic, but combined with the far lower dV of the burn, it should get my burn time down to around - as you said - 30 minutes rather than two hours. Ideally, I'll be able to break my burn down even further, by splitting it into one burn to edge of SOI and a second to Jool. This is all assuming that you're right, of course. But if you are, this whole setup just got way more practical.

"Less than two hours," is the best answer you're getting from me, who is currently struggling with a TWR of 0.05 for a Jool ejection burn.

My difficulty with gravity assists is that I find them very unpredictable, and I have yet to find a decent way of figuring out how much dV they use. Usually, I'd compensate for this just by packing in spare dV, but due to the nature of this mission, I'm trying to operate on as lean a dV budget as I can. Do you happen to know any way of calculating an effective gravity assist dV?

Multiplying my TWR by ten is... not an option I'm loathe to reveal the exact nature of the mission, but I've more or less already stacked on all the engines I have room for. I could maybe double my engine power, but that'd add a lot of weight (and hence cut out a lot of valuable dV) and not make a huge dent in my burn time. Anyway, bringing more fuel is probably my best bet. It means another set of fuel tanks to add on to the ship and another three fuelling runs or so to KEO (I'm bringing my tanks up empty for weight reasons), but it'll probably let me get the extra 2,270m/s on (going by your numbers, it'd be more efficient than the KEO burn and the dV for exiting Kerbin's SOI plus burning to Jool is only about 5,000m/s in total - does that look right to you?).

That seems like the most viable way to do it without screwing up, although it does beg the question of how much dV I waste this way (I've only got a couple of hundred m/s to spare, if you'll recall).

Not sure if you missed it in my OP, but the main assembly's already been constructed in Keostationary Orbit. So from the sounds of what you're saying, that's one of the larger problems fixed. Question is, since I'm in KEO, can I do one single burn, or am I still going to need to do multiple? (Most dV maps are telling me that I need 3,800m/s or so to transfer to Jool from KEO, so I don't have much dV to spare when it comes to fixing up my orbit.)