Jak-109 Driad: Long Range, Modular, Prospecting Starship.

[Jakalth]

I've been playing around with the idea of making a super heavy and very large modular starship. The results turned into the Jak-109 Driad. This craft is modular, so it can be sent up to orbit much easier. It is quite large, close to half again bigger then the VAB. Has a crew capacity of 104. And when fully fueled, can weigh more then 1,500 Tons. The starship has no capacity to enter atmosphere and survive so it's to remain in orbit or in trans planetary space once assembled. It's fuel capacity is immense, giving it a total Delta-V of well over 8,000 while still having a respectable TWR of around 1.3. It has 21 docking ports for bringing along nearly all the equipment, landers, probes, and satellites it could possibly need for exploring a different planetary system. Loads of solar panels so even if things go bad, you have power generation to spare, and quite a sizable reserve of mono propellant for maneuvering it's hefty bulk. As well as the ability to relink the segments if the kraken tries to pull them apart.

The Driad in all it's lengthy beauty.

Lets take it from the top.

And the Key to it's ability to stay intact while maneuvering: The reinforced docking ports, aka: docking port senior with 4 standard docking ports on outriggers, to give the docking system the rigidity it needs to hold together.

The sections require nearly perfect alignment so that all 5 ports link up correctly. Luckily, the fuel and engine segments are designed to be the same on all 4 sides so it only requires being aligned to the closest 90 deg. Also, each section has it's own core for maneuvering and plenty of RCS authority to allow for the maneuvers needed for docking. Only the crew section is single sided and has just one side up. But luckily, the rest do not so once linkage is achieved, the craft only needs to be rolled until it's facing the right way.

Maneuvering this craft is very slow. Even with the massive amount of RCS authority it has, and the added reaction wheels in the crew and engine segments, it is a slow process. But changing orbit, once it is pointing the right way, goes quickly thanks to the 5 "Mammoth" engines and their combined 20,000 units of thrust. So no 12 minute burns for this starship.

With it being modular, it is entirely possible to add a second or even third fuel segment to the craft, increasing it's range even further. The possibilities are great. But the ability to maneuver, and it's great TWR, will drop dramatically with each added segment.

The crew and fuel sections are best sent up empty with their own launch vehicles to bring them into orbit. But the engine section has enough delta-v to launch its self into orbit fully loaded with no need for any boosters. Although adding boosters can be fun.

I hope you enjoyed taking a look at this craft. It was quite the build but was fun to make none the less.

[eddiew]

That is... chunky. I like the thought put into the docking ports ^^

Dare I ask the part count? xD

[Jakalth]

You'd be a bit surprised. It's only 562 parts on the beast. And I still get at least 15 fps when flying it. What helps is that all the docking ports, other then the ones linking the segments together, are shielded. This way they don't slow the game down as much.

Now... Mission plan. Anyone have a mission idea for me to try with this craft? I have it in orbit, just need to fully refuel it and load it up with probes and have a location to shoot for.

Oh, I also forgot. The engine section has 4 large cargo bays for holding even more stuff. So this big ship can take a lot of stuff with it on a mission, but to where... Hmmm.

Edited August 22, 2015 by Jakalth

[problemecium]

Something bigger than mine - I have been challenged!

[Jakalth]

And, now for the craft files. I delayed releasing the craft files until I had fixed a few things with the segment launchers. The Driad comes in 3 segments, crew, fuel, and engines. Each segment has it's own way to get up into orbit. Once there, they snap together to make the mother ship. In Kerbal Orbit the Driad will need to be refueled, stocked with satellites, probes, and landers for it's mission, and have the rest of it's crew brought up. Details of each segment will be stated separately.

The Crew segment:

This segment houses the life support systems, crew quarters, and snack dispensers every Kerbal needs for a successful mission. It comes with minimal solar collectors, enough to keep it powered on it's own, but a good supply of fuel for the RCS system it has for orbital maneuvering. The nose mounted docking port is for ease of crew transfers and for the ever important snack restocking. The crew segment has an ultra high gain communications tower equipped with a high gain antenna, 2 medium range folding antenna, and a pair of EVA communications antennas. This segment also houses the planetary survey equipment needed to scan a planet from orbit and any moons you might find nearby, no matter what side of the craft the planet might be on(yes even upside down for when Jeb does his show boating). The launch profile of this segment is a bit rough and requires keeping the craft basically vertical until it is over 12Km up. At this point a very shallow gravity turn can be started with the turn being inched slowly over further as you continue to climb. This means it does not allow for a truly efficient orbital burn. But its lifter has plenty of fuel to make up for this. Once in orbit, the lifter will need to be manually undocked from the docking port. Price for this segment and lifter: ~613,000 Kredits

The Fuel segment:

This segment's main purpose is to house fuel for the engines and generate power with it's array of solar panels. This segment is also equipped with 12 docking ports for attaching many of the various probes, satellites, and landers needed to complete the various missions the Driad is capable of performing. It has room for nearly half the fuel the Driad carries on a normal mission, and a good amount of fuel for it's onboard RCS system. Just to be on the safe side, the fuel segment has an auxiliary monopropellant tank on it's tail end for extra maneuvering fuel for docking. It needs to be noted that the top of the fuel segment(the end with the nose cone) connects to the crew segment, and the bottom(the end with the lifter and extra monopropellant) connects to the engine segment only. It will not link up properly if attached the other way around. The launch profile of this segment is the same as the crew segment, but it tends to be a little more sensitive to leaning during the gravity turn, meaning it has to take an even less efficient orbital path. There is a separator to blow off the lift engine once it is in orbit and closing in on docking with the other segments. It is advisable to leave the extra monopropellant tank in place untill all it's monopropellant can be transfered into the onboard tanks. It is also advisable to leave the nose cone in place until you are ready to connect it with the other segments so that it is easier to tell which end is which. The winglets on the front of the segment should be jettisoned as well, once in orbit, to free up docking space. Price for this segment and lifter: ~450,000 Kredits

The Engine segment:

This segment is the main propulsion for the Driad. It houses the 5 Mammoth engines and has 8 docking ports and 4 large cargo holds for carrying equipment for your mission. This segment only has minimal power generation in the form of a few solar panel arrays, two of which are hidden under the control fins during launch. This segment has extra fuel tanks on it's nose to give it a little extra breathing room during orbital flight due to it having only just enough fuel to reach orbit. The fuel segment can launch it's self too orbit, not needing any other form of propulsion to aid it. It's flight profile is about the same as the crew segment, but it is a little more forgiving during it's gravity turn, allowing slightly more tilt then the other two segments, but you should hold off on starting your gravity turn untill over 12Km with this segment as well. Once in orbit, the fins should be jettisoned to make room for the solar panel deployment and to free up space for the docking ports to be used. Also, draining fuel from the nose mounted tanks and undocking them will be needed before this segment can be connected to the others. Also note, this segment has a LOT of TWR. Too much in fact. You will want to run the engines lower then normal to keep the segment from accelerating too quickly. Like all other segments, this one is equipped with plenty of fuel for it's RCS system to aid in orbital maneuvers and docking. Price for this segment: ~406,000 Kredits

Total price for launching the whole Driad: ~1,469,000 Kredits, not counting the cost of refueling, equipment loading, and crew delivery.

The docking segments can only connect to certain others due to their being two different docking port arrays, one for the back of a segment, and one for the front. This means that two fuel segments can connect to each other as long as they connect front to back, and it means that the engine and crew segments can be connected together directly if wanted. It's only an issue with the fuel segment having two docking port ends and the fact that a front docking port array can not connect properly to another front array, while a back array also can not connect properly to another back array.

Hope you all enjoy this craft as much as I had at making it.

[AlextheBodacious]

sfs sfs fssf sffsffs sfs pllllllllllllleeeeeeeeeeeeeeeeeeeeeeaaaaaaaaaaaaaaaaaaaassssssssssssssssssssssssssssseeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee?

[Jett_Quasar]

That ship is just crazy - I love it! What I'd really like to see is some pics of it around other worlds. If you could refuel that puppy it could do a grand tour.

JR

[Jakalth]

I'm currently working on sending this craft, initially, to Jool with a full compliment of landers, probes, and satellites for it's various moons. The mission preparation work is on hold for the next couple of days as I'm busy with trade fair projects atm. But so far, I've got a small amphibious ssto built for Lathe as well as a drop pod. Plans are in place for some refueling pods to convert ores into fuel for the Driad as well as at least 1 mining craft to descend onto one of the moons to gather the ore for the Driad to convert. I will have pictures posted of the various craft I'll be using once I've got them finalized.

The one snag that may hold this back is the fact that I haven't fully refueled the Driad yet so I don't have the Delta-V numbers I'll need to calculate it's true range yet. But, if sufficient Delta-V can be added, I might just make a run for Eeloo after going to Jool. Either by way of a refueling stop at kerbin to restock on probes, or directly from the Jool system after transferring ores up from the moons of the system.

Here's hoping next week gives me more time to send this craft on it's grand tour.

[DMSP]

lol, this is what I have always wanted!

Sadly it is 300 Parts too many.

Is there a chance you could make a smaller version?

It would mean a lot to me!

Thank you!

[Jakalth]

Sad news everyone... I finally got back to setting up the mission to the Jool system and, while I was gone, the Kraken decided to play with the Driad and broke all it's fuel routing...

*un-docks the segments and re-docks them*

Good news everyone. The fuel routing issues have been fixed. It's good to see that the Kraken resistance of the docking port system holds up to an actual Kraken attack.

I've fully refueled the Driad in orbit. It ended up taking me 8 refueling trips bringing the craft 15 full S3-14400 fuel tanks total. The cost to refuel the craft ended up somewhere over 3,025,000 Kredits. With the massive payload of fuel on board I checked the delta-V reading for the engines... Huh... That's not right. I checked again. Broken... The Version of the Kerbal Engineer mod I was using was glitching out on me... So, I checked for a newer version, installed it, and reloaded the game. This is when I found out where my problem was...

Remember when I said this craft had over 8,000 Delta-V of fuel on board? Well, that was the version of KER being broken... :\ The final numbers I have for the Driad is about 4,200 Delta-V with a TWR of 1.92 and a total mass of 1,420tons, give or take a few tons. I don't even know if this is enough to reach Jool anymore... Could someone with more experience at long range missions let me know for sure?

If it's still a go, I'll have a Lathe capable, amphibious, spaceplane ready to dock with the Driad along with an accompanying drop pod/lander with a 2-stage ascender, both destined for Lathe exploration. I have a very carefully designed, and quite rugged, unmanned drop pod destined for the lander eating monster known as Tylo. I'll have 2 on board for redundancy. Vall has a manned lander with lots of science equipment on board made especially for this icy moon. Then Pol and Bop have a shared, high efficiency lander that will work on both of the little moons. As well as a good sized ore mining craft to gather ores from Pol for refueling the Driad. Although I fear it will take longer to refuel the Driad this way then I'm willing to spend on a single task, somewhere around 80 trips between the driad and the surface of Pol... And to process these ores, I have a simple IRSU pod that can dock onto any of the docking ports and recieve ores brought up by the mining pod.

The parts of the mission are all built, but the sadly lacking Delta-V of the Driad now has me wondering if this is even a viable mission anymore, in it's current configuration...

[FlipNascar]

Your best bet, given that you know what it is you want to do when you get there, is make some assumptions using a ∆V map. By the looks of it, unless you really are prepared to mine Pol and send up the goods... You may want to look at alternative engine layouts (modular is good for something!). K2RLs may be a good choice as they've got a higher ISP. But I don't know if you're already too massive for those to benefit. Someone did do some charts for that...

Those two tools may help you on your quest to send some serious tonnage across the Kerbol system.

[AxleMC131]

Man, this is incredible! And only 562 parts for that? Wow.

It's a shame it doesn't have the dV to get to Jool - Jolly_Roger is right, doing a grand tour in something this size would be a truly epic venture. Still, awesome work! Love the ingenuity with the docking ports, and it's not a bad looking craft either.

[selfish_meme]

Sad news everyone... I finally got back to setting up the mission to the Jool system and, while I was gone, the Kraken decided to play with the Driad and broke all it's fuel routing...

*un-docks the segments and re-docks them*

Good news everyone. The fuel routing issues have been fixed. It's good to see that the Kraken resistance of the docking port system holds up to an actual Kraken attack.

I've fully refueled the Driad in orbit. It ended up taking me 8 refueling trips bringing the craft 15 full S3-14400 fuel tanks total. The cost to refuel the craft ended up somewhere over 3,025,000 Kredits. With the massive payload of fuel on board I checked the delta-V reading for the engines... Huh... That's not right. I checked again. Broken... The Version of the Kerbal Engineer mod I was using was glitching out on me... So, I checked for a newer version, installed it, and reloaded the game. This is when I found out where my problem was...

Remember when I said this craft had over 8,000 Delta-V of fuel on board? Well, that was the version of KER being broken... :\ The final numbers I have for the Driad is about 4,200 Delta-V with a TWR of 1.92 and a total mass of 1,420tons, give or take a few tons. I don't even know if this is enough to reach Jool anymore... Could someone with more experience at long range missions let me know for sure?

If it's still a go, I'll have a Lathe capable, amphibious, spaceplane ready to dock with the Driad along with an accompanying drop pod/lander with a 2-stage ascender, both destined for Lathe exploration. I have a very carefully designed, and quite rugged, unmanned drop pod destined for the lander eating monster known as Tylo. I'll have 2 on board for redundancy. Vall has a manned lander with lots of science equipment on board made especially for this icy moon. Then Pol and Bop have a shared, high efficiency lander that will work on both of the little moons. As well as a good sized ore mining craft to gather ores from Pol for refueling the Driad. Although I fear it will take longer to refuel the Driad this way then I'm willing to spend on a single task, somewhere around 80 trips between the driad and the surface of Pol... And to process these ores, I have a simple IRSU pod that can dock onto any of the docking ports and recieve ores brought up by the mining pod.

The parts of the mission are all built, but the sadly lacking Delta-V of the Driad now has me wondering if this is even a viable mission anymore, in it's current configuration...

I think your problem is twr, too much engine

[Rune]

Sad news everyone... I finally got back to setting up the mission to the Jool system and, while I was gone, the Kraken decided to play with the Driad and broke all it's fuel routing...

*un-docks the segments and re-docks them*

Good news everyone. The fuel routing issues have been fixed. It's good to see that the Kraken resistance of the docking port system holds up to an actual Kraken attack.

I've fully refueled the Driad in orbit. It ended up taking me 8 refueling trips bringing the craft 15 full S3-14400 fuel tanks total. The cost to refuel the craft ended up somewhere over 3,025,000 Kredits. With the massive payload of fuel on board I checked the delta-V reading for the engines... Huh... That's not right. I checked again. Broken... The Version of the Kerbal Engineer mod I was using was glitching out on me... So, I checked for a newer version, installed it, and reloaded the game. This is when I found out where my problem was...

Remember when I said this craft had over 8,000 Delta-V of fuel on board? Well, that was the version of KER being broken... :\ The final numbers I have for the Driad is about 4,200 Delta-V with a TWR of 1.92 and a total mass of 1,420tons, give or take a few tons. I don't even know if this is enough to reach Jool anymore... Could someone with more experience at long range missions let me know for sure?

If it's still a go, I'll have a Lathe capable, amphibious, spaceplane ready to dock with the Driad along with an accompanying drop pod/lander with a 2-stage ascender, both destined for Lathe exploration. I have a very carefully designed, and quite rugged, unmanned drop pod destined for the lander eating monster known as Tylo. I'll have 2 on board for redundancy. Vall has a manned lander with lots of science equipment on board made especially for this icy moon. Then Pol and Bop have a shared, high efficiency lander that will work on both of the little moons. As well as a good sized ore mining craft to gather ores from Pol for refueling the Driad. Although I fear it will take longer to refuel the Driad this way then I'm willing to spend on a single task, somewhere around 80 trips between the driad and the surface of Pol... And to process these ores, I have a simple IRSU pod that can dock onto any of the docking ports and recieve ores brought up by the mining pod.

The parts of the mission are all built, but the sadly lacking Delta-V of the Driad now has me wondering if this is even a viable mission anymore, in it's current configuration...

Four km/s seems about right for a ship equipped with engines with about 300s isp and normal mass ratios. If you want a dV in the 8km/s range, you have to go nuclear.

That said, a transfer to Jool done right can cost less than 3km/s. Depart from Munar orbit, where you refuel your ship testing out the ISRU system in the process (I have a feeling you will find your miner is too tiny to refuel your ship in any reasonable amount of flights). Then you start with a ~800m/s free kick by dropping down to kerbin from Munar altitude, and the transfer will be less than 2 km/s. Once you are getting close to the Jool system, fiddle with the trajectory so Tylo or Layhte captures you into a stable orbit with a gravity assist for free, and from then on you are on your own, but you have a whole system of moons to play with gravity assists and aerobrakes that should make things cheap is you know your stuff.

A few tricks to save on mass launched to Jool would be to have a propulsion section that doubles as miner, and to have the landers do multiple duty (a Tylo lander upper stage can be a great lander for Pol, Bop, or Val). That way the "mothership" is only the habitation section and part of the fuel tanks.

Rune. This makes me remember my Medusa.

[Azimech]

Awesome ship, almost a space station with engines!

[Jakalth]

@selfish_meme Lowering TWR(by shutting down some of the engines) has no effect on delta-v. It's a more fundimental problem with the craft. It's total mass consists of 80% fuel, and that fuel weighs more then what you'll get in return from propulsion. So it's gone way past the point of diminishing returns. But that's not the point of the craft, the point of it is it's sheer size. heh Was worth checking though, so thank you.

@FlipNascar I'll look into different engines and see if I can reconfigure the propulsion section for longer range. But with the craft being 1,400+ tons, there isn't much that will be able to push it with real gusto. And after testing what selfish_meme suggested, shows that the craft needs close too 12,000 units of thrust.

@Rune Thank you. That is some good info you provided. But as it stands, mass of the landers is not really much of an issue. The total mass of the craft so completely dwarfs the mass of the tiny landers I have planned that their total mass will have negligible effects on the crafts delta-V. That and I have plenty of room for multiple craft being brought along for the ride. I wouldn't mind hooking this craft up with nerv engines, if it wasn't for the fact that it would require at least 150 of them to push this craft around with any form of speed. It's just too big for that... But following your suggestion on orbits just might do the trick. I just hope the sloo......ooow maneuvering of this craft doesn't become too much of an issue for orbit changes.

I might end up going with a much lighter and simpler Jool transfer vehicle some time, but I built this craft and I want to do something with it first. And I believe I can muster the delta-V to at least insert into the Jool system.

[selfish_meme]

@selfish_meme Lowering TWR(by shutting down some of the engines) has no effect on delta-v. It's a more fundimental problem with the craft. It's total mass consists of 80% fuel, and that fuel weighs more then what you'll get in return from propulsion. So it's gone way past the point of diminishing returns. But that's not the point of the craft, the point of it is it's sheer size. heh Was worth checking though, so thank you.

@FlipNascar I'll look into different engines and see if I can reconfigure the propulsion section for longer range. But with the craft being 1,400+ tons, there isn't much that will be able to push it with real gusto. And after testing what selfish_meme suggested, shows that the craft needs close too 12,000 units of thrust.

@Rune Thank you. That is some good info you provided. But as it stands, mass of the landers is not really much of an issue. The total mass of the craft so completely dwarfs the mass of the tiny landers I have planned that their total mass will have negligible effects on the crafts delta-V. That and I have plenty of room for multiple craft being brought along for the ride. I wouldn't mind hooking this craft up with nerv engines, if it wasn't for the fact that it would require at least 150 of them to push this craft around with any form of speed. It's just too big for that... But following your suggestion on orbits just might do the trick. I just hope the sloo......ooow maneuvering of this craft doesn't become too much of an issue for orbit changes.

I might end up going with a much lighter and simpler Jool transfer vehicle some time, but I built this craft and I want to do something with it first. And I believe I can muster the delta-V to at least insert into the Jool system.

What I meant by TWR was the efficiency of your engines or ISP, like Rune said, you have a very high TWR indicating low ISP engines. I just said it in a much worse way without ads

[Jakalth]

What I meant by TWR was the efficiency of your engines or ISP, like Rune said, you have a very high TWR indicating low ISP engines. I just said it in a much worse way without ads

Alright, I get what you meant now. I can be a bit slow on the pickup sometimes. I'll be looking into different engine configurations to see if I can get its range increased. We'll see, if I can get even another 500 delta-V out of it, that will help.

[Jakalth]

Well, found a fatal flaw in the craft as it stands. with the 5 mammoth engines for power, it has more thrust then the craft can handle. During the try to send it Jool, the engines got so excited to finally be used that they flew strait through the fuel section, when I went full throttle, and sent the crew section into a tumble. not much survived the spontaneous dis-assembly that followed... Just a little too much thrust for the ship too handle... O_o

If I swapped out the engines for something more efficient and lowered it's TWR by half or more it might still be viable... but that's a lot of work just to fix a fundamental flaw with the craft. At least the crew, and "most" of the crew segment survived intact. Only lost the docking ports, the primary solar arrays, and half the comm tower of that segment. Nothing survived intact of the rest of the craft.

One thing to be noted, until I went full throttle, the docking port setup stayed mostly rigid with only minimal flexing of the craft. And when I say mostly rigid, I mean I was only seeing about a 1 deg angle of flex. Even while turning, with full RCS and SAS control, there was never more then 1 deg of flex in the craft, and it dampened down to basicly unnoticable within a few seconds of finishing the maneuver.

[Rune]

Well, found a fatal flaw in the craft as it stands. with the 5 mammoth engines for power, it has more thrust then the craft can handle. During the try to send it Jool, the engines got so excited to finally be used that they flew strait through the fuel section, when I went full throttle, and sent the crew section into a tumble. not much survived the spontaneous dis-assembly that followed... Just a little too much thrust for the ship too handle... O_o

If I swapped out the engines for something more efficient and lowered it's TWR by half or more it might still be viable... but that's a lot of work just to fix a fundamental flaw with the craft. At least the crew, and "most" of the crew segment survived intact. Only lost the docking ports, the primary solar arrays, and half the comm tower of that segment. Nothing survived intact of the rest of the craft.

One thing to be noted, until I went full throttle, the docking port setup stayed mostly rigid with only minimal flexing of the craft. And when I say mostly rigid, I mean I was only seeing about a 1 deg angle of flex. Even while turning, with full RCS and SAS control, there was never more then 1 deg of flex in the craft, and it dampened down to basicly unnoticable within a few seconds of finishing the maneuver.

Yup, the great problem with big motherships in KSP, they make you realize that everything you knew about rockets assumes that they are rigid bodies, and those behemoths surely aren't. So how do you handle the wet noodle? It's easy, you don't try to push it, because it will compress: you pull it so it wants to stay straight.

That is why I put the Medusa link, so you can see an example of puller mothership. They work great!! And since Squad fixed the gimbal code in 1.0 so it takes into account the position of CoM, you don't even have to disable gimbals. But since I am setting up an expedition to Moho, I can actually offer up-to-date examples now! This is one of my Base Packs, prepared for transfer by adding some fuel and a couple of Drive Pods (the ore tanks are great to hold reaction mass for the nukes, that thing has MR>2 and upwards of 5km/s):

Another good example of the configuration is the manned ship for the same Moho trip. Built around one of my Von Braun ring stations, I slapped a few drives around the circle, and hung all heavy payloads and the "small" chemical SSTO that will serve as lander behind it.

There are like four five single docking port connections joining the SSTO to the "drive section", one of them is 1.25m, and yet I have no fears that it will stay on target like a champ, even with a couple more ore tanks in tow like it needs to make the dV for the transfer (Kerbin-Moho is a hell of a costly transfer, let me tell you). For starters, the thrust is nothing to write home about, I'm looking at around 1m/s², so it will be a long burn out, broken in several passes. Low force, low stress on the frame. But even if I had high TWR chemical engines, the worst that could happen is that the docking ports stretch a bit, because the structure is dynamically stable: if it get misaligned, the force resulting from the imbalance tends to align it back. Hope that helps you build the next one!

Rune. And now you know why I haven't released anything new lately: I'm busy using the stuff I already have.

Edited September 23, 2015 by Rune

[Jakalth]

Nice. Once again, that is some very useful info Rune. Much appreciated. Maybe I can resurrect the Driad as a puller ship instead of a pusher after I figure out a few things with my current project. Oh, is the ore tanks a higher density fuel source then the lf/ox tanks? IF so, that might be useful for making a more compact design.

Currently working on a replacement for the Driad, for the Jool run. I used your suggestion of having the drive section double as a heavy lander and the refueler. Ends up, it is possible to have a nuke powered lander that can land on Pol, Bop, and Vall, and still have the delta-V to bring most of it's fuel back to the orbiting mothership. Good call on that one Rune. But, right now, the craft is a pusher design. Although, less then half of the primary thrust actually comes from the rear multi-role segment. I have over half of the thrust being contributed from the central fuel segment. So it is a bit of a hybrid push/pull craft. The front crew segment is quite light and will only be hauling two Lathe drop ssto's so it might still be safe enough to pull this off. This craft is about half the size of the Driad and has less then 300 parts atm. 6,200 m/s of delta-v as well, unloaded. Will be quite a bit less once loaded, guessing around 5k.

Now I just need to build a nice reusable tug for de-orbiting the ssto's once I reach Lathe(RCS powered or lf/ox fueled, not sure yet). The ssto's fuel load is very small and they are relatively tiny compaired to what I've been building lately. Also made them completely amphibious with a 70m/s landing speed on water and jettison-able floats for easier to-orbit burns.

The tug only needs to shrug around a max of 30 tons while de-orbiting the ssto's.

[KSACheese]

Wow. Just. Wow.

[Rune]

Nice. Once again, that is some very useful info Rune. Much appreciated. Maybe I can resurrect the Driad as a puller ship instead of a pusher after I figure out a few things with my current project. Oh, is the ore tanks a higher density fuel source then the lf/ox tanks? IF so, that might be useful for making a more compact design.

Currently working on a replacement for the Driad, for the Jool run. I used your suggestion of having the drive section double as a heavy lander and the refueler. Ends up, it is possible to have a nuke powered lander that can land on Pol, Bop, and Vall, and still have the delta-V to bring most of it's fuel back to the orbiting mothership. Good call on that one Rune. But, right now, the craft is a pusher design. Although, less then half of the primary thrust actually comes from the rear multi-role segment. I have over half of the thrust being contributed from the central fuel segment. So it is a bit of a hybrid push/pull craft. The front crew segment is quite light and will only be hauling two Lathe drop ssto's so it might still be safe enough to pull this off. This craft is about half the size of the Driad and has less then 300 parts atm. 6,200 m/s of delta-v as well, unloaded. Will be quite a bit less once loaded, guessing around 5k.

Now I just need to build a nice reusable tug for de-orbiting the ssto's once I reach Lathe(RCS powered or lf/ox fueled, not sure yet). The ssto's fuel load is very small and they are relatively tiny compaired to what I've been building lately. Also made them completely amphibious with a 70m/s landing speed on water and jettison-able floats for easier to-orbit burns.

The tug only needs to shrug around a max of 30 tons while de-orbiting the ssto's.

Glad to be of help! It's the reason we are here after all, learn from one another. Hope to see the new one soon!

And yeah, Ore is denser, especially much denser than liquid fuel. Consider a single big ore tank holds about 15mT of ore that can be 100% converted into liquid fuel! As comparison, a Big Red holds 32mT of LFO mix, so you can have almost the same mass in half the space, even for LFO. The trouble is lugging the refinery along, that's 4mT extra, of course, and unless you want truly awful TWR, a buffer "holding tank" to make the burns in a reasonable time (a single refinery will only allow a single nuke to run at ~2/3rds thrust indefinitely on its output). In my case, since the refineries were part of the payload... it would have been a shame to launch with the tanks empty, considering the effort I made setting up mining bases.

Rune. I haven't looked at tankage ratios, because I don't want to find out at which point ore tanks with a refinery get a better fraction than fuel tanks. So cheaty...