IRSU - In Orbit or Landed?

[mousethethird]

So, I wanna set up colonies/refueling stations all over Ike and Duna. What would prove more efficient/least difficult? I've already made a pseudo-list of pros/cons of each.

• ISRU Refining in Orbit
  

+Dont have to worry about lining up docking ports on the ground.

+Less delta-v spent.

+Craft not meant for landing have a source of refueling

+Overall simpler design

+Able to move into other orbits

-Generally heavy

-Wobbly, with stock joint strength (given that a linear design is chosen)

-High part count

-To refuel, you need to go through the hassle of rendezvous and docking

-Ore needs to be ferried to orbit, instead of converted on the surface after its mined

• ISRU Refining on land
  

+Immobile, so no fuel spent moving

+Hell, maybe even mobile on land with wheels

+All the heaviness is "negated" by being grounded (not a problem, imo)

+Could be built into a ground base

+No need for ferrying

+Stable

+Depending on the celestial body, more sunlight, therefore more power

-Hard to land on some celestial bodies

-Spend fuel to refuel other craft

-Lining up docking ports on the ground

And of course, this is just a list off the top of my head. Any others want to add to the list for either? I myself lean more towards in orbit ISRU, but I really can't build any efficient designs that encompass what im looking for. Suggestions would be nice, and I'll add pros/cons to the list as I see them; as for actually building the thing, I'll take suggestions there too.

Edit: I more-or-less got the answer I was looking for, but feel free to add more stuff, designs in particular.

Edited May 20, 2015 by mousethethird

[Goomblah]

I use mining trucks that contain solar panels and fuel cells, a small LF+O tank, a large ore container, an ISRU unit, and four drills. With an engineer on board, it can mine and refine ore efficiently enough to keep itself running constantly off of part of its fuel production via the fuel cells, while still churning out fuel at a pretty fast rate. It is wheeled for mobility, and has four "Thud" radial thrusters to allow it to land safely from orbit. It's designed to dock with a special fuel carrier which is essentially a flying orange tank; that orange tank then uses part of the produced fuel to reach orbit and dock with a waiting space station, where it offloads almost all of its fuel, leaving just enough to deorbit. It then lands as close as possible to a miner, which drives up to it and docks, then begins to fill the tank up all over again.

The main advantage with surface refining is that you can use the fuel production capabilities of the lander alongside fuel cells to keep the miner running constantly; day/night is no longer even an issue. Just keep churning endlessly, filling up orange tank after orange tank. I don't think anyone is advocating that you should land your ships to refuel them; especially with interplanetary ships with low TWR, it's simply not possible. I think the main discussion is: Haul fuel up to orbit, already refined; or carry up the ore and refine it in orbit.

[Captain Sierra]

Some tips:

The klaw can be used to connect vehicles together on the ground easily. I have one on the back of my tanker rover for connecting to my wellheads.

Notice the lack of docking ports on the sides of the wellhead.

Ore is mass neutral. This means your efficiency does not change whether you haul raw ore to orbit and refine there, or refine on the ground and haul fuel to orbit.

A few things you do NOT want to do: haul drills or refineries on your tanker shuttles. These are both heavy and will disadvantage you considerably. My personal suggestion would be to use a wellhead like in my image and haul product to orbit from that. Whether the wellhead or an orbital station handles the refining is up to you. An efficient mining operation will have both ground and orbital elements for different reasons. I'd be happy to explain my current Munar architecture but that would get lengthy, so by request only for sake of brevity.

[peachoftree]

If you dont want to line up docking ports, just use this.

[mousethethird]

I think the main discussion is: Haul fuel up to orbit, already refined; or carry up the ore and refine it in orbit.

The way you worded it really clicked; A lot of my problems didnt take fuel ferrying into account. It seems kinda weird to me to spend fuel to put more fuel into orbit. I am absolutely awful at building land bases/ground docking, so I feel In orbit ISRU is the way to go. Unless of course there's a way to make ground docking less of a hassle to line up and etc

edit: I didnt even think of the claw. my palm is placed firmly on my face.

I'd be happy to explain my current Munar architecture but that would get lengthy, so by request only for sake of brevity.

Please do! I'd love to see what others have going for this.

Edited May 19, 2015 by mousethethird

[Laie]

Why bother with trucks?

(note the placement of the lander can -- landing this thing in IVA is fun!)

[Captain Sierra]

Please do! I'd love to see what others have going for this.

Okay, since you asked.

The current Munar architecture is split up into a lot of small parts as a lag preventative. Doing this lets me have a lot more equipment on the ground.

The Wellheads:

First up is these wellheads I'm dropping down. They're capable of landing, can store up to 45,000 liters of raw ore, and have enough solar power to run themselves constantly, daylight providing. These wellheads are my extraction points and they are scattered all around the main bases in the area. 4 drills provides acceptable extraction rates while untended.

The Tankers:

The tankers cart ore from the wellheads and, when necessary, fuel back to them to allow relocation. The tankers deliver the ore to a central fuel depot & refining station. Each ore tanker can empty two whole wellheads before being full. They can drive at up to 80kph on level-ish ground. The current base fuel depot that is there now looks like this:

This has already been landed, but alas no good screenshots.

The hub there serves as secondary storage and primary power generation.

The Refining Base:

The refining base, mentioned above, handles processing and storage of raw ore into fuel. I also plan to expand it with limited extraction capabilities. This base is where the shuttles will haul fuel up to orbit to a munar fueling depot.

Orbital Station:

The fuel is carted up to an orbital station (not yet built) for additional storage. This is the gateway from the operation to the rest of the Kerbin SoI. This station will likely also have ore refining capabilities. The operation as a whole is meant to ship fuel, but should be able to ship raw ore if fuel reserves are insufficient.

Other Components:

The kerbals responsible for operating the tankers and keeping everything in working order will be staying at a separate MKS base (I use USI life support) out of physics range from everything else (a common theme; everything is out of physics range of everything else).

There are also unmanned tanker shuttles which haul materials to and from orbit.

Operation:

Whenever a wellhead is full, a tanker rover is dispatched to unload it and those nearby (which are likely nearing full). The tanker rover brings the crude back to the refining base where it is stored. When the base's LFO reserves are cut into, it refines some of the held crude into fuel to replenish the reserves. The orbital station serves as the fuel point for munar crafts, as well as tanker tugs hauling fuel down to my very-LKO fueling stations (designed for SSTOs). When that has empty fuel cans delivered or when its on-board fuel reserves take a sizable hit, the shuttles deliver more fuel from the base to the station.

Efficiency:

The key to efficiency here is that, while this is a many-step process from extraction to usability, fuel is only expended in one leg of the process, shipping to orbit. For lower gravity worlds like Minmus, non-fuel-consuming wheeled vehicles are not a viable option, but the low gravity makes sub-orbital hopping far more viable. On the Mun, the gravity is high enough to make rovers usable, which I leveraged to minimize the amount of fuel utilized in what is my largest, highest yield ISRU operation yet.

[mousethethird]

Whooph. Quite a complex operation. My planned mining operation on Ike was a lot simpler.

• An ISRU converter is attached to an interplanetary ship in orbit of Ike. Docking ports, holding ore ferries with drills, a Duna rover, a Duna Lander, and a habitat that stays on Duna. How all of that would get to Duna is beyond me, its one of the design challenges Im having right now. Multiple launches, yeah, but I like all-in-one launches.
  
• Ship drops off Ore ferry to Ike, it fills up, it takes off and rendezvous with the station, and everything gets refueled. Repeat as necessary.
  
• Other three get dropped on Duna, with only the lander going back and forth. Other habitat components get shipped from Kerbin every so often.
  
• Maybe, if I can design it properly, refueling station (mining and conversion direct on surface) on Duna.
  

Eventually, if I can get a working design, I'll end up sending this type of mission to Jool. I guess the entire op is a test run for that, where fuel would be most needed for moon-hopping out by Jool.

[Captain Sierra]

Here's how I'd run that:

Multiple launches from kerbin to load everything on to a properly large mothership. Mothership transfers from Kerbin to Duna. Mothership drops station & Duna gear in LDO on arrival. Mothership boosts up to Ike & begins fueling operations. Mothership returns to LDO, picks up the lander returning to orbit, & departs for Kerbin.

The only major inefficiency in your plan is you're hauling the drills to and from orbit every time you come back with a load of ore. Unlike, say, Kethane, where drills are light, stock drills are heavy. Ore may be mass neutral but hauling around the mining & refining equipment is not. Downside is there isn't much of a way to fix that without majorly complicating the mission architecture.

[mousethethird]

Downside is there isn't much of a way to fix that without majorly complicating the mission architecture.

I just thought of this;

A two section mining rig -- One half, holding the drill, batteries+solar/rtg, a probe core, structure stuffs and an upwards facing docking port. The other half, some radial engines, a fuel tank, an ore container, another probe core, bat+solar/rtg, and a downward facing port. That way, the drill can stay on the surface, and just the ore goes into orbit.

Quick and sloppy, but it fufills its duty. Of course, I could make it more aesthetically pleasing with some time, but it's function over form for me right now. Missing are rcs thrusters for the top section.

(legs are from MRS, rest is Ven's stock revamp btw)

Edited May 20, 2015 by mousethethird

[Captain Sierra]

I just thought of this;

A two section mining rig -- One half, holding the drill, batteries+solar/rtg, a probe core, structure stuffs and an upwards facing docking port. The other half, some radial engines, a fuel tank, an ore container, another probe core, bat+solar/rtg, and a downward facing port. That way, the drill can stay on the surface, and just the ore goes into orbit.

This requires you do do a perfect precision landing. You have to set down right on top of that docking port. The difficulties that may cause you might make it worthwhile to just haul the drills. Even if this were my mission, I probably wouldn't do that.

[Requia]

Am I the only one that just hauls the entire processing assembly around? There's free fuel for a return trip wherever you're going. Full ore tanks are basically fuel tanks that pump really slowly.

Edited May 20, 2015 by Requia

[mousethethird]

This requires you do do a perfect precision landing. You have to set down right on top of that docking port. The difficulties that may cause you might make it worthwhile to just haul the drills. Even if this were my mission, I probably wouldn't do that.

You are correct; note, this is Ike thats gonna get drilled into. With rcs lateral thrusting and high twr at the surface (with Ike's low-ish gravity) it's not too difficult, though yeah, probably too much hassle for a simple ore collection. Throwing some wheels and a claw on the upper half might prove easier.

(btw, really diggin' the support and kindness dude)

[Wanderfound]

The all-in-one option can work:

That's more about refuelling itself than providing fuel for others, though.

[Captain Sierra]

You are correct; note, this is Ike thats gonna get drilled into. With rcs lateral thrusting and high twr at the surface (with Ike's low-ish gravity) it's not too difficult, though yeah, probably too much hassle for a simple ore collection. Throwing some wheels and a claw on the upper half might prove easier.

(btw, really diggin' the support and kindness dude)

I'm a bit of a resourcing guru. Been playing with Kethane since I bought the game back in 0.20.2, switched to Karbonite in 0.24, and now giving stock a shakedown in 1.0.2.

Wanderfound just posted an excellent example of a design which benefits from being all-in-one.

You said mothership so I envision something like this (image from Parameciumkid, not me) but smaller.

Thats not something you can just land on Ike & refuel.

[mousethethird]

While that thing is absolutely beautiful (and oh my god, it has portable stations? ), it would leave my computer smoking and sputtering. Ive cobbled together a more modest design for a Kerbin-Duna transfer, with my proposed back and forth lander and ISRU converter built into it. Since I still havent figured out my ore collection method or Duna Surface Stuff, it's not moving anywhere for right now. Its more or less just going to go into its orbit and stay there as a station, either in Ike or Duna orbit. The way it's currently put together, it requires mass to be balanced around the sides to keep it from rotating (or powerful enough reaction wheels). Its a low part thing, not meant to be complicated or extravagant. Also note - Docking port on the butt end of the lander. I think thats where my Ore collector with sit, with etc on the four other ports. And of course, modular to a certain degree, but not Jool-grade.

It's a pretty little thing, imo. The mass balancing is what sets it back, but I purposely didnt want to use cargo bays (I feel they are too big and clunky, and they wobble so much)

Edited May 20, 2015 by mousethethird

[nfpinto]

i have a question.

i use KIS and KAS, and as i nthe picture, i have one rover / miner at minmus surface, and landed a ore transport ship.

Jebediah is on the right ship, while dilsel is on the left. i linkedboth of then with KAS struts (with a conextion point in the ground), and it seems that both turned into one ship so i can pass the ore from one to another.

So, is it possible for me to land several ore containers and link everything, so my miner fullfil all of then? that way, no need to dock everything, just to put near.

[Dilli]

I figured ISRU Refining in orbit by a medium sized refueling craft is better than on the surface. The main reasons are:

You can have a tanker that docks / rescues stranded craft and provides the fuel they need (as opposed to carrying a bit of every fuel);

The Tanker will have good range while being efficient (need more delta V -> convert ore to the required fuel while in flight);

[KerikBalm]

With ISRU, I can forgo efficiency for the sake of convenience.... I just haul the ISRU refinery back and forth to/from orbit.

So... your points

* ISRU Refining in Orbit

+Dont have to worry about lining up docking ports on the ground.

- Didn't have to worry about that anyway (claw, or just take the refinery with you up to orbit, but you refined on the ground)

+ Less delta-v spent.

- I don't see how you can say that... its not even less fuel spent ... if the ISRU equipment is less than the extra mass you have to set aside for fuel for the ascent (which I already calculated, for Moho, is the case, in another thread)

+ Craft not meant for landing have a source of refueling

- Can have that anyway with an orbital fuel depot. If your surface refinery is capable of landing, its capable of getting into orbit... just build one that can get into orbit with a lot of fuel, and it can refine and then launch itself as a temporary fuel depot

+Overall simpler design

- Not really, now you need seperate a lander which has ore tanks and fuel tanks, and you need to get the ratio right, and its always hauling dead weight either in the form of empty ore tanks on landing, or empty fuel tanks after ascent.

+Able to move into other orbits

- same thing is true of surface refining + launching fuel to orbit. Right now I have a fuel depot at Mun in equatorial orbit (career, pre-ISRU unlock), when I want to send a lander to the poles, I land my ISRU craft *anywhere there is ore*, fill it up, and launch t into the orbit I want (polar)... now I've got a temporary fuel depot for my science lander to refuel at after visiting the poles.

-Generally heavy

+ as if surface refineries aren't?

-Wobbly, with stock joint strength (given that a linear design is chosen)

+ ?? why, its 1x 2.5 m part, that you can dock to any fuel tanks/ore tanks that serve as your propellant depot

-High part count

+ ?? why, its 1x 2.5 m part + solar panel

- To refuel, you need to go through the hassle of rendezvous and docking

+ I do that anyway, and I refine (mostly) on the surface. Transfering fuel on the surface is worse IMO.

-Ore needs to be ferried to orbit, instead of converted on the surface after its mined

+ Isn't this just restating what this idea is? I still use orbital fuel depots, even with surface refining.

*ISRU Refining on land

+Immobile, so no fuel spent moving

- Nope, not immobile, If you can drop it down safely from orbit, you can put it back into orbit after a refuel (exception: designs that land on parachute)

+Hell, maybe even mobile on land with wheels

- How is being both immobile and mobile a + ?

+All the heaviness is "negated" by being grounded (not a problem, imo)

- no its not negated, that mass still matters to launch to LKO, to transfer, and to safely deorbit at the target destination. Also, why is it particularly heavy?

+Could be built into a ground base

- Ok, so what?

+No need for ferrying

+Stable

- Orbits are very stable in KSP too, I don't see this as a plus

+Depending on the celestial body, more sunlight, therefore more power

- how? In all cases you have light and dark cycles. All that matters is the period. A slowly rotating body will have a long day and a long night (mun for instance), whereas in orbit, nights are rarely longer than 30 minutes.

- Hard to land on some celestial bodies

+ You need to land anyway to drill the Ore. Orbital refining implies regular landings of an ore tanker.

-Spend fuel to refuel other craft

+ You do that anyway, spending fuel to lift ore up

-Lining up docking ports on the ground

+ Use the claw, or just take the whole refinery to orbit.

What it comes down to is detailed in this post:

http://forum.kerbalspaceprogram.com/threads/121794-Has-anyone-managed-to-create-a-miner-capable-of-net-gain-to-orbit-on-Moho?p=1950595&viewfull=1#post1950595

If no surface refining, your craft needs to bring down the fuel for deorbit+ the fuel for ascent with full ore tanks.

If there is surface refining, your craft needs to bring down only the fuel for deorbit.

That severely cuts into the payload fraction, and for some bodies (ex: moho) makes net gain very difficult.

The downside of having to bring fuel for the ascent again will result in setting aside more mass for that fuel (+ the ore needed to replace that fuel after it is consumed) than the mass of the convertor.

Using the convertor on the surface is more efficient, and it makes operations simple.

Land: mine and convert, launch.... done, your craft is in orbit, ready to go somewhere else or provide fuel to others.

You can have a dedicated surface refiner to improve efficiency, and that makes it more complex.

In the case of a single craft that lands, refines, and goes back into orbit:

For the sake of efficiency, it might as well fill up the ore tanks before going to orbit... why carry empty ore tanks up?

Thus it might as well refine that ore in orbit when there is space in its other tanks.

For maximal efficiency (ie payload fraction of the tanker that goes too and from the surface), you'd surface refine and have thr drills, ISRU converter, and the ore tanks stay on the surface.

[mousethethird]

With ISRU, I can forgo efficiency for the sake of convenience.... I just haul the ISRU refinery back and forth to/from orbit.

You do make good points. For me, it's all about the fuel; the more there is that can be used, the better. After some research, yeah, ground conversion does sound like the most simple and efficient operation. I don't feel that shipping an all-in-one is necessary, but fuel getting sent up instead ore seems like my best option. I'll get on redesigning my station/mothership to accomodate.

If any tips on making either ground refineries or balanced motherships could be thrown out there, I would appreciate it. The ISRU conv doesn't have surface attach, which is a serious setback for me making it land-able.

I'm just gonna get stock joint reinforcement and try not to worry about wobble.

Also just real quick: all the pros/cons listed in op are specifically for me. I'm not the best designer.

Edited May 21, 2015 by mousethethird

[Geschosskopf]

You do make good points. For me, it's all about the fuel; the more there is that can be used, the better. After some research, yeah, ground conversion does sound like the most simple and efficient operation. I don't feel that shipping an all-in-one is necessary, but fuel getting sent up instead ore seems like my best option. I'll get on redesigning my station/mothership to accomodate.

If any tips on making either ground refineries or balanced motherships could be thrown out there, I would appreciate it. The ISRU conv doesn't have surface attach, which is a serious setback for me making it land-able.

Refining on the ground and moving product to space is the way to go if you measure efficiency as units of fuel delivered to orbit per unit of ore mined. But there are other ways measure "efficiency" (or perhaps "fun quotient" instead), depending on what's important to you and all methods that bring together the necessary parts and resources work. So use whatever you feel most comfortable with .

As to design tips....

1. Ground-based ISRU base can be tiny.

All it needs are drills, the ISRU, enough power, and 1 each of the smallest tanks for ore and each type of product. You do not need huge ground storage tanks for either ore or product. The big product tanks are part of the consumer vehicle, which you connect (dock, claw, KAS) to the base before starting production. So, you connect consumer and base, and start the drills. As soon as a small amount of ore gets in the tank, start the ISRU. As soon as a small amount of product appears in its tank, start pumping it into the consumer.

The system will be limited by whichever process is slowest (drilling, refining, or pumping). Usually, it's drilling, so what you'll see eventually is nothing at all in any of the base's tanks but the tanks in the consumer gradually filling up as ore is converted and pumped out as product as fast as it's coming out of the ground. NOTE: This only works in places where you have good ore on a good landing field. But in this case, because the base is small, it can easily be a rover. This allows you to land the consumer anywhere in the vicinity and drive the base up to it, which simplifies both flying and connecting.

2. Mothership?

I'm usually not a fan of putting everything in 1 basket. First, 1 failure can doom the whole mission. Second, big ships are slow, hard to maneuver, and laggy. Besides, why go to all the trouble of setting up a refueling system, only to pack it up and take it somewhere else? So what I prefer to do is send out flotillas of small ships each with a specific role. Each individual ship is thus easier to deal with and cheaper. Plus, most of them won't be coming home anyway. They'll be permanent fuel systems at the various planets, which can be used later by other expeditions. But of course, OTOH, huge motherships are cool .

[mousethethird]

With motherships, you get everything a mission needs all in one big, laggy pack. All benefits of a station, all slapped together for transport, landing, and in this case, refuelling. I guess it's more the thought of realism than anything else for me; you wouldn't stuff a few humans into an Orion without a habitat for em on a 9 month journey to Mars. But, for probes, there's not a problem sending them to other places individually, other than me having to oversee them individually. I might just do that.

As far as bringing refuelling things with me, if I do that, I can "hop" from planet to planet. If I refuel around Duna, I can send a fully fueled ship to Dres more efficiently than direct from Kerbin. And then, more efficiently from Dres to Jool. Kerbin-Jool direct ~ 9000 dV with Kerb launch included. From Dres, only about ~4700 dV. With refuelling at every stop, I could effectively do a grand tour if I wanted.

Edited May 21, 2015 by mousethethird

[Goomblah]

If any tips on making either ground refineries or balanced motherships could be thrown out there, I would appreciate it. The ISRU conv doesn't have surface attach, which is a serious setback for me making it land-able.

I put half of the inline components on one end of the converter, and half on the other so I have radial/surface mounting points on either end:

Regarding motherships and anything that will be pulling heavy loads around:

Avoid mounting docking ports radially, unless you are double- or triple-docking along the main axis of acceleration. I learned this with my first cargo hauler:

This was not a good idea. Those fuel tanks bend and flop all over the place while the ship is under acceleration, and docking ports do not like torque forces very much. Whenever possible, connect payloads so they are parallel to the direction of thrust; docking ports are much more resistant to tension and compression forces than angular ones.

[Mesklin]

It is depend where you are planing to do mining operations.

On Minmus like bodies best place for refueling station with ISRU is on orbit and shuttles with drills for mining and transporting ore from surface to station. Under best decision I am meaning more simple and enough efficient. Theoretically, maximum efficiency you will achieve if you place ISRU units on orbit and on surface for minimizing fuel consumption by shuttles (you need fuel reservoir on shuttle only for one operation: ascend or descend).

On atmosphere-less bodies like Mun and heavier (and for Dune) optimal way is placing ISRU unit on both side of supply chain (some sort of mobile ISRU base or/and mobile tankers with rovers for refueling shuttles on the ground)

On planets with oxygen (Laythe and Kerbin) best place for ISRU is also on orbit (landing cost is close to zero) and SSTO is the the best decision for mining and transporting ore to orbit, especially on Laythe.

[nfpinto]

behooold!

Frigate with a lot of space to a lot of things

red main conteiner is LFO, ores ( that giante bay closes xD), converter and stuff. has a nuclear generator