Is orbital body ore farming viable?

[glen.mack]

So, I've been thinking about this, and while it will obviously vary from craft to craft, I don't think the idea of bringing ore to an orbital station for processing is generally viable anywhere but Minmus, where you can essentially pick it up and throw it into orbit. Am I wrong? (considering doing some general math on the subject and maybe adding it to the wiki)

The problem isn't getting it into orbit, of course, it is using less fuel to get it to orbit than you can make out of the stuff you bring to orbit. (That's before you even consider the "profit" margin) Has anyone done this, or are asteroids the best resource for interplanetary mother-ships? (by that I actually mean ships you never intend to land.)

[Temstar]

No, even on places like Duna you can easily build a surface to orbit tanker that can carry up much more ore than the fuel it uses to land and take off. Remember also that the tanker doesn't have to be fuelled on orbit from the orbital refinery using the ore it carried up - it's easier to just have refining capability on the ground as well and refuel the tanker rocket on the ground while you're filling it with ore.

That, and because atomic rockets.

Edited December 30, 2015 by Temstar

[glen.mack]

14 minutes ago, Temstar said:

No, even on places like Duna you can easily build a surface to orbit tanker that can carry up much more ore than the fuel it uses to land and take off. Remember also that the tanker doesn't have to be fuelled on orbit from the orbital refinery using the ore it carried up - it's easier to just have refining capability on the ground as well and refuel the tanker rocket on the ground while you're filling it with ore.

That, and because atomic rockets.

Could you post an image or craft file? I can't get my head around how you could transport more than 1500 dv worth of ore to orbit...

[Temstar]

Here's something I threw together:



Here's something that you could use to move ore between surface of the Mun and Mun orbit. It burns 25 tons of liquid fuel to move 60 tons of ore up to orbit with plenty of delta-V for both the descent and ascent.

[cantab]

Mun mining seems to be widely enough, I assume it works fine. Consider that you're landing with payload empty, then flying back up with it full, which makes the fuel requirement much less than for landing and returning the same heavy payload.

On paper I can make a ship capable of landing itself on Moho, filling up 15 tons of ore, and launching it back to orbit using 12 tons of LFO overall. (Note that this ship does not carry the mining drills itself, it's just an ore hauler). While a slim margin that is a net gain, and means that shipping ore to orbit is viable almost everywhere.

That said if you refine your ore into fuel on the surface you gain a further advantage, because you don't even need your fuel for the ascent when you land. But you can still refine some on the surface and ship more raw ore into orbit if you like.

[glen.mack]

So I ended up with this non-atmospheric low gravity miner.

After some reading I realised I have been confusing units and mass, and 1 unit of ore represents 10kg, (I thought it was 1kg), so yes, of course it's viable.

Edited December 30, 2015 by glen.mack

[sardia]

If you really need ore based money that badly, why not drive a refinery on kerbin onto the grass. Mine the ore, crack it into liquid fuel, and recover?

[AbacusWizard]

Is there any reason to lift ore from the surface up into orbit? Why not just process it on the surface and bring the fuel up to orbit?

[Shpaget]

17 hours ago, Temstar said:

Here's something I threw together:



Here's something that you could use to move ore between surface of the Mun and Mun orbit. It burns 25 tons of liquid fuel to move 60 tons of ore up to orbit with plenty of delta-V for both the descent and ascent.

That's a beautiful design, but the part clipping bothers me a bit. Care to share the craft file? I'd love to take it apart and examine in detail.

[Foxster]

I haven't yet found a use for mining and converting to fuel on any kind of regular basis. You can make any kind of practical mission in the system with one launch from Kerbin. 

Perhaps if you are into making huge, inefficient but aesthetically pleasing (to you) craft that require lots of fuel or you are using a mod that makes the system bigger then it might be worth doing from a practical point of view. 

However, it is a very interesting thing to do just as a technical challenge.   

[Evanitis]

I tend to place orbital refineries on Minmus and moons of planets that I'm interested in during career games. But I'm a lazy overbuilder who rarely touches math. I prefer to eyeball my designs. Having ISRUs around means I can just throw random crafts towards random bodies and decide what to do once I'm there. If I make mistakes near a mining operation, I usually don't need an interplanetary rescue to fix those. In the worst case scenario, I can just send home the Kerbals with the refinery, or in some loose parts of it.

 

Of course, if you take pleasure in pre-planning and perfectly executing all your missions, mining has no point.

[Temstar]

5 hours ago, Shpaget said:

That's a beautiful design, but the part clipping bothers me a bit. Care to share the craft file? I'd love to take it apart and examine in detail.

If you insist:
http://www./download/ec8hxsnfwqc271h/Ore_Tanker.craft

I threw it together pretty quickly.

[Shpaget]

Thank you.

[glen.mack]

9 hours ago, AbacusWizard said:

Is there any reason to lift ore from the surface up into orbit? Why not just process it on the surface and bring the fuel up to orbit?

The reason is fractional payload.

The ISRU is 4.25 tonnes. If you want to build a vessel just designed to mine and lift fuel to orbit, you build something like Temstar's rig, which could handle another 4.25t and lose barely 5-10 delta V when full.

On my design, it's about 400, not to mention the extra time I'd spend on the surface processing. In a higher orbit, you spend less time blocked from the sun, so more electricity for processing.

I wanted to design it as part of a go anywhere mothership, but the smaller the miner is, the less tolerance it has for an ISRU. If I drop it on the surface, it's gone so I only have 1 refueling stop, using the small converter only gives me the fuel that will fit in the tanks, and that becomes more of a fractional payload if I have to bring tanks too.

My miner is 37t wet, and should be able to bring 30t of ore up from most moons. It has a pretty bad TWR, but, the bonus is I can leave the ore on the mothership, have it process while I go back down to the moon and get more.

 

[Rune]

The avantage of refining on orbit is not having to choose the LF/OX ratio beforehand. Instead, you refine as you use it. Plus, it's the most compact way of storage.

But keeping a refinery on the ground is crucial! That way you fuel the ore tanker with "free" fuel, and don't consider what is in its tanks as payload. Bottom line, even in deep gravity wells you can stockpile ore in orbit, if you can lift off with enough fuel to land again empty afterwards (I.E: not in Tylo)

 

Rune. My latest Grand Tour architecture wouldn't be possible without ISRU.

 

 

 

[AbacusWizard]

I just have a combination mine/refinery with plenty of solar, lots of backup battery power, and a few "landing pads" (docking clamps) on the surface of Minmus, plus a large LF/OX tanker that lands on the landing pad, waits patiently to be filled up with delicious fresh-baked fuel, and then detaches and takes off up to orbit, where it acts as an orbital fuel depot for whatever needs it. When it runs out I land it and repeat the process.

I can see the merit in the "high orbit means more sun exposure" argument, but time isn't too much of a problem here, since I'm mostly using it to refuel either small Minmus landers that don't need all that much fuel anyway or huge interplanetary ships that won't be back for another top-up for a few years anyway.

[KerikBalm]

On 12/31/2015 at 5:24 PM, glen.mack said:

The reason is fractional payload.

The ISRU is 4.25 tonnes. If you want to build a vessel just designed to mine and lift fuel to orbit, you build something like Temstar's rig, which could handle another 4.25t and lose barely 5-10 delta V when full.

On my design, it's about 400, not to mention the extra time I'd spend on the surface processing. In a higher orbit, you spend less time blocked from the sun, so more electricity for processing.

Anytime you need to reserve more than 4.25 tons of fuel for the ascent, it is more efficient to bring the big ISRU with you, than to just bring ore tanks with no ISRU convertor and try to bring unrefined ore to orbit.

To put that in perspective, its a FL-T800 tank... if you use more than that to get your ore up, you should be using an ISRU

^This was the case before we got the mini-ISRU. With the mini ISRU coming in at 1.25 tons, if you use a little more than a FL-T200's worth of fuel to get your ore to orbit, you should carry along this mini ISRU convertor. In this case, your orbiting craft should have the large ISRU, because its fuel:ore yield is 10x higher.

I like to do massive landers with massive tanks on Mun/minmus (a KR-2L is my lander engine), so that I don't have to do lots of landings followed by rendevous to supply fuel depots... the lander basically is a fuel depot. When it gets that big, the ISRU mass is not very significant... and I take mostly fuel to orbit. If using a mini ISRU, you want to take mostly ore to orbit, with just the minimal fuel capacity needed to get that ore to orbit and dock it (otherwise it takes a lot longer, as you'll need to drill 10x more ore to fill up the fuel tanks due to the inefficient conversion of the small convertor)

 

I could do single launch missions to pretty much anywhere, but I like to do orbital assembly... fully reusable systems with tugs, spacious crew compartments for interplanetary journeys/stays on the surface, to put up orbiting fuel depots+ labs around the target planet/moon, and to get results from all science experiments for multiple biomes.... and I often I want to be able to "play around" in the system, not just carefully execute maneuvers, treating every drop of fuel as irreplaceable, so I take ISRU... Except for Tylo, Eve, Moho, and Eeloo.

For moho, I did a fully reusable/recoverable mission, spacious crew accomodations (but not as spacious as my other missions), a full science lander + orbiting fuel depot (but only enough lander fuel for 3.5 landings... so 3 landings... I'm thinking a landing near a biomer border and a suborbital hop could have been more efficient)... but it took me two launches. I didn't use ISRU at all, and departed from LKO, not Mun/Minmus.

I could have reduced the size of the mission even further, in theory, using ion drives for capture at moho and kerbin... but aint nobody got time for that.

Launching this as the payload to LKO without using any fuel... is not easy:

So yea... ISRU could help a lot.

In theory I could have reduced the size even further and still made it fully reusable/recoverable, by having it stage even more, but then the stage recovery/reuse would be a lot more complicated and take years for stages to re-encounter kerbin again.

[suicidejunkie]

How much benefit do you actually see from the refining in orbit in regards to the fuel choices?

I've never seen the advantage, but maybe I'm just looking at a scale that's too large?  3 popsicle tankers, and 6 popsicle fuel depots might just swamp any fluctuations in usage.

[bewing]

9 hours ago, AbacusWizard said:

I can see the merit in the "high orbit means more sun exposure" argument

Even in low orbit, a polar orbit gets you 25% more light than an equatorial orbit in a year (ie. 75% instead of around 50%). Which is still better than a high orbit.

[suicidejunkie]

That math doesn't check out...

An arbitrarily high orbit reduces the occlusion of the sun to an arbitrarily low time per orbit; for extremely high kerbin orbits, the mun will block the sun just as much as kerbin will.

A maximally tight polar orbit will get you 50% sunlight, except on two orbits per year when you're face on to the sun.  A wider polar orbit will leave you in the sun for additional days per year.

For the same orbital distance, the polar orbit will get you a little more sun on average, but I doubt it is worth the extra dV or the much more restricted launch windows required to rendezvous.

[mjl1966]

On 12/31/2015 at 6:00 AM, Foxster said:

I haven't yet found a use for mining and converting to fuel on any kind of regular basis. You can make any kind of practical mission in the system with one launch from Kerbin. 

Perhaps if you are into making huge, inefficient but aesthetically pleasing (to you) craft that require lots of fuel or you are using a mod that makes the system bigger then it might be worth doing from a practical point of view. 

However, it is a very interesting thing to do just as a technical challenge.   

 

On 12/31/2015 at 7:22 AM, Evanitis said:

I tend to place orbital refineries on Minmus and moons of planets that I'm interested in during career games. But I'm a lazy overbuilder who rarely touches math. I prefer to eyeball my designs. Having ISRUs around means I can just throw random crafts towards random bodies and decide what to do once I'm there. If I make mistakes near a mining operation, I usually don't need an interplanetary rescue to fix those. In the worst case scenario, I can just send home the Kerbals with the refinery, or in some loose parts of it.

 

Of course, if you take pleasure in pre-planning and perfectly executing all your missions, mining has no point.

I don't understand how ore can be useless.  The most immediate useful application that comes to mind is leapfrogging.

At first glance, doing something like going to Jool via Duna seems inefficient.  It takes a lot less dV to just go to Jool from LKO.  But, what if you set up a basic fuel colony on Duna?  There are ways via mods to set up a colony that is self sufficient.  At that point, every gram of fuel you refine on Duna is free return on investment.  That being the case, all I have to do to get from Krbal to Jool is put up enough dV go get to Duna, which is way cheaper than the total dV for Jool.  Once I get to Duna, the rest is free dV. 

Same argument for mun: all you need to go anywhere is dV to get to the Mun.  From there, dV is free.

Even if not totally free, I bet the dV mined from Mun and Duna is cheaper in the long run than dV purchased on Kerbin.  This becomes useful if you're objective is to establish and grow permanent colonies

Or does the math totally break down somewhere?  My retort here is conceptual, not analytical.

All this brings to mind an idea for science.  Right now, the only reason to go to Duna is to go there.  But what if each planet had "special" science that is necessary to unlock certain branches in the tech tree?  Hmmmm.......(Or am I the hundredth monkey on this?)

[cantab]

Arriving at or departing from a specific highly-inclined orbit is a nuisance. I wouldn't put my ore refinery in a polar orbit. Maybe something like a 30 degree inclination, that's a good compromise between access from the surface and access to escape/interplanetary trajectories.

[glen.mack]

My interplanetary mother-ship is finished...

Pity getting it all to orbit is going to take twice as long...

[Alshain]

On 12/30/2015 at 7:43 AM, Temstar said:

No, even on places like Duna you can easily build a surface to orbit tanker that can carry up much more ore than the fuel it uses to land and take off. Remember also that the tanker doesn't have to be fuelled on orbit from the orbital refinery using the ore it carried up - it's easier to just have refining capability on the ground as well and refuel the tanker rocket on the ground while you're filling it with ore.

That, and because atomic rockets.

Depends on your definition of 'easier'. I would rather make 20 trips back and forth from the surface than perform one surface docking. 

 

OP, Kethane is much better suited to orbital refining, of course there is still a loss simply from carrying the drills everywhere, but it doesn't have the ridiculous engineer requirements that the crappy stock system does so you can do automated drilling with a probe.  If you want an annoying chore, use stock ISRU.  If you want a fun gameplay mechanic, use Kethane.

Edited January 3, 2016 by Alshain

[KerikBalm]

On 12/31/2015 at 11:16 PM, Rune said:

 Bottom line, even in deep gravity wells you can stockpile ore in orbit, if you can lift off with enough fuel to land again empty afterwards (I.E: not in Tylo)

Except since SSTO landers without ISRU are possibe on Tylo... If you can start in orbit andland on tylo with all the fuel needed to get bck to orbit, then you can start on the surface of tylo (fueled by an ISRU) and get to orbit with all the fuel needed to land again. The margins are pretty small though making it a tedious undertaking to stockpile large amounts of fuel by ISRU on Tylo. It can be done though.

 

14 minutes ago, Alshain said:

Depends on your definition of 'easier'. I would rather make 20 trips back and forth from the surface than perform one surface docking.

Its made much easier with the Claw. I've started using fuel trucks with claws for supplying stuff on the surface of Laythe. Still, I find it much easier to just take the converter everywhere, that way I can land at the closest "hot spot", and not be limited to a location that I've previously placed equipment