Small drills vs asteroids

[Sharpy]

Yesterday's events made me think... just how lossy are the small drills?

I used a large ISRU and two small drills to mine a class D asteroid. There was a two-star engineer on board. I didn't manage to fill up one orange tank before the asteroid was completely depleted - and it wasn't some fuel-poor weirdo, it started with good 80% mass usable as fuel.

That feels like way too little off asteroid this size. Are the drills at fault, depleting the asteroids at excessive pace while producing pitiful amount of ore?

[Streetwind]

Pretty sure there is no yield difference between the two drills. The small one produces more heat for the same extraction rate, has a lower extraction rate, and doesn't work at all unless concentration is greater than 2.5% (always true on an asteroid). The engineer Kerbal also only affects extraction rate.

The thing that makes a yield difference is the refinery... the small one has a 90% loss rate. But you said you used the large one, which has 0% loss, so... yeah, I got nothing.

I mean, there used to be a bug where you got much less output if you ran engines at the same time as the ISRU. Not sure if that is still a thing or not. Also, you said you were filling a tank.

[Leftotian]

The only thing that wastes ore is small isru. Drills are always produce 1:1, they can't waste any ore. D asteroid will give you 5-20 orange tanks of fuel. 

[Sharpy]

22 minutes ago, Streetwind said:

I mean, there used to be a bug where you got much less output if you ran engines at the same time as the ISRU. Not sure if that is still a thing or not. Also, you said you were filling a tank.

It's still there - as drills outpace ISRU while ore tanks are full, they keep depleting the asteroid at full rate while ISRU produces fuel at whatever rate it does. Since usually ISRU outpaces the drills, the situation normally occurs when engines are burning slowly (and while ISRU works, engines are throttled to like 1% their power, yet another bug.)

Say, drills produce 0.1 units of ore per 'game tick'. ISRU converts that to 0.1 units of fuel normally, keeping the ore tank empty. But if the ore tank is full, and the fuel tank misses 0.03 units of fuel due to engine burn, ISRU takes 0.03 units of ore, makes 0.03 units of fuel, and then drill take 0.1 unit of ore from the asteroid and fill up the missing 0.03 units in the tank. Also, if drills manage to put 1 unit of ore per tick, while ISRU can pick 0.1, 0.9 gets wasted - but that would require way more drills than ISRUs. Other than that, just make sure your engines are off. And fuel cells. Fuel cells can truly murder an asteroid because they draw minimal amount of fuel, and are hard to notice, plus usually needed for operation of the machinery. So, drilling with full tanks and active fuel cell (even just one small) drains the asteroid at nearly the same pace as with empty tanks.

 

But in my case the ore tank was empty, the fuel tank was empty, the big ISRU worked just fine, with proper cooling, and the small drills worked normally, with cooling active, too, and engines were most definitely off.