This is Rover. He refuels ships by biting them and wagging his tail (drilling).

Rover acts very differently depending on whether or not I'm watching him. Warping through a full day while he's under my direct control gives me X Liquid Fuel. But, if a day goes by when I'm gone, I get less than 1/6 X.

This problem appears to be independent of whether I supplement production with solar panels or use fuel cells. It seems, "away" production is limited by ore storage.

See that little ore tank on his head? The problem goes away if I use three large ore storage tanks instead. They add considerable weight to Rover, and in theory shouldn't be necessary, because the converter entirely consumes the ore output of the drills.

Has anyone else experienced this behavior? Are there any mods that correct this?

Rover 16T

  • 1
    +1, note that in regards to the part of your question asking for mods; recommendations are off-topic here, but the basis of your question is more so about why this happens so it should be alright.
    – Timmy Jim
    Commented Apr 21, 2017 at 16:44
  • And I can't ask if anything is a bug or not either here. Where are the rules because I can't find them anywhere on this site. Is it OK if I ask here, or do I have to post a question on meta?
    – PJ7
    Commented Apr 21, 2017 at 18:08
  • The help link at the bottom of the page.
    – Timmy Jim
    Commented Apr 21, 2017 at 18:08
  • There is also the help drop down at the top right. It's fairly common for most websites to be designed this way.
    – Timmy Jim
    Commented Apr 21, 2017 at 18:12

1 Answer 1


At high time accelerations (above 1000x) the game simplifies many processes, especially for "distant craft". No sun tracking (if you were in a shadow of a mountain, out of power, the power won't return if the craft returns into sunlight), no craft-craft collision tracking (that one's true even for meager 5x), and in particular discrete steps per resource get bigger.

Say, at 1x your craft processes stored ore at 0.2 unit per tick, then mines to refill, at 0.1 unit of ore per "game tick". When you set time to 10000x this doesn't mean the game calculates 10,000 ticks in the time it calculated one. It just multiplies the base values: 0.2x10,000 = 2000 ore used per game tick, converted to fuel, then 0.1x10,000 = 1000 ore mined.

Except it checks against capacities too. If your tank contains only 300 ore, all of it will be used up, and you're getting fuel out of 300 units ore instead of 2000. Then your drill provides 2000 ore, but there's tankage for 300, so the game stores 300, discarding the rest. For all practical purposes, you're operating at ~1/6th the original rate.

And what's worse, if it was an asteroid, not returning it! Just discarding, depleting the asteroid at full speed, while producing far less fuel. This is also the case when your production outpaces consumption; your ISRU removes 5 units, drills provide 20 units, but there's only room for 5 units... even though you have 10,000 units of ore storage, but not enough EMPTY.

Yep, I don't think there are mods to work around that. Your options are to fast-forward slower, or provide enough tank volume... or just accept the losses.

  • Well that certainly looks like a bug, and an easily fixable one too - put consumers before storage in this type of calculation and the problem goes away. I wonder how easy it would be to mod that "deep" into the game engine.
    – PJ7
    Commented Apr 24, 2017 at 19:41
  • @PJ7: it's not that easily fixable. It's a separate loop run of production from all available producers, that looks for empty storage, and a separate loop of consumption for all consumers, looking for full storage. There is no mechanism that would feed output of a producer directly into a consumer. At least for ore - it seems electric charge doesn't exactly follow these rules (solar batteries can feed EC directly to devices that need them, no battery needed).
    – SF.
    Commented Apr 24, 2017 at 22:49
  • 1
    As a practical consideration regarding design to take this situation into account, be aware that the maximum "tick" in computing the next ore/other resource levels is 6 hours. So if your tank can hold six hours of resource output, you won't get bitten by this. Source: forum.kerbalspaceprogram.com/index.php?/topic/…
    – Atario
    Commented Sep 3, 2017 at 7:38

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