Mining asteroids

Later in the game there are three units called:

Robo-Miners (you need tech-level 10 in minerals-extraction,
Robo-Farmers (level ten in organics-extraction),
Robo-Rad-Extractors (level ten in radioactive-extraction)

If you have developed the tech the units are available and you can put them in a ship and send it out for mining.

Do the ships have to periodically return or do they automatically and continuously provide the resources while staying in place?

Build something like a large satellite or a starbase/space station in the asteroid's sector, place resource gatherers and a source of supplies. The base/satellite will then automatically gather resources every turn. It doesn't even use the supplies, it just has to have some. That is, I think so.

Note: it DOES use supplies, allbeit a little.
When the supplies run out, mining stops; So don't forget a solar pannel.

~Myrath

Yeah now you mention it you're right. I just remembered a game where I had lots of mining bases and I gave them supply gatherers so they wouldn't all drain the supplies the system's supply base gave out.

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"Good morning, Pooh Bear," said Eeyore gloomily. "If it /is/ a good morning," he said. "Which I doubt," said he.

Thanks everyone, you've helped to clear up one of my earliest misconceptions about the game. Time to supercharge my empire...

Another somewhat related question - In a finite resources game, how long does it usually take for the resources of a planet (or asteroid) to be depleted?

Well it appears to be a little different. I am waiting for a PBW game to start which will have finite resources so of course I gave it a try first. Rather than have facilities that say something like gathers 1000kt a year, and the planet has a concentration of say 150%, so 1500kt a year, you have facilities that again gathers 1000kt a year, but in this case the planet might be like this 2mT minerals, 750kt organics, 3mT radioactives. Amount gathered for each facility doesn't change for each planet but each turn the amount on the planet goes down. So in this case if it was an organics gatherer it guess it would last 750 turns. Much longer if it was another resource. In a normal game if you want organics you'd be looking for a planet with a high concentration. With finite resources you'd want one filled with it.

Sounds like a game would be over well before the resources run out.

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"Good morning, Pooh Bear," said Eeyore gloomily. "If it /is/ a good morning," he said. "Which I doubt," said he.

Wouldn't crystal tech allow you to put off your depletion by generating artificial resources? (I forget the precise facility involved)

Hopefully two weeks old doesn't count as Necromancy.

Interesting, Solar collectors would appear to be a bigger advantage. That hadn't occurred to me, and they do better the more stars the system has. I am playing a crystal game and I use solar collectors in ssytems that only have one star and it does well. Good use of a planet that has cocnetrations like 15%, 30%, 35%.

Make sure you have enough resource gatherers to offset the maintenance cost of the vehicle...