What can i really get from an asteroid?

[GRM]

I just got to an asteroid and really only science i could get was surface sample. Is there anything i miss? Do i need to take it back to kerbin? or is it just kinda useless?

[Chibbity]

You can mine ore from it and turn it into fuel.

[andylaugel]

If you play career mode, you may get contracts to put an untouched asteroid in a certain orbit.

[killer_Foxy]

build a base on it

[Jupiter3927]

Space potatoes are only really useful for fuel and a bit of science.
Sometimes they look cool so you can give Kerbin (or Duna or whatever) a cool new moon.
You can recover them on Kerbin for some funds too.

[Goro san]

Capture big one, park it on low orbit and youll have nice long term refuling station on your hands.

[strask]

Originally posted by Goro san:

Capture big one, park it on low orbit and youll have nice long term refuling station on your hands.

That's a great idea, but in my experience the fuel you can get out of even a big 'roid is pretty limited, at least compared to the amount of fuel you probably spent trying to capture it.

[Goro san]

Originally posted by strask:

Originally posted by Goro san:

Capture big one, park it on low orbit and youll have nice long term refuling station on your hands.

That's a great idea, but in my experience the fuel you can get out of even a big 'roid is pretty limited, at least compared to the amount of fuel you probably spent trying to capture it.

This is my capture vessel:
http://steamcommunity.com/sharedfiles/filedetails/?id=1181042422
Once shipped to orbit it has fuel storage of 3000dV (5 nuclear engines). And is permanently left there.
DeltaV it has can intrecept (and usually do full caprure manuvers) just about anything, if it doesnt it is flying rafinery and can refuel while manuvering from said asteroid.

So yeah after its in orbit more or less infinite fuel, all you need are space rocks to catch.

PS, yes, it is fully stock (i only use grafical/interface mods).

[RoofCat]

Originally posted by strask:

Originally posted by Goro san:

Capture big one, park it on low orbit and youll have nice long term refuling station on your hands.

That's a great idea, but in my experience the fuel you can get out of even a big 'roid is pretty limited, at least compared to the amount of fuel you probably spent trying to capture it.

how about this - 2600t left on high Minmus orbit. E class asteroid.
It was sent to Minmus due to contract, but I have one with 2000+t on perfect 80-80km LKO too.
http://steamcommunity.com/sharedfiles/filedetails/?id=834671528

or even better with Nukes and distributed solar solutions to avoid shadows during burns.
This was an early test, you need only 2 Nukes in fact since conversion is limited anyway. D class asteroid here.
http://steamcommunity.com/sharedfiles/filedetails/?id=846581518
I definitely do recommend pulling solutions instead of pushing ones. Keep in mind though all engines need some free space to work. Also you don't need large tanks on asteroid miner. You can convert ore into fuel straight into docked ship tanks as needed.

There are 3500t asteroids (class E) flying around. I wouldn't recommend them due to time needed for all burns, but D class with slightly below 2000t is just perfect. Rather quick capture, plenty of fuel. I don't know what type of monster ships you build, but I didn't need much fuel for my upper stages. And once launched, those babies can operate forever. Just catch new asteroid once one is depleted.

You can calculate delta v the same way you do it for ships. It all depends on wet/dry mass. Since asteroids are so big and you use rather small miners (you really should), they get close to theoretical limits for each engine type corrected by the dry mass of asteroid itself. Best asteroids ar with 92% ore or those colorful ones with even 95%.

Lets say you have 3500t, 90% asteroid and your mining ship has 50t dry mass (which is plenty for those babies). So your total mass is 3550t and total dry mass is 400t.
Terriers:
345*9.81*ln(3550/400) = 7389m/s
Nukes:
800*9.81*ln(3550/400) = 17134m/s
Since most asteroids are close to Kerbin orbit, you need just ~1000m/s to capture and circulize them. Which doesn't sound a lot compared to those numbers above, right? You can aerobrake btw too.

I have sent one "nuclear" D class asteroid passing Kerbin SOI to 5Gm solar orbit (which is slighlty less than Moho if it were on circular orbit). It still had 700t+ "fuel" down there after circularization!
Considering most rescue ships (with 22ooo launch delta v) need only 10..15t of fuel at that point for return, I could operate that solution for years. Except I got bored of those rescues.

And this is how it got launched from Kerbin. Doesn't look too expensive, right?
http://steamcommunity.com/sharedfiles/filedetails/?id=907393592
It's the most advanced version. It has enough delta v to do suicidal 180° intercepts and more. And provides safe return capsules for pilot and enginer with a lot of delta v considering the miner itself. It can return from low solar easily and recover those hard working kerbals back on Kerbin.


Mining asteroids is good business and you only need to build those ships once. They can work forever with new asteroids appearing. The only problem - it is even more interesting (challenging) to do all without them. Like trying to build those 22ooo m/s ships without Xenon (which is too easy) for example. And asteroid redirect burns can take up to 2 days with those small ships on huge E class ones. Which is 12 h. Even with 4x phys time warp it will take 3h realtime. You can watch 2 movies in that time.

[strask]

Originally posted by RoofCat:

Mining asteroids is good business and you only need to build those ships once. They can work forever with new asteroids appearing. The only problem - it is even more interesting (challenging) to do all without them. Like trying to build those 22ooo m/s ships without Xenon (which is too easy) for example. And asteroid redirect burns can take up to 2 days with those small ships on huge E class ones. Which is 12 h. Even with 4x phys time warp it will take 3h realtime. You can watch 2 movies in that time.

And here I think we (well, you) get to the root of my problem -- I can't stand long burns. Five minutes? Ok. But half an hour or more is simply intolerable. Thus, I use more engine than you.

The situation I was recalling involved a class E being sent to munar orbit for a contract. I caught the thing, arranged a Mun intercept, and used quite a large amout of fuel slowing it down to make orbit around Mun, But my engine was the huge 3.75 meter one, not the quad-engined thing but the other one from the same company. And that engine's ISP is nowhere near nukes.

Following achieving Mun orbit, I tried to refuel from mining the asteroid and exhausted its resources. I don't remember specific numbers, but I was unimpressed by the amount of actual LFO produced. It's possible it was a really low % 'roid maybe? Regardless, thanks for your detailed and informative post!

[RoofCat]

that's why you shouldn't build big ones. When your ship is as big as an asteroid, you waste all the captured resources just to move your ship and your launch costs can be extreme. Which makes no sense from a business perspective. It's a mining ship. It is meant to be efficient. Not a death star interstellar tugship trying to move another death star.

There is reason you don't need large engines for this. Large engines use more fuel than even multiple ISRU could provide realtime! ISRU mining ships are about realtime propulsion.
Multiple ISRU would add to the costs with all the rest as well. ISRU can produce enough fuel for 2 Darts to work at 10% or so iirc even if you use 3 flows (240% total performance) on ISRU.

If you use Nukes, you are actually limited to single conversion flow, which reduces available fuel amount and thus propulsion realtime a bit more even considering Nukes need less in the first place due to higher Isp. But you save on cooling and solar that way. Which has mass too. And nukes have more than twice the range. Even though they are expensive too.

I have no idea how many ISRU you would need for Rhino engine to work at 100% while mining. 20..50?

Asteroids are slow. That's what annoyed me, you and I guess everybody else. But if you are into empire builds, they do work fine. Better than surface mining for most bodies in fact.

[Toastie Buns]

Dock them together until you can clearly see them from the ground.

Edit: or you could put them in a semi synchronous orbit around moons and have them pass inches above your bases for COOL factor. The real challenge is avoiding mountains on your buzzing pass, but it'd make your surface base more interesting.

[Astronaut]

You can get a surface sample, funds for redirecting it, and there's a mod called dmagic orbital science that lets you perform asteroid expierments