On refueling and replica missions

[Jestersage]

My understanding of refueling in KSP is that it involves capturing an asteroid or landing on a planet/moon, and then mine, then covert them into fuel, right?

If so, was there any real life plans (on paper only, duh) to Mars or Venus that also involve refueling outside of Earth?

If not, I am trying to see if it's possible to do a Direct Ascent to Duna/Eve without refueling.

Edited August 5, 2016 by Jestersage

[pandaman]

15 minutes ago, Jestersage said:

My understanding of refueling in KSP is that it involves capturing an asteroid or landing on a planet/moon, and then mine, then covert them into fuel, right?

If so, was there any real life plans (on paper only, duh) to Duna or Eve that also involve refueling outside of Earth?

Mining  and converting to fuel IRL on Duna or Eve no.  Maybe Mars or Venus though.

(Sorry, couldn't resist that one).

I believe they have ideas of separating hydrogen and oxygen from water ice on the Moon to use as fuel, so I guess that's a possibility anywhere that has water or water ice.

[MaxwellsDemon]

Several versions of Mars-mission proposals are based on sending a 'fuel-factory' lander ahead of the crewed mission to prepare return-trip fuel.  It hasn't actually been done, at least yet, but it's not merely science fiction; I understand that it's considered possible.   I think there's still debate over the practicalities and whether it's actually an economical way to do it.   

[dafidge9898]

1 hour ago, Jestersage said:

If so, was there any real life plans (on paper only, duh) to Mars or Venus that also involve refueling outside of Earth?

There was one, actually. It's known as Mars Direct, and it planned on using the Sabatier reaction to create methane to use as fuel, and then electrolysis with the remaining water to create oxygen to use as oxidizer. 

Here's the wikipedia article: https://en.wikipedia.org/wiki/Mars_Direct#Mission_scenario

Edited August 5, 2016 by dafidge9898
Electrolysis part

[Finox]

There were some ideas floated in NASA for the proposed Mars Sample Return Mission to refuel the return rocket on Mars.   The mission has not yet been flown, or funded, but there were several ideas to use the CO2 in the Martian air as fuel.   I recall one was essentially a mini version of the Mars Direct proposal, another involved turning CO2 into carbon monoxide and oxygen and using that as a (rather poor) rocket fuel.   The most interesting one was to bring borane to use as fuel and then simply fill a tank with Martian air.   Borane will burn with CO2 and give you an ISP of around 300, which isn't half bad considering that your "oxidizer" is free.

[Firemetal]

Well refueling can also be sending another vessel over and docking/grabbing it and transferring the fuel over. That is a different kind of refueling but it is refueling.

[Jestersage]

So there's no way to go direct ascent with a lab to Duna without refueling?

[polytechnique]

1 hour ago, Jestersage said:

So there's no way to go direct ascent with a lab to Duna without refueling?

No, no, you can do it... it just may not be the most efficient way of doing it. Refueling on the surface can save you lots of money and size on lifter hardware and fuel... but you don't have to do it if you don't have access to the technology.

[Snark]

3 hours ago, Jestersage said:

So there's no way to go direct ascent with a lab to Duna without refueling?

Sure you can do it. After all, mining wasn't introduced to the game until 1.0, and plenty of folks explored the solar system before then.

Besides, going to Duna only takes very slightly more dV than going to the Mun, if you do it right.

[Alshain]

5 hours ago, Jestersage said:

So there's no way to go direct ascent with a lab to Duna without refueling?

It's just a matter of building a lifter big enough to carry both the lab and the fuel to get you there.  It's certainly possible.  I don't use the stock ISRU at all, and don't even use Kethane as much as I used to, yet I can get large interplanetary transports out to Eeloo, and back again without refueling.

Edited August 6, 2016 by Alshain

[Sharpy]

12 hours ago, Snark said:

Besides, going to Duna only takes very slightly more dV than going to the Mun, if you do it right.

Return, though, takes only little less than launch to the Mun, while return from the Mun is really cheap. Still, the roundtrip is probably less than one-way trip to Laythe. And Duna's low pressure allows you to use vacuum engines like the nuke, no need to haul heavy, inefficient Boars or Mammoths.

[Majorjim!]

The mars portion of the cancelled constellation mission was to have the ascent lander refuelled from converting the martian atmosphere. Interesting that none i know of use any kind of drilling. It is all atmospheric conversion. 

I wish KSP had atmospheric conversion parts. Drilling is dumb. 

Edited August 6, 2016 by Majorjim!

[Hodari]

20 hours ago, Majorjim! said:

Interesting that none i know of use any kind of drilling. It is all atmospheric conversion.

Probably because anything based on drilling would require you to know exactly what the composition is of the rocks you're drilling in...and that will vary greatly based on exactly where you land.  With the atmosphere, you more or less know what you're going to get.

[Majorjim!]

Just now, Hodari said:

Probably because anything based on drilling would require you to know exactly what the composition is of the rocks you're drilling in...and that will vary greatly based on exactly where you land.  With the atmosphere, you more or less know what you're going to get.

Yeah true, although you could have differing concentrations of atmospheric gas at different locations too.

[magnemoe]

4 hours ago, Majorjim! said:

Yeah true, although you could have differing concentrations of atmospheric gas at different locations too.

Not much, atmosphere is pretty much the same anywhere, exception is top of volcanoes and smokestacks. 
Drilling is harder but more interesting on Moon or astroids, could also be used on Mars as we know its plenty of permafrost. 
You also have the options to use both, combining co2 on mars with co2 in the atmosphere to make methane and oxygen.