The Solar System... In Terms Of Propellant Farming

[Spacescifi]

As long as rocketry is relied upon, tanker spaceships will also be relied upon. It is easier to refuel off a tanker than ISRU.

ISRU bases could also supply the tankers when the time came.

 

Yet I was curious just what each planet offered in terms of propellant.

 

Earth: Everything but hard to access.

Moon: Maybe a bit of ice but not a lot compared to other options. Plenty of  stuff for solid boosters though.

Mars: Methalox. What else not sure.

Mercury: Not a clue, but I reckon any barren world you can use to maje solid boosters.

 

Venus: Plenty of options Some harder to get than others.

 

Neptune: Ditto.

Jupiter: Ditto.

Saturn: Ditto

 

Whatdo you know on this?

 

 

 

 

Edited August 2, 2021 by Spacescifi

[GoSlash27]

Spacescifi,

7 hours ago, Spacescifi said:

Mercury: Not a clue, but I reckon any barren world you can use to maje solid boosters.

All chemical rockets come down to hydrogen and oxygen, even SRBs. Any planet/ body that doesn't have both elements in some form in abundance is a dead end. Mercury does have both elements, but I wouldn't call them abundant.

Best,

-Slashy

[Rakaydos]

6 minutes ago, GoSlash27 said:

Spacescifi,

All chemical rockets come down to hydrogen and oxygen, even SRBs. Any planet/ body that doesn't have both elements in some form in abundance is a dead end. Mercury does have both elements, but I wouldn't call them abundant.

Best,

-Slashy

I've heard good things about aluminum/oxygen SRBs.

[Spacescifi]

2 hours ago, Rakaydos said:

I've heard good things about aluminum/oxygen SRBs.

 

Moon has plenty of that. Moon great for SRB fuel. Chemical is not as muchm

[GoSlash27]

2 hours ago, Rakaydos said:

I've heard good things about aluminum/oxygen SRBs.

While aluminum is pyrophoric, it can't actually ignite without first burning hydrogen. You still need a flammable binder.

Best,

-Slashy

[Rakaydos]

5 minutes ago, GoSlash27 said:

While aluminum is pyrophoric, it can't actually ignite without first burning hydrogen. You still need a flammable binder.

Best,

-Slashy

Clearly, your ignition oxidiser isnt sufficently energetic. Put enough Florine atoms in, and anything will burn.

[magnemoe]

Guess Mercury has some polar ice if the axial tilt is as low as I think. 
Venus problem is getting stuff out of its atmosphere. 
Outer solar system, more ice than you can use and so cold hydrogen is easier to handle.  Downside is that solar is inefficient 
 

[MKI]

What does "propellant farming" even look like on a Gas Giant? Sure all of them are literally made of fuel... but what would "farming" look like? 

 

[jimmymcgoochie]

Venus’ atmosphere is almost entirely CO2 and it also has some water vapour clouds above the deadly acid soup of its lower atmosphere, so put some really big lighter than air balloons in there (CO2 is denser than normal air and hydrogen could be used since there’s no danger of explosions due to a lack of oxygen) with atmospheric harvesters to hoover up CO2 and H2O then turn them into usable resources like methane, hydrogen and oxygen which could then be launched to space. Getting the rockets back to one of the floating platforms might be a bit more difficult, but if you’re building large scale infrastructure in the Venusian atmosphere you have bigger challenges to solve first. Also, don’t fall off…

Mars has a few resources that could be useful- a thin but usable CO2 atmosphere and water ice at least at the poles (and possibly under the ground elsewhere) again allow for some fuel production; there’s also all that rusty dust full of iron that could theoretically be turned into steel using carbon from the atmosphere, allowing more complex pieces of machinery or equipment to be made on the surface. The lower gravity and thinner atmosphere are good for launching to orbit too. If Phobos and/or Deimos have any water on/in them then they’d be even better places to set up shop due to the miniscule gravity and the fact that they’re both already orbiting Mars, so need much less fuel to reach low Mars orbit than launching from its surface.

Titan is another obvious option- water and some hydrocarbons like methane and ethane are readily available on its surface, no need to even chill that methane down as it’s already a liquid. Lack of solar energy due to distance from the Sun and the thick atmosphere could be compensated for with nuclear power, either fission or (assuming the technology exists) fusion powered by gas harvesting from Saturn’s exosphere. Some form of SSTO aircraft would be the obvious choice of launch vehicle, taking advantage of the atmosphere rather than fighting against it; maybe an air-breathing nuclear engine would be the best option since that atmosphere is nitrogen and has next to no oxygen in it.

For most small bodies beyond the asteroid belt including most of the gas giants’ moons, water ice is in abundant supply but solar power is not. Bring your own reactors and just melt down an entire moon then electrolyse it for hydrolox.

[kerbiloid]

Mercury is for the ion drives.
Cesium, too.

1 hour ago, MKI said:

What does "propellant farming" even look like on a Gas Giant? Sure all of them are literally made of fuel... but what would "farming" look like? 

At least, it requires high-end nukes or fusionukes just to reach the orbit.

***

Any piece of rock is a propellant, if throw it fast.

[MKI]

21 minutes ago, kerbiloid said:

At least, it requires high-end nukes or fusionukes just to reach the orbit.

I get it that "rockets" are needed to get the propellant back into orbit to use elsewhere, but what about the actual "refinery".

I can image something like some giant floating city in the clouds doing "refining" of the gases all around when "in the atmosphere".  Except is that even physically possible, or would such a setup only be in Star Wars via "anti-gravity magic"?

Or would it be something like giant blimps that can carry a whole refinery + launch/landing platforms for rockets? 

Or something totally different, like a high eccentricity setup where the refinery/ship enters the atmosphere only temporary to get some gasses and then flies back into a higher orbit?

 

 

 

 

[Spacescifi]

1 hour ago, jimmymcgoochie said:

Venus’ atmosphere is almost entirely CO2 and it also has some water vapour clouds above the deadly acid soup of its lower atmosphere, so put some really big lighter than air balloons in there (CO2 is denser than normal air and hydrogen could be used since there’s no danger of explosions due to a lack of oxygen) with atmospheric harvesters to hoover up CO2 and H2O then turn them into usable resources like methane, hydrogen and oxygen which could then be launched to space. Getting the rockets back to one of the floating platforms might be a bit more difficult, but if you’re building large scale infrastructure in the Venusian atmosphere you have bigger challenges to solve first. Also, don’t fall off…

Mars has a few resources that could be useful- a thin but usable CO2 atmosphere and water ice at least at the poles (and possibly under the ground elsewhere) again allow for some fuel production; there’s also all that rusty dust full of iron that could theoretically be turned into steel using carbon from the atmosphere, allowing more complex pieces of machinery or equipment to be made on the surface. The lower gravity and thinner atmosphere are good for launching to orbit too. If Phobos and/or Deimos have any water on/in them then they’d be even better places to set up shop due to the miniscule gravity and the fact that they’re both already orbiting Mars, so need much less fuel to reach low Mars orbit than launching from its surface.

Titan is another obvious option- water and some hydrocarbons like methane and ethane are readily available on its surface, no need to even chill that methane down as it’s already a liquid. Lack of solar energy due to distance from the Sun and the thick atmosphere could be compensated for with nuclear power, either fission or (assuming the technology exists) fusion powered by gas harvesting from Saturn’s exosphere. Some form of SSTO aircraft would be the obvious choice of launch vehicle, taking advantage of the atmosphere rather than fighting against it; maybe an air-breathing nuclear engine would be the best option since that atmosphere is nitrogen and has next to no oxygen in it.

For most small bodies beyond the asteroid belt including most of the gas giants’ moons, water ice is in abundant supply but solar power is not. Bring your own reactors and just melt down an entire moon then electrolyse it for hydrolox.

 

Thanks.

 

So all gas planets have a little oxygen?

 

Seems like they are full of everything else but oxygen.

 

How would do about propellant farming on Uranus, Saturn, or Jupiter? Same way as Titan or Venus?

Jupiter has 2g gravity too... so that's an issue.

 

Seems like gas worlds either tons of carbon dioxide or hydrogen, while oxygen which is related to living things is either low or nonexistant.

I don't know what each gas world has, but I know some are rich in carbon dioxide and hydrogen.

 

 

4 minutes ago, MKI said:

I get it that "rockets" are needed to get the propellant back into orbit to use elsewhere, but what about the actual "refinery".

I can image something like some giant floating city in the clouds doing "refining" of the gases all around when "in the atmosphere".  Except is that even physically possible, or would such a setup only be in Star Wars via "anti-gravity magic"?

Or would it be something like giant blimps that can carry a whole refinery + launch/landing platforms for rockets? 

Or something totally different, like a high eccentricity setup where the refinery/ship enters the atmosphere only temporary to get some gasses and then flies back into a higher orbit?

 

 

 

 

 

A balloon platform might work, so lobg acid clouds or high winds don't rip it apart. Which is an issue on certain gassy worlds. Jupiter has a storm bigger than Earth called the red spot, and I reckon I read that other gassy worlds have storm issues too.

[Rakaydos]

4 minutes ago, MKI said:

I get it that "rockets" are needed to get the propellant back into orbit to use elsewhere, but what about the actual "refinery".

I can image something like some giant floating city in the clouds doing "refining" of the gases all around when "in the atmosphere".  Except is that even physically possible, or would such a setup only be in Star Wars via "anti-gravity magic"?

Or would it be something like giant blimps that can carry a whole refinery + launch/landing platforms for rockets? 

Or something totally different, like a high eccentricity setup where the refinery/ship enters the atmosphere only temporary to get some gasses and then flies back into a higher orbit?

There's a concept involving an "air" breathing ion drive, at the upper edges of the exopshere, that can compensate for the drag of flying that low, while scooping atmospheric gasses and storing them to be delivered elsewhere once the tanks are full. The earth based version of this concept would orbit at around 150-200 km- I do not know what the equivilant would be for gas giants.

[kerbiloid]

4 minutes ago, MKI said:

I can image something like some giant floating city in the clouds doing "refining" of the gases all around when "in the atmosphere".  Except is that even physically possible, or would such a setup only be in Star Wars via "anti-gravity magic"?

Compared to the amount of gas to be pumped through the scoop, it's probably easier to keep it floating by throwing down part of that gas, previously heated by the onboard reactor (powering the scoop).

Then periodically raise the thrust and get into orbit.

The reactor should be fuelde by the same gas, so separated the hydrogen isotopes, and use D+³He, as this is a kind of aneutronic fusion.

So, probably it will be looking like a floating funnel, sucking the gas from top and levitating on the torch of hot hydrogen from the nozzle below..

[Nuke]

there are some forms of electric propulsion that can use a wide array of remass options.

some craft will be designed for specific high efficiency propellant, mostly used on warships and deep space explorers, perhaps freighters and especially tankers. so these will use hydrogen primarily, perhaps helium and other lightweight fuels for maximum isp. 

meanwhile your rock hoppers will use versatile engines that can run on practically anything they might find as a byproduct on an asteroid. they take a hit on their specific impulse, but if they can find enough remass to get to the next rock, they can stay in business. they might not only have versatile engine but multiple sets of other options. say multi-fuel capable mpd thrusters, simple chemical engines, or even things like mass drivers. its a lot of dead weight to carry around (along with refinery and mining equipment) but you only have to get to the next rock or commodity station. 

[Spacescifi]

39 minutes ago, Nuke said:

there are some forms of electric propulsion that can use a wide array of remass options.

some craft will be designed for specific high efficiency propellant, mostly used on warships and deep space explorers, perhaps freighters and especially tankers. so these will use hydrogen primarily, perhaps helium and other lightweight fuels for maximum isp. 

meanwhile your rock hoppers will use versatile engines that can run on practically anything they might find as a byproduct on an asteroid. they take a hit on their specific impulse, but if they can find enough remass to get to the next rock, they can stay in business. they might not only have versatile engine but multiple sets of other options. say multi-fuel capable mpd thrusters, simple chemical engines, or even things like mass drivers. its a lot of dead weight to carry around (along with refinery and mining equipment) but you only have to get to the next rock or commodity station. 

 

Rockhoppers be uncrewed. Too slow to warrant crew.

The fastest burning thristy ships be crewed.

Only thing faster burning and more thirsty be military.

[Nuke]

i still i think it works out. versatility is a tradeoff with efficiency.  sometimes you need it and other times you dont. i agree that the miitary are going to hog up most of the high efficiency remass for their own needs. hydrogen is pretty abundant though so there is still plenty for other classes of ships. but you are probibly going to need to get it at either a major base, or a fuel depot. like skimming gas giants will be your main source, and you will have tankers bring it as far out of the gravity well as possible.  either to a station or to a moon with a large orbit and a little gravity. or in the deep solar system where you have a lot of water ice (explorers would need to be self refueling and would work similar to the rock hoppers, but without strip mining the whole thing or refining every scrap of material as their main product is survey charts for the rock hoppers). in the astreroids though, you are just going to have whatever volatiles you can find in the rocks. 

Edited August 3, 2021 by Nuke

[kerbiloid]

And we should find an AM asteroid to mine, as it's too expensive and dangerous to manufacture and store it.

Though, an AM Orion charge could require anti-tungsten, and thus an anti-iron pusher plate.

[GoSlash27]

On 8/2/2021 at 11:48 AM, kerbiloid said:

Mercury is for the ion drives.
Cesium, too.

At least, it requires high-end nukes or fusionukes just to reach the orbit.

***

Any piece of rock is a propellant, if throw it fast.

That's one thing Mercury has an abundance of; the raw materials to make solar panels and surface solar intensity.

Best,

-Slashy