Author Topic: Hydrocarbon energy storage and use on the Moon  (Read 1615 times)

Offline bradjensen3

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Hydrocarbon energy storage and use on the Moon
« on: 09/19/2017 08:54 PM »
A major problem for any future lunar colony is energy storage and use.

Most people think of solar energy as the expected energy source for a moon colony, but there is a big problem with this. Nights on the moon ar 13 and a half days long.

In order to power the lunar colony during these almost-two-week-long nights, you would need huge batteries.

This would severely limit the energy use by the colony.

You also have a safety problem here. A disaster affecting the battery backup system could be a death sentence to the people living on the moon.

One possible solution to this is to follow nature's efficient way of storing energy, as hydrocarbons. Even if you primary way of storing solar energy is in batteries, a secondary emergency system of several small diesel generators could burn Rp-1 and lunar-derived oxygen to produce power.

Diesel generators have a great reliability and safety record on the earth and great power to weight ratios.

You could not fuel it on pure oxygen because of the heat factor, but you could cylcle thru some exhaust to thin out the oxygen on the input side of the diesel process.

The cost of getting Rp-1 to the moon would be extremely high since there is a 6.4 km/sec delta v from LEO to the lunar surface.

There are numerous methods of using solar energy to convert CO2 and water back to hydrocarbons.  More are being developed each year.

If you use a mostly-closed cycle, you could store solar energy as hydrocarbons and then reuse the hydrocarbons to generate electricity, produce mechanical motion, and provide CO2 to lunar indoor plantations.

The moon seems to lack carbon, which might be a greater issue than the limited supply of water.

Hydrocarbon fuel may be a good way of bringing both water and carbon to the moon.

Of course, there might be concentrated sources of carbon on the moon.

According to a recent article,

"Three quarters of known asteroids are classed as Carbonaceous or "C-type", dark, carbon-rich objects.

Read more at: https://phys.org/news/2017-09-asteroid.html#jCp"

While the population of near earth asteroids is lower than this percentage, it is very likely that the moon has had numerous impacts of these asteroids over its billions of years of existence.

Much of the carbon in the asteroids has likely combined with the oxygen from moon rocks to make Co2.

Most of that Co2 will have escaped from the moon's gravity well, but a small percentage of it is likely to have become trapped as dry ice in the same permanent-shadow traps that hold much of the moon's water.









Offline Darkseraph

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Re: Hydrocarbon energy storage and use on the Moon
« Reply #1 on: 09/19/2017 09:22 PM »
That's a solution in search of a problem if I've ever seen one.

Would be far simpler to electrolyse water ice into hydrogen and oxygen for use in a fuel cell and skip the weight and expense of converting anything to hydrocarbons. As luck would have it, the conditions on the Moon that allow water to survive in frozen form are also great for storing liquid hydrogen and oxygen with low boil-off.

Or you know, just bring the giant batteries. Batteries have improved a lot in weight and have the added benefit of no moving parts or components that can suddenly depressurize. The regions of the moon that have the water resources also benefit from shorter lunar nights and more consistent access to solar power. It may work out better to just haul lots of solar panels and batteries and place them in sensible locations. Any bases on the Moon are going to be relatively small in the near term, so plain batteries may be perfectly viable.
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Offline savuporo

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Re: Hydrocarbon energy storage and use on the Moon
« Reply #2 on: 09/20/2017 12:07 AM »
"Edison" or Ni-Fe batteries can be made on moon with entirely local resources ( minus trace amount of bismuth and sulfur, the latter being used in modern versions to improve efficiency ). Also note, NiFe batteries are getting  a fresh look as grid-scale storage solution on earth right now, so there's decent synergy for developing this.

Carbon just isn't present, so it's a really bad idea.
« Last Edit: 09/20/2017 12:07 AM by savuporo »
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Offline matterbeam

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Re: Hydrocarbon energy storage and use on the Moon
« Reply #3 on: 09/24/2017 10:00 PM »
That's a solution in search of a problem if I've ever seen one.

Would be far simpler to electrolyse water ice into hydrogen and oxygen for use in a fuel cell and skip the weight and expense of converting anything to hydrocarbons. As luck would have it, the conditions on the Moon that allow water to survive in frozen form are also great for storing liquid hydrogen and oxygen with low boil-off.

And if you really don't want to handle cryogenic volatiles, there's the option of storing hydrogen in the form of hydrogen peroxide and simply freezing it.

Frozen hydrogen peroxide is very stable and auto-decomposes just by warming it.

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Offline stefan r

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Re: Hydrocarbon energy storage and use on the Moon
« Reply #4 on: 09/27/2017 10:35 PM »
Sodium is 0.6% of the surface lunar surface.  Sodium hydride has been seriously proposed as a medium for hydrogen storage on earth.

Hydrocarbons are not efficient.  Crude oil exists in liquid form and can be pumped out of the ground.  Converting electrical energy into hydrocarbons and then extracting electrical energy from the hydro carbons would generate a very small percentage of the original.  A combustion engine like a diesel generator needs to exhaust.  Retaining an exhaust gas adds a lot of complications and machinery.  The already low efficiency would be worse.

Magnesium-Iron alloys will produce Hydrogen when in contact with water.  Hydrogen becomes water after passing through a fuel cell membrane.  With this set up you need only a small amount of hydrogen and no carbon.  Iron and Magnesium are the fifth and sixth most abundant elements (O, Si, Al, Ca).  Pellets of FeMg alloy have been seriously proposed as a fuel for automobiles on earth.  Huge piles of FeMg or the spent pellets could be moved around with bulldozers, conveyor belts, trucks and standard cargo containers.  FeMg does not leak into space.

A serious permanent Lunar colony would benefit form solar panel manufacturing.  That makes construction of a silane (SiH4) plant worth considering.  Not a good method for regular energy storage, but in emergencies you could burn a tank of it.  At high temperatures silane decomposes to silicon and hydrogen.  You could react silane with water and get even more hydrogen. 

Carbon that is imported to the moon is expensive and will be in high demand.  Scarce commodities are not a good choice for fuel. 

Offline matterbeam

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Re: Hydrocarbon energy storage and use on the Moon
« Reply #5 on: 09/27/2017 10:41 PM »
Sodium is 0.6% of the surface lunar surface.  Sodium hydride has been seriously proposed as a medium for hydrogen storage on earth.

Hydrocarbons are not efficient.  Crude oil exists in liquid form and can be pumped out of the ground.  Converting electrical energy into hydrocarbons and then extracting electrical energy from the hydro carbons would generate a very small percentage of the original.  A combustion engine like a diesel generator needs to exhaust.  Retaining an exhaust gas adds a lot of complications and machinery.  The already low efficiency would be worse.

Magnesium-Iron alloys will produce Hydrogen when in contact with water.  Hydrogen becomes water after passing through a fuel cell membrane.  With this set up you need only a small amount of hydrogen and no carbon.  Iron and Magnesium are the fifth and sixth most abundant elements (O, Si, Al, Ca).  Pellets of FeMg alloy have been seriously proposed as a fuel for automobiles on earth.  Huge piles of FeMg or the spent pellets could be moved around with bulldozers, conveyor belts, trucks and standard cargo containers.  FeMg does not leak into space.

A serious permanent Lunar colony would benefit form solar panel manufacturing.  That makes construction of a silane (SiH4) plant worth considering.  Not a good method for regular energy storage, but in emergencies you could burn a tank of it.  At high temperatures silane decomposes to silicon and hydrogen.  You could react silane with water and get even more hydrogen. 

Carbon that is imported to the moon is expensive and will be in high demand.  Scarce commodities are not a good choice for fuel.

I agree with most of your conclusions, but you forget that magnesium and iron will be locked up in oxidized states in the lunar crust. Extracting them releases a lot of oxygen.

If energy storage is the only concern, then recombining the oxygen with the magnesium or iron you've extracted is much more efficient that reacting those elements with another product. By recombining, I mean combustion.
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Re: Hydrocarbon energy storage and use on the Moon
« Reply #6 on: 09/28/2017 12:12 AM »

I agree with most of your conclusions, but you forget that magnesium and iron will be locked up in oxidized states in the lunar crust. Extracting them releases a lot of oxygen.

If energy storage is the only concern, then recombining the oxygen with the magnesium or iron you've extracted is much more efficient that reacting those elements with another product. By recombining, I mean combustion.

Stirling engines and heat pipes can be used to convert heat from burning magnesium into electricity. Stirling convertors are being developed for nuclear power in space.

An alternative to solar panels is solar Stirling. On the Moon the mirrors can be made out of polished iron or aluminium.

Offline stefan r

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Re: Hydrocarbon energy storage and use on the Moon
« Reply #7 on: 09/29/2017 11:01 AM »

I agree with most of your conclusions, but you forget that magnesium and iron will be locked up in oxidized states in the lunar crust. Extracting them releases a lot of oxygen.

If energy storage is the only concern, then recombining the oxygen with the magnesium or iron you've extracted is much more efficient that reacting those elements with another product. By recombining, I mean combustion.

Overall reaction Mg + O -> MgO

Mg H2O -> MgO + H2
2H2 + O2 -> 2H2O

The hydrogen gas can be used in a fuel cell for electricity.  Direct combustion of magnesium would generate a lot of heat.  The original post referred to diesel generators as a substitute for batteries.

Offline Katana

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Re: Hydrocarbon energy storage and use on the Moon
« Reply #8 on: 10/01/2017 10:03 AM »

I agree with most of your conclusions, but you forget that magnesium and iron will be locked up in oxidized states in the lunar crust. Extracting them releases a lot of oxygen.

If energy storage is the only concern, then recombining the oxygen with the magnesium or iron you've extracted is much more efficient that reacting those elements with another product. By recombining, I mean combustion.

Overall reaction Mg + O -> MgO

Mg H2O -> MgO + H2
2H2 + O2 -> 2H2O

The hydrogen gas can be used in a fuel cell for electricity.  Direct combustion of magnesium would generate a lot of heat.  The original post referred to diesel generators as a substitute for batteries.
Mg or Fe works well in batteries

Offline DarkenedOne

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Re: Hydrocarbon energy storage and use on the Moon
« Reply #9 on: 10/01/2017 12:58 PM »
Nuclear power is the solution for powering a Moon base.  It is as simple as that.  All of these elaborate solutions for trying to make solar power work are really just a giant waste of time.

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Re: Hydrocarbon energy storage and use on the Moon
« Reply #10 on: 10/01/2017 01:48 PM »
Nuclear power is the solution for powering a Moon base.  It is as simple as that.  All of these elaborate solutions for trying to make solar power work are really just a giant waste of time.

NASA has been testing the 1kWe Kilopower nuclear reactor at  Los Alamos this summer. Providing any manned rover uses less than 10kW that should be a viable power source.

Online spacenut

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Re: Hydrocarbon energy storage and use on the Moon
« Reply #11 on: 10/01/2017 01:55 PM »
Several years ago Russia developed a 20 ton nuclear power plant that could be used in space.  20 tons isn't that hard to take to the moon. 

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Re: Hydrocarbon energy storage and use on the Moon
« Reply #12 on: 10/01/2017 02:35 PM »
Several years ago Russia developed a 20 ton nuclear power plant that could be used in space.  20 tons isn't that hard to take to the moon. 

it is TODAY but not in the not too distant future.
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Online A_M_Swallow

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Re: Hydrocarbon energy storage and use on the Moon
« Reply #13 on: 10/01/2017 11:52 PM »
Several years ago Russia developed a 20 ton nuclear power plant that could be used in space.  20 tons isn't that hard to take to the moon. 

20 tons could power a base but is too heavy for a rover.

Offline KelvinZero

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Re: Hydrocarbon energy storage and use on the Moon
« Reply #14 on: 10/02/2017 12:06 AM »
I think the title should be changed to CHEMICAL energy storage and use on the moon.

Even with nuclear power there is many possible reasons to want to be able to eventually build batteries or capacitors out local materials. I will be thrilled to see the first electric engine and battery built entirely out of moon resources.

Offline hop

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Re: Hydrocarbon energy storage and use on the Moon
« Reply #15 on: 10/02/2017 03:10 AM »
I think the title should be changed to CHEMICAL energy storage and use on the moon.
Another option is for solar is thermal storage. Storing sufficient energy to last the lunar night might require prohibitive scale, but OTOH reflectors and heat reservoirs could be easier to produce locally than many other options.

I don't really agree with DarkenedOne's assessment that nuclear is the one obvious solution. As ever in space, there are trades, and the winning trade will depend on the details. For large settlements, it will likely be a combination.

Offline savuporo

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Re: Hydrocarbon energy storage and use on the Moon
« Reply #16 on: 10/02/2017 04:24 AM »
Several years ago Russia developed a 20 ton nuclear power plant that could be used in space.  20 tons isn't that hard to take to the moon. 

20 tons could power a base but is too heavy for a rover.

For any mobile thing yes, but as a central power source recharging batteries and/or fuel cells for anything that moves, nuclear option is fine. 20 tons is way too large though.
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Offline stefan r

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Re: Hydrocarbon energy storage and use on the Moon
« Reply #17 on: 10/03/2017 05:45 PM »
Nuclear power is the solution for powering a Moon base.  It is as simple as that.  All of these elaborate solutions for trying to make solar power work are really just a giant waste of time.

A nuclear reactor does not produce electricity or mechanical energy.  The heat from a nuclear reactor usually drives a turbine.  This uses a Carnot cycle.  Nuclear power works on Earth because we have lots of air and water to use as a heat sink.  On the moon you need a large panel to radiate the heat.  There is elaborate plumbing involved.  Radioisotope thermoelectric devices have less plumbing but still need a radiator panel. 

During the night you could dump the nuclear reactor's heat into the station and let the station's surface radiate.  During daylight you need to protect the station from overheating.  That could be done with some sort of screen or maybe a ... panel.

The power needs are going to be variable.  Life support (agriculture?) sets a minimum power output.  Human life support also needs redundant systems.  So around 3 weeks of unused fuel cells and batteries need to be distributed in the habitat modules.  Fuel cells can also provide drinkable water.    Rocket fuel production and metallurgy drain a lot of watts but they can wait for 2 weeks. 

A polar telescope would benefit from constant power supply.  A hot nuclear reactor would have adverse effects.  If you run a power line from the far side of a hill then you can also put solar panels on that hill.

Solar panels are handy when there is no power grid.  A rover can use them while roving for example.  If we are talking about "later" when there is a power grid then you have 24 hours of sunlight. 

Offline TrevorMonty

Re: Hydrocarbon energy storage and use on the Moon
« Reply #18 on: 10/03/2017 07:04 PM »
Beaming power from Solar Satellites is another option. There are power transmission methods laser and microwave. Laser is less efficient around 15%, a 100kW SS would result in 15KW at lunar base. The plus side is base receiver is simple solar panels which can also be used with sunlight.
Microwave is more efficient at >70%, downside is large complex rectenna for receiving power.

A SS at L1 can supply power 24/7 but base has to be on earth side, L2 for darkside. A orbiting SS can supply power intermittently to multiple locations on surface, add enough SS to same orbit and power delivery is 24/7.

The big plus of SS is most of mass of power system is in orbit not on surface.
« Last Edit: 10/03/2017 07:08 PM by TrevorMonty »

Offline Asteroza

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Re: Hydrocarbon energy storage and use on the Moon
« Reply #19 on: 10/03/2017 11:32 PM »
Beaming power from Solar Satellites is another option. There are power transmission methods laser and microwave. Laser is less efficient around 15%, a 100kW SS would result in 15KW at lunar base. The plus side is base receiver is simple solar panels which can also be used with sunlight.
Microwave is more efficient at >70%, downside is large complex rectenna for receiving power.

A SS at L1 can supply power 24/7 but base has to be on earth side, L2 for darkside. A orbiting SS can supply power intermittently to multiple locations on surface, add enough SS to same orbit and power delivery is 24/7.

The big plus of SS is most of mass of power system is in orbit not on surface.

If you are on the lunar near side, direct beaming of power from earth via a minimum of 3 beaming stations is feasible, with a preference for lasers due to associated rectenna size for microwave beaming. Though anybody in between the moon and your beaming station will not like you...

Offline DarkenedOne

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Re: Hydrocarbon energy storage and use on the Moon
« Reply #20 on: 10/04/2017 04:27 PM »
Nuclear power is the solution for powering a Moon base.  It is as simple as that.  All of these elaborate solutions for trying to make solar power work are really just a giant waste of time.

A nuclear reactor does not produce electricity or mechanical energy.  The heat from a nuclear reactor usually drives a turbine.  This uses a Carnot cycle.  Nuclear power works on Earth because we have lots of air and water to use as a heat sink.  On the moon you need a large panel to radiate the heat.  There is elaborate plumbing involved.  Radioisotope thermoelectric devices have less plumbing but still need a radiator panel. 

During the night you could dump the nuclear reactor's heat into the station and let the station's surface radiate.  During daylight you need to protect the station from overheating.  That could be done with some sort of screen or maybe a ... panel.

The power needs are going to be variable.  Life support (agriculture?) sets a minimum power output.  Human life support also needs redundant systems.  So around 3 weeks of unused fuel cells and batteries need to be distributed in the habitat modules.  Fuel cells can also provide drinkable water.    Rocket fuel production and metallurgy drain a lot of watts but they can wait for 2 weeks. 

A polar telescope would benefit from constant power supply.  A hot nuclear reactor would have adverse effects.  If you run a power line from the far side of a hill then you can also put solar panels on that hill.

Solar panels are handy when there is no power grid.  A rover can use them while roving for example.  If we are talking about "later" when there is a power grid then you have 24 hours of sunlight.

First of all there is a simple reason why no instrument has survived on the surface of the Moon or Mars for more than a year without nuclear power.  The thing you need most on the Moon or Mars is heat.  Human habitats especially need large amounts of heat because unlike the electronics in the rovers, which can easily endure freezing temperatures, our core body temperature needs to be remain 98 degrees.  On the moon each night is 13 days long.
 On Mars the nights are about as long as they are on Earth, but the winters are twice as long.  In fact I would be willing to bet you that a permanent habitat on the Moon will likely need more heat energy than electrical energy.  On top of that many of the things you want to do like produce rocket fuel involve endothermic chemical reactions that require heat.  Nuclear cogeneration systems are ideal because they can provide both heat and electricity. 

Secondly have you ever done any calculations to determine what you would need to have "3 weeks" of power in batteries or fuel cells.  You are talking about a ridiculous amount of mass.
« Last Edit: 10/04/2017 04:32 PM by DarkenedOne »

Offline matterbeam

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Re: Hydrocarbon energy storage and use on the Moon
« Reply #21 on: 10/04/2017 04:55 PM »
First of all there is a simple reason why no instrument has survived on the surface of the Moon or Mars for more than a year without nuclear power.  The thing you need most on the Moon or Mars is heat.  Human habitats especially need large amounts of heat because unlike the electronics in the rovers, which can easily endure freezing temperatures, our core body temperature needs to be remain 98 degrees.  On the moon each night is 13 days long.
 On Mars the nights are about as long as they are on Earth, but the winters are twice as long.  In fact I would be willing to bet you that a permanent habitat on the Moon will likely need more heat energy than electrical energy.  On top of that many of the things you want to do like produce rocket fuel involve endothermic chemical reactions that require heat.  Nuclear cogeneration systems are ideal because they can provide both heat and electricity. 

Secondly have you ever done any calculations to determine what you would need to have "3 weeks" of power in batteries or fuel cells.  You are talking about a ridiculous amount of mass.

Energy, or mass. Thickly insulated habitats can drastically reduce the heat leaking out of human-occupied spaces. They will mass a lot, but potentially less than an electrical power supply and heating system to compensate for the heat loss. If the insulation is made out of local materials, then it is the best option.

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Offline hop

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Re: Hydrocarbon energy storage and use on the Moon
« Reply #22 on: 10/04/2017 09:14 PM »
First of all there is a simple reason why no instrument has survived on the surface of the Moon or Mars for more than a year without nuclear power.
Opportunity has been operating on Mars for over 13 years. Admittedly, it does use RHUs for heating some components, but all electrical power comes from solar. The Yutu rover and lander were also solar powered (reportedly with RHUs on the rover at least, but to what extent is unclear). AFAIK, the lander is still operating.

Quote
The thing you need most on the Moon or Mars is heat.
Things like exposed actuators tend to need significant heating, but this is not necessarily true for habitats. You don't have to go very far underground to get a pretty steady temperature. Equipment and humans generate significant waste heat, and vacuum + MLI is a very good insulator.

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Re: Hydrocarbon energy storage and use on the Moon
« Reply #23 on: 10/04/2017 09:24 PM »
@hop
Are you the author of Hop's Blog? http://hopsblog-hop.blogspot.co.uk/
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Offline hop

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Re: Hydrocarbon energy storage and use on the Moon
« Reply #24 on: 10/04/2017 09:30 PM »
Are you the author of Hop's Blog? http://hopsblog-hop.blogspot.co.uk/
Nope. I believe the author is Hop_David on this forum.

Offline DarkenedOne

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Re: Hydrocarbon energy storage and use on the Moon
« Reply #25 on: 10/05/2017 04:14 AM »
First of all there is a simple reason why no instrument has survived on the surface of the Moon or Mars for more than a year without nuclear power.
Opportunity has been operating on Mars for over 13 years. Admittedly, it does use RHUs for heating some components, but all electrical power comes from solar. The Yutu rover and lander were also solar powered (reportedly with RHUs on the rover at least, but to what extent is unclear). AFAIK, the lander is still operating.

Exactly like I said.  Those missions would be practically impossible without the RHUs.  There are weeks where the Mars rovers would not collect enough power to do anything, but the RHUs kept them warm enough to survive.
 With solar power and batteries you simply are not able to generate and store enough energy to keep the rovers warm at nights and during the winter.  With humans it becomes a much bigger issue.  You need much more heat.  You also need a very constant and reliable amount of power. 

Quote
Quote
The thing you need most on the Moon or Mars is heat.
Things like exposed actuators tend to need significant heating, but this is not necessarily true for habitats. You don't have to go very far underground to get a pretty steady temperature. Equipment and humans generate significant waste heat, and vacuum + MLI is a very good insulator.

Sure but the first outposts will not be underground.

Offline hop

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Re: Hydrocarbon energy storage and use on the Moon
« Reply #26 on: 10/05/2017 06:36 AM »
Exactly like I said.  Those missions would be practically impossible without the RHUs.
Not really. Each MER used 8 RHUs, with ~1 W thermal output per RHU (https://solarsystem.nasa.gov/rps/rhu.cfm). An extra ~200 Wh/day would certainly be annoying to supply with solar, but you could do a pure solar MER if you really had to.
Quote
Sure but the first outposts will not be underground.
No, but they will be in vacuum.

There's certainly arguments to be made for nuclear reactors, but keeping the habitat warm doesn't seem like a particularly compelling one to me.

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