Energy on the Moon

[harlock]

I'm talking about a Moon base powered by sunlight only.

The problem is how to store electric energy for the long night!

The absence of air makes me think about electrostatic energy storage.

E=1/2 C * V^2

It'd need billion Volts(today Vmax is 25 million Volts)...

[fiveworlds]

What is stopping you staying on the bright side of the moon??

[zapatos]

What is stopping you staying on the bright side of the moon??

 

Which side is that?

[fiveworlds]

Wherever is day surely it is possible to make something that will move on solar power. Don't forget the moon is a lot smaller than earth and rotates way slower.

Edited April 2, 2017 by fiveworlds

[Endy0816]

North pole could actually work.

 

There's also earthshine, not sure how intense it is though. Probably going to need to store heat during the days too.

[fiveworlds]

It works out at about 12 miles an hour. 6786 moon circumference/24/28

[zapatos]

Which side of the moon is the bright side?

[Strange]

I'm talking about a Moon base powered by sunlight only.

The problem is how to store electric energy for the long night!

 

 

Batteries.

Pressurised gas.

Freezing CO2.

Use electrolysis to generate hydrogen and oxygen.

[Danijel Gorupec]

I guess, maybe even flywheels could be an option (free vacuum; less gravity; moon rotates more slowly - all this potentially helping with loses). Especially if electric cargo-launching systems will be used (might require flywheels anyway).

[mistermack]

Store hot water, and use it to boil liquid CO2 and send it through a turbine. Like a steam turbine here on Earth.

Or just use warm water and let the pressure off to produce steam. Might have trouble with the water freezing that way, though.

[swansont]

What is stopping you staying on the bright side of the moon??

A moon base implies a fixed location.

 

I guess, maybe even flywheels could be an option (free vacuum; less gravity; moon rotates more slowly - all this potentially helping with loses). Especially if electric cargo-launching systems will be used (might require flywheels anyway).

It would have to be sealed. The dust on the moon wreaks havoc on mechanical systems. The particles are very fine and get charged, without readily losing their charge while in vacuum.

 

https://www.sciencedaily.com/releases/2008/09/080924191552.htm

[J.C.MacSwell]

Which side of the moon is the bright side?

The one currently facing the Sun...but somehow I think you know that

[Enthalpy]

Energy, and even more decent temperature, is a BIG difficulty if wanting to spend the night on our Moon.

 

Up to now, astronauts and probes have targeted the day side. I don't know of any one (I may have missed it) that passed a night there.

 

Most plans want radioisotopic heat generators (which means ²³⁸Pu) to keep the probe on temperature. Yuk.

 

If reducing the activity to nearly zero, a probe can hibernate during night time. My figures are there

http://www.scienceforums.net/topic/85103-mission-to-bring-back-moon-samples/#entry919546

 

For a manned base, just digging in the soil keeps a reasonable temperature for the night. This is but necessary for the day too, and to protect against radiation, and against micrometeoroids, so the choice is already done.

 

Some energy, that is electricity, is also necessary to a manned base, and lithium batteries are just good at that. Hydrogen and fuel cells can be considered; the benefit is discussable and the drawbacks clear. Flywheels and compressed gas store less energy per kg than batteries.

 

Imagine that every astronaut needs 200kWh in 24h (3x my consumption but night is permanent there). Over 14 days, 5 people need 50GJ. Safe Li-polymer stores 500kJ/kg so this needs 100t batteries. This is a problem, so they will have to save energy a lot. Some heavy uses, like air and water recycling, can hopefully work during daytime only.

 

Other solutions are difficult. Heat a big pile of regolith during daytime, extract energy from it during nighttime.

[mistermack]

Have a series of parabolic solar reflectors orbiting the Moon in such a way that your base is always bathed in light, even at night.

It wouldn't be particularly hi-tech to arrange. There is no atmosphere to dilute the reflected sunlight, it would be just a question of getting the materials into the optimum Moon orbit, and maintaining the correct angle as the reflector orbits.

 

A bit like shining a torch from above. Easy.

[Enthalpy]

Sorry I botched the estimate of the lithium battery.

 

100kWh per astronaut in a month, so 5 people over half a month nighttime need 900MJ, so the safe Li-poly battery weighs 2t, feasible. Optimize a bit, hope for lighter safe batteries - or send 2t there. With my sunheat engine, all becomes easier

http://www.scienceforums.net/topic/76627-solar-thermal-rocket/page-3#entry900362

[Endy0816]

Have a series of parabolic solar reflectors orbiting the Moon in such a way that your base is always bathed in light, even at night.

It wouldn't be particularly hi-tech to arrange. There is no atmosphere to dilute the reflected sunlight, it would be just a question of getting the materials into the optimum Moon orbit, and maintaining the correct angle as the reflector orbits.

 

A bit like shining a torch from above. Easy.

 

There are natural "Peaks of Eternal Light" that are along those lines.

 

https://en.wikipedia.org/wiki/Peak_of_eternal_light#Lunar_north_pole

 

 

 

Eventually would need to look into different strategies as the colony expands or seeks to take advantage of more distant resources though.

[mistermack]

 

There are natural "Peaks of Eternal Light" that are along those lines.

 

https://en.wikipedia.org/wiki/Peak_of_eternal_light#Lunar_north_pole

 

 

 

Eventually would need to look into different strategies as the colony expands or seeks to take advantage of more distant resources though.

It's certainly a way of providing constant power. It would depend on the desirability of the North Pole as a base though.

You could mount reflectors on the peaks with the best light conditions, and direct the light to anywhere with a clear line of sight.

[Airbrush]

The moon base should be close to a natural ice supply. The ice is used to make water, and air for breathing, and hydrogen fuel. Use the fuel to power generators.

 

The moon is tidally locked with the earth, so all the moon missions were planned on the day side, because they never stayed long enough to experience the moon night.

[mistermack]

I don't think power is going to be a problem on the Moon, in the long run.

There is so much solar energy available in space, that can be diverted down with a simple orbiting mirror, I think that energy will be the last of the long-term problems. A space-mirror can be incredibly thin and light, and yet cover a vast area so it's payback per gram of weight is enormous.

In the very early stages, power might be a temporary headache, but not long-term.

 

I would imagine that there will be a number of space stations, in orbit around the Moon, which are big enough, and rotate fast enough, to give 1 g of artificial gravity, so that Moon workers can do shifts on the Moon, without harming their health with the low gravity effects.

Cosmic radiation, safe atmosphere, and low gravity are the main problems I think. Energy will be abundant.

[Airbrush]

I would imagine that there will be a number of space stations, in orbit around the Moon, which are big enough, and rotate fast enough, to give 1 g of artificial gravity, so that Moon workers can do shifts on the Moon, without harming their health with the low gravity effects.

 

That seems like a great idea to me! That goes also for missions to Mars. First establish orbiting space stations that rotate at 1 g so crews can have comfortable recreational breaks and sleep at normal 1 g. Maybe they work for their shift on the moon or Mars, and then they launch into orbit (or a space elevator) to get 48 hours of R&R at the orbiting space station.

Edited April 5, 2017 by Airbrush

[swansont]

Launching a payload is a fairly expensive act.

[Endy0816]

Launching a payload is a fairly expensive act.

 

Yeah, I think we'll need to look at simulating gravity on the surface or find medical solutions.

 

Not talking anything too unrealistic in managing muscle mass and bone loss. We do need more research on gestation in space though.

[Airbrush]

Launching a payload is a fairly expensive act.

 

How about a space elevator?

 

With low gravity, better technology, and an endless supply of water-ice to create hydrogen fuel, maybe launching modest payloads of astronauts from the surface of the moon or Mars into orbit could be a daily routine?

Edited April 5, 2017 by Airbrush

[mistermack]

The gravity on the Moon is so low, that a space elevator would be taking a sledgehammer to crack a nut.

The amount of rocket power needed to lift off from the Moon is tiny. You only have to compare what the astronauts lifted off in on their return journey, to the gigantic rockets needed to lift men off from the Earth. It was tiny, and most of it was living space. The rockets were negligible.

 

It's actually possible to build a gun, that would shoot materials off the surface of the Moon into orbit, just using normal shell propellant.

The lack of atmosphere makes the job easier.

Or you could build electrically driven railguns, that don't need propellant at all, just electrical power.

 

Mars would be a totally different problem though. Lifting off from Mars would need big rockets, with lots of fuel, due to it's much higher gravity than the Moon.

[Airbrush]

Then it looks like astronauts on the moon can have an orbiting recreation and sleeping station with artificial gravity, but astronauts on missions to Mars will be deprived of normal gravity for the entire length of their mission, or the remainder of their life if they plan to never return to Earth.

 

It seems like it could be easy to generate one g gravity on the trip to and from Mars, but alas that is probably not going to happen. Right? I believe there are no plans for ANY artificial gravity during missions to Mars.

Edited April 6, 2017 by Airbrush