Why Go Back to the Moon?

Good stuff. I would add that a permanent moon base would give us an off planet refueling station where our spacecraft would not need to work so hard to escape gravity to return to space, as well as one that's not going to crash down anytime soon. Minerals could eventually be tapped to provide fuel and raw building materials on the moon, and conceivably greenhouses could be built to provide some degree of self sufficiency.

there is also oxigen and water on the moon we just have to learn how to get it

I wonder if we will ever do anything with the moon other than visit it.

populate it with prisoners - like an Alcatraz?

They closed alcatraz.   

like to see someone swim out of that one


but no it will be a fueling station becouse it is easier and cheaper to get things off of the moon than off the earth

Actually, most humans find that it's easier to fuel down here on Earth.

I'm still trying to figure out how it could preserve human life if the Earth is destroyed. If the Earth is destroyed, the Moon is not long for this world. Without the Earth's gravitation pull making it run circles around us, where will it go? Probably into the Sun or worse, shoot off into space. Well, not really worse. But still, it would not just stick around right here.

actually the moon has a perfect orbit around the sun

ie

in it's orbit around the earth. the moon never moves away from or toward the sun

which means that if the earth wasn't here the moon would follow the same path around the sun. although the earth maybe keeping it from being pulled into the sun.

as far as saving humanity if the earth goes pop the moon will probable go pop just before or just after

Good stuff. I would add that a permanent moon base would give us an off planet refueling station where our spacecraft would not need to work so hard to escape gravity to return to space...

The use of lunar materials to create rocket propellents and other fuels is a research field that I have spent a lot of time studying. There have been economic studies performed to determine if such propellents/fuels would be less costly than delivering equivalent materials from Earth. I will caution that these economic models still have a great deal of uncertainty, due to the unproven nature of such activities. Preliminary results, however, show that on the lunar surface, lunar-derived propellents would be cheaper, but as soon as you get to low-lunar orbit (LLO), the costs (Earth-LLO transport vs. lunar-production + lunar surface-LLO transport) become roughly comparable. Of course, these economics will evolve as infrastructure on the Moon develops. As the capital costs of lunar production facilities amortize, it will clearly be cheaper to get propellants from the lunar surface to LLO than to get them from the Earth's surface to LLO.

...as well as one that's not going to crash down anytime soon.

I'm sorry, I'm not sure exactly what you were expressing. Perhaps, (A) that this lunar refueling station will not crash down anytime soon relative to an Earth-orbiting refueling station, or (B) that a lunar-launched spacecraft will not crash down as often compared to Earth-launched spacecraft. Both interpretations offer interesting insights.

A. If we built an Earth-orbiting spacecraft refueling station, as long as it is not in low-Earth orbit (LEO), there is no significant risk of it de-orbiting due to drag or gravitational influences. It is not clear, however, where the highest demand for refueling will be. It may be in LEO, or it may be in Geostationary orbit (GEO), where most telecommunication satellites are located. Most GEO satellites now use electric-ion propulsion engines, which don't need to be refueled too often.....so you may be right that a LEO-based station would require its own significant "orbital maintenance."

In any case, I think the most interesting difference between a lunar-based refueling station and an Earth-based refueling station is that a lunar-based station would have ALL the materials needed for its continued maintenance readily available, whereas the materials for maintaining a LEO-based station would have to be delivered to LEO or salvaged from dead satellites in LEO. I will elaborate on this in other posts.

B. It is interesting to point out that an Earth-launched rocket is inherently more risky than a lunar-launched rocket. This is due to two factors, (1) Earth's large gravity and (2) Earth's atmosphere. Factor 1 requires that these rockets use large amounts of propellants to achieve orbital velocity, and the more propellents, the more complicated and risky the rocket must be. Factor 2 again increases the amount of propellant needed and also adds the difficulties of aerodynamic forces/pressure and aerodynamic heating. A lunar "ascent vehicle" can be made to be relatively simple and, therefore, more reliable. If anyone has seen the Apollo Lunar Module ascent engine in person, you were likely surprised by its amazing simplicity (and small size).

Have you not heard? The US has had a station on the moon for over a decade now!

Just kidding, really



The last part of this sentence, why particularly those? What is your reasoning here? How would this play a part?

Interesting article btw

Minerals could eventually be tapped to provide fuel and raw building materials on the moon, and conceivably greenhouses could be built to provide some degree of self sufficiency.

The lunar regolith (i.e. soil made up of broken rocks) and surface rocks/boulders have signicant amounts of aluminum, titanium (in some regions), iron, calcium, and magnesium. Lunar regolith can also be made into concrete blocks for use in building structures simply by heating it up using a modest-sized solar concentrator. This process is made even more simple by the natural vacuum environment, which prevents overheating and overpressurizing of manufacturing facilities--it can simply be done "outside."

The two most abundant materials on the lunar surface, however, are oxygen (>40%) and silicon (>20%). Oxygen can be made into oxidizer for rockets and fuel cells or for breathing. Water is also made up mostly of oxygen (by weight, which is the important part for space travel). Silcon, in the form of can be made into solar cells (by the way, solar energy production is much more efficient on the Moon than on Earth), semiconductor devices, and glass/quartz (which are roughly 2 parts oxygen, 1 part silicon).

Greenhouses can definitely be built on the lunar surface (hence why I mentioned glass). The design of lunar greenhouses have been studied substantially. There are some regions near the poles of the Moon that have near constant sunlight, which is a big plus for building plants. There are no clouds on the Moon and, in fact, virtually no atmosphere, unlike Earth's atmosphere which blocks much of the Sun's photosynthetic potential. ...these are the also the primary reasons that solar energy production on the Moon is much more efficient than on Earth.

there is also oxigen and water on the moon we just have to learn how to get it

Oxygen yes, water maybe. We need robotic missions in the next decade or two to anwer the "maybe." NASA is well on its way to completing one such mission (actually one dual mission). It's called the Lunar Reconnaissance Orbiter (LRO) with the attached Lunar Crater Observation and Sensing Satellite (LCROSS....the "crater" part is because the water is believed to be in the permanently shadowed regions of polar craters). Also, several other nations are nearing launch of their own lunar spacecraft (China, India, and Japan).

The KEY part of your comment, however, was "we just have to learn how to get it"! This is a HUGE challenge, and we need active research and significant investment in this area. Tell your congresspeople this!!!!

Ok, I've gotta attend to some other things. I'll try to post more replies soon.

Thanks for everyone's interest!!!!

water yes i just watched on science channel all they have to do is cook or press the dust to get water. we just don't quite have it down yet

water yes i just watched on science channel all they have to do is cook or press the dust to get water. we just don't quite have it down yet

Yes, IF there is water there. The evidence for water on the Moon though is still a bit iffy. I can provide more details if anyone is interested. The bottom line is we need to send more instruments there to find out for sure if there's water and in what concentration it exists.

Also, even though extraction of water ice from the lunar regolith is MUCH easier than extraction of oxygen or other materials from the regolith, it is no trivial task. Operating machinery in a 50-90 K cold trap (that's -223 to -183 Celsius or -370 to -298 F) is definitely a significant engineering challenge.

there is water there in the dust

when you pick up a handful of moon dust you are also picking up oxygen and water

it is in every handful we just have to learn how to destill it effecintally

and i need to learn how to spell.


your talking about standing water

i am talking about water in the dirt

as far as this is all you have to do is have a big enough building/truck for people to work in the dust comes in one end and oxygen, water, building material goes out the other

there is water there in the dust when you pick up a handful of moon dust you are also picking up oxygen and water it is in every handful we just have to learn how to destill it effecintally and i need to learn how to spell.your talking about standing water i am talking about water in the dirt

If you are talking about there being the constituent elements that make up water (hydrogen and oxygen), then yes, there is "water" in lunar regolith. But it turns out there is very, very little hydrogen (about 100 parts per million or less).

At the lunar poles, however, the situation may be different. There may be up to 1% water ice mixed in with the lunar regolith. It may be in higher concentrations in some smaller areas, but the best we know is that averaged over areas as large as 100s square kilometers, the concentration could be as high as 1%. This evidence is mainly neutron spectrometer data from the Lunar Prospector mission, radar data from the Clementine mission, and some ground-based radar data. Still, this data does NOT *uniquely* identify water as the substance contained in these permanently shadowed craters. I would have to go into more detail about the data sets to tell you all the possibilities and how strong the data is in suggesting it is water. There is plenty of info out on the internet, though, and for now I'd just like to say, the bottom line is the cat is not out of the bag quite yet.

as far as this is all you have to do is have a big enough building/truck for people to work in the dust comes in one end and oxygen, water, building material goes out the other

It is not so simple. First of all, we have no known lubricants that can operate at 50-90 K, so we will have to invent new ones, in order to have moving parts operate in permanently-shadowed craters on the Moon. There are other operational challenges. For example, in permanently-shadowed, there is no direct communications link to Earth, so you will probably need a communications relay satellite in lunar orbit, or a communications tower along the rim of the crater. In addition, you need some way to get to the bottom of the crater, which is no trivial task. Finally, digging up and moving around of lunar regolith is no easy task. There was recently a competition to design machines to do this...none completed the goals of this competition. I'm not saying it can't be done, but it's not easy. Check out this website for more details: http://www.californiaspaceauthority.org/regolith/

Lastly, extracting water ice mixed in with lunar regolith is relatively straight forward, but extracting oxygen from pure lunar regolith (i.e. lunar regolith not containing water ice), is NOT an easy task. You have to heat the regolith up to VERY high temperatures, and there are some nasty chemical reactions involved. I can provide more details for anyone interested.

I wonder if we will ever do anything with the moon other than visit it.

I wonder, too.....but I'm pretty certain we will inhabit the Moon, at least to the level that we inhabit Antarctica permanently for scientific research. The Moon, in fact, may become more inhabited than Antarctica because there is potential for a large amount of industry on the Moon and also the potential for spaceports based on the Moon. It may become a "gateway" to other points in the solar system. Most likely, however, is it will be a cheap source of materials and supplies for spacecraft that will stay in either high-Earth-orbit, or travel to other parts of the solar system.

Lastly, I wanted to mention....I do more than wonder! "Be the change you want to see in the world [universe]!" Everyone can help in expanding the boundaries of human civilization. If you think it's important to preserve the human species beyond Earth's limited lifetime, you can start by writing your Congressperson TODAY. We spend far less than 1% of our federal budget on protecting our species' long-range survival........even a full 1% spent on our future would allow us to progress much, much faster and be in much less risk of establishing a permanent foothold in space before it's too late!

populate it with prisoners - like an Alcatraz? They closed alcatraz.

This is an interesting thought....but I actually think the exact opposite. We should leave all the criminals and extremely lazy people on Earth. One nice thing about Earth is it's difficult to escape from (because of its large gravitiy). You also have to pack very carefully before you leave because you can only afford to take the things you really need. So big, heavy things like guns and bombs, that you don't really need in space, can be left at home. There are no violent criminals in space that we know of (ok, I'm anticipating comments about Lisa Nowak, but she had only pepper spray and a BB gun....and these items didn't make it to space, only to Florida), so no need to bring weapons to space to protect against criminals.

Anyways, this is my dream about space. We can conscientiously build new societies and cultures in space, learning from our 100,000s of years of history on Earth. Don't get me wrong....EARTH IS A COOL PLACE...It's where I grew up my whole life...but it's a far from perfect place, so when we establish our civilization in space, we should be careful about the rules we set up, what we bring there, and even WHO we bring.

but no it will be a fueling station becouse it is easier and cheaper to get things off of the moon than off the earth

Very true. Delta V is a measure used in rocket science to measure the magnitude of maneuvers made to get to different places (orbits in space). Delta V is short for "change in velocity," and it is roughly* equal to the incremental change in velocity that a rocket undergoes to get to its desired orbit. It is also roughly* proportional to the amount of propellent needed to perform such maneuvers.

Anyways, bottom line:

Delta V to reach low-Earth orbit (from Earth surface): ~9 km/s
Delta V to reach low-lunar orbit (from lunar surface): <2 km/s
* I say "roughly" equal because there are other "sinks" of energy when a rocket converts its fuel's chemical energy into kinetic energy, in order to achieve a particular orbit. The quantity "delta V" is really just an artifact of the "rocket equation", rather than a quantity having a specific, accurate physical meaning. It is only "roughly" equivalent to the amount of propellent needed for similar reasons and the mathematics of the rocket equation show this. If anyone finds me to wrong, however, PLEASE let me know. I spent many, many hours trying to convince myself that delta V should be roughly proportional to the amount of propellant used, and I only achieved ~95% success in convincing myself.

Actually, most humans find that it's easier to fuel down here on Earth.

I get your point. Currently our cars, planes, rockets, and other transportation devices all get their fuel from Earth. But the primary source of this fuel (hydrocarbons) is being depleted faster than it is being replaced, and a simple equation will show that, if these two rates stay roughly the same, our hydrocarbons will eventually run out. More likely though, they will become more and more expensive, therefore people will look more and more towards other sources of concentrated energy. For reasons slightly too complicated and lengthly to explain at this very moment, I can prove that the only solution to our growing energy needs is to import energy from beyond Earth. I can also prove that, at some point, our demand for energy will outgrow Earth's ability to give off the heat that all energy eventually gets converted into. Therefore, if our population and energy needs continue to grow, we will have no alternative but to export some of our human activities to outer space.

See my previous post (Thursday) regarding economic studies comparing Earth-based refueling to lunar-based refueling. As infrastructure on the Moon and in high-Earth orbit (in particular) develops, it will become easier and easier (i.e. cheaper and cheaper) to refuel in space, and since Earth-based fuels will increase in price, more and more people will evenually choose to refuel in space.

Hopefully I will be able to post these alleged proofs I refer to here at a later point, if there is enough interest. I encourage you all, however, to go to the library (or amazon.com or some other source of literature) and check out some books by Gerald O'Neill. He thought of all this stuff before I was even born.

Ok, now I give some other people a chance to write.

I was letting this article rest a few days to give other people a chance to comment...but it seems the interest may have fizzled out. In any case, I want to answer the rest of the questions posed in previous comments.

The last part of this sentence, why particularly those? What is your reasoning here? How would this play a part?

Well, one reason I want the U.S. to lead in space exploration and settlement, asides from my pride in being a U.S. citizen, is that the U.S. has a pretty decent human rights record, compared to some other nations. In particular I was thinking about the U.S. in comparison to China, but Russia unfortunately isn't far ahead of China these days.

Space plays a part because by extending human activities to space and to other planets/worlds, we are in effect extending human civilization--with all of its associated rules, laws, culture, and values--into virgin worlds. I would rather the U.S. play a leading role in this development, rather than a country which does not allow basic human rights, such as freedom of speech, freedom of press, and freedom of religion.

The applicability and establishment of international law in Outer Space is a subject that has attracted great interest from "space lawyers" and others. Much has been written on it, and there are five basic treaties that form the foundation of space law. The most important of these is the Outer Space Treaty of 1967. Basically though, these are just weak tentacles of an already weak Earth-based system of international law. Until laws have a local enforcement mechanism, by definition, they have no force. As the moon gains independence from Earth, it will also gain independence from any enforcement mechanism of Earth laws, and therefore, it will need its own systems of laws and law enforcement.

Let me know if this is still unclear, or if you have more questions on these issues.