Slamming the Moon

[cosmictraveler]

Sending AI robots to other planets to study them and return samples to Earth would be safer, cheaper and wiser for the time being. We must learn allot more about the dangers in space like radiation damage, isolation and people getting along with each other for 2 years together in isolation.

[Fraggle Rocker]

why do we need a moon base?

So we can explore the rest of the solar system and perhaps ultimately build an interstellar craft. Of course we can build giant spaceships on earth but it costs a fortune to lift them into space.

There are lots of clever ideas for building them in space such as the space elevator, which would at least not require us to actually launch the whole frelling ship from the earth's surface. But they still require lifting all of the materials into a low orbit and that still requires an enormous amount of energy.

The best thing to do is to build them on a body with much lower gravity, for example the moon. Especially if that body already has its own supply of the raw ingredients for building it. We know it's got some of the metals and such, but the Slammer will tell us whether it has some of the more volatile materials. The moon's gravity is something like 1/6 that of earth, which means (if my math is correct without looking it up) it will only take 1/36 of the energy to lift a spacecraft off the moon than off of earth. A huge saving, especially if we're going to build a whole fleet of these puppies to do a thorough job of manned exploration of our own system.

Of course when we get to the point of exploring the rest of the galaxy we've got the old problem of the limitation of relativistic speeds--unless future physicists find some Star-Trecky way around that, the probability of which is very low but not zero. It might take more than a hundred thousand years to find the next civilization. That means we'll have to build generation starships, which are entire spacegoing cities, with a big enough population to keep civilization going with only fleeting and increasingly time-delayed contact with earth. These things will be too big to even launch from the moon. They'll probably be constructed by hollowing out an asteroid and fitting all the technology into it. There might not be any one asteroid with all the raw materials needed to build the ship so they'll end up schlepping stuff around anyway. Hopefully from one asteroid to another, not out of earth's humongous gravity well or even the moon's

But that's a problem for another generation.

[decantemix]

Thiere's a newer candium. Space-Dust.

[sowhatifit'sdark]

Exactly! thanks
I was just wondering why anyone cares if there is water on the moon. I can see spending the money on mars, but the moon?

I would guess that they want it as a place to start longer missions from and as a giant mine and because it is there and there is compulsiveness to do these things. They will get around to Mars sooner or later. Hopefully they will actually tackle habitual destructive patterns long before that incredible expenditure of money.

[cosmictraveler]

Of course we can build giant spaceships on earth but it costs a fortune to lift them into space.

Then build them in space above the Earth.

[decantemix]

Maybe they ought to try Pluto. Yeah, shoot at that, missile of Plutonium ought to due the trick.
Of course, they big a mission, don't be near Ground Zero, button freaks; abound, and there could be a slight bit of a problem.

That stuff can kill you, even if you clear, the air. And, bragg too much...

[Fraggle Rocker]

Then build them in space above the Earth.

Duh? Whether you lift the parts and materials one at a time or all together as a completed spaceship, it's still the same total mass and it's still going to take more or less exactly the same amount of energy to get it out of our gravity well and into orbit.

The whole point of lunar manufacturing is to find and utilize materials that aren't at the bottom of such a deep gravity well so you don't have to expend so much energy to take them into space.

[Challenger78]

Also, we want to have nukes on the moon too. In case earth becomes rebellious.., Much cheaper to use gravity and re entry than to launch something.

[Orleander]

If the moon split in half, how would it affect the earth?

[Fraggle Rocker]

If the moon split in half, how would it affect the earth?

I think you should start a new thread for that one!

[eburacum45]

Yes, there is oxygen on the Moon: it is in fact the most abundant element.
From Wiki

Elements known to be present on the lunar surface include, among others, oxygen (O), silicon (Si), iron (Fe), magnesium (Mg), calcium (Ca), aluminium (Al), manganese (Mn), titanium (Ti). Among the more abundant are oxgyen, iron and silicon. The oxygen content is estimated at 45%. Carbon (C) and nitrogen (N) appear to be present only in trace quantities from deposition by solar wind. Neutron spectrometry data from the Lunar Prospector indicate the presence of hydrogen (H) concentrated at the poles[1].

[eburacum45]

I'll state the situation as I see it again; the Solar system will one day be explored and settled, but it will be explored and settled using spacecraft mostly built from Lunar iron, aluminium and titanium ,with solar power collectors made from lunar silicon and supplied with oxygen from the lunar rocks.

Also present on the Moon are rare earth rocks, which may supply uranium and thorium to fuel fission-powered spacecraft; but even without fission power, these spacecraft built from lunar materials can use solar-electric propulsion.

Once a manufacturing base is established on the Moon only lightweight shuttles will be needed to ferry people off the Earth where they will rendezvous with lunar spacecraft.

[orcot]

Once a manufacturing base is established on the Moon only lightweight shuttles will be needed to ferry people off the Earth where they will rendezvous with lunar spacecraft.

That's one hell of a rosy picture.

Perhaps oneday but not in 50 years (hell pretty sure it won't be like that in a 100 years). Lack of hydrogen lack of gravity, lack of solar radiation, to much solar radiation take your pick

[Orleander]

I'll state the situation as I see it again; the Solar system will one day be explored and settled, but it will be explored and settled using spacecraft mostly built from Lunar iron, aluminium and titanium ,with solar power collectors made from lunar silicon and supplied with oxygen from the lunar rocks.....

why? Why not Earth aluminum, titanium and iron? It would be a heck of a lot cheaper.

[orcot]

why? Why not Earth aluminum, titanium and iron? It would be a heck of a lot cheaper.

Earth is one massive planet if you would combine the mass of all the other silicate planets (mercury, venus, mars) the entire asteroid belt and our own moon you would still come mass short to form a second earth. That's a big gravity well to get out of. Therefore anything that's heavy and (relativly) simple to construct will be a lot cheaper to produce on the moon

[Fraggle Rocker]

why? Why not Earth aluminum, titanium and iron? It would be a heck of a lot cheaper.

Cheaper if you're building an artifact to use on Earth. If you're building an artifact that has to be hoisted into space, the energy required to do that is enormous. We're not talking about a little ol' space shuttle here but something much larger. Lifting it into space against earth's gravity would require so much fuel that it would cancel out any savings from the cheap materials a hundred times over. Merely lifting the materials themselves to use for construction in orbit or on the moon is still just colossally expensive.

It's cheaper to build a factory on the moon, send a crew there, use lunar materials to build your artifact, and hoist it into space from the moon's much weaker gravity, using a whole lot less fuel. It really is. This is pretty straightforward math and it's been double-checked.

[cosmictraveler]

It's cheaper to build a factory on the moon, send a crew there, use lunar materials to build your artifact, and hoist it into space from the moon's much weaker gravity, using a whole lot less fuel. It really is. This is pretty straightforward math and it's been double-checked.

But there's no oxygen or water on the moon so how can you build anything without those two elements?

[Orleander]

Cheaper if you're building an artifact to use on Earth. If you're building an artifact that has to be hoisted into space, the energy required to do that is enormous. ...

ooooo, right.

so what if these things we're slamming the moon with break off a chunk of it. Then what? I mean, does the moon have moonquakes? If it does, does that mean there are fault lines? What if it hits one?

[eburacum45]

But there's no oxygen or water on the moon so how can you build anything without those two elements?

Did you not read my link? Oxygen is the most common element on the Moon numerically. What is missing is hydrogen; but even that is not completely absent.

[Fraggle Rocker]

So what if these things we're slamming the moon with break off a chunk of it. Then what? I mean, does the moon have moonquakes? If it does, does that mean there are fault lines? What if it hits one?

I think you're going to have to start a separate thread for these questions. I'm not sure the few people who could answer them are keeping up with this one.

However, from the science I've studied I know intuitively that the energy of a seismic event, or the energy required to stimulate a seismic event, is several orders of magnitude greater than the energy we could muster. Underground nuclear explosions register very low on seismometers, and the Richter scale is logarithmic.

I'll leave it as "an exercise for the reader," as they say in the textbooks, to estimate the mass of a tectonic plate, and then the energy required to overcome the frictional force holding it tightly to the adjacent one.

The Earth has tectonic plates defined by fault lines because of the way it was formed. It's a relatively thin crust of solid matter floating on a soft center of creamy goodness--I mean molten metal. It's so incredibly thin in proportion to the planet's size that it is buffeted around by the currents in the liquid below, and it gets torn, twisted, bent and crumpled. As a result it is not a nice smooth spherical coating like dipped chocolate (I must be hungry). It's a bunch of disconnected fragments of a surface that keep bumping and grinding and riding up on each other, forming mountain peaks and ocean floors and gaps that are filled in by new molten material or "lava" percolating to the surface and cooling. The discontinuities between these "plates" of thin solid superficial matter are called fault lines.

AFAIK we're not entirely sure how the Moon was formed. It could be a fragment of a defunct planet that was caught in our gravity well, or it could be a giant MarsMallow the goddess brought over to have with her hot chocolate before she got distracted by the expansion of empty space that makes it look like the Theory of Relativity is invalid. It's been postulated that it's a piece of Earth that broke off a few billion years ago, but I suspect that's science fiction or Velikovskian crackpottery. But then if Q and Walt weren't here to stomp me I'd say the same thing about the expansion of empty space.

In any case we don't know exactly how the Moon is "constructed," whether it has fault lines or is one well-assembled object. A soft-center, a truffle, or a peanut M&M?

Do we even know its internal temperature? Can you use a chocolate-tempering thermometer on astronomical objects?