to get a head start on the dick measuring contest with china.

As the sun runs out of hydrogen in its core, it will start to fuse helium which will increase its surface area and the amount of heat the Earth recieves from the sun.  As Earth's interior cools, its iron core will solidify causing Earth's magnetic field to weaken, and as Earth's magnetic field weakens the planet will be subject to radiation while solar wind hastens the removal of the atmosphere.

Of course, this process is on the scale of millions of years, but why not get an early start?

Maybe because we're currently in a bit of a pinch economically and the money NASA receives for these pet projects could be better spent elsewhere? I'm not saying cut them out forever or disband NASA, but this is really not the time to be spending millions and millions on space projects that won't have any followup for years and are doing this because of a situation that will happen millions of years from now.

It isnt that space isn't economical, its that its economic effect are unknown.  In 1950, we had no idea how important satellites would be for our economy, but because we spent lots of money on NASA and they developed this technology, we were able to reap the benefits of it.

What short term benefits could we get from a lunar base?  The best example I can think of is Helium-3 supplies on the Moon, which is a highly efficient energy source.  Because the Moon has no atmosphere, the moon is thought to contain large amounts of Helium-3 on its surface.  If abundant amounts of Helium-3 are on the Moon's surface, and Helium-3 is as efficient and cost effective as scientists think it is, then it would be very economical to ship Helium-3 from the Moon to Earth.  I'm not sure on the specifics, but I've read that one ton of Helium-3 would supply all of Earth's energy needs for a year, which would more than cover the transport costs from the Moon's low gravity to Earth and the maintenance of a lunar base that mined Helium-3.

Fair enough. Good points. I concede my argument.

hahahaha lmao no wonder the US is in so much debt. Who gives a rats ass if theres water/ice on the moon. Thats 79 million dollars wasted.

Read three posts up.

Another issue is astriod/meteor impacts.  We know big ones have hit earth numerous times and we know big ones are still out there....we are trying to catalogue them and risk assess them but its not as easy as you might think.

The lunar base does two things for this, one short term one much longer term. 

In the short term a lunar base provides a location for a space based telescope completely free of the atmosphere and its scintillation and image distortion effects (they can correct for this to a degree however).  For example an earth-based telescope has its EM spectrum almost entirely blocked (only IR gets through) by the atmosphere. Now obviously we can already accomplish much the same thing with satellites like the hubble but these require constant attention in regards to the debris flying about the planet and the fuel that is expended in avoiding a disastrous collision.  The result is that a sattelite telescope has an operating lifespan of a decade or so while a lunar observatory could operate for century or more with no worry about wear and tear from debris or the elements and having sufficiently low power requirements as to be operable by solar panels. 

Of course the advantages of a lunar telescope go far beyond the astroid/meteor catalogue as well.  An advantage of the lunar telescope for cosmological purposes is that the integration time is greatly increased.  Essentially when taking pictures of things very very very (super very) far away a telescope is left focused on the object for as long as possible to allow a long exposure time...essentially things that are so far away as to be completely faint even to the telescope have to be allowed to slowly send their emissions (of whatever type we are trying to detect) over the course of days, weeks, and in some cases even months.  The integration time is the length of time the scope can focus on an object uninterrupted..on the moon this is 14 days, on earth it is about half a day depending on where you are.  This might not seem important for us back here on earth but cosmology has been an a source of study for theoretical physists for a few decades now and expanding our knowledge of the universe has consistently led to expanding our knowledge of physics...which certainly can have beneficial impacts here in the short term.

The long term benefit is the foundational knowledge gained in a lunar base moves us several steps closer to a martian base and beyond...Things that could concievably solve the "all of our eggs in one basket" issue mentioned before.  The sun burning out however is probably one of the least pressing reasons that the "eggs in one basket" idea is an issue.  There are potential threats to earth that we know have hit it before that could literally happen any day...we just don't know.  These are of course 1 in a million type of issues...so its not worth worrying about and indeed if they were the only reason it would be questionable whether or not it was worthwhile even in good economic times.

Just wanted to add this to the list of reasons, not to pile on or anything, just to add to the information available here.

With that said as far as your point of "there are better economic times to do this in"...I actually agree.  I certainly think that at this point in time there are better things to spend our time, energy, and especially our money on.  However, missions are scheduled and planned years and sometimes decades in advance and economic issues are an unforseen variable that, if allowed to cancel such a mission, would likely prevent it from ever happening or prolong it significantly.

I'd also argue that doing these types of missions opens up new avenues for better technology to get to space.

It's kind of like the argument of 'We shouldn't be working on learning how to fish! We must stay on land because we could do more for our crops!'.

There are a lot of advantages to more space funding from public and private sources. We must remember that great countries have been founded bettered society (US, Australia, NZ for examples) because of people traveling long distances for colonization and resource acquisition.

A few quick-hit reasons on why the moon and space in general is good for the economy:

- Helium 3. As we all know, energy production is very critical in concerns to the economy. 15 tons of HE3 per year would fuel America's energy needs for a year. The moon has billions of tons of this resource. At a current valuation of $1.5 million USD per KG, it is quite lucrative to utilize. HE3 is also useful in refrigeration, as a reaction between HE3 and HE4 results in a cooling process that can cool items down to 2-4 Kelvin.
- Solar energy. Without clouds, and direct access to the sun, we can generate far more energy in space from solar plants than here on earth. Very critical if we want renewables.
- Minerals & Exotics. Some resources on earth are very difficult to extract such as gold, platinum, and aluminum. On asteroids, these elements are very easy to obtain. For example, the asteroid 433 Eros has much gold, platinum and aluminum which is very easy to extract (no mining is required other than simply digging up the asteroid).

There are millions of other reasons - Metal foams, colonization, science, ect.