Why Explore the Moon | Hacker News Reader

Why Explore the Moon

jatan.space

They really don't make a good case, because the case for the moon is much weaker than Mars.

• The moon has much more limited scientific value compared to Mars. Mars has a 4 billion year history that may have included life and may still include life.

• Despite that much greater distance due to Aerobraking Mars takes less fuel to land on and it's easier to land large cargo ships on.

• Mars has far more resources, it's awash with water and CO2 making fuel production easy, and metals are literally laying about on the surface. The moon is a desert of rocks and dust that only has water in polar craters that is likely mixed into rock percentages at absolute zero.

• Mars is far easier to survive long periods on. The moon is a desert of dangerously razor sharp dust that alternates between two weeks of intense heat and two weeks of near absolute zero temperatures. Mars atmosphere is thin but it means it's temperature ranges are far less extreme, and it's surface soil has been eroded. It also has a lower radiation environment, but that's a minor concern. Most importability water and CO2 and metals are easy to access.

• Returning people from Mars is much easier than the Moon because high volume in-situ fuel production on Mars is easy, while probably not going to be possible on the Moon for decades.

Virtually all lunar research can be done tele-robotically since it's only 3 seconds away. That's impossible on Mars, where we've had a robot trying to dig a hole for over a year. Sending humans to Mars will vastly increase our scientific knowledge of Mars, they will explore more of Mars in a few weeks than rovers have in 50 years.

The answer is send more robots to the moon, but send the astronauts to Mars.

Fascinating, thanks! I knew most of these points in some fashion, but wasn't tying them together in such a coherent view.

Surprise!

On Moon there is almost unlimited Helium-3: https://en.wikipedia.org/wiki/Helium-3 "Much speculation has been made over the possibility of helium-3 as a future energy source. Unlike most other nuclear fusion reactions, the fusion of helium-3 atoms releases large amounts of energy without causing the surrounding material to become radioactive."

"The abundance of helium-3 is thought to be greater on the Moon than on Earth, having been embedded in the upper layer of regolith by the solar wind over billions of years,[5] though still lower in abundance than in the Solar System's gas giants"

Sounds a bit different than, allmost unlimited. Also, there are great quantities of gold in seawater on earth. That does not mean, we have those great quantities avaiable.

Well - if we can get to the Moon, use it's H-3 as fuel for some engine, then maybe we can colonize Solar system.

I know - energy is one of issues, but there are many more - solving cosmic radiation, life support systems, etc.

There is plenty of Helium-3 on Earth too, which doesn't matter because Helium-3 doesn't matter. We can't build working fusion reactors now, and won't be able to do it for decades, and Helium-3 may not even be the best fuel when we do have working fusion reactors.

It's like Columbus asking Queen Elizabeth for billions to explore Texas so we'll have fuel for Model Ts.

It might have been difficult for Columbus to contact Elizabeth, given that their lifetimes did not overlap ;-)

It's even harder than I thought!

There is no use for Helium-3 at this point in time. The reason Fusion is not getting invented is not because of a lack of Helium-3.

Getting excited about Helium-3 on the Moon in 2020 is like a caveman in Europe getting excited about the easy availability of crude oil in Saudi Arabia.

We have zero use for Helium-3 at the moment. It is not at all clear if fusion will ever be solved, and it is absolutely clear that it's not going to be solved in the next two decades.

"is absolutely clear that it's not going to be solved in the next two decades"

What makes this absolutely clear? I am genuinely asking.

A couple of reasons.

1. Because it takes over a decade for an amazing, clean, cheap, new power-generating technology to reach 3% of overall energy production. Look at how slow the absolute uptake (Or lack thereof) of wind and solar has been. They've been incredibly cost-efficient for a very long time, but actual real-world adoption has been slow. It's taken them two decades to reach a few percentage points.

2. We don't have an amazing, clean, cheap, working version of fusion.

3. We don't even have a working version of fusion, actually.

4. Even if ITER, or some other research group demonstrates commercially viable above-break-even-for-cost energy generation tomorrow, it's still going to be at least a decade of engineering efforts to build out the supply chains that will cheaply be able to manufacture all the esoteric components that go into building fusion reactors.

5. Neither ITER, nor any other group is currently even close to making such an announcement. (See #3)

6. And the reason for that is that there's still hundreds of hard engineering and materials problems to solve in this field. Not solve cost-efficiently - just solve.

7. And then, after we solve them, we'll need to solve them again, but this time in a cost-efficient manner. (See #2)

So, there is no way on heaven or Earth that in twenty years, fusion power generation will exceed 3% of overall energy production, regardless of access to He-3. I will take fifty-to-one odds on this.

In fifty years? I don't think it's likely, but it is possible.

Thanks for the reply.

On that note, you should watch: https://www.imdb.com/title/tt1182345/

For those interested, further reading on ESA's Moon scientific goals https://sci.esa.int/documents/34161/35992/1567260389633-ESA_...

Because it is there.

How did water ended up on moon?

That's a good question! The sources of lunar water are poorly understood.

Some of it is formed as a result of hydrogen ions in the solar radiation hitting the oxygen present in the surface and forming water, and then being transported to the permanently shadowed regions. Another source, and likely a major one, is asteroids and comets, which were impacting vigorously during the early solar system.

But to truly differentiate between the sources of water, sample are needed. This hasn't been done yet but will open a huge box of mysteries and also give insights into how the Moon formed.

Wasn't the moon originally created due to a collision with the earth? Was there not any water for Earth to share with the moon when that happened?

We, as humanity, simply have to explore beyond Earth to survive in the long term (meaning really long term, like next 1000 years). Moon, Mars, and beyond. It's evident that Earth is not big enough for all of us, today. What about the next 1000 years? Our population growth rate over the millennia looks very much like covids spread ;) so I guess there's nowhere else to go than space.

In the really long term, like the next 5 billion years, definitely yes. But for mere survival we do not have to leave earth. At some point population growth would simply stagnate. When there is less food than humans. (which is a factor for quite some humans now)

Now the side effects of this scenario on a big scale might wipe out humanity (if food wars get nuclear), but they don't have to.

In either case, I am 100% pro space colonization, but I don't think we need to dramatize it.

Nice sub/read, thank you!

Also: Trump signs executive order to support moon mining, tap asteroid resources

[1] https://www.space.com/trump-moon-mining-space-resources-exec...

One of these days Alice, bang! zoom! straight to the moon!

At a glance the article doesn't seem to mention military motivations which are probably gonna be the driving force of lunar exploration.

What are the military motivations? What advantage does it provide?

There is no advantage. The US Army made plans for a moon base in 1959 but abandoned the project as pointless and unaffordable.

http://www.astronautix.com/h/horizonlunaroutpost.html

Your link, interesting as it is, doesn't point to any particular criticism of the idea, and given its age might not be much relevant today anyway, had it done so.

Far too expensive and far way to be useful for anything.

The moon is at the "top" of Earth's gravity well and has relatively low gravity itself. A simple launch system would allow you to shoot rocks at targets on earth whenever you want, using them as kinetic projectiles without the launch costs of putting rods into low Earth orbit. The down side, of course, is that any attacks from the moon would be slow, taking hours at minimum to reach targets.

Compared to conventional explosives, and especially compared to nukes, this is an ineffective and expensive way to flatten a target. A moon base of this type would only start to make sense if you assume that you want to completely flatten dozens of cities without resorting to nuclear weapons. It makes good sci-fi, but doesn't actually make sense.

In the case of a moon base, yes - it would be a non-nuclear strategic weapon. In the case of orbital-start kinetic strikes, no - you get effectively unstoppable area of denial strike ability anywhere in the world faster than any rocket-based system.

It takes a fair amount of delta-v to "drop" something from Lunar orbit to Earth. It also takes a long time to reach its target. Accurate targeting would be a challenge without active guidance. Even hitting a city would be a bit tricky, and if you're firing projectiles that can flatten large areas such that you don't need accurate targeting everyone's gonna treat that like a nuke, so you may as well just use nukes. I find it hard to believe the costs of establishing and maintaining even an automated Lunar launch system of this sort would be anywhere near worth it, compared with many other options.

as I understand it, "fair amount of delta-v" is quite the understatement. the delta-v needed to realize that gravitational potential energy is equivalent to the moon's orbital velocity. aside from atmospheric drag in the launch phase, you're not saving much energy compared to strapping a bunch of rockets on an earth rock and letting it fall back down. much cheaper and more effective to deliver a nuke via ballistic missile.

The moon is at the bottom of it's own rather deep gravity well. Landing equipment and men there is many times more expensive than putting them in low earth orbit.

Returning mass from the moon takes about two thirds the delta v of just getting something into LEO from earth, and that fuel has to be shipped from earth, so another order of magnitude more expensive. That's why the Apollo lander returned so little mass.

And moon projectiles take days to reach Earth, are easy to track and intercept.

So no, putting kinetic projectiles in LEO is far cheaper, far more accurate, far harder to stop, and can hit targets within minutes. A Falcon Heavy could lift 100,000 lbs of "rods from god" with fuel to LEO for less than $150M. That would only get a few thousand pounds of equipment/fuel to the moon.

The moon has no military value for Earth. Far too expensive, far too far away.

It seems to me the projectile launching base would itself be an easy target.

Reply on news.ycombinator.com