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Comment by WalterBright | Hacker News Reader

The foreseeable future for man in space is the moon, not Mars. The moon is close - orders of magnitude easier to get there and back again. Its gravity well isn't a prison. You can probably launch stuff from there to earth with a linear accelerator. It's full of natural resources that can be used to build colonies and space ships. There's no environment to degrade.

Mars doesn't make any sense. The moon does.

And besides, once we learn how to build bases on the moon, which will take trial and error, it will make it a LOT easier to build one on Mars where mistakes are not recoverable. What are you gonna do on Mars when you find out you forgot the soldering iron? Die. Moon bases can be resupplied.

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Mars has some stuff that the Moon doesn't: volatiles.

According to Wikipedia (https://en.wikipedia.org/wiki/Volatiles):

In planetary science, volatiles are the group of chemical elements and chemical compounds with low boiling points that are associated with a planet's or moon's crust or atmosphere. Examples include nitrogen, water, carbon dioxide, ammonia, hydrogen, methane and sulfur dioxide.

Of these the only one we're likely to find on the moon is water, and there probably isn't very much of it. In comparison, there's a whole bunch of water just sitting on the Martian surface in the northern polar ice cap. Carbon dioxide and nitrogen are available literally all over the planet -- sure the Martian air is thin, but compressing it is a fairly trivial exercise.

And if we can figure out how to aerobrake large vehicles then the delta-V to Mars isn't a whole lot different than to get to the Moon.

Mars is a much better science target as well. It's pretty unlikely that there was ever any life on the moon, but with Mars it seems like there is a real possibility. Mars also appears to have experienced geological processes similar to the earth. Studying the up close may allow us to learn things about similar processes on earth.

It's farther away, and that certainly adds a lot of difficulty and risk, but it is still reachable with essentially the same technology as the moon, and there are compelling reasons to go.

(That said, I totally think we should use moon missions as a testing ground for the technology needed for a Mars mission.)

> adds a lot of difficulty and risk

That's a vast understatement. Don't forget expense and time! Orders of magnitude more.

I don't think there's any realistic way of getting a sustainable base on Mars without doing it first on the moon. On the moon you can learn from mistakes. On Mars you die from the first mistake.

Mars will be a dangerous environment, but it won't be as dangerous as the moon. For example, if your Mars base is set up near the polar cap or near easily mineable permafrost, then a major atmospheric loss can be replaced by combining oxygen cracked from the ice using electrolysis and nitrogen sourced from the martian atmosphere. It is unlikely that a moonbase would have a similar option.

The martian atmosphere may not provide a lot of radiation protection but it provides way more than you get on the moon. And again, if you've got access to ice, you can use it to fairly easily create radiation shielding for your base.

It could be a situation where difficulty of receiving aid from Earth is offset by a lower risk of things going catastrophically wrong.

That said, if I was planning a mission to Mars, I would want extensive redundancy throughout all of my systems. One thing to keep in mind, a modern Mars mission does not need to be mass-limited in the same way that the Apollo missions were. SpaceX has already greatly reduced the cost of putting mass in orbit, and if Blue Origin can actually make New Glenn work, then you are looking at a substantial reduction from SpaceX's current cost-to-orbit.

Radiation shielding on the moon can be done by living in a crevasse.

We have yet to know what can be produced from Moon materials. A couple bags of rocks tell is pretty much nothing about the variety that may be available. After all, what would a couple bags tell you about Earth?

Does it matter? I think there will be enough qualified candidates who know, understand and are willing to take the risk.

One thing worth noting is the soil, if memory serves, the moon soil hs been described as being very sharp and clingy with some properties of asbestos, as in its very problematic. This is because there has been no water, winds etc to grind the sand as on earth.

Now on Mars the soil has been moved by winds and other natural phenomenon, so it should be far less problematic to just brush it off, not to begin on the more useful composition of it, I can imagine the iron will come in handy when the habitat gets to the point where they can start refining and producing.

Mars soil is apparently toxic chemicals [1]. Antarctica is looking good in comparison.

[1] https://www.theguardian.com/science/2017/jul/06/mars-covered...

There are advantages and disadvantages. Closeness is a big issue, I'll grant you that. Robots on the Moon's surface can get quick guidance form humans on Earth much more quickly than robots on Mars. And if something goes wrong you can get home more quickly.

The gravity well difference is a thing but isn't straightforward. You need twice as much delta-v to take off from Mars as from the Moon (3800 m/s versus 1730 m/s). But on the other hand Mars has an atmosphere and while it isn't think enough for you to touch down gently with a big mass you'll only need 200 m/s or so to cushion your landing. But you need heat shields on Mars, but you need those to get back to Earth too. But lack of atmosphere means you could maybe use a mass driver to help take off from the Moon.

Mars has a gravity that's 2/5 of Earth's while the Moon's is 1/6. Is that important for human health? We have no frigging clue since the budget for a centrifuge on the ISS was cut.

The Moon rotates once every month and Mars once every 24 hours. If you're using solar panels it's a big deal making it though the lunar night, you'll need lots of batteries, maybe 25 times the weight of your panels. On Mars you need maybe the weight of your panels in batteries. There are the Peaks of Eternal Light on the south pole of the moon where this isn't an issue and you can just keep pointing your solar panels at different parts of the horizon all month.

And finally the martian atmosphere provides some protection against radiation and small meteors. It's not a super friendly environment in either case with no magnetic field so you'll probably be spending a lot of time under ground in either location.

So, it's complicated and I'm not willing to say that one is the true path and the other is stupid.

> [low gravity] human health

I'm sure it won't be good. But with a moon colony you can rotate people back to earth. Not practical with Mars.

> solar

The poles are one solution. Another is to put a large mirror in orbit to reflect power to the moon base.

Don't bother reflecting light when the moon base is in darkness, just beam down power.

There's no solar night at the poles, and tall structures are easy to build in low gravity.

The moon is certainly more accessible, but the purpose of having a base there is more less clear from both a practical and a scientific perspective.

The scientific/engineering (and cultural/sociological) gains from a human return to the moon would be tiny compared to a Mars mission, and any funding (think tens of billions) allocated to such a mission will necessarily push a Mars mission back by a decade or more.

First, the science -- while the robotic mission to Mars have yielded many insights about the early history and present state of the planet, a human geologist could do more in a day or two than all of the rovers have done thus far. A small group of human scientists could completely rewrite the textbooks in a short stay on Mars. Can the same be said about a moon mission?

Second, living on the moon would be much more difficult (temperatures, micrometeorites, lack of ISRU, etc. etc.), and involve very different challenges than living on Mars. Most of what we learn on the moon will simply not translate to Mars--it will certainly not be a lot easier to live on Mars once a moon base is established, we would nearly be starting from scratch.

This is a perennial debate in the human spaceflight program, and I understand the desire to do something given decades of inaction. However, we must be honest about what we stand to lose if we shift our focus to a return to the moon. There is precious little gain from both a science and engineering perspective.

Good points on both sides of the debate. Why not do both? Imagine the "we" is really 7.4 billion people (~195 countries) so it would seem that surely we could support each others' efforts to reach both destinations. What an achievement for humanity that would be!

It's a nice sentiment, but if you pool all the money NASA devote to human spaceflight there's barely enough to maintain R&D for a Mars mission with landing in the next 15-20 years, any split in funding between Mars and a manned Moon program, you're seeing a Mars landing easily past 2050.

It's really a zero-sum game, unfortunately.

I believe WOOKIE_pizza was referencing an international effort.

The purpose of being on the moon is having it as a massive manufacturing place for building things to move outward in the solar system. Lifting things out of the earth's gravity well is just too expensive.

Compare the size of the Saturn 5 rocket to get to the moon with the size of the rocket needed to come back.

I do not see the challenges of building a habitat on the moon that much different from Mars. You have (essentially) zero atmosphere, lots of radiation, the same problems with building a pressure dome, etc.

Landing men on Mars is certainly romantic, but it will be so expensive and time consuming that it cannot have much practical value.

The cost of shipping factories (and many raw materials) in pieces from the Earth to the Moon and then assembling them there should certainly outweigh just building and launching from Earth, especially as private companies perfect reusable rockets.

Beyond just the gravity difference and the scarcity of any resources for in-situ utilization on the Moon, temperatures will vary from <-100 degrees at night to > 100 degrees (celcius) during the day. This is a vastly different regime than Mars, which has a much more temperate day-night gradient.

Landing men on Mars is certainly romantic, but it will be so expensive and time consuming that it cannot have much practical value.

It will be both expensive and time-consuming, but just imagine the science a few geologists could do on Mars, and what they will reveal about not just the red planet but also about our own.

> scarcity of any resources

All we know about that is from a few bags of rocks. Nobody knows what the real situation is there, not even close. It might be like the proverbial caveman freezing to death sitting on a coal deposit.

There are also a lot of information get by various type of spectrometers in satellites. For example, you can read: https://en.wikipedia.org/wiki/Lunar_Prospector#Scientific_ex...

> The Lunar Prospector GRS produced the first global measurements of gamma-ray spectra from the lunar surface, from which are derived the first "direct" measurements of the chemical composition for the entire lunar surface. This data effectively maps the distribution of various important elements across the Moon. For example, the Lunar Prospector GRS has identified several regions with high iron concentrations.

That says nothing at all about what is under the topsoil.

> shipping factories

The idea is to ship the factories that build the factories that build the factories that build the factories that can build large ships in large quantities.

If only life were an RTS game :)

If we are talking about taking advantage of resources not available on Earth, the untold riches of the Asteroid Belt are eminently more accessible from Mars.

Asteroids present other major difficulties, such as being much, much farther away, and having no gravity.

What resources are we missing on earth ? I mean resources that we miss because they're in too low quantities for useful applications (not resources that are scarce and useless or resources whose scarcity is the result of politics)

One element I can think of would be platinum. It's high price is one of the reasons why fuel cells aren't cost effective at the moment.

Gold for radiation shielding?

I'm not sure how true that is, gravity wells being what they are

> Compare the size of the Saturn 5 rocket to get to the moon with the size of the rocket needed to come back.

That is not fair comparisson. Saturn V needed to also lift the rocket that came back.

So did the rocket that came back. Quite a bit of mass did get left behind though.

Would you be interested in bringing Empire to space? To the Moon is possible but difficult and short-lived. I'd prefer the ISS, bandwidth is okay, it would run for months, just need to keep the computational requirements reasonably low (should be possible for a turn-based game). Participants connect via Internet. I'd manage the space stuff, you bring the fame and the fun. (I played Empire Deluxe from 1994-2003 excessively with friends, what a time. Would be a nice way to give back.) It's very spontaneous, but let me know what you think.

> Would you be interested in bringing Empire to space?

What, bring the moon under iron control? I like the way you think!

Great, let's check it out. I'll send you an email over the weekend.

100 percent agree.

The most logical plan I heard was the following: Solar power works way better, and potentially nonstop at the poles of the moon. Use that energy to cook moonrock into building materials and lauch it all into orbit on an electromagnetic mass driver. Then design and build Oniell cylinders, once we have rigorous tests of artificial gravity on humans. If you want a Mars base after the fact, go for it. Put a station in orbit around Mars that recieves deliveries from the moon.

> The most logical plan I heard was the following: Solar power works way better, and potentially nonstop at the poles of the moon.

the problem is, unless you're at the pole, you have 2 weeks of power followed by 2 weeks of pitch black darkness, so you have to have a lot of batteries or the station isn't livable 50% of the time.

Build two bases?

Run a power cable from the pole. Put a mirror in orbit. Put a nuclear reactor on the moon (don't have to worry about safety issues, which should lighten it considerably).

No, the moon doesn't make any sense. It's a big, dusty, radiation-blasted rock. Sure, we could build bases there, but why would we? That's the question Apollo managers could never answer and why the program was ultimately shut down.

.Net Rocks podcast did a fantastic episode (A Geek Out episode) recently on why we should consider building moon bases - https://www.dotnetrocks.com/default.aspx?ShowNum=1424.

TL;DR Version (From show notes): We have not explored much of the moon at all, we can extract fuel and manufacture things on the moon, we need to understand how humans function long term in low gravity (rather than freefall), and finally, there are some unique science opportunities on the moon.

> It's a big, dusty, radiation-blasted rock.

So is Mars. I do think we should be seeking out extremophiles on Earth and seeding Mars with them to see if anything takes hold, but I seem to be in a minority of one on that notion. :-)

Ah ... I doubt it would work and be worth the effort and I doubt we should do that, before we explored mars for indiginous life first!

("probably terran!" ... reference to the the mars chronicle from K.S.Robinson)

> before we explored mars for indiginous life first!

We already have. It's a liveless rock. How much more do we keep moving the goal posts and beating that dead horse?

Maybe until we explored a bit more, than a few areas on the surface? Mars is HUGE.

Potential areas for life might be in vulcanic areas underground.

Might not be a high chance, granted. But the chances that anything from your project survives are far lower - but it would definitely damage research on current or historic life on mars a lot.

Eventually our microbial biomes will merge with any ecosystem or planet we visit. It's virtually guaranteed. This shouldn't stand in the way of our visiting, we should simply be prepared for intermixture.

> Maybe until we explored a bit more, than a few areas on the surface? Mars is HUGE.

That's true. But life does have a way of spreading around. And beware of constantly shifting the goal posts.

I remember an SG1 episode, they turned up on a planet which was a frozen wasteland for as far as the eye could see, no evidence of any life later than microbes.

Turns out the planet was earth - they were in Antarctica.

Clearly not comparable, but there's a big difference between salt flats in Namibia or the seater in Antarctica and landing in downtown manhattan or the Brazilian rainforest.

We've successfully sent half a dozen probes to mars, we've barely scratched the surface.

Besides what all the others have said in favor of moon, I would add: https://what-if.xkcd.com/124/

Seriously, I bet there are many rich people willing to go to the moon, if reasonable safe and fast. And this probably could be done with the moon quite soon ... and all of that would be a BIG push for everything else in space.

(especially if we manage to build rocket factorys on the moon...)

The "dark" side of the moon is shielded from earth's considerable RF emissions. It's a great place to stick a massive radio telescope.

> Mars doesn't make any sense. The moon does.

I agree, except for the fact that the moon has already been done, and Mars has not. That being said Mars would be a colossal waste of money, robbing resources from real science that is currently getting done in space. If you think the James Webb telescope stymied other scientific efforts, just wait until the US goes all in on Mars.

https://www.nytimes.com/2016/11/22/science/nasa-webb-space-t...

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