Why colonize Mars and not the Moon?

[mfb]

It's not about easier or harder. It's about rarity.

Rarity is exactly what makes it hard.
A cubic kilometer of average Earth's crust has gold with a worth of a billion dollars. But extracting the gold out of that would cost much more than a billion dollars.

How frequent is platinum on Moon? How much does it cost to collect and extract it? How does that compare to Earth?
You have a few asteroids on the surface, but it is unclear how efficiently you can collect them, and how much extracting the interesting metals out of them would cost.

 

[Chronos]

The value of rare commodities is market driven. Vanity items will have little utility in a space based economy compared to oxygen, water and food. We need to ponder the economic realities of a space based society before we can anticipate supply and demand. I seriously question the market value of commodities, like rare metals and gems, far from earth. What do you think a mining company would offer for a solid gold asteroid beyond the orbit of Mars?

 

[Vanadium 50]

but Earth is the only known class-M planet around here

This is Star Trek, not science.

 

[Stavros Kiri]

This is Star Trek, not science.

True as a term, but in essence means :
"Earth-like planet, the Class M designation is similar to the real-world astronomical theory of life-supporting planets within the habitable zone."
[Normally requires atmosphere "composed of nitrogen and oxygen and an abundance of liquid water necessary for carbon-based life to exist."]
(source: wikipedia)

Obviously Mars and Moon aren't ...

P.S. the above explanation in terms of Astronomical and Astrobiological terms is science ... just longer to explain or quote ...
[But truly thanks for pointing it out!]

 

[Al_]

How frequent is platinum on Moon? How much does it cost to collect and extract it? How does that compare to Earth?
You have a few asteroids on the surface, but it is unclear how efficiently you can collect them, and how much extracting the interesting metals out of them would cost.

Asteroids, and meteorites, can contain raw metals that in some cases need no extraction or processing at all.
http://www.space.com/30074-trillion-dollar-asteroid-2011-uw158-earth-flyby.html
Such things have been collecting on the Moon's surface for the last, approx 4 billion years, since most of it was last molten.
There are spectral methods that can spot elements from great distances, say from low moon orbit. Then send in the robot digger.
Compare the cost to Earth? Well, I don't know. At what stage in the deveolpment of the colony?
But don't forget - precious metal mining can be extremely profitable. Costs can be far below sales prices. Sitting on a gold mine.

 

[Al_]

What do you think a mining company would offer for a solid gold asteroid beyond the orbit of Mars?

That depends on the cost to go get it.
Which depends on satellite costs and launch costs.
Which depends on satellite tech, and if you launch from a low g place like the Moon.
So, for a Moon colony with ice mines and fuel production, basic metal bashing for satellite bodies, and imported avionics and robotics, a gold asteroid looks like a good opportunity to make some big money.

 

[Al_]

Vanity items will have little utility in a space based economy compared to oxygen, water and food.

True, so maybe the Gold gets dumped to Earth for cash, the Silver is kept for wiring, some of the Platinum for use as a catalyst and the rest dumped, and all the water ice and other volatiles kept.

 

[Al_]

You have a few asteroids on the surface

Have you seen the Moon?

 

[Al_]

The moon is like a sample of Earth's crust, but without the chemical processes to enrich some metals in some places.

Yes, and no. There were different processes, and still are. The isotopes ratios are similar, but not identical.

 

[1oldman2]

As usual Jason has put together a good piece here.
http://www.planetary.org/blogs/jason-davis/2017/20170126-moon-vs-mars-hsf.html

 

[Al_]

As usual Jason has put together a good piece here.
http://www.planetary.org/blogs/jason-davis/2017/20170126-moon-vs-mars-hsf.html

He makes a good point about the abrasive nature of Lunar dust. I think that walking on the surface will come to be seen as an emergency procedure only. Robots can be made with hard abrasion resistant exteriors and rotary joints with extremely good dust seals, even in vacuum. I'm sure in future, in space generally, they will be the outside workforce. They will either work autonomously or under Virtual Reality telepresence control from a person in a sheltered habitat or on Earth.

In fact that is one big advantage that the Moon has over Mars - the signal delay is much less. Getting a robot to the Moon is one of the easier things considered here, and if that robot has arms and the ability to work there under Earth control, we have a huge asset to help various stages of development of Lunar activity.

 

[mfb]

In fact that is one big advantage that the Moon has over Mars - the signal delay is much less. Getting a robot to the Moon is one of the easier things considered here, and if that robot has arms and the ability to work there under Earth control, we have a huge asset to help various stages of development of Lunar activity.

=> Rovers to Moon, humans to Mars?

Even when controlled by a human, current rovers cannot do many things a human can. Picking up a rock? Yes, but only with a dedicated arm to do so, and it won't work if the rock has an odd shape. Breaking the rock free first? Better have an additional arm with a hammer. Picking up dust? Another tool. Cleaning solar cells? We don't have a tool for that yet. There are to many rocks in the way? You have to go somewhere else. Wheels getting stuck? Oops. Some other part has some minor technical defect? The tool won't be useful, or in the worst case break the whole rover (e. g. solar panels that don't deploy).

 

[1oldman2]

I realize the following pushes the limits of acceptable sources for this thread, I did find it relevant (as well as a little dated) enough to mention it though.
Its just possible there may be some points worthy of discussion as its in the general subject area of the thread.
http://blogs.discovermagazine.com/crux/2014/09/08/where-build-off-world-colonies/

 

[nikkkom]

Asteroids, and meteorites, can contain raw metals that in some cases need no extraction or processing at all.

These metals are usually Fe and Ni. We have them here on Earth in abundance. Even if pure Ni is lying on the Moon, merely packing it up and sending to Earth would cost more than producing it from Earth's ores.

But don't forget - precious metal mining can be extremely profitable. Costs can be far below sales prices.

Handwavium with not a shred of calculations. Show us reasonable economic estimates that any metal on the Moon is profitable to extract and sell on Earth.

 

[Stavros Kiri]

I realize the following pushes the limits of acceptable sources for this thread, I did find it relevant (as well as a little dated) enough to mention it though.
Its just possible there may be some points worthy of discussion as its in the general subject area of the thread.
http://blogs.discovermagazine.com/crux/2014/09/08/where-build-off-world-colonies/

Some interesting points there. Is the part about Venus reasonable though? Also, with just 0.38 of Earth's gravity on martian surface, they fail to mention that this creates also a problem for the atmosphere to be terraformed (something that needs to be dealt ...) , as discussed previously here about gravity on Mars (etc.) ...

 

[mfb]

The gravity of Mars is sufficient to keep the atmosphere. Over millions of years, we would probably want an artificial magnetic field to reduce losses due to solar wind, but that is irrelevant today. If humans are still around in a million years, they will solve that issue with technologies we cannot even imagine today.

The lower gravity and the lack of a magnetic field are no obstacles to terraforming.

http://blogs.discovermagazine.com/crux/2014/09/08/where-build-off-world-colonies/

The article is completely outdated in terms of plans to go to Mars.

 

[1oldman2]

The article is completely outdated in terms of plans to go to Mars.

True, thus my disclaimer. "I realize the following pushes the limits of acceptable sources for this thread, I did find it relevant (as well as a little dated) enough to mention it though. "
I do have to admit to a certain amount of "literary License" in post #343 but after reading some of the earlier posts regarding Nuking martian moons and comparing martian colonies to Dubai, well I figured what the hell... "Its just possible there may be some points worthy of discussion as its in the general subject area of the thread."

 

[1oldman2]

Some interesting points there. Is the part about Venus reasonable though? Also, with just 0.38 of Earth's gravity on martian surface, they fail to mention that this creates also a problem for the atmosphere to be terraformed (something that needs to be dealt ...) , as discussed previously here about gravity on Mars (etc.) ...

From a personal viewpoint, I don't know enough about terraforming to comment on Mars or Venus, (either one would have to be a very long term project and I would defer to mfb's opinion on the matter.) As for Mars it seems there are some environmental conundrums that science needs to work out besides the atmosphere, radiation, perchlorates (https://phys.org/news/2015-06-future-issues-perchlorate-poses-colonizing.html), transportation etc. For example there doesn't appear to be an explanation for, https://www.nasa.gov/feature/jpl/nasas-curiosity-rover-sharpens-paradox-of-ancient-mars
"Mars scientists are wrestling with a problem. Ample evidence says ancient Mars was sometimes wet, with water flowing and pooling on the planet's surface. Yet, the ancient sun was about one-third less warm and climate modelers struggle to produce scenarios that get the surface of Mars warm enough for keeping water unfrozen."

"We've been particularly struck with the absence of carbonate minerals in sedimentary rock the rover has examined," said Thomas Bristow of NASA's Ames Research Center, Moffett Field, California. "It would be really hard to get liquid water even if there were a hundred times more carbon dioxide in the atmosphere than what the mineral evidence in the rock tells us." Bristow is the principal investigator for the Chemistry and Mineralogy (CheMin) instrument on Curiosity and lead author of the study being published this week in the Proceedings of the National Academy of Science.

 

[Stavros Kiri]

The gravity of Mars is sufficient to keep the atmosphere.

How do you justify that? [If you already have earlier and I missed it you can just quote it ... ; it's been a long discussion ...] Are you sure that with a little over 1/3 of the gravity on Earth we can have on Mars a thick and high enough earth-like-terraformable atmosphere (including ozon layer etc ...)? I haven't done the math.

 

[nikkkom]

How do you justify that? [If you already have earlier and I missed it you can just quote it ... ; it's been a long discussion ...] Are you sure that with a little over 1/3 of the gravity on Earth we can have on Mars a thick and high enough earth-like-terraformable atmosphere (including ozon layer etc ...)? I haven't done the math.

The existence of current Mars atmosphere is a proof that rate of escape is low enough.

The key here is that thicker atmosphere, at the same temperature, generally does not escape faster than a thin one (as long as mean free path at the surface is such that molecules can't escape directly from surface).
IOW: if you add CO2 to Mars so that you have 1 bar pressure at the surface, this thicker atmosphere will survive for hundreds of millions of years, if not billions.
(O2/N2 atmosphere will evaporate somewhat faster, because these molecules are lighter than CO2.)

 

[litup]

The usual two-way trip plans have 4-6 months in transit, about 1.5 years on the surface and 4-6 months back. Total mission duration ~2.5 years, more than half of the mission at the surface of Mars.
Changing those times significantly would need much more powerful rockets.As self-sufficient as possible, especially for bulk material, is certainly interesting to limit transportation needs. You don't want to produce computer chips on a Mars colony (unless the colony is huge already), but you certainly want to produce most of the goods you use there.A colony on Mars would tell us a lot about the ecosystem on Earth as one of many byproducts.

Sure, more powerful rockets based on today's chemical rockets but there are others afoot, like VASIMIR and so forth, where you would need some kind of multimegawatt power source, most likely nuclear. At even 1/10 g trip time is about a week or two. One problem about Mars: Not much in the way of magnetic fields aroun Mars. That however can be solved if and when we develop room temp superconductors, I envisioned a superconductive loop around the equator, a few turns with about 20,000 amps flowing and you get a planet wide field like Earths only a bit weaker, maybe half gauss or so, still good enough to stop the bad guys coming from the sun Next would be to build up some kind of atmosphere. Not in my pay grade:) but with a planet wide field, the sun would not be stripping O2 from the atmosphere like it has for the past few billion years. If the superconductor loop was room temp plus a bit, the field would never go away unless somebody blew up the cable.

 

[mfb]

How do you justify that? [If you already have earlier and I missed it you can just quote it ... ; it's been a long discussion ...] Are you sure that with a little over 1/3 of the gravity on Earth we can have on Mars a thick and high enough earth-like-terraformable atmosphere (including ozon layer etc ...)? I haven't done the math.

Simple comparison of the gravitational potential and the mean thermal energy of molecules.

The Martian escape velocity is 5.03 km/s, at 100 km height this drops a bit to 4.96 km/s. A single oxygen atom needs an energy of 2.05 eV to escape. At an exosphere temperature of 300 K (source), the average kinetic energy is just 0.039 eV, a factor 50 below the energy needed to escape. For oxygen molecules, the factor is 100. Thermal escape of oxygen (and nitrogen) is completely negligible. For hydrogen molecules, the ratio is 6.6 - some will escape. For single hydrogen atoms, the ratio is just 3.3 - they have a significant chance to escape. At 300 K, the fraction of single hydrogen atoms should be small, however.@litup: As discussed, such a magnetic field could be interesting a million years in the future, it is irrelevant for the next thousands of years. We could build it with nearly present technology (cool the superconductors). If there are humans that want a magnetic field on Mars in a million years, they will probably solve that issue with technology we cannot even imagine today.

 

[1oldman2]

Well, this is the direction in which the "powers that be" are currently leaning.
http://www.spaceflightinsider.com/o...irect-nasa-moon-establish-sustained-presence/

 

[mfb]

We'll see if that bill gets passed. Even if it does, it is something beyond the timescale of the current administration. The current official SLS plans are an unmanned maiden flight in 2018, and a manned mission to lunar orbit in 2021. I heard that the components are behind schedule, and the 2018 flight will nearly certainly get shifted. So let's say we have a maiden flight in 2019 and a manned mission in 2022. A lunar lander making an unmanned flight in 2024, with a manned mission 2025?

 

[Al_]

Rovers to Moon, humans to Mars?

For a colony, they need each other. They need to be in the same place.

current rovers cannot do many things a human can

A rover is not a multi-purpose robot. See NASA's space robot, Robonaut. https://robonaut.jsc.nasa.gov/R2/

I realize the following pushes the limits of acceptable sources for this thread, I did find it relevant (as well as a little dated) enough to mention it though.
Its just possible there may be some points worthy of discussion as its in the general subject area of the thread.
http://blogs.discovermagazine.com/crux/2014/09/08/where-build-off-world-colonies/

Touches on the important question of gravity : How high does gravity have to be before it is strong enough to raise a child healthily?
Short answer : nobody knows. But there are ways to find out. For example, raise apes in low-g. Monkeys on the Moon!
Maybe build a rotating space station at say 0.9g and raise children there. And adults living a long time in Moon gravity - what would that do? We could and should start to research these questions.

The movie "The Space Between Us" has a plot twist where a boy raised on Mars is too unused to the gravity to survive on Earth. I am not aware of any good evidence to either justify or refute this.

Show us reasonable economic estimates that any metal on the Moon is profitable to extract and sell on Earth.

I was referring to the case when a Lunar colony is already underway, and I was not referring to Nickel.
Gold, Platinum or Palladium, perhaps. It also depends on having a Lunar source of rocket fuel available, and the ability to make crude heat shields on the Moon. Maybe make them from basalt fibre and aluminum?
The rocket can be re-used. After lauching the payload into Earth re-entry orbit it heads back to the Moon.

 

[sophiecentaur]

Eventually, if we had the technology to transform Mars into a habitable planet,

That concept always makes me smile. So far, we are doing a pretty good job of transforming Earth into an Uninhabitable planet. You first need to 'transform' the whole attitude of humans to their environment. I'm not suggesting it's impossible but I wouldn't bet my last £ on it.

 

[mfb]

For a colony, they need each other. They need to be in the same place.

Humans will always have robots around, but the other direction is not true.

A rover is not a multi-purpose robot. See NASA's space robot, Robonaut. https://robonaut.jsc.nasa.gov/R2/

The https certificate is broken.
Rovers are the best robots we have now. Yes, they will improve in the future, but for now humans are far superior to robots, even if we compare humans to remote-controlled robots.

 

[Al_]

I just want to remind you that colonisation is not the same as terraforming.
Colonisation is a much earlier step. It requires enclosed, pressurised habitats comparable in size to buildings on Earth, as opposed to planetary scale modifications.

 

[Al_]

Rovers are the best robots we have now

That's a matter of opinion.
http://www.bostondynamics.com
http://robonaut.jsc.nasa.gov/R2/

 

[nikkkom]

> Show us reasonable economic estimates that any metal on the Moon is profitable to extract and sell on Earth.

I was referring to the case when a Lunar colony is already underway, and I was not referring to Nickel.
Gold, Platinum or Palladium, perhaps.

"Perhaps" is not a reasonable economic estimate. It's a sign you do not know.

Today, after we spent some 60 years of R&D on launch vehicles, a kilogram of any cargo sent from Earth to LEO on a cheapest rocket costs about 1/10 of one kilogram of gold.

Lunar launch infrastructure would need about a century of active development to reach this efficiency.