Talk:Cost of energy on Mars

Good catch about the more practical 2 MW reactor, will use that instead of Kilopower, and likely nuclear will rule the day. Perhaps the discussion about thorium should go into the Thorium page?

In general it would be simpler to remove all mentions of nuclear fuel limitations from this page, as it's rather speculative, one way or another?

Thorium reactors are cheaper, or more economical. They are not more efficient in the usual sense of efficiency. Kilopower is only 25% efficient and future Martian reactors might not be optimized for fuel efficiency but for cooling system costs.

• There is no way a reactor with moving parts will last 50 years. It's entirely speculative. 10 years is speculative too, of course, so likely a range or a table would be better. In that case, of course solar can go into a table as well.

• Igneous rocks may not be precise enough. granites vs basalts might be a better division, and basalts, I believe, are poor in thorium. Again best discussed on the Thorium page.

If solar is not the primary power source, it becomes more attractive. A Martian colony is likely to be power starved. Some industrial processes could be scheduled for periods of peak sun. For example, a solar furnace could be loaded at night, and in the day time fire ceramics. Solar heat could be moved into masses with high thermal inertia, which would keep the colony warm at night. Growing plants require gigantic amounts of light, and with an approximately 24 hour day (??), solar is suitable for crops. A fair (??) bit of water is frozen in the subsurface soil of Mars, and solar power could heat patches of ground to release water vapour to be captured and condensed.

• Erased this as it has nothing to do with the cost of solar, but rather with technologies and only confuses the issue. Direct solar can be used with any other technology, be it photovoltaic or Nuclear. Waste thermal energy will also come from either a nuclear reactor or cooling of production areas.

If we are going to compare solar and nuclear, a fair comparison should include the cost of developing a specific nuclear reactor for Mars.

• The assertion that Mars is extremely low in radioactive should be discussed. Radioactive ores on Earth are usually found in igneous rocks, and Mars has had a similar history of vulcanism, indeed, Mars has more igneous rocks exposed on the surface than Earth. Thorium and radioactive potassium has been found by the Odyssey orbiter, but it does not detect ore bodies, but dust and surface soils to a maximum of 1 meter deep. (If Odyssey was orbiting Earth, it would not find thorium ores, but rather detect the low levels of Thorium found in soil everywhere.) So I do not consider the low levels of potassium/thorium found by Odyssey to be strong evidence that Mars lacks radioactive ores.

• • This is wrong. the average thorium on Earth in dirt is known and is about 6ppm. If the average dirt on Mars is 1 ppm, then the availability will be lower. Six times less is not slightly less.

Sorry to say this but sources (5) and (7) are wrong, they seem to be convincing fabrications. The same author, in longer papers, goes on to discourse about the Face on Mars, Martian nuclear wars and other follies. Actually, just read reference 7 to the end, wonder at how that author ever got published, and erase the reference.

// Rick here. Make a page which organizes the arguments for amount of U/Th/K on Mars? Spend more time on this later.

Michel: The Thorium page presents the arguments about surface concentrations. It would be good to add the arguments about abundance and core separation mechanisms. If much of the northern hemisphere is a former sea, then the Thorium might be at the bottom of it :-) However then the southern hemisphere should have more and that is not visible in the satellite data. It only takes one mine to make Thorium or Uranium work as an energy source, of course. We can compare with thorium on the Moon, mapped using similar instruments, where a known geological mechanism called Kreep created concentration of up to 10 ppm in large areas, but where the basalts are between 0 and 2 ppm.

Granites on Earth, on the other hand, have a normal concentration of 22 ppm, and there are large formations at over 50 ppm.

There are likely to be granites on Mars: https://arstechnica.com/science/2015/07/curiosity-finds-continent-building-rocks-on-mars/ So these might be possible sources for Thorium concentrations. Time to send geologists!!

Meteoritic impacts might also have helped to concentrate minerals, hence metals, in hydrothermal vents, or in magmatic chambers. However, the minerals need to have been there in the first place.

I have moved most of the discussion of the rarity of radioactives into its own page. Welcome comments there.

Warm regards, Rick.

I've redone the calculation with the much improved reactor. As expected, nuclear now wins the race. The developments costs are a hopelessly speculative subject, but likely the army/ US gov in some manner will foot the bill to develop small nuclear reactors, so I've excluded them. I have a spreadsheet if you are interested.

Nice job on the revision Michel. However, I don't see cost and mass estimates for a) equipment to track the sun across the sky, b) the batteries + methane generators to keep them up for weeks or months long dust storms, and c) automated equipment to dust the panels.

Moving parts are liable to be problematic on Mars because of the dust.

Super accurate numbers are not needed. Even very favourable, super-optimistic values are ok. But I think that SOME value would be better than none, so that they can be considered and updated if better information comes along.

Warm regards, Rick.

The mass target is 3.5 kg/m2 to take the rotation elements, batteries and backup power systems into account. The NASA Mass target is actually 3 kg/m3, so I'm pretty confident. I'm not too worried about the dust. The rovers have been doing OK despite it all. And the motion is very limited and repetitive so should be easy to have booties around the moving parts. Yes, the point of the article is to have a target, not to be precise. I think my conclusion is more or less in the ballpark, but yes, will evolve with time, as it has just done :-) Best, Michel