Starship Asterisk*

Just seen this:

https://vimeo.com/25401444

Could be a real technology for manufacture beyond Earth?
Mars's sand would probably do the same - Would it work with lunar regolith?

John

JohnD wrote:
Just seen this: https://vimeo.com/25401444

Could be a real technology for manufacture beyond Earth?
Mars's sand would probably do the same - Would it work with lunar regolith?

I'm for putting coal miners back to work...on Mars

(They could use a little global warming.)

neufer wrote:I'm for putting coal miners back to work...on Mars

(They could use a little global warming.)

To bad Mars never had a Carboniferous Age. Better to outsource methane expellers.

JohnD wrote:Just seen this:

https://vimeo.com/25401444

Could be a real technology for manufacture beyond Earth?
Mars's sand would probably do the same - Would it work with lunar regolith?

John

Could work a lot better on the Moon than on Mars. Sunlight would be more intense and the sun would move across the sky much slower, making focusing aiming easier. Less heat loss in a vacuum too.

Bruce

That wasn't my doubt, but is regolith 'fusible'?

In the absence of an answer, I did some research:
Terrestrial sand is mainly quartz, Silicon dioxide, unless the underlying rock or the rock the sand has come from is something else, like limestone.
Lindsay in "Lunar Stratigraphy and Sedimentology" (p. 237) lists the chemistry of lunar soils sampled by Apollo missions and they vary little around 46% SiO2. So the Solar Sinter should be valuable on the Moon.

But on Mars? NASA figures for Martian sand composition seem to show show a very different picture, much less SiO2, more Al2O3: https://mars.jpl.nasa.gov/multimedia/im ... ageID=4910
But authors who have used this result interpret this to mean a composition very similar to sand or lunar regolith: https://reprage.com/post/home-made-simulant-mars-dirt
So I'm puzzled!
John

Al²O³ melts at a higher temperature than SiO², (2072 and 1713 degrees C respectively) and the ambient temperature on daytime Mars is much lower than on the Moon. Still, other than being a bit harder to do on Mars it should still be doable, I would think. Calls for experiments on both worlds.

It might not work on low g asteroids though. The melt might spread too easily I would think.

Bruce

John, your Solar Sinter question prompts this: Can electric arc welding be done in space or in low g? Have any experiments been done?

Yes,BDM, https://awo.aws.org/2015/07/welding-in-space/ but that's not the question.

Bruce, in my experience, the weld pool has a surface tension that holds it together, and searching the literature finds that molten steel has an ST ten times greater than water! http://lib.dr.iastate.edu/cgi/viewconte ... ontext=rtd and http://www.engineeringtoolbox.com/surfa ... d_962.html (1.0 erg/cm2 = 0.001N/m) So it won't spread out easily.
I felt like you that Al2O3 might not fuse as easily as SiO2. But is there that much aluminium in Mars' sand? Will someone interpet the NASA figures for me, please? AS mentioned, they look as if there is much more Al2O3 than SiO2, but the guy who 'simulated' Mars soil used a Moon-like mix.

John

JohnD wrote:Yes,BDM, https://awo.aws.org/2015/07/welding-in-space/ but that's not the question.

Thanks John. Sorry I wasn't able to answer your question as well as you answered mine.

Bruce, in my experience, the weld pool has a surface tension that holds it together, and searching the literature finds that molten steel has an ST ten times greater than water! http://lib.dr.iastate.edu/cgi/viewconte ... ontext=rtd and http://www.engineeringtoolbox.com/surfa ... d_962.html (1.0 erg/cm2 = 0.001N/m) So it won't spread out easily.
I felt like you that Al2O3 might not fuse as easily as SiO2. But is there that much aluminium in Mars' sand? Will someone interpet the NASA figures for me, please? AS mentioned, they look as if there is much more Al2O3 than SiO2, but the guy who 'simulated' Mars soil used a Moon-like mix.

John

Aluminum oxide is whitish, but Mars is the red planet, so shouldn't there be a lot of iron in Mars' sands? At least, that's where I thought its reddish color came from. Is this assumption wrong? Will search to see ...

Yep, the red color comes from iron oxide dust. There's much more Si and Fe than Al on the surface of Mars.

Bruce

BDanielMayfield wrote:Yep, the red color comes from iron oxide dust. There's much more Si and Fe than Al on the surface of Mars.

Maybe. Almost certainly, the most common elements in the martian crust are oxygen and silicon, as we see on the Earth and generally in rocky material everywhere. On Earth there is more aluminum than iron in the crust; on Mars the evidence is conflicting (mainly because of a shortage of samples and limited methods of measurement). Meteorites suggest the martian mantle may have more iron than Earth's, which volcanic processes may have delivered to the surface. In any case, however, it's likely that (as on Earth) the amounts of iron and aluminum on the surface are similar.

OK! Looks like the Solar Sinter will be useful on either Mats or the Moon! What could it make, though?

The video showed a largish machine, just about manhandleable. Should the ambition be to scale it up to construct a whole habitat room, or keep it this size and make bricks?

John

The rig shown in the Vimeo had a very wide focal point, which would be fine for bulky items (such as walls, bricks, etc.). It should be possible to refine the design for a smaller beam however, allowing for the production of many different items.

How brittle/fragile the output is might be a big problem, especially if whatever is made has to hold in your air. Breakage (and even just leakage) would be deadly.

Bruce

Surely the 'resolution' of this tech is the grain size of the sand?
Anything much smaller than a brick would be rather 'fuzzy'.

Bricks need mortar, I realise, unless they can be made to lock together like a jigsaw.
Sealing? Spray/paint the inside with something impervious.

Breakage? Have you ever hit a brick wall with your car, or fist?
John