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#1 2018-03-10 18:42:41

Void
Member
Registered: 2011-12-29
Posts: 2,345

Inverted Domes.

I have always been uncomfortable with the words "Dome" and "Greenhouse".  As they are represented on Earth they seem really stupid for Mars.

Typically I have annoyed the people here with aquatic devices.

Now I will propose an alternative for a real possible greenhouse with pressurization internal.

I do not prefer a inverted half dome.  But I will begin with it.

Say you had a metal frame inside of a circular wall, and a berm piled on the outside of the circular wall.  Then wrap the metal frame with tensile cables crossing strait across the top.  But the top of the frame will be concave.

I do not trust glass panes in a frame to hold air pressure.  Not on a Mars where they may be subject to day night temperature shifts, and a large differential pressure.

So I propose a balloon inside to fill the metal frame.  This will be periodically replaced or patched as might be practical.

Then having listened to RobertDyck, I propose to indeed add windows of glass, so that U.V. absorbing solar cells can be placed on top of those glass windows.  The purpose to absorb and use the U.V. to generate electrical power but to let through the light that the plants need.

But I want to modify that.  Instead of a half sphere, I want concave in only one dimension.  A rectangle of stone wall with berm around it, and cables lashed around the circumference of a rectangular concave glaze structure.

https://en.wikipedia.org/wiki/Concentrated_solar_power

Not like this:
330px-1901_solar_motor.jpg
 
More like this:
330px-Parabolic_trough_at_Harper_Lake_in_California.jpg

They have supplied me with words: "Parabolic Trough".

However not a concentrating mirror, a greenhouse glaze.

So a greenhouse that is perhaps capable of holding a pressure properly, and dealing with U.V., and allowing less durable "Plastic" films to be the "Balloon".

Added to that would be two other items I think.
1) Yes put a few inches of water on the bottom.  Reason:  Day night temperature fluctuations.  A thermal tempering method.
*But your plants would be in planters which extend above the shallow water, so that you can grow "Normal" crops in a more "Normal" way, per the efforts of Robert Dyck and Spacenuts work.
2) I would like the metal frame to have interior tubes, so that you could use it as a radiator.

......

Oh! Something to add.  A diffuse reflector wall to be installed on the leeward to the source sunlight side of the Parabolic Trough.

That to improve the lighting conditions inside the greenhouse, while not creating too much thermal shock to the glass and other parts.



Done.

Last edited by Void (2018-03-10 19:03:48)


I like people who criticize angels dancing on a pinhead.  I also like it when angels dance on my pinhead.

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#2 2018-03-10 19:06:00

Antius
Member
From: Cumbria, UK
Registered: 2007-05-22
Posts: 1,003

Re: Inverted Domes.

I am not sure I understand exactly what you are proposing.  Do you mean a concave metal frame with a berm counterweight?

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#3 2018-03-10 19:17:14

Void
Member
Registered: 2011-12-29
Posts: 2,345

Re: Inverted Domes.

Alright it is hard with words.

Suppose you make a rectangular metal frame.  Then warp the top downwards to make a concave.

Then to add strength, wrap the frame with some high tensile cables, around the lesser dimension.

Then fill the frame with a plastic balloon.

Then place glass panes into the concave part of the frame.

And existing by this time should be a block wall around the perimeter of the device, and pushed against the block wall a berm.

Then on top of the berm a reflective wall, but in the northern hemisphere only on the north side, and in the southern hemisphere only on the south side.

I prefer defused reflection as I did some experiments with shining a concentrating mirror output through normal window glass, and found that it will crack from thermal shock as the sun moves.


I like people who criticize angels dancing on a pinhead.  I also like it when angels dance on my pinhead.

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