Ice Station Thuban

I realized I basically did the whole build log while writing up the instructions, so check out the instructions. Some more pictures there too.

So for this log I will write what I learned, pros and cons:

Cons:

• The triangular panels are very heavy. Smaller panels could have resulted with a higher order tesselation, but it would have increased the number of unique shapes to keep track of and orient. The tradeoff would have resulted in longer management time, and may have made it impossible to complete in the timeframe available. Managing fewer, but larger and heavier panels may have been faster, but was certainly not easy, and was actually dangerous. The panels are slippery, because they are made of ice, and they are pointy, being triangles. They do drop, and they do drop on your foot. I would say there was approximately a 25% casualty rate on these triangles just from slip and fall.
• The wooden panels were thin, because I was looking for the least expensive solution for these forms.That in itself was not a con, but the thin wood flexed outward from the weight of the water. This means the edges were not quite straight, and therefore two adjacent triangles always had a gap of an inch or two somewhere along the seam. A mortar made of snow and water worked quite well to fill these gaps, but it did lead to imprecision in placement, further leading to spherical aberration errors that required constant correction.
• The large panels each had a large thermal mass, making them take a very long time to freeze, even when the air temperature was very cold. Scooping out an air channel in the snow under the center of the form to create airflow and potential heat transfer may have helped a few percent.
• Rhombic triacontahedron tessellation required that each triangle be placed in the correct orientation every time. Two shapes were mirror images, so it could get confusing, and I did make some mistakes I had to correct.
• Plastic sheeting would develop pinholes. That would cause water to drain out faster than it could freeze, but too slow to notice the leak. Easily fixed with more plastic sheeting, but detecting this problem took hours, resulting in huge delays in the manufacture of a single panel. Significant when a single panel is such a large percentage of the total hemispherical area, and you are racing the weather.
• Oh my aching back.
• Oh my freezing hands.

Pros:

• The triangular panels were large, so when one was placed, it took up a large solid angle comprising the hemisphere. The placement task could be done quite quickly.
• Rhombic triacontahedron tessellation provided a low number of unique triangular shapes, while providing a high degree of spherical approximation.
• Sound effects: inside the dome was highly echoic and various focal points for sound existed. Two people talking inside the dome could find certain spots with an amplification effect.
• Light effects: looked cool!
• Unique - only one on the block!

Here are some pretty pictures from after the melt.