farmerben

I know a roofer who shingled a geodesic dome "once". Key word "once".

What is the optimal size for domes and similar structures on Mars or on the Moon? How would you approach the problem? What are the constraining limits? 1. Wind loading or other structural parameters on Mars, not applicable on the Moon. 2. Manufacturing limited. Being easier to manufacture a small sheet of glass than a large one, and so on for other components. Pyramids would actually be much simpler and stronger to build than domes using aluminum and glass. 3. Transport limited. Components have to fit inside a fairing for interplanetary travel so that sets the size constraint. 4. Human scale. If you can fit everything you need into 100m2 then why build bigger? Even for agriculture on Earth it's usually better to build several small greenhouses rather than one huge one. 5. Constrained only by imagination and budget. Flying and jumping sports might become the most popular activities on the Moon. So a humungous aerodrome is desirable for purely entertainment purposes.

Robert Zubrin says that if we warmed Mars by 10 degrees C, then CO2 would outgas from the soil raising the pressure to almost 1/3 atm.

How warm could you make Mars? Enhanced global warming with CFC gasses can help you reach Mt Everest level environments according to Zubrin. But, what if you wanted to go warmer than that and become downright tropical. Can you do it with greenhouse gasses?

I have two major objections to the multi-verse theory as espoused by people like Sean Carroll. A few times I have talked with physicists who believe in the multiverse and they dismiss my objections as if I just don't know what I'm talking about and am not making a real point. These are my two arguments. 1. The set of Pythagorean right triangles is an cardinally countable infinite set. If anything possible can be found in an infinite set. then anything possible is a Pythagorean right triangle. The same argument works for uncountable sets. The length of sides and angles of triangle is uncountable. Therefore everything is a triangle. 2. In optics a typical sheet of glass will allow 95% of photons to pass and 5% to reflect. It depends on angle and a few variables but we need not go into all that. The same result is obtained if you send one photon at a time into the glass. Every photon splits the possible universes in two, one in which it reflected and one where it didn't. There are only two possible states yet one of them appears 95% of the time. So whenever a photon hits glass does the inverse split in 2 or does it split in 20 so the equation is balanced and we have 19 universes in which the photon was transmitted and 1 universe where it didn't?

A human would have a hard time turning around. A cat can do it. Basically touch your toes with your fingers then roll around to a full backbend. Dunno a human that can do it, almost though.

Within a few years we could have a solar collector near the south pole in perpetual sun, 20 km away from the known ice fields. Human exploration will include looking for lava tubes. And then figuring out if lava tubes can be sealed to create habitat. One method of searching for lava tubes is to set up a grid of seismometers and set off some dynamite. That could generate an acoustic subsurface map.

On the Mississippi river the towboats do not stop to refuel. Tender boats come out and refuel them with diesel in motion. I wonder to what degree you could do the same thing on batteries? The big towboats use about 10,000 kW of power.

Given that weight is a big issue and the square cube law. This could be a partial solution for ships.

What is the difference between crushed glass and sand? Can you use them interchangeably in concrete? If you were to spread crushed glass on the environment, would that be worse than spreading sand?

Another idea. What about using wood? Very little wood is "wasted" at saw mills, but more of it goes into fuel than engineered products. The engineered wood products require process heat after all. Anyway when you saw lumber anywhere from 25-50% of it ends up as wood chips and they will oxidize eventually one way or another.

Do staircases work in Martian or Lunar gravity? So do you want much larger steps to leap up to, or are staircases governed by the flexibility of the average person and need to be the same size?

i made it to lvl 8. not easy

Don't waste my time on another LEO station if it doesn't have a centrifuge.

It looks like they had plenty of extra fuel, albeit the mission was unloaded.

The top fins on starship took reentry damage. Good thing they are steel.

Competitors should be designing payloads right now. Think about how cheap the next Mars rovers will be. It's time to go find some lava tubes.

I guess it would be bad to sweep dust out an airlock, future collision hazard and all that.

Given the shortage on nuclear development on land, I see no reason to prioritize it on the water. Everything on boats break much more often due to the constant wave motion. Actually dirty maritime fuels reduce global warming due to the aerosol effect. https://www.livescience.com/planet-earth/climate-change/cutting-pollution-from-the-shipping-industry-accidentally-increased-global-warming-study-suggests

The chances of a nuclear accident are too high for this sort of thing. Meanwhile an electrical propulsion system that takes up less volume than an ICE is not necessarily better. What matters is the weight and the amount of extra water displaced. The engine rooms on conventional ships are huge and mostly empty space. Shipping containers are typically loaded to 25 tones or less. On US roads that is about the maximum weight without special permits. That's about half full with lithium batteries. Cargo ships also like to load the heaviest containers at the bottom and empties on top.

I'm not sure what tools. I've picked up tidbits like they used sharkskin for sandpaper. The red boats above I think are modern replicas of boats that were built in the late 17 or early 1800s. Even if you assume metal axes and metal chisels, it's still pretty impressive. For that matter the totem poles of the pacific northwest are impressive carvings if you wanted to make one without metal tools. One source I read said Europeans used to lash hull planks together with leather until the Vikings invented the technology of nailing planks to the hull. The Romans appear to have used mortise and tenon (peg or biscuit) joinery to bond planks edge to edge. Anyhow that is an astonishing number of skilled man hours that go into building a ship, akin to building a temple. The Viking clinker method sped things up considerably. Metal axes and knives were the first things traded by early Spanish explorers. One preferred method for introducing yourself was to hang a tomahawk in a tree some distance from a village. The next time you return sit still under that tree with a blanket full of trade goods. Indigenous cultures almost universally understood and wanted to trade.

Back to modern times, the material most suitable for building multihulls today is aluminum. Your other choices are carbon fiber, steel, fiberglass, wood, etc. Aluminum alloy is much cheaper than carbon and much more corrosion resistant than steel. What we need is robots who perform the function of the English wheel, weld, and so on.

Polynesians did piece together their hulls sometimes with intricate joinery to bond the bow and sterns, and side planks to raise the freeboard. They were lashed together and the seams were stuffed with breadfruit tree bark, which seems to have been good watertight caulking. Dovetail joinery and wooden pegs they knew of also. Some of the master woodworking was a closely guarded secret held by certain lineages.

Lots of chemistry in this video about separating alloys from lunar dust.

The Scottish guy is dependent on shore power just not every day. If I were Fletcher Christian, I'd learn the Polynesian technology for boat building rather than try to make metal nails and so on. A 30m catamaran with over 2m of freeboard sounds totally plausible to me using traditional methods.