TheAserghui

TheAserghui t1_j25kk4p wrote

Its cheaper to manufacture space based structures and needs in space/on low gravity enviroments, because its not about money its about the energy costs.

Try running with a 20 kg vest and also with a 50 kg vest. One is easier.

There is a reason manufacturing happened in the European colonies: it was cheaper to develop self-suficency instead of waiting for transport ships to provided raw materials or finished products.

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TheAserghui t1_j23nbz7 wrote

The Lunar Gateway would be a way-station, a place to hold supplies for continual missions, much like gas stations on the highway allow us to travel farther than one tank of gas.

11.2 KM/S delta-V to escape Earth's gravity

2.38 KM/S delta-V to escape Moon's gravity

The space craft have to do 20% the work to bring material up from industrial processing sites on the moon. Every extra kilogram of weight requires more engine fuel to generate that 11.2 KM/S just to get off earth. By shifting the construction effort to the Moon we are able to greatly reduce fuel costs to get off Earth. With a Lunar Gateway our off-Earth shipping weight would be reduced to that of people and basic living necessities. Instead of trying to ship up heavy items like steel girders, concrete, and the like.

Currently only 4% of the Falcon 9's weight is the actual payload to Low-Earth Orbit. That's 549,054 kg to get 22,800 kg off the ground and to an ISS equivalent location.

If the Lunar Gateway was the material size/weight equivalent to the Burj Khalifa, then it would weigh approx 500,000,000 kg (500,000 tonnes). To build that structure with Earth materials in Low-Earth Orbit, it would require approx 21,930 individual launches from Earth... not including the manning, equipment, and living supplies needed by the construction team.

Tldr: building in space with material from the Moon is a lot cheaper and allows for bigger spacecraft to be built.

https://letstalkscience.ca/educational-resources/stem-in-context/escape-velocity

https://www.grc.nasa.gov/www/k-12/airplane/rockth.html

https://www.spacex.com/vehicles/falcon-9/

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