Submitted by Significant_Youth_73 t3_zy2na7 in space
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
hawkwings t1_j25cggq wrote
Lower escape velocity is not the same as cheaper. Is steel on the moon the same price as steel on Earth? Is fuel on the moon the same price as fuel on Earth? If resources on the moon are more expensive than resources on the Earth, it might be cheaper to launch from Earth. If your main goal is cheaper, then we should wait until we have cheap resources on the moon before working on LG.
It is possible to mine things on the moon, build things on the moon and leave those things on the moon. I'm not sure what the Lunar Gateway gets you. Supplies can be sent to the moon on one-way spaceships. People flying to the moon will be in a hurry. If docking slows them down, that could be a problem, because that means more radiation and more life-support resources.
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.
hawkwings t1_j26m5ry wrote
On Earth, the new world environment is very similar to the old world environment which is why there are so many invasive species. You can't release pigs and horses on the moon and expect them to survive. The industrial revolution occurred more than a century after much of the new world was colonized.
Not launching from the moon is cheaper than launching from the moon. In the early days of resource extraction, it may be better to use those resources on the moon instead of launching them. LG wouldn't be useful until we have more resources than we need on the moon.
TheAserghui t1_j26mgcn wrote
Yes, but the LG will most likely start out as a simple way-station between Earth and the Moon
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