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The Lunacy of Artemis

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Re: The Lunacy of Artemis

#371

Post by imglorp »

exe34 wrote: post #358
objclxt wrote: post #249

Earlier quoted context omitted.

> They do this on earth every time they fuel the rocket. I understand it will be more difficult in space, but I don’t see why specifically this problem is the real engineering target over say, reuse. The article goes into this in some detail. In particular: * You have to get the propellant into space. This is going to take a large number of flights (~15) at a pace that has not been done before for a vehicle of that s…

> There is no gravity: whereas on earth the propellant separates relatively cleanly into liquid and gas this isn't the case in space can you use a plunger, instead of a pump? more like a syringe?

Yeah, a 9 meter diameter one, which adds mass and volume and complexity and detracts from the payload.

Instead what they do is use thrust to accelerate the whole vehicle a little, which presses all the liquid into one end of its tank where it can be pumped out. Instead of carrying special settling thrusters, they originally planned to use ullage gas for this but it's not clear that can work.

deeper discussion with math: https://forum.nasaspaceflight.com/index.php?topic=60124.60

Re: The Lunacy of Artemis

#372

Post by pookha »

RobotToaster wrote: post #242
LargeTomato wrote: post #26

We are going to The moon for two reasons. First, we want to set up a more permanent base. Nasa refers to this as "we're here to stay" The second reason we are going to the moon so that we can put the first person of color and the first woman on the moon. That is explicitly an Artemis mission purpose. Only time will tell if either of these two missions were actually worth it. One more point > Early on, SLS designers m…

It seems crazy to me they've managed to use shuttle parts to make a design that seems older and worse than the shuttle. People called the shuttle a truck, but they've used parts from it to make something that looks like a Ford model-T in comparison.

The moon has trillions of dollars in water, helium, and metals (rare earth, titanium, etc). It's an f'ing goldmine and controlling said resource will be something hostile authoritarian regimes (China) would seek out. There's simply no excuse that the US should be this bad at making a system to reach the moon. The Chinese have committed insane sins and dropped massive amounts of space hardware on the earth (luckily it landed in the ocean). We should be dunking on them but instead we've got this buffoonery?

Re: The Lunacy of Artemis

#373

Post by exe34 »

imglorp wrote: post #371
exe34 wrote: post #358

Earlier quoted context omitted.

> There is no gravity: whereas on earth the propellant separates relatively cleanly into liquid and gas this isn't the case in space can you use a plunger, instead of a pump? more like a syringe?

Yeah, a 9 meter diameter one, which adds mass and volume and complexity and detracts from the payload. Instead what they do is use thrust to accelerate the whole vehicle a little, which presses all the liquid into one end of its tank where it can be pumped out. Instead of carrying special settling thrusters, they originally planned to use ullage gas for this but it's not clear that can work. deeper discussion with ma…

plastic balloon?

Re: The Lunacy of Artemis

#374

Post by wtetzner »

usrbinbash wrote: post #263
throwawayffffas wrote: post #213

> Conversely, if SpaceX and Blue Origin can’t make cryogenic refueling work, then NASA has no plan B for landing on the moon. If SpaceX and Blue Origin can't. Then Nasa will find someone who can. Cryogenic refueling is the projects real engineering target. Landing on the moon in the twenty twenties just isn't that impressive anymore. The Artemis program is nominally about going to the moon, but it really isn't. It's…

> It's about building and living in habitats beyond low orbit And what for if I may ask? And please don't say "technological development" or "colonizing space". ad Development): Most of the tech that needs to be developed for this, is what is commonly called space plumbing: Figuring out ways to make human bodily functions not immediately fail in space. Next to none of these technologies benefit humanity at large in a…

> Figuring out ways to make human bodily functions not immediately fail in space. Next to none of these technologies benefit humanity at large in any way.

What a weirdly confident statement. I could imagine all kinds of technology coming from that that would benefit life on Earth.

Re: The Lunacy of Artemis

#375

Post by z0r »

grecy wrote: post #304
z0r wrote: post #278

Earlier quoted context omitted.

Imagine being born in a habitat on another planet that is further away from Earth in travel time than one's lifespan, and being robbed of your birthright to experience the natural wonders and beauty of the cradle of humanity.

Imagine being born on an earth where millions of species have gone extinct, where there are hardly any old growth forests left, no bison roaming the central/western US plains and where thousands of water bodies around the world are so toxic they'll kill you if you fall in.

I am an advocate of wildlife conservation efforts, and regularly donate to charities that work to conserve species and their habitats.

I am just replying to a single comment, so forgive me for addressing everyone else as well as you here. I think it's very funny that people are making obvious replies to my comment to defend against (the also very obvious) observation that perhaps being born and dying in a tin can on another planet might be an undesirable fate for the vast majority of the human race.

Re: The Lunacy of Artemis

#376

Post by jodrellblank »

usrbinbash wrote: post #267
LargeTomato wrote: post #26

We are going to The moon for two reasons. First, we want to set up a more permanent base. Nasa refers to this as "we're here to stay" The second reason we are going to the moon so that we can put the first person of color and the first woman on the moon. That is explicitly an Artemis mission purpose. Only time will tell if either of these two missions were actually worth it. One more point > Early on, SLS designers m…

> Only time will tell if either of these two missions were actually worth it. No time required, we already know the answer: neither of these two goals is worth the enormeous pile of resources burned to achive it. 1. A permanent human presence on the moon serves what purpose exactly that Robots cannot do? If we want to set up shop there: Why not send robots and an automatic laboratory-repair-bay? It's the moon, we can…

Money isn't burned when spent on space programs. resources, e.g. fuels are, but money is spent, it stays down here on Earth, employing people, boosting corporate profits (and therefore pension funds and other things which invest in them), employing people (who maybe women and people of colour).

Re: The Lunacy of Artemis

#377

Post by hehdhdjehehegwv »

wffurr wrote: post #301
throwawayffffas wrote: post #213

> Conversely, if SpaceX and Blue Origin can’t make cryogenic refueling work, then NASA has no plan B for landing on the moon. If SpaceX and Blue Origin can't. Then Nasa will find someone who can. Cryogenic refueling is the projects real engineering target. Landing on the moon in the twenty twenties just isn't that impressive anymore. The Artemis program is nominally about going to the moon, but it really isn't. It's…

The advanced technologies you're describing are part of Artemis. The other part is a huge pork barrel jobs project for the SLS workforce across the country, in as many states as possible.

Nobody in congress will vote to kill jobs in their district. The military industrial complex figured that out a while ago, which is why at least one screw for some weapon or aircraft is produced in every state.

If NASA is going to use the same playbook to be benefit space exploration, I’m not remotely upset.

Re: The Lunacy of Artemis

#378

Post by hifromwork »

usrbinbash wrote: post #298
margalabargala wrote: post #289

Earlier quoted context omitted.

> And what if China gets there first? How exactly would that benefit them, in a geopolitical sense? If China gets there first, the enormous amount of international credibility and resulting soft power that they will gain internationally, at the US's expense, will be immense and will be worth the resources they spend several times over.

> the enormous amount of international credibility and resulting soft power You know what is giving China soft power? Funding projects around all of Africa. You know what is not giving western countries soft power? Burning Billions on Space Programs that serve zero purpose and could achieve more with much less investments, if we just continued sending robots. Again, I know where I would allocate my resources if I had…

I'm not a geopolitics expert, and I assume you're not either, so I'll just say what I feel. As an European, deep down my unconscious mental picture of the situation here is probably this: USA is a geopolitical and economic power, China is a far away country that assembles parts and devices for western companies. This mental picture is wrong and hilariously oversimplified (I know rationally that it's wrong), but this is the stereotype I've absorbed from my society.

If both counties actively tried to win, and China managed to build a Moon base before the US that would probably make a huge blow to that (subconscious) mental picture.

Re: The Lunacy of Artemis

#379

Post by echoangle »

usrbinbash wrote: post #337
hersko wrote: post #326

Earlier quoted context omitted.

> That is not going to happen, without technology that currently only exists in Science Fiction, like artificial gravity, for the simple reason that we require 1g to live, let alone thrive. Artificial gravity is easily generated via rotation or thrust. > 1. How does this "immediate access" benefit the aforementioned "very large, permanently spaceborne crafts", which apparently won't be moored to planetary bodies? It…

> Artificial gravity is easily generated via rotation or thrust. https://space.stackexchange.com/questions/1308/why-are-there... Sure, "easily". > It will be far easier to get materials into space from the moon than from the much deeper gravity well of earth. No it won't, for a very, very simple reason: Every single kilogram of stuff you launch from the moon, has to be launched FIRST from exactly that "deeper gravity…

Just to nitpick the gravity argument: I think a major reason there currently is no spacecraft with artificial gravity is that microgravity is the whole point of space currently. You could probably build a spacestation with two sides and a long tether, but you don’t want that because you couldn’t do the interesting research anymore.

Re: The Lunacy of Artemis

#380

Post by pantalaimon »

exe34 wrote: post #373
imglorp wrote: post #371

Earlier quoted context omitted.

Yeah, a 9 meter diameter one, which adds mass and volume and complexity and detracts from the payload. Instead what they do is use thrust to accelerate the whole vehicle a little, which presses all the liquid into one end of its tank where it can be pumped out. Instead of carrying special settling thrusters, they originally planned to use ullage gas for this but it's not clear that can work. deeper discussion with ma…

plastic balloon?

What plastic is elastic at those temperatures? (-182 °C)
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