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The Lunacy of Artemis

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Re: The Lunacy of Artemis

#331

Post by ryandrake »

usrbinbash wrote: post #279
jwells89 wrote: post #273

Earlier quoted context omitted.

Long-term habitation of surfaces of bodies other than that of Earth is a stepping stone to being able to live in space long term in very large, permanently spaceborne crafts. It’s easier to develop these things on the moon, mars, etc because of immediate access to materials that’d need to be launched into orbit otherwise. In the long term, it may make sense to build shipyards on the moon, on Mars, or somewhere in the…

> a stepping stone to being able to live in space long term in very large, permanently spaceborne crafts. 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. > because of immediate access to materials that’d need to be launched into orbit otherwise. 1. How does this "immediate access…

You're getting piled on, but you're absolutely right. We don't even have the capability to permanently inhabit Antarctica, which has 1. an atmosphere of breathable air at the right pressure, 2. survivable temperature range, 3. abundant water, 4. a magnetic field and radiation shielding, 5. safe transit to and from. How does anyone think we can inhabit Mars, which doesn't have any of these?

Build a city of 100K on the northern-most habitable tip of Antarctica and have it (physically, socially, and economically) last 10 years, and I'll be convinced that we are ready to at least attempt Mars.

Re: The Lunacy of Artemis

#332

Post by billbrown »

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…

This is why nearly all ocean exploration is done via remotely-piloted vehicles instead of the massive yet cramped submersibles they started with. The explorers still get to do the science they love but they do it from a comfortable surface ship in shifts.

Re: The Lunacy of Artemis

#333

Post by nathan_compton »

jwells89 wrote: post #273
usrbinbash wrote: post #263

Earlier quoted context omitted.

> 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…

Long-term habitation of surfaces of bodies other than that of Earth is a stepping stone to being able to live in space long term in very large, permanently spaceborne crafts. It’s easier to develop these things on the moon, mars, etc because of immediate access to materials that’d need to be launched into orbit otherwise. In the long term, it may make sense to build shipyards on the moon, on Mars, or somewhere in the…

"the vastness of the universe and never be able to touch any of it in person."

No matter how much of the universe we touch it will always just be a vanishing sliver.

Re: The Lunacy of Artemis

#334

Post by elsonrodriguez »

usrbinbash wrote: post #312
elsonrodriguez wrote: post #299

Earlier quoted context omitted.

We covered more ground in a lunar rover in a week than any of our mars rovers covered in a year.

> We covered more ground in a lunar rover in a week than any of our mars rovers covered in a year. And this counters my argument...how exactly? Even forgetting the fact that scientific progress isn't measured in "kilometers driven" (just count the number of experiments that Perseverance carries, and compare the amounts of data produced(, there is no technical reason a robot cannot drive as far as a vehicle carrying h…

If our world-wide herculean efforts towards building a self driving robotic car have yielded mediocre results, I have low expectations for a robotic field geologist built on a NASA budget.

Also note that even with the limitations, the humans surveyed more ground. Remove the limitation by making the rover a mobile habitat and now the humans can have an even more expansive and productive mission.

Ultimately we're going to colonize space, why take 50x the time to gather the science needed for that goal, when worst-case we can spend 50x the budget and just put humans there to incidentally also gather knowledge on how to live in space.

Re: The Lunacy of Artemis

#335

Post by nathan_compton »

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…

People who get miffed at putting women and poc in space also don't want to spend more on social services, though, so its kind of a false dichotomy. It's not like if we could somehow convince the powers that be to cancel the space program they would put it all into education, jobs programs and basic income.

Re: The Lunacy of Artemis

#336

Post by jwells89 »

ryandrake wrote: post #331
usrbinbash wrote: post #279

Earlier quoted context omitted.

> a stepping stone to being able to live in space long term in very large, permanently spaceborne crafts. 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. > because of immediate access to materials that’d need to be launched into orbit otherwise. 1. How does this "immediate access…

You're getting piled on, but you're absolutely right. We don't even have the capability to permanently inhabit Antarctica, which has 1. an atmosphere of breathable air at the right pressure, 2. survivable temperature range, 3. abundant water, 4. a magnetic field and radiation shielding, 5. safe transit to and from. How does anyone think we can inhabit Mars, which doesn't have any of these? Build a city of 100K on the…

It may just be a misunderstanding on my part but aren’t there treaties that make anything bigger than science outposts impractical in Antarctica?

Re: The Lunacy of Artemis

#337

Post by usrbinbash »

hersko wrote: post #326
usrbinbash wrote: post #279

Earlier quoted context omitted.

> a stepping stone to being able to live in space long term in very large, permanently spaceborne crafts. 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. > because of immediate access to materials that’d need to be launched into orbit otherwise. 1. How does this "immediate access…

> 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 well" here on Earth. Including btw. the fuel required to launch it. Because the Moon is shockingly devoid of any steelworks, factories, fuel refineries, Astronaut training facilities, food processing plants or any of the other myriad sources of stuff required in space.

So yeah, launching something from 1/6th of Earths gravity is easier. However, all this does, is add another launch to the equation.

> How do you see us developing the technology for humans to leave the solar system if we never develop the technology to visit the moon?

For the same reason why we developed radio transmission, without first inventing super-sonic carrier pidgeons.

Technology does not only advance incrementially. Ever so often, a radically new technology emerges, that is leaps and bounds better than existing systems, and often wasn't developed from these systems either.

And btw. Rocket Engines are just one such technology as it happens. Before them, the strongest way to propel something through the air, were propellers, a technology which we since improved by alot, but is still incapable (and never will be capable to) put things into space.

So no, doing what we have done before is not a reqirement for finding a much better way to do it.

> Also, you don't need to "cheat physics" to explore space.

Where exactly did I assume that? But you do need to cheat our current understanding of physics for FTL travel.

Re: The Lunacy of Artemis

#338

Post by PopePompus »

nathan_compton wrote: post #333
jwells89 wrote: post #273

Earlier quoted context omitted.

Long-term habitation of surfaces of bodies other than that of Earth is a stepping stone to being able to live in space long term in very large, permanently spaceborne crafts. It’s easier to develop these things on the moon, mars, etc because of immediate access to materials that’d need to be launched into orbit otherwise. In the long term, it may make sense to build shipyards on the moon, on Mars, or somewhere in the…

"the vastness of the universe and never be able to touch any of it in person." No matter how much of the universe we touch it will always just be a vanishing sliver.

And the flip side is that the resources available in the universe are practically inexhaustible. A few quadrillion humans wouldn't strain it.

Re: The Lunacy of Artemis

#339

Post by dotnet00 »

throwawayffffas wrote: post #212
dotnet00 wrote: post #137

Earlier quoted context omitted.

F-1 was a design based around the limits of its time. The engineers were concerned about the challenges of controlling a large number of smaller engines, plus concerns about reliability with large numbers of smaller engines. It also had to be designed 'by hand', computers were not advanced enough to do much of the simulation driven refinement used nowadays. So, they traded off efficiency for large size, potential com…

> Now the technology has caught up, we can make small, highly efficient, powerful, reliable and restartable engines, and can control large numbers of them. Can we? Starships keep exploding. I get it, great engines are built on heaps of blown up engines. But are we there yet?

'Starships keep exploding' is kind of like saying 'tests keep failing' in test-driven development. Yeah, the tests for the stuff you're actively writing or haven't written yet are going to fail until you finish working on them and to someone who doesn't have a debugger it's just going to look like a crash...

People have forgotten how much destructive testing NASA used to do back in the Apollo era (eg with the Ranger program, 9 were launched over 5 years, the first 5 were total failures, 6th was a partial failure).

SpaceX has pretty rapidly improved in Raptor reliability, we've gone from seeing them routinely spitting out green flames (ie eating themselves) on the early tests, to now routinely firing them on the test stand without issue (with the exceptions assumed to be when they're trying to probe the limits). We've gone from them having trouble lighting them reliably, to lighting and maintaining all engines at launch on both vehicles in the most recent test flight. Similarly it's been a while since we've seen a static fire where an engine failed to light. This is despite the constant performance upgrades pushing its already world leading specs even higher.

The most recent explosions were very likely not due to the engines. For the booster, iirc the theory based on the public data is that the oscillations due to some issue with the grid fin control system caused the propellants to slosh around very hard, damaging the plumbing, causing the engines to shut down and the booster to smash into the water. The Starship had a very visible leak under its skirt that caused it to be unable to maintain attitude, I think the theory with this is that it was a stuck or damaged valve in the RCS.

And, of course, as the other poster mentioned, they're almost at the point where what's failing is the reusability rather than launch, the only launch related milestone left to prove out is engine relight in vacuum. While they will probably figure out reuse eventually, it is not strictly necessary for HLS, especially as it pertains to the Starship itself (which is a much bigger challenge than the booster). The booster is the most expensive part of the vehicle, so their priority is to get reuse for it working. If they encounter significant hurdles with reusing the Starships, they can throw them away for early HLS launches and still be cheaper than SLS.

As far as controlling large numbers of engines and having them be cheap, restartable and throttleable, we have the Merlin in Falcon 9 and especially Falcon Heavy as an example. Heavy has to control 27 engines at liftoff. For powerful, highly efficient engines, we have the RS-25 in Shuttle/SLS and BE-4 in Vulcan/New Glen as additional examples.

Re: The Lunacy of Artemis

#340

Post by mft_ »

ryandrake wrote: post #331
usrbinbash wrote: post #279

Earlier quoted context omitted.

> a stepping stone to being able to live in space long term in very large, permanently spaceborne crafts. 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. > because of immediate access to materials that’d need to be launched into orbit otherwise. 1. How does this "immediate access…

You're getting piled on, but you're absolutely right. We don't even have the capability to permanently inhabit Antarctica, which has 1. an atmosphere of breathable air at the right pressure, 2. survivable temperature range, 3. abundant water, 4. a magnetic field and radiation shielding, 5. safe transit to and from. How does anyone think we can inhabit Mars, which doesn't have any of these? Build a city of 100K on the…

Not sure if that's a good argument. There are lots of places more hospitable and less remote than Antarctica that aren't inhabited either - the reasons why a large number of people would inhabit an area or not are complex.

We have the technology as a species to be able to inhabit Antarctica; there's just no compelling reason to do so at present, so we don't.

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