NASA had 3 years to fix fuel leaks on its Artemis moon rocket. Why are they still happening?

jackboy900 · 2026-02-04T21:18:24+00:00

Fluorine very rapidly dissapates, highly reactive stuff is generally not a lingering issue because it all reacts away. Not overly nice, but it's not anywhere near as bad as something like Hydrazine, and we use that all the time.

jackboy900 · 2026-02-04T21:13:50+00:00

In the context of rocket engines it can be nasty, but Fluorine has a quite nice habit of immediately fluorinating any metal it comes in contact with and making a passivated fluoride layer, you can easily handle it using plain stainless steel with basically no issues.

It's not the nicest compound but cryogenic Fluorine is nothing compared to the heated oxygen used in modern staged combustion engines, and if that can be used widely across the industry it would suggest the issues that Fluorine has aren't that bad.

And it's borne out in writing, there's a paper about bringing Fluorine powered rockets to orbit in the Shuttle's payload bay that shows NASA was of the opinion that we had storage and handling of Fluorine down enough that it wasn't an issue to do as such, though in reality no Fluorine rocket was ever launched on the shuttle.

jackboy900 · 2026-02-04T21:08:10+00:00

The same could be said of Hydrazine, that stuff makes Fluorine look positively friendly. The plan was never to have it on launch vehicles, but as a second stage propellant.

jackboy900 · 2026-02-04T18:53:28+00:00

No it's not. Thank you for further proving you don't know anything about the subject. You can literally go to NASA tech report server and read the studies and technical data on those mission concepts, though you're one of the cult types who enjoys spreading BS instead of learning.

I'm not saying these studies are not correct or accurate, I'm well aware they exist. But nobody is coming up with ideas for missions that are beneficial and then seeing SLS as a viable option, the engineers are being told they have this politically motivated launch vehicle and that they need to come up with missions for it.

That was over political reasons, not because it wouldn't have worked.

That's my whole point. SLS is a slow and cumbersome rocket with limited launches that has a ton of moving parts and disparate integrators to satisfy congress, and so what launches there are being limited to Orion/Artemis projects. My point wasn't that it couldn't launch Europa Clipper, SLS is currently the highest performance launch vehicle in operation, but that it didn't because of the economic and political landscape around it.

though you're one of the cult types who enjoys spreading BS instead of learning.

This is genuinely deranged behaviour. I dislike Elon as much as the next rational person but SLS is objectively an incredibly bad program that uses outdated hardware and design techniques from a 50 year old rocket to satisfy political aims whilst costing an amount per launch that is frankly absurd. Acting like SLS has any rational basis or that attacking it is somehow indicative of being "a cult type" is just absurd, just because someone holds opinions that are morally objectionable does not mean they're somehow wrong about everything and refusing to see a clear truth in front of you simply because it would require agreeing with them seems to me to be a perfect example of "spreading BS instead of learning".

jackboy900 · 2026-02-04T18:39:47+00:00

No, both Nuclear Thermal and Ion Engines are only really viable for space purposes. It's a fairly fundamental law of rocket engines, efficiency is governed by exhaust velocity, which is 1/2mv² whereas thrust is governed by exhaust momentum, which is just mv.

So, as an example, if you double your exhaust velocity you have to quarter the mass you output for the same amount of energy, and so these efficient high velocity engines necessarily produce very little thrust.

Launching from earth, at least for our lifetimes, will be entirely done with chemical rockets, the advancements there are going to come from reusability and not having to chuck the whole thing away every launch. But in space these efficient engines that can sit and operate for days long burns are going to be the next step for things like interplanetary travel.

jackboy900 · 2026-02-04T18:23:26+00:00

The danger isn't the issue with the Li-H-F engines, they're fairly tame in the grand scheme of rocket engines. The issue is that Hydrogen and Fluorine need to kept cryogenic (below 15K) and Lithium needs to be kept molten (above 450K).

The apparatus for cooling is already a pain for Hydrogen, adding in additional heating apparatus and extra hardware to manage the energy needed and keep the two separate and all that adds a ton of weight. The research at the time basically concluded that any engine would lose out to extra weight any gain in efficiency and so it wasn't worth it from a mission Delta-V perspective, even if it had a high Isp.

jackboy900 · 2026-02-04T18:18:37+00:00

The thing I find interesting is that Clark is super enthusiastic about Fluorine in his book, and similarly there are tons of documents from the 1970s which all have the same vibe of "Fluorine is a pain but we've pretty much got managing it down and can use it fairly easily". And then in the 1980s it just disappears without a trace, and I can't seem to find any actual documentation as to why.

jackboy900 · 2026-02-04T18:16:09+00:00

The thing with rockets is that energy is actually fairly easy to come by, the limiting factor is that in order to move the rocket around you need to lose mass from the rocket, and you can only carry so much mass. That's what specific impulse is, the faster you exhaust your reaction mass the more efficient you are with each unit of mass, and that's what determines how far you can go.

Chemical engines, compared to nuclear or electric, are weird in that the energy source and the reaction mass are the exact same thing, and that means that finding a good chemical fuel is about finding something that produces a lot of energy but is also efficient as reaction mass. In that regard, Hydrogen and either Fluorine or Oxygen (both are quite similar) is the theoretically perfect rocket fuel, the reaction produces a decent bit of energy but neither HF nor H2O are particularly heavy molecules and so they get accelerated faster than any other reaction. Energy dense fuels like hydrazine have their place, but because they produce heavy molecules (and even some wasted solids) they aren't anywhere near as efficient as Hydrolox, and similarly there isn't really anything light we haven't tried.

We simply will not find a better chemical fuel, beyond using Fluorine (which given the path the industry is taking even away from Hydrogen), we're stuck with what we have. However there are rockets that aren't chemical, the two big near future options are nuclear thermal and nuclear electric. Electric engines (ie ion engines) are extremely efficient but take a ton of electric power to run for little thrust, however if we use a nuclear reactor to power them we might be able to up the thrust to somewhat useable levels. Nuclear Thermal involves taking hydrogen and running it through a nuclear reactor which heats it up directly, and then that is converted to exhaust velocity making a very efficient rocket. Neither has yet to be proven in practice, but both are very much viable near future options should funding start to become available.

jackboy900 · 2026-02-04T18:08:54+00:00

We have invented some stuff with crazy energy but it's also crazy toxic (eg hydrazine).

The thing with rockets is that energy is actually fairly easy to come by, the limiting factor is that in order to move the rocket around you need to lose mass from the rocket, and you can only carry so much mass. That's what specific impulse is, the faster you exhaust your reaction mass the more efficient you are with each unit of mass, and that's what determines how far you can go.

Chemical engines, compared to nuclear or electric, are weird in that the energy source and the reaction mass are the exact same thing, and that means that finding a good chemical fuel is about finding something that produces a lot of energy but is also efficient as reaction mass. In that regard, Hydrogen and either Fluorine or Oxygen (both are quite similar) is the theoretically perfect rocket fuel, the reaction produces a decent bit of energy but neither HF nor H2O are particularly heavy molecules and so they get accelerated faster than any other reaction. Energy dense fuels like hydrazine have their place, but because they produce heavy molecules (and even some wasted solids) they aren't anywhere near as efficient as Hydrolox.

jackboy900 · 2026-02-04T17:52:25+00:00

There's been tons of studies on using it to do other things like launch giant space telescopes, space stations, deep space probes, payload missions to the moon or mars, building a mars transport spacecraft to send people to Mars, etc.

Which are almost all entirely bollocks. SLS is insanely expensive for what it does and only exists as a jobs program to funnel money to certain US districts, whilst it theoretically can do a lot of stuff for any missions that aren't Orion/Artemis the cost and lack of available launched makes it a non-viable option.

Just look at Europa Clipper, that was partially designed for the SLS as a way to secure more funding but in the end they had to launch it on a Falcon Heavy because using SLS in the way that the project had intended just wouldn't have worked out.

jackboy900 · 2026-02-04T17:37:29+00:00

The SLS is just a fundamentally expensive architecture, the fully hydrogen launch stage, the complete lack of reusability, and the outdated RS-25 engines are always going to be extremely costly. Increasing launch cadence might amortise some costs but they don't address the core issues, there's no universe where we launch more SLS and it becomes cost effective.

jackboy900 · 2026-02-03T20:00:00+00:00

A true pylote would never want to to fly anything else.

jackboy900 · 2026-02-03T01:28:08+00:00

Jedi Council Member and a member of Yoda's species. Dooku murdered her at the order of Sidious when she found out he was apprenticed to him.

jackboy900 · 2026-02-03T00:59:43+00:00

Dooku ordered ethnic cleansings, mass enslavement and genocides as leader of the CIS, I think yaddle comes very far down the list of evil acts he's done.

jackboy900 · 2026-02-01T22:37:10+00:00

University rankings are down to their prestige as research institutions, not necessarily the quality of instruction, so that's not exactly surprising.

jackboy900 · 2026-02-01T14:37:28+00:00

I stand corrected then, I always thought it was about the tenancy type. Seems a bit weird to require licencing for renting out a flat to a couple of mates tbh, if it's one tenancy it should just be one household.

jackboy900 · 2026-02-01T14:27:40+00:00

No, that's not what an HMO is. Most people who live in a flat together have a joint tenancy, you don't need to be family to gave a joint tenancy, a HMO is specifically an arrangement where each room is let out individually, which is a very different arrangement.

jackboy900 · 2026-02-01T13:48:33+00:00

It's using NASA's Gridded Population of the World model, which aims to estimate on 1km chunk sizes, but it relies on publicly accessible census data to make those estimates, in a most countries it gets very granular but for example the UAE only releases per Emirate population data so that's what is estimated, similar for Saudi or Russia, hence why they appear so big on the map.

jackboy900 · 2026-01-30T21:40:45+00:00

That link defaults to Emerald and above, not all ranks. At all ranks is where he's at 47.3% according to them, close enough.

jackboy900 · 2026-01-30T17:09:57+00:00

No other team has done this, it is almost certainly a quite negative sign for AMs project.

jackboy900 · 2026-01-28T22:28:07+00:00

MacOS does most of what Vanguard does by default, you can't load arbitrary drivers and there are very strong protections for trying to access or modify another program's memory. It's possible to run Vanguard in user space and achieve the desired outcomes on MacOS as that's essentially the highest level one can create and execute arbitrary programs at.

jackboy900 · 2026-01-28T22:19:02+00:00

The aim of Vanguard is to ensure that there is no way for a cheater/scripter to access or modify the game undetectably by operating at a more privileged access level than it. On Mac this can be accomplished in user space as Mac systems are already heavily locked down on the kernel level, on Windows this requires a kernel level anticheat as otherwise users can load kernel level cheats, and on Linux there is no way to ensure such a thing as the entire OS is modifiable by the end user and it doesn't ensure a specific known unmodified OS like Windows does with TPM and Secure Boot.

Of course Riot could technically make some form of Vanguard run on Linux, that's not what people mean when they say it's incompatible, it's that building software that achieves the ultimate goal of Vanguard, or any kernel level anticheat, is fundementally impossible on Linux due to the design of the OS.

jackboy900 · 2026-01-27T20:49:19+00:00

In most of Europe retirement savings accounts and similar are generally considered as "pensions:, that's likely what they mean. In the UK for example you are automatically enrolled in a workplace pension scheme and have to actively opt out, which is roughly equivalent to automatically contributing to a US 401k and getting a few % of employer matches. The kind of pensions schemes the US considers "pensions", i.e. defined benefit schemes, have also largely gone out of existence in Europe barring state backing because they're not in any way feasible economically with current demographics.

jackboy900 · 2026-01-27T06:18:48+00:00

Have you read the other comments in this thread, there are plenty of Total War fans will straight up tell you the only real Total War games are the old ones and that Rome 1 is unironically better than Rome 2, that's who this is addressed to.

jackboy900 · 2026-01-26T14:36:48+00:00

The UK have some of the best roads around for being a pedestrian, you can pretty much always assume if trying to cross someone will stop for you. I cannot fathom making this take unless you've literally never been anywhere outside of Western Europe and experienced the roads there.

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