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Artemis II safely splashes down

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Re: Artemis II safely splashes down

#301

Post by adrian_b »

tedd4u wrote: post #203
SoftTalker wrote: post #170

Earlier quoted context omitted.

The '70s were not hopeful. Economy was terrible, Vietnam ended but still hung over the culture, Watergate, Three Mile Island, Iranian hostage crisis, cold war threatening to turn hot at any moment, double-digit mortgage rates.... and Disco.

Definitely not the 70's. I think the most recent age that might have counted as hopeful was really between the fall of the Berlin Wall (1989) through the beginning of the GWOT (9/11/2001). So basically the 90's.

The seventies were a more representative time for technological hopes, during a time when it was not yet clear which are the right technological choices. The nineties were a time of rapid technological progress, but most of it was perfectly predictable, without surprises. The only thing that was surprising during the nineties was how important the Internet became in practice, even if the evolution of its underlying technology was not surprising.

The time correctly delimited by you was the time of the greatest false political hopes, when everybody around the World believed that we got rid of the communist blood-sucking parasites and now the World would become that which had been described for decades in the propaganda of the Voice of America, where the political elites are held accountable for their actions, so if they are bad they are replaced through democratic elections, and the bad commercial companies are eliminated by competition in the free market.

Instead of this happening, already a couple of years before 9/11 a wave of destructuring many important historical companies happened, followed by a huge wave of mergers and acquisitions that has continued until today and which has eliminated competition from most markets, so that they are now dominated by quasi monopolies. Then the democratic elections have brought to power worse and worse human beings, all of whom have been much worse than some citizens that would have been randomly selected for those positions.

Nowadays, the economies of USA and of the other "Western" countries, and also their political institutions, resemble much more those of the socialist countries that they mocked during the seventies, than those of USA and W. Europe of that time.

So all the hopes of the nineties were naive and none of them was realized.

Re: Artemis II safely splashes down

#302

Post by slow_typist »

areoform wrote: post #76
irjustin wrote: post #51

Earlier quoted context omitted.

> Artemis acceptable crew mortality rate is 1 in 30. This seems insane to me. That X decades later we accept, with all our advancements in tech, a weaker system than ever before. That if we send 30 people we _accept_ that one is possible to die. That's the starting point? That's what we document as acceptable?

Yes, and the memories of Apollo are made rosy by hagiography. I even wrote an entire thing to explain why, https://1517.substack.com/p/1-in-30-artemis-greatness-and-ri... (yeah, shameless plug, sorry - it's more for the citations than not. You can read the standards and reports I've linked to) But if I'm allowed to repeat myself from elsewhere in the thread and the meat of the above thing, It's physically not possibl…

Wouldn’t the soviets or any other adversary prepare against letting NASA capture their satellites? You need a very small amount of C4 in the satellite to destroy the shuttle in the event of capture. Tampering with other entity‘s satellites can best be done with satellites. That also frees resources needed for bringing life support systems to orbit.

Re: Artemis II safely splashes down

#303

Post by d1sxeyes »

stetrain wrote: post #248
shash wrote: post #242

Earlier quoted context omitted.

Is 12 enough of a sample size to make a statistical judgement? What if there were 20 more which didn’t have a loss of life? Is it then 1/30? What if there were 20 more? The risk factor is calculated _per mission_ from what I understand. You can have three accidents in a row and nothing for decades but the risk itself can still be 1 in 30.

So the risk factor for Apollo could have actually been 1/1000 but they were just really unlucky?

If I toss a coin four times and it comes up heads three and tails once, it doesn’t mean that there’s a 75% chance that this coin lands heads up. Be careful about conflating risk factor and mortality rate.

Re: Artemis II safely splashes down

#304

Post by slow_typist »

rvnx wrote: post #196
atherton94027 wrote: post #62

Earlier quoted context omitted.

This was the farthest humans ever travelled from earth, even farther than apollo 13. Intuitively the farther you go the higher the risks are

They could go twice the same distance, the risk would be roughly the same at that point. It's mostly the complexity and changes that make it more risky once the initial trajectory is in place.

You need a lot more impulse and more fuel to go twice as far. Probably more correction burns. A longer final burn before entering the atmosphere. So the risk of loosing the engine is much higher and probably increasing more than linear with burn time/change of impulse.

Re: Artemis II safely splashes down

#305

Post by throwpoaster »

areoform wrote: post #76
irjustin wrote: post #51

Earlier quoted context omitted.

> Artemis acceptable crew mortality rate is 1 in 30. This seems insane to me. That X decades later we accept, with all our advancements in tech, a weaker system than ever before. That if we send 30 people we _accept_ that one is possible to die. That's the starting point? That's what we document as acceptable?

Yes, and the memories of Apollo are made rosy by hagiography. I even wrote an entire thing to explain why, https://1517.substack.com/p/1-in-30-artemis-greatness-and-ri... (yeah, shameless plug, sorry - it's more for the citations than not. You can read the standards and reports I've linked to) But if I'm allowed to repeat myself from elsewhere in the thread and the meat of the above thing, It's physically not possibl…

Shuttle was awesome and the people who love to hate it can personally fight me.

Re: Artemis II safely splashes down

#306

Post by cmiles8 »

irjustin wrote: post #51
areoform wrote: post #11

Glad that they're safe and sound. It's worth pointing out that this is the first extremely public, widely acknowledged high risk mission NASA has done in over 50 years. The Shuttle was risky, but it wasn't thought of or acknowledged by NASA as being risky until very late in its lifecycle. According to NASA's OIG, Artemis acceptable crew mortality rate is 1 in 30. Roughly 3x riskier than the shuttle. There genuinely i…

> Artemis acceptable crew mortality rate is 1 in 30. This seems insane to me. That X decades later we accept, with all our advancements in tech, a weaker system than ever before. That if we send 30 people we _accept_ that one is possible to die. That's the starting point? That's what we document as acceptable?

Space is hard. If we didn’t accept these parameters we wouldn’t go to space. Apollo lost one entire crew and almost two, the Space Shuttle lost two missions where the whole crew died. The risks are real.

Re: Artemis II safely splashes down

#307

Post by elevatortrim »

rustyhancock wrote: post #286
atonse wrote: post #101

I had to explain to my wife and kids (not that I'm in this field, but I also have to remind myself) that we are able to pinpoint where the craft will land, when it will land down to the minute, because of ... just ... math. And we're able to get them there and back because of science. It all boils down to equations that describe the world accurately, and a way of experimentation, iteration, thinking that gets us all…

I'd add a caveat to this. We can do this because of war. We know where it will land accurately because that maths and physics has been sharpened with butt loads of data. Even the reentry blackout has links to war in Plasma Stealth[0]. That data was mostly obtained because we want to know where our ICBM warheads will land. And where the enemies ICBM warheads will land so we can work on the problem of shooting them dow…

To say “because of war”, you would also have to prove we could not do it without war.

Re: Artemis II safely splashes down

#308

Post by the__alchemist »

shash wrote: post #242
stetrain wrote: post #159

Earlier quoted context omitted.

1 out of the 12 crewed Apollo missions resulted in the death of the crew, so a 1 in 12 effective mortality rate. Apollo 13 was a very close call. If that had ended in failure the mortality rate would have been 1 in 6. So 1 in 30 would be a pretty clear improvement from Apollo, and we are a lot better and more thorough at modeling those risks and testing systems than we were during the Apollo program.

Is 12 enough of a sample size to make a statistical judgement? What if there were 20 more which didn’t have a loss of life? Is it then 1/30? What if there were 20 more? The risk factor is calculated _per mission_ from what I understand. You can have three accidents in a row and nothing for decades but the risk itself can still be 1 in 30.

Your point is fair and and important distinction. I think when estimating a risk factor though, this empirical data, while a low sample size, is a valuable statistic because it's empirical, and not that small of a sample size. Maybe going forward, we have 3 risk levels:

  - Historical. Low N as you say. (Even though each mission and spacecraft is different and they're spread out over time, there's value in this)
  - Bureaucrat number; absurdly low, but looks good to politicians etc
  - Engineering estimate

Re: Artemis II safely splashes down

#309

Post by JumpCrisscross »

_moof wrote: post #224
JumpCrisscross wrote: post #145

Earlier quoted context omitted.

> subsonic lift is well understood and has been for decades I said easy. Not well understood. I can fly planes. It’s hard, and has limited room for fucking up. (It’s also hyperbole to suggest we understand lift. We don’t.) Piloting a boat is easier and more forgiving. Hence, splashdown. You don’t need direction. You don’t need lift. Parachute physics is a backbreaker, but it’s symmetrical. Same for splash.

You're a VC arguing with an aerospace engineer about aerospace engineering. I'm also a pilot (CFI). My day job is space operations. And I can tell you've had too many hangar arguments about how wings work. Pilots don't understand lift. Aero engineers understand it just fine.

I love this comment. Thank you. For what it’s worth, I’m not a CFI but I did study actual astronautical engineering. Not much good once we’re in an atmosphere, which, granted, is where the boats and planes go. But I’ll stand by my statement that nobody—apart from interplanetary reëntry and drone teams—fundamentally understands lift. (I certainly didn’t when I was solving analytic solutions by hand.)

Re: Artemis II safely splashes down

#310

Post by pjc50 »

brianjlogan wrote: post #82

As an American I feel like I've been going through a bit of an identity crisis from what I remember growing up. Probably the rose tinted glasses of being a child but being from Florida I always had a sense of amazement and wonder as I heard the sonic boom of the shuttle returning to earth. Really felt like I was coexisting in this incredible scientific powerhouse of a country full of bright and enabled peoples that k…

From one of the ground staff for Artemis: https://bsky.app/profile/captnamy.bsky.social/post/3mi36brfw...

"1968 and the country was on fire. Vietnam. Assassinations. Civil unrest. Protests.

Apollo 8 was the one bright event of a terrible year.

2026 and the country is on fire. Iran. Corruption. Fascists. Civil unrest. No Kings.

I hope Artemis II will stand out as a bright spot for our country."

Some more background on her: https://chicago.suntimes.com/news/2026/04/01/chicagoan-amy-l...

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