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Artemis II safely splashes down

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Re: Artemis II safely splashes down

#381

Post by b112 »

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?

That's the starting point? That's what we document as acceptable?

Better to document risk, than lie to brave volunteers. And they knew the risk, and wanted to go. So I see zero issues here.

Re: Artemis II safely splashes down

#382

Post by brewdad »

fnord77 wrote: post #345
areoform wrote: post #76

Earlier quoted context omitted.

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…

> We're a very primitive species, compared to what? We're the most advanced species we know of. It might even hold true over the entire universe. All species might top out at where we are. We don't know.

What a sad view of the universe. To hold that humanity in the year 2026 is the best the universe can do.

Re: Artemis II safely splashes down

#383

Post by api »

antonvs wrote: post #378
api wrote: post #154

Earlier quoted context omitted.

2.4% is not bad given how new this still is and how extreme the speeds and energies are. Note that all the fatalities have been launch or landing related, not in space itself. Clawing out of this gravity well is tough. Make Earth a bit larger and you’d never get off it without something like NERVA or nuclear pulse Orion. I wonder sometimes if that’s another thing to toss in the Fermi paradox bucket. Many rocky planet…

> I wonder sometimes if that’s another thing to toss in the Fermi paradox bucket Here we are, half a century after the first moon landing, doing a flyby of the moon in preparation for landing and supposedly for establishing a base there that makes no sense. We’re not even close to being able to send humans to the nearest planets, and even if we did send people to Mars, in one of the most pointlessly dangerous and exp…

It’s a logical extrapolation if you think life is a natural phenomenon. It would be exceedingly weird to see no evidence for it, but of course we have not been looking long or far.

And yes, space flight is brutally hard. Look up the history of sailing. Look up the Polynesian indigenous peoples and how long that took, through multiple waves of exploration, or the people who walked across a land bridge to North America during the ice age. Space flight is easier and safer than some of those feats, given the tech they did it with at the time.

If there is a fantasy it’s the idea that we’d have bases on the Moon and Mars by now. What we are doing today is the equivalent of early Polynesians hollowing out some logs and going fishing.

Re: Artemis II safely splashes down

#384

Post by Someone »

Nifty3929 wrote: post #371
Someone wrote: post #325

Earlier quoted context omitted.

> Artemis acceptable crew mortality rate is 1 in 30. Roughly 3x riskier than the shuttle Do you have a link? I’m asking because it is very easy to make mistakes when comparing risks. For example https://news.ycombinator.com/item?id=47725961 translates that into “That if we send 30 people we _accept_ that one is possible to die.” If that interpretation is correct, given Artemis has a crew of four, that looks more like…

I'm pretty sure that the chances that one dies in a mission is nearly the same as the chance that they all die. Very high correlation approaching 1.

That’s precisely my point. The question is what a crew mortality rate of 1 in 30 means.

If it means that, on average, a team member dies every 30 flights, with a crew of four, it’s likely there are fatalities in ‘only’ one in every 120 flights.

For space shuttle, that number was about one in every 60 flights. So, with that interpretation, Artemis would be about twice as safe as the Space Shuttle.

If, on the other hand, it means that, if you step aboard Artemis, your chance of dying during the flight is about one in 30, the Space Shuttle would be about twice as safe as Artemis.

Re: Artemis II safely splashes down

#385

Post by jjk166 »

d1sxeyes wrote: post #367
stetrain wrote: post #366

Earlier quoted context omitted.

> 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. No, but it means that to ensure that I do better on my next set of coin tosses I need to beat 3 in 4, not 1 in 2.

But you doing better is independent of the risk involved. The chances of you getting 3/4 heads or better is around 31%, so theres ~69% chance you’ll do worse next time round. Doesn’t change the fact that each coin toss is still 50/50.

> Doesn’t change the fact that each coin toss is still 50/50.

That assumes a fair coin. The fact is you don't know what the odds were of getting heads or tails for that particular coin, all you know is that you got 3/4 heads. And in this analogy, a few hundred coins have every been made, in maybe a dozen styles, none of which have been fair, so you have no good reason to believe that this particular coin should have 50/50 odds of landing heads up.

Re: Artemis II safely splashes down

#386

Post by zellyn »

sph wrote: post #280
matt_daemon wrote: post #239

I had this in the back of my mind today https://idlewords.com/2026/03/artemis_ii_is_not_safe_to_fly.... Glad they got home safe and sound!

Not for the same reason as you, the whole time I was thinking "I'm pretty sure NASA can assess the risk of their mission better than an Internet famous blogger" , despite the sentiment on HN at the time being very negative after reading these words [1]. These days the only qualification required for people believing anything you say is to have a blog and strong critical opinions about $AUTHORITY. Software engineers s…

And really well-reasoned arguments. And a decades-long sterling reputation for cantankerous but insightful contrarian takes. And references in the article to astonishingly well researched articles by people who have talked to NASA engineers and read non-public documentation. It’s like anyone can be taken seriously these days…

Re: Artemis II safely splashes down

#387

Post by cloche »

monocasa wrote: post #157
Ifkaluva wrote: post #98

Can somebody help me understand why this does a water landing, like the old Apollo missions, instead of like the space shuttle that lands like a plane?

A big part of the reason is that Orion (and Apollo) reentry speeds are way higher due to the orbital mechanics involved in going to the moon and back. Today's was actually the fastest manned reentry ever attempted. For reference the shuttle generally reentered at ~17.5K mph, and today's was 24K-25K mph. It's not clear that we could build a craft with wings that could survive that. So then you're looking at adding fue…

What would prevent them from entering into an orbit around Earth for a day or so and use that to slow down? Is that possible and would that make the reentry less risky?

Re: Artemis II safely splashes down

#388

Post by tedd4u »

jiggawatts wrote: post #295
TheOtherHobbes wrote: post #288

Earlier quoted context omitted.

I wondered about that. Winching someone who can barely walk and is wearing a spacesuit into a helicopter over choppy water is safer and quicker than parking them on a motor boat and sailing back to the mothership? What was the real reason? Tradition? Lack of imagination? Photo opportunities? The rest was great tho.

To play devil's advocate against my own argument: The nearest ship was about 5 km away, which is a decently long boat ride. In choppy waters with a small boat that could be less than ideal for someone who may be injured, weak from an extended stay in microgravity, etc. I assume the plan -- written months or years before the landing -- also had to factor in the possibility that the ships wouldn't have been so close. T…

100%. Easy to criticize this but you have to remember these are the people that planned and executed a successful moon mission. Pretty sure they know what they are doing and have thought about things in more that just a passing way.

Re: Artemis II safely splashes down

#389

Post by jasomill »

pdonis wrote: post #167
areoform wrote: post #76

Earlier quoted context omitted.

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…

The Smithsonian article on John Young that you linked to is a good one. The only John Young quote they didn't include that I wish they had was his response to the proposal to make STS-1 an on purpose RTLS abort: "Let's not practice Russian roulette."

Also "RTLS requires continuous miracles interspersed with acts of God to be successful."[1]

[1] https://web.archive.org/web/20171208090538/http://www.tested...

Re: Artemis II safely splashes down

#390

Post by tedd4u »

gcanyon wrote: post #344

Has NASA (or anyone) said anything about how the heat shield performed?

Still waiting to see comparison to A1’s used heat shield. Obviously it worked at least just well enough. They have a new formulation apparently for use with subsequent missions. New might be better but obviously it has not been tested in a real re-entry scenario so also kinda concerning for the next flight.
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