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Comment by GMoromisato | Hacker News Reader

This is a more balanced take, in my opinion:

https://arstechnica.com/space/2026/01/nasa-chief-reviews-ori...

Camarda is an outlier. The engineers at NASA believe it is safe. The astronauts believe it is safe. Former astronaut Danny Olivas was initially skeptical of the heat shield but came around.

And note that the OP believes it is likely (maybe very likely) that the heat shield will work fine. It's hard for me to reconcile "It is likely that Artemis II will land safely" with "Artemis II is Not Safe to Fly", unless maybe getting clicks is involved.

Regardless, this is not a Challenger or Columbia situation. In both Challenger and Columbia, nobody bothered to analyze the problem because they didn't think there was a problem. That's the difference, in my opinion. NASA is taking this seriously and has analyzed the problem deeply.

They are not YOLO'ing this mission, and it's somewhat insulting that people think they are.

View on HN

If you play a single round of Russian roulette with a revolver, it is likely you will not die, but it is also not safe to do that. The same idea applies here.

The foam shedding/impact problem was heavily analyzed throughout the Shuttle program, and recognized as a significant risk. Read the CAIB report for a good history.

That report also describes the groupthink dynamic at NASA that made skeptical engineers "come around" for the good of the program in the past. Calling Camarda an outlier is just a different way of stating this problem.

It looks like they did some worst case testing that was reassuring, so that it isn't Russian roulette? Any comments on that? I suppose their composite testing and temperature projections could also be wrong, and their trajectory changes might not be mitigating enough for the heat shield chunking, but that's a few different things all simultaneously being wrong for a catastrophic failure to occur.

The NASA engineers wanted to understand what would happen if large chunks of the heat shield were stripped away entirely from the composite base of Orion. So they subjected this base material to high energies for periods of 10 seconds up to 10 minutes, which is longer than the period of heating Artemis II will experience during reentry.

What they found is that, in the event of such a failure, the structure of Orion would remain solid, the crew would be safe within, and the vehicle could still land in a water-tight manner in the Pacific Ocean.

I think the point of the article is that there is no particular need to send humans in Artemis II.

Sure, they made tests. But it's not the same as trying in real conditions. The argument is that if they were able to predict everything with tests before the real flight, then Artemis I wouldn't have had those issues. But we know what happened.

But then no spacecraft is safe to fly. We're obviously willing to accept a much higher level of risk sending humans to the moon than in other situations. I think I read somewhere at a 1 in 30 chance of them all dying was acceptable. Not too far off from Russian roulette!

I don't see it so much as no spacecraft is safe to fly, but rather no spacecraft should have a crew on it so long as there are major safety questions.

This is not the Shuttle that couldn't be flown without a crew.

Pro tip: you’re supposed to use a revolver.

Who says I'm not?

https://www.rockislandauction.com/detail/62/1323/rare-and-un...

Juggle five guns after loading one.

> If you play a single round of Russian roulette with a revolver, it is likely you will not die, but it is also not safe to do that. The same idea applies here.

Fundamentally space travel is not save, it cannot be (atleast at our Technological level) Space is unimaginably hostile to life. We cannot reduce this danger to zero.

This is (no offense) intellectually dishonest. Nobody wants the risk to be zero. What we want is that, if there is a specific KNOWN flaw in a life-critical system, that the flaw is addressed and the shuttle re-tested before humans are placed in it.

There's no good reason not to do this, except as a lazy cost-cutting measure (and, presumably, under time pressure to perform the eventual moon landing mission within the timeframe of Trump's presidency).

Have you bothered to ask the astronauts on board if they want to risk it?

You're getting clicks, they're going to the moon and there's a lot of people on Earth who would happily take any tradeoff for that.

Hang on, without a dog in this fight, have I asked the people who trained their whole lives to drive cool cars if this particular cool car, which they were not involved in designing or building, is safe to drive? Is that what you are asking?

They asked if the astronauts "want to risk it", not if it was actually safe. Those are very different questions. The astronauts are, in fact, the world's leading experts on whether or not they personally want to risk it, so it's not entirely unreasonable to think that they could answer that question.

It just depends on whether you think that the fact that they accept the risks is reason enough to let them fly a potentially-dangerous spacecraft.

I know we all have a lot of respect for astronauts, but the fact is that they blindly trust whoever tells them "it's safe enough" that it is, actually, safe enough.

Artemis II doesn't need astronauts to do its flights. Astronauts are trained to survive in a spaceship that does not need them to do anything at all. That it is their dream to survive in such a spaceship does not say at all that they have any valid idea of how much risk they are taking.

We can say "maybe the astronauts would accept to fly knowing that they have a probability of 1/30 of dying" all we want, but that doesn't answer the question here, which is: what is the probability that they die?

The article says "we don't really know: the first test flight was very concerning, and we used the exact same methods to prepare the second flight, so we won't really know how unsafe it is until we try it".

Sure, they have made tests on the ground. But the first flight proves that those tests are not enough, otherwise Artemis I wouldn't have had those issues in the first place.

This is a perfect way to put it.

Artemis II is not safe, at least by the standards we apply to things. It's the third flight of a capsule, on the second flight of the rocket, and the first flight of things like the life support system.

At the end of the day, one of the reasons astronauts are respected is they understand those risks, and go into space anyway. That doesn't mean we shouldn't try to minimize risks - but at some point the risk becomes acceptable, and the cost of reducing it too great.

To paraphrase a quote from Star Trek - risk is their business.

Taking a related quote from Dollhouse: "That is their business, but that is not their purpose."

> there's a lot of people on Earth who would happily take any tradeoff for that

That's not reassuring, though. And it isn't just about them.

The astronauts are cool with it. They are basically brainwashed to rationalize exceptional trust in all of the people and components so that they are able to focus on the task at hand.

I wouldn't say brainwashed, but they're definitely aware of the political angles related to succeeding with a career at NASA and almost always agree to play ball without causing trouble for the org.

That's a fair way to put it. Though I know people who honestly believe the mantraof trust, to the exclusion of data.

Yeah, the astronauts aren't nearly as rational and clear-thinking as HN posters.

Have you bothered to ask the gambler if they want to risk it?

No offense to the astronauts of course, but asking people that have dreamed of this opportunity their whole life doesn't actually tell you all that much about the actual safety of the mission as a whole.

That “balanced take” severely mischaracterizes dissenting expert Camarda’s attitude, so it’s not balanced at all. Its answer to “Could the NASA engineers convince Olivas and Camarda?” is a “maybe” for Camarda, which couldn’t be further from what Camarda had to say himself, which is he was more concerned after the meeting than before.

From Camarda’s own account after the meeting:

> Hold a “transparent” meeting with invited press to “vet” the Artemis II decision with one of the most public technical dissenters, me, in attendance (Jan 8th, 2026).

> Control the one-sided narrative and bombard the attendees with the Artemis Program view

> Do not allow dissenting voices to present at the meeting

> Do not even allow the IRT or the NESC to present their findings

> Rely on the attending journalists to regurgitate the party line and witness the overwhelming consensus of knowledgeable people

The whole thing is a good read https://docs.google.com/document/d/1ddi792xdfNXcBwF8qpDUxmZz...

Characterizing someone being (slightly?) more diplomatic as “maybe convinced” is shameful.

"It is likely that Artemis II will land safely" and "Artemis II is Not Safe to Fly" are both compatible with the probability of a disaster on reentry being 10%.

> In both Challenger and Columbia, nobody bothered to analyze the problem because they didn't think there was a problem.

Being pedantic, NASA management "ignored" engineers - because money.

That said, I 100% agree with you assuming:

> “We have full confidence in the Orion spacecraft and its heat shield, grounded in rigorous analysis and the work of exceptional engineers who followed the data throughout the process,” Isaacman said Thursday.

I only say assuming not that I don't believe Isaacman, but historically NASA managers have said publicly everything's fine when it wasn't and tried to throw the blame onto engineers.

With Challenger, engineers said no-go.

With Columbia, engineers had to explicitly state/sign "this is unsafe", which pushes the incentivisation the wrong direction.

So, I want to believe him, but historically it hasn't been so great to do so.

There were a lot of mistakes with Challenger and Columbia--I totally agree. But I don't think it was money. It's not like the NASA administrator gets a bonus when a rocket launches (unlike some CEOs, maybe).

I think the problem with both Challenger and Columbia was that there were so many possible problems (turbine blade cracks, tiles falling off, etc.) that managers and even engineers got used to off-nominal conditions. This is the "normalization of deviance" that Diane Vaughan talked about.

Is that what's going on with the Orion heat shield? I don't think so. I think NASA engineers are well aware of the risks and have done the math to convince themselves that this is safe.

> It's not like the NASA administrator gets a bonus when a rocket launches

It's related to funding. I mean it's always money, right?

But in Challenger's case, there was very heavy pressure to launch because of delays and the rising costs. I remember in a documentary they explicitly mentioned there was a backlog of missions and STS-51 had been delayed multiple times. To rollout/fuel, costs a LOT and challenger had been out on the pad for a while. Rollback was a material risk+cost.

For columbia, yea less about money. They ignored the requests to repoint spy sats and normalized foam strikes.

> I think NASA engineers are well aware of the risks and have done the math to convince themselves that this is safe.

And that's the way it should be. Everything has a risk value regardless if we calculate it or not. It's never 0... (maybe accidentally going faster than light is though?) We just need to agree what it is and is acceptable.

Story time - I was a young engineer at National Instruments and I remember sitting in on a meeting where they were discussing sig figs for their new high precision DMMs. Can we guarantee 6... 7 digits? 7? and they argued that back and forth. No decisions but it really stuck with me. When you're doing bleeding edge work the lines tend to get blurry.

> It's related to funding. I mean it's always money, right?

This sounds more like there is money in the room than it’s about the money. None of the decision makers personally profited from saying go. It was much more of a prestige thing.

Challenger: Saying don't go would probably have cost them their jobs.

Columbia: It had previously barely survived foam damage. They figured out where the offending foam had come from and fixed that part--but only that part.

man, if you need 7 digits, call HP.

Camarda isnt an outlier. Lots of people left that project after the Experimental Flight Test, which was done with the honeycomb (making Avcoat truly Avcoat) in 2014. Without Avcoat, spalling was inevitable and breakoff, oh yeah.

The design change by LM, not commentedkn by Textron is like. a beehive with no honeycomb-a crystallized block of honey.

i'll take the structural support of honeycomb any day.

It's a normalization of deviance. That is what Charlie is bringing voice to. Many of us fear reprisals and even when talking to heads of, like with Columbia, we are ignored.

So, Charlie is a voice of many people, not an outlier.

In the space shuttle disasters the hardware had at least been used more than once. A huge lot of this one is only tried and tested on paper.

And the idea that 'if we throw this much money at it, it really must be fine' I don't buy either. Look at how that worked out for Boeing.

For all my feelings about Musk I would much rather step into a rocket that has exploded in all kinds of imaginable situations before so they know how the materials and design actually behave in real world scenarios. I do really think that is the way to go.

I do not even remotely trust his management anymore. It looks very much like corner cutting. Cut until it fails and back off a bit is not a good approach when you need some redundancy.

> For all my feelings about Musk I would much rather step into a rocket

Definitely, but we still have to figure out if Musk is such a genious or NASA is full of retards.

Neither is true IMO but musk just picked the right development model.

Big space never did this because the current megaproject cost plus is just what they want, a blank check.

Witn SpaceX Musk was mainly wasting his own money especially in the beginning. So it made sense. It just makes sense, it's not even a 'shortcut'.

Ps yes he did get some grants but not beefy unlimited ones.

Another thing SpaceX has going for it is when their tests fail everyone just points and laughs at Musk. When a NASA launch fails the taxpayers don't want to pay for it any longer.

The laughing was at the start, before Falcon 9 made it into orbit.

There was very little laughing at the starship RUDs. I think it's pretty clear that this development model is far superior now.

Don't forget that big space had a big incentive to paint it as useless, to protect their pork barrel.

TFA is ridiculous with its stance. Yeah, there's this aspect of the design they can't test in their labs. It might even be an important aspect. But safety isn't a boolean "safe"/"not safe", it's a risk assessment, and I'm quite sure there are 100 (or 10000) other things they didn't test for. As long as they're taking all of this into their risk calculations… it's fine.

And if it doesn't blow up due to heat shield failure, TFA (and its references) will be forgotten.

And if it does blow up due to heat shield failure, TFA (and its references) can suddenly claim prescience, all the while this is one of thousands of factors that went into the risk assessment. If one really wanted to claim prescience, it'd need to be a ranking of a sufficient number of failure modes.

To illustrate the problem: I hereby claim they will have a "toilet failure". Now if they actually have one, I'll claim `m4d ch0pz` in rocket engineering.

(P.S.: it's a joke but toilet failures on spacecraft are actually a serious problem, if it really happens… shit needs to go somewhere…)

Does a jammed toilet fan count as failure?

https://news.ycombinator.com/item?id=47603657#47610348

In that case, go on claiming rocket engineering m4d ch0pz.

OH FOR FUCK'S SAKE

> And if it doesn't blow up due to heat shield failure, TFA (and its references) will be forgotten.

The HN hivemind will remember, he's a well known user with a well known site.

Let's hope there is no accident, but after the landing there will be reports anyway. We will take a look at the report of the shield and see if it shows a problem in spite it didn't explode, and compare with the prediction in the article. He may even write another article after the fly.

For comparison, I remember the Feynman appendix. One important detail was that Nasa said the the probability of accidents was 1/100000, but he concluded that it was closer to 1/100. Nobody expect to fly a hundred Artemis missions to get a good statistic. Even if the current version explosion rate is super high like 1/10, then you can probably fry a few missions without problems if you cross your fingers hard enough.

I'm not super happy with the pattern of thinking in these numbers; arguing 1/100000 vs 1/100 for "accidents" is again a boolean thing. They probably had a very specific definition, which does make this viable, but we don't have that definition here. So the numbers are meaningless to us. And not having that definition, "accidents" is a sliding scale… e.g. I'm pretty sure astronauts injured themselves banging various bodyparts against various parts of the spaceship. That's technically an accident.

And in this concrete example — the heat shield isn't boolean either. I don't know how steep the gradient between pass and fail is, but it certainly exists, and it's possible they come back successfully but with it singed significantly outside expected parameters. (Even "less than expected" would indicate a problem here IMHO.) That does mean it's not necessarily a question of having enough boolean datapoints.

A high enough threshold for "accident" is a death. In the space shuttle the "accident" rate was 2/135 that is somewhat close to 1/100, but it shows that 1/100000 is too optimistic.

You can pick a more strict safety criteria, but the result would be (something)/135 >= 2/135 > 1/100 >> 1/1000000

Yes… for the space shuttle. But where is what on this for Artemis II? Especially if it has more heat shield failure modes that are not immediately deathly, the whole consideration becomes non-obvious. Is it possible the astronauts will arrive back "well toasted" but alive and OK other than heatstroke? (Probably not, but that's the kind of question involved here...)

(Also, technically [you may begin your eyeroll] even death isn't a simple boolean condition. I guess brain death should do it.)

Anyway all I'm saying is that all of these considerations need more qualifiers to be really useful.

> The engineers at NASA believe it is safe. The astronauts believe it is safe.

This take completely ignores Camarda's observations that there is a culture of fear spreading at NASA which punishes whistleblowers. I'm not saying he's 100% correct, but how can you claim such a take is truly balanced if there's a possibility one of the parties is engaging in a cover-up?

The engineers at NASA & astronauts aboard Columbia & Challenger also believed the programs were safe.

>The NASA engineers wanted to understand what would happen if large chunks of the heat shield were stripped away entirely from the composite base of Orion. So they subjected this base material to high energies for periods of 10 seconds up to 10 minutes, which is longer than the period of heating Artemis II will experience during reentry.

> What they found is that, in the event of such a failure, the structure of Orion would remain solid, the crew would be safe within, and the vehicle could still land in a water-tight manner in the Pacific Ocean.

Indeed, this is a much more balanced take. And it turns out that the OP armchair expert is assuming NASA doesn't know what they are doing or is negligent.

The OP links a document from former astronaut Charles Camarda, who NASA explicitly invited in to check their work, and who observed the press conference the Ars article comes from. He addresses every point in it, including that one. Just because an article is contrary to a strident opinion doesn't make it 'balanced'. It matters whether the actual facts are true or not.

https://docs.google.com/document/d/1ddi792xdfNXcBwF8qpDUxmZz...

This report from astronaut Camarda is indeed a bomb. Scaring.

I mean, it isn't like there are not multiple precedents for NASA to find a surprise safety issue, talk it down, and then see it literally blow up in their faces.

NASA is an institution and the incentives align with launching despite risk in cases where the risk was completely unanticipated. The project has its own momentum that it has gathered over time as it rolls down collecting opportunity costs and people tie themselves to it. If you think an astronaut would pull out of a launch because of a 5% risk of catastrophe... well you are talking about a group of people which originated from test pilot programs post-WWII where chances of blowing up with the gear was much much higher, so even though modern astronauts don't have the same direct experience, it isn't beyond reason to assume they inherent at least a bit of that bravado.

>The engineers at NASA believe it is safe.

it doesn't matter.

https://en.wikipedia.org/wiki/Artemis_II

"It will be the second flight of the Space Launch System (SLS), the first crewed mission of the Orion spacecraft, and the first crewed mission beyond low Earth orbit since Apollo 17 in 1972."

such "second/first" were ok 60 years ago. Today the only reason for that is that the SLS isn't reusable while the cost is hyper-astronomical.

Today's tech complexity, engineering culture and overall managerial processes don't allow the first/second to succeed as a rule. Even the best - Space X - has got several failed launches back then for Falcon and now for Starship.

Of course we wish success, and it will probably succeed - just like the Russian roulette so aptly mentioned in the sibling comment.

All of the controversy over the heat shield is obscuring the much bigger safety issue: Artemis has had only a single unmanned test flight. By contrast, the Saturn launch system had seven successful unmanned tests before being trusted with a crew, including two unmanned flights of the complete Saturn V stack. And even then, three astronauts were lost during ground testing of the crew capsule due to a critical design flaw. Artemis's closest modern counterpart, the SpaceX Starship, has had 11 test flights, several of which resulted in loss of the vehicle. There is no reason to believe that Artemis has a significantly higher reliability rate than Starship or Saturn V. Even without the heat shield controversy, this is the most dangerous mission NASA has launched since the first flight of the Space Shuttle.

> Artemis's closest modern counterpart, the SpaceX Starship, has had 11 test flights, several of which resulted in loss of the vehicle.

I don't think you can compare the two. Starship's risks are so high failure is almost the expected outcome, it's a trial and error based process. Starship and Artemis is an apples/oranges comparison with respect to how the programs approach risk tolerance.

Until Artemis actually flies a comparable number of missions, any advantage in reliability is pure speculation. Which is not a good way to approach crewed spaceflight. I don't think the two programs are as different as you think, prospectively: both take great care to ensure that their vehicles don't fail. Starships may be cheaper than the SLS, but they're still very expensive. SpaceX doesn't go into a flight expecting to lose a vehicle. The difference in culture is more in the reaction to failure. As a private company, SpaceX moves very quickly in the wake of failure, whereas NASA has in recent decades become much more cautious once a failure has occurred. And while you say SpaceX is more tolerant of risk, I would note that they've never flown a crew on a launch vehicle that had only one previous unmanned launch. Falcon 9 had 85 unmanned launches before there was a crew aboard. And they expect to launch 100 unmanned Starships before they fly one with a crew.

Now which program seems the more risk tolerant?

SpaceX was clear about their policy of flight testing earlier in the development phase. They expected to lose rockets, I do not believe those should count against the launcher.

They do not expect to lose a given vehicle. They are tolerant of losing some vehicles over time, because they understand that every flight may be affected by unknown unknowns. There is certainly no evidence that they expect to lose crewed vehicles, or that they are tolerant of crew loss.

I think the high loss rate for Starship can largely be traced back to the choice of using steel for the vehicle, which drastically reduces margins across the system. You could certainly say that they had a higher expectation of failure because they made that choice. In that sense, I understand your point. But to the best of their ability, they try to fly every vehicle successfully.

They haven't lost a crewed vehicle.

The only Starship loss that bothers me is the first one. I have no problem with "let's see if this works", I have a problem with dismissing the opinions of all the experts and launching without a flame trench. You don't need to be a rocket engineer to see that when you give all that energy no place to go a lot of it is going to get reflected back at the rocket.

What should be counted against them are the two operational Falcon 9s that were lost. The second one especially bothers me: we didn't really need that part anyway is not an answer to why the part failed!

> They haven't lost a crewed vehicle.

Yes, that's my point. SpaceX understands they need to do many unmanned flights before trusting a launch system with a crew. NASA is trusting Artemis with only a single unmanned flight. That is very high risk tolerance, to the point of recklessness in my opinion, compared to SpaceX.

> It's hard for me to reconcile "It is likely that Artemis II will land safely" with "Artemis II is Not Safe to Fly", unless maybe getting clicks is involved.

Look up the term "expected value". If pressing a button has a 10% chance of destroying Earth, it is both 1) likely that pressing it will do nothing AND 2) the case that pressing it is extremely unsafe.

for human spaceflight we want a lot more than "likely" (>50%). The standard is usually "extremely likely" (~1/100 to 1/1000 chance of failure)

Maybe. What was the probability of Loss of Crew during Apollo? There were 9 crewed missions and 1 almost killed its crew (I will omit Apollo 1 for now). I could argue that Apollo had a 1 in 20 chance of killing a crew. Indeed, that was one reason given for cancelling the program.

The first Shuttle launch probably had a 1 in 4 chance of killing its crew. It was the first launch of an extremely complicated system and they sent it with a crew of two. Can you imagine NASA doing that today?

In a news conference last week, a NASA program manager estimated the Loss of Mission chance for Artemis II at between 1 in 2 and 1 in 50. They said, historically, a new rocket has a 1 in 2 chance of failure, but they learned much from Artemis I, so it's probably better than that. [Of course, that's Loss of Mission instead of Loss of Crew.]

My guess is NASA and the astronauts are comfortable with a 1 in 100 chance of Loss of Crew.

> There were 9 crewed missions and 1 almost killed its crew (I will omit Apollo 1 for now). I could argue that Apollo had a 1 in 20 chance of killing a crew.

That's not how risk analysis works.

Let's say every Apollo mission had gone flawlessly, and no one even came close to dying. Would you then say that the risk of death for future missions would be zero? No, of course not.

I thought I'd look this up. If you've had 9 successful attempts, assuming nothing has changed between them and no other prior knowledge about success probability, then Laplace’s Rule of Succession says the probability of the next mission being a success is about 83.3%, i.e. there is a 1 in 6 chance of failing next time.

> and no other prior knowledge about success probability

This phrase is misleading, as Laplace's Rule of Succession is equivalent to assuming a uniform Bayesian prior over all values of p. That is, before any experiments, a 50% chance of success. Depending on the situation, this may be roughly accurate or wildly wrong. You cannot appeal to this rule to resolve the situation.

Well, obviously if we have a better prior, then that's better. But assuming no other knowledge, and especially if we think that other people's priors could be intentionally misleading, this rule seems to offer the best estimate.

Generally speaking, you never truly have "no prior knowledge". Some relevant past experience, or "common sense", or something tips you away from "all probabilities are equally likely". I think this rule is rarely a best estimate.

If you only look at this data it would be the most reasonable guess.

Of course one should also analyze the technical sytems involved and then it is clear that 0% failure is not reasonable.

Bayes rule has existed for nearly 300 years, there is no excuse for ‘only look[ing] at this data’ and that is NEVER a reasonable thing to do.

> I could argue that Apollo had a 1 in 20 chance of killing a crew.

NASA computed the chance of “landing a man on the Moon and returning him safely to Earth” as less than 1 in 20. I would think a lot more than 1 in 20 of those failures would result in killing crew members.

https://ntrs.nasa.gov/api/citations/20190002249/downloads/20...:

“Appreciating and deemphasizing risk in Apollo

Joseph Shea, the Apollo program manager, chaired the initial Apollo systems architecting team. The “calculation was made by its architecting team, assuming all elements from propulsion to rendezvous and life support were done as well or better than ever before, that 30 astronauts would be lost before 3 were returned safely to the Earth. Even to do that well, launch vehicle failure rates would have to be half those ever achieved and with untried propulsion systems.”

The high risk of the moon landing was understood by the astronauts. Apollo 11's Command Module pilot Mike Collins described it as a “fragile daisy chain of events.” Collins and Neil Armstrong, the first man to step on the moon, rated their chances of survival at 50-50.

The awareness of risk let to intense focus on reducing risk. “The only possible explanation for the astonishing success – no losses in space and on time – was that every participant at every level in every area far exceeded the norm of human capabilities.”

However, this appreciation of the risk was not considered appropriate for the public. During Apollo, NASA conducted a full Probabilistic Risk Assessment (PRA) to assess the likelihood of success in “landing a man on the Moon and returning him safely to Earth.” The PRA indicated the chance of success was “less than 5 percent.” The NASA Administrator felt that if the results were made public, “the numbers could do irreparable harm.” The PRA effort was cancelled and NASA stayed away from numerical risk assessment as a result.

1/100 is absolutely terrible. Shuttle had 1.5% failure rate. Bonkers.

[edit]

For comparison, commercial aviation has something like 1 in 5.8m or 6x 9's of reliability.

There have been 412 manned space flights, ever, by anyone, anywhere.

A large commercial airport handles many times that number of flights every single day. Worldwide there are a hundred times more flights per day than the number of manned space flights in history.

I suspect every model of commercial plane has flown far more flights than all the human rated rockets put together.

It's not terrible for space flight. Flying a rocket to the moon and commercial aviation are obviously very different things.

It is easy to reconcile these two statements.

The "likely" in "likely ...to land safely" and "likely to work fine" is not nearly good enough.

> In both Challenger and Columbia, nobody bothered to analyze the problem because they didn't think there was a problem.

False on both counts. Both the SRB joint design issue and the foam shedding were known, researched and dismissed very early in the shuttle program. They suspected it after STS-1 and confirmed it within a few flights.

No. They were noted, the fact that they didn't destroy the vehicle was taken as evidence they wouldn't destroy the vehicle. Neither received any real scrutiny.

As a former NASA guy I would trust Eric Bergers measured and detailed reporting here over that blog post that says they are all going to die

As he shows that Olivas changed his mind:

“ Olivas told me he had changed his mind, expressing appreciation and admiration for the in-depth engineering work done by the NASA team. He would now fly on Orion”

Anyway we live in an age of armchair experts in youtube (who are often very smart but quick to rush to judgment without enough context)

The article explains the situation in a more balanced and fair light

How about former NASA engineer Charles Camarda? Linked from the article: https://docs.google.com/document/d/1ddi792xdfNXcBwF8qpDUxmZz...

I agree, this report from astronaut Camarda should really alarm NASA.

Not really - read the Berger article for more details above -Camarda is older, in his 70s and his attitude overall (based on the reports) reads more like an ego bruise than serious reflection on the engineering problem

Obviously concerns should be vetted by the engineering teams involved but it appears they have been addressed to meet the needs of the mission

It's kind of sad that we've become so risk averse. Risks should be fully disclosed but let the adventurers adventure.

Would Columbus' ship ever have been allowed to sail in the modern day? Proximity wingsuit flying and free-climbing is legal and people choose to do it even though the probability of death is extremely high. Spaceflight is significantly safer and far more beneficial to humanity, yet we block it. No one counts the lives lost due to slowing scientific progress but we should. How much further behind would we be scientifically if Darwin hadn't ventured out on the Beagle due to endless safety reviews. Would the US be what it is today if Lewis and Clark had to prove to congress that the trip was safe?

Given the opportunity, many of us would choose to die as part of a grand adventure in service to humanity vs. wither away of old age.

I wish I could downvote this comment more than once. It's incredibly ghoulish to use the perfectly-sensible argument that modern culture is too risk-averse to handwave away known critical safety problems. Those two things are completely orthogonal. Yes, astronauts should be willing to accept that there are "unknown unknowns" and that they will be facing some amount of unquantifiable risk, and they should be celebrated for this. That does not, not at all, mean that when a mission comes back with heat shield failures we know should not have happened, and multiple Inspector-General reports say the ship is not safe, those concerns should be blown off with rambling about Charles Darwin. That's pure insanity.

Or to put it another way, if you were the manager on the day of the Challenger launch issuing the "go" command over the objections of the Thiokol engineers saying it was unsafe to launch in below-freezing temperatures, would you have done so with paeans to Christopher Columbus? That's the sense I get from your post.

>Camarda is an outlier. The engineers at NASA believe it is safe. The astronauts believe it is safe. Former astronaut Danny Olivas was initially skeptical of the heat shield but came around.

How do you explain so many people believing it is safe?

The problem is risks are far too easy to brainstorm, anyone can come up with endless risks that it takes endless time to mitigate.

If I were the manager for challenger, I would have run the o-ring experiment as soon as it was brought up as a concern. Put the fuel pumps in a freezer, test if they leak. Feynman famously demonstrated it with a glass of icewater. Experiment is what separates made up risks from real risks, I would have definitely told the engineers to take a hike and would have hit launch if they couldn't provide experimental evidence of o-ring failure in cold temps. (Spoiler alert: in that case they easily could have)

No. That famous demonstration only touched on the real failure mode--the rings were covering up other failure and in the cold could not do so.

The real test was creating a full-scale test of ignition, an engine containing mostly inert filler (to occupy the fuel volume) and just enough fuel to reach stable burning.

> How do you explain so many people believing it is safe?

The article itself answers this question: institutional incentives leading to heavy social pressure to agree with the groupthink and declare something is safe when it is not. And we know that the scenario it lays out is highly possible, because it has already destroyed two Space Shuttles. Now that this has happened twice, the burden of proof is on the people saying it's not happening again, especially when the OIG's report directly contradicted what NASA had been saying about the heat shield up to that point (indicating they were lying and had to hastily retcon their story).

>the burden of proof is on the people saying it's not happening again

This specifically I take issue with. You had a bug in your software before so now the burden is on you to formally prove your software is bug-free.

The burden of proof should remain on the naysayers. Take a plasma torch to the heatshield pock marks and see how long it takes to burn through. Do experiments just as Feynman did with the o-rings. Let the outcome of the experiment, not office politics decide.

I'd say when two conditions are true:

1) you have an established pattern of behavior of ignoring safety concerns (Challenger, Columbia), and

2) people are alleging that you are doing the same thing now, with independent auditing from the OIG backing them up,

that's sufficient to shift the burden of proof back onto you.

Your attempt at a gotcha with the heatshield is just ridiculous: everyone already agrees the heatshield works in small-scale testing. That's the entire problem! It failed on the actual mission and NASA couldn't explain why, so instead they pivoted to trying to explain why the failures don't matter.

(EDIT: As an addendum, I'll also add that you don't even need to go back to Columbia to find an example of NASA lying about safety to protect reputations. Remember when they insisted for months that the Starliner mission was going just fine, and then eventually they said the astronauts weren't coming back on it, and then it landed and the final report was that there multiple failures leaving it on the knife edge of total catastrophe? And remember how that was less than two years ago? You're a maniac if you take the safety claims of this organization at face value)

> In both Challenger and Columbia, nobody bothered to analyze the problem because they didn't think there was a problem.

Problems with the O-Rings had been known and on the morning before the challenger launched the engineers begged management to delay the launch.

Minor nitpick: OP didn't say "maybe very likely". He said "hopefully very likely". They are, in my mind, different things.

Absolutely not. I will not even consider the word of an organization that has repeatedly failed to learn from its past mistakes. They need to demonstrate an ability to learn first, and to do so they need to take these concerns seriously. That means no astronauts on Artemis II.

They have analyzed the problem with 1D non-coupled models that are so poorly matched to reality they would receive an F in a high school science class.

They are YOLOing it. It is insulting that clowns like yourself continue to cover for them.

NASA lowers its standards every time an accident happens. When they designed Shuttle, they intended for a failure rate of 1 in 10,000 or thereabouts.

Remember, it was meant to fly dozens of times per year. At the real failure rate, we would have lost dozens of Shuttles by now. The public would have shut NASA down in protest for massacring astronauts.

Good job moving the goalposts.

> They just slink away, and then when the next event happens, they cry wolf again. When they happen to be right 2 of ~130 times, they get to say "see I told you so!" and go on speaking tours about how they figured it out but NASA wouldn't listen, say they should be considered for a leadership position in NASA etc.

NASA does not have a single model that accurately predicts the heatshield damage. They are lying about this fact and crossing their fingers that all is okay. That might work in SWE's little AWS and GCP world, it doesn't work during hypersonic reentry. IOW they are gambling.

If you have a college degree, especially one that taught statistics, put it in a shredder and remove it from your CV. This is embarrassing.

The issue with arguments like this is that people who make the claim "it's not safe!" never feel the negative consequences when everything goes to plan. They just slink away, and then when the next event happens, they cry wolf again. When they happen to be right 2 of ~130 times, they get to say "see I told you so!" and go on speaking tours about how they figured it out but NASA wouldn't listen, say they should be considered for a leadership position in NASA etc. To the people who think they are YOLO'ing it and that disaster is inevitable, they should be willing to actually put something on the line (promising never to talk about the topic again, money, etc.) and have some skin in the game. Otherwise, such claims are worthless.

You seem to have ignored an important statement in your reply. Will you be willing to put $20,000 on a bet whether or not the Artemis will have a catastrophic failure? Or willing to record a statement and release it on all of your social media if the Artemis does not have a catastrophic failure? It is extremely easy to sit on the sidelines at home and say to delay everything because something may go wrong, and you will actually be right, because eventually something always goes wrong occasionally. But the people who actually get work done have to make decisions.

Ask Charlie Camarda.

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