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 is a world where they don't make it back home.
I am grateful that they did. And I'm grateful that we're going to go even further. I can't wait to see what Jared's cooking up (for those who don't know, he made his own version of the Gemini program in Polaris and funded it out of pocket).
> 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 possible at our current level of technology to make this "safer" due to the distances and energies involved. Even with the Commercial Cargo and Crew Program (C3P), NASA has set the acceptable mortality threshold at 1 in 270 over the entire mission and 1 in 1000 on ascent / descent. If they could set it higher by gaming the math, they would. They can't.
We're a very primitive species, and the forces involved here are genuinely new. And no, Apollo wasn't much better either, at least 10 astronauts were killed in training or burned alive, as well as (far worse, because astronauts sign up for the risk) one member of ground staff.
People love to hate the Shuttle, and it ended up being subpar / fail expectations due to the political constraints NASA was under, but the Shuttle was a genuine advance for its time – a nonsensical, economically insane advance, but still an advance. If you look at the Shuttle alternative proposals / initial proposals as well as stuff like Dynasoar and Star Raker, you'll see NASA iterating through Starship style ideas. But those were rejected due to higher up front capital investment at the time.
The Shuttle is an odd franken-turduckling, because it was designed for one mission and one mission only. And that mission never happened. That cargo bay existed to capture certain Soviet assets and deploy + task certain American space assets and then bring them back to Earth.
And that's the bit that's hard to emphasize. The fact that the Shuttle could put a satellite up there, watch it fail, then go back up, grab it, bring it back, repair it, then launch again was an insane capability.
Was the program a giant fuck up at the end? Yes. But does that mean Artemis will be safer than the Shuttle? No. That's not how the energetics, time from civilization, acceptable risk profiles etc. work out.
Adding to it - Apollo 13 was a mission where 3 men should have died, but somehow didn't. If it had happened while the LM was on the moon, you would have had the CSM lose power, and then two men on the moon would have had no way to return home.
(And for the shuttle design mission - my understanding is it was likely the ability to do a HEXAGON-style film return mission in a single orbit, before the Soviets knew what was happeneing.)
note - I can't verify any of the following, it's more - for lack of a better term - aerospace nerd fan theory at this point.
Post-collapse, people think that the Buran justification was paranoia. But based on what I've read / seen (though this is getting hard to source, so I might be just good ol' hallucinating here), they weren't entirely wrong. The subtext around that large payload bay had to do with the Soviet pursuit of systems like Fractional Orbital Bombardment System (FOBS) https://en.wikipedia.org/wiki/Fractional_Orbital_Bombardment... that weaponized space.
Again, there's a reason for those ASAT tests. There's a reason for the weird specifications set in the early 1970s for the Shuttle. And I don't think deploying a spy satellite alone is it. But this is speculation. AFAICT, nothing was put on paper.
It would have been an incendiary WW3 starting act to capture a Soviet asset. But I think it is understandable if certain people within the American blob wanted that capability at hand.
I wish I was immortal. I'd drop everything for a decade and try to find people from the time who're still alive (and some still are!) and ask them these questions directly - on the record – for posterity's sake. I suspect, we came much closer to war via space than most people think. And because we didn't, we'll eventually repeat these mistakes.
The only people who took seriously the idea of a Shuttle FOBS were the Soviets, and frankly not even all of them; as far as I've ever seen credible evidence to substantiate, it never went much past a single position paper from the early 80s. The idea that Buran was meant as a MAD-restoring FOBS has, so far as I know, not even that much support. (If you know of primary sources, in translation or otherwise, please link them.)
Read Payne Harrison's 1989 novel Storming Intrepid, followed by NASA publication SP-4221, "The Space Shuttle Decision," from 1999. [1] The first is a pretty good depiction of what you're imagining, and the second explains why the imagination of a technothriller author is where that idea went to die. Then maybe give your head a shake. If Reagan had violated the Outer Space Treaty - via NASA of all agencies! - how do you imagine it'd have stayed secret over these forty years just past?
Nice article, although I'm not so sure about this part:
> There’s a reason why there wasn’t an Apollo 18, or 19 and 20. Even though funding had been secured, an executive decision was made to kill the program early, because LoC was inevitable.
Was funding really secure? I believe that was the main sticking point; a quick search [0] seems to confirm this, and the John Young quote below backs it up: "Even if they’d had the money..." Not to say the risk wasn't a factor too of course, but it doesn't look like funding was otherwise guaranteed.
Anyway, I think what sets the risk of the Shuttle apart from Apollo is summed up nicely in one of the quotes (in reference to the Apollo program): "The awareness of risk led to intense focus on reducing risk." In the Apollo program, there was a pattern of rigorously hunting down and eliminating any possible known risks, leaving unknowns as the primary source of risk; on the other hand, the Shuttle program let known risks accumulate continuously until crews paid the price for a bad draw.
When debris hit Atlantis on STS-27 [1] and the shuttle only survived on a one in a million stroke of luck -- the completely broken tile happened to be over an aluminum mounting plate -- it should have been taken as a free lesson on one more known source of risk to eliminate. Instead, it led to seven people dying completely preventable and unnecessary deaths a few years later.
Spaceflight is inherently risky, it's true. That's why things like the Orion heat shield are so worrisome; because it is physically possible at our current level of technology to make it safer, and yet for political / funding / etc. reasons we're not doing the best we can.
I often think about the shuttle program in relation to all these crazy complicated, wildly expensive, and incredibly fragile space telescopes we're sending to LEO or the Earth-Sun L2. Would be damn useful to be able to repair/upgrade these things like with Hubble.
Obviously I realise the shuttle program was pretty far away from being able to head out to the Earth-Sun L2(AB, and wasn't even working towards it. But man, it would be nice to have that ability.
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."
NASA certainly took many risks back then. People remember Apollo 11 for the landing, but for example on Apollo 8, with a fire roughly 2 years earlier that killed 3 astronauts, they had one manned mission (Apollo 7) and then immediately sent Apollo 8 around the moon with ONE rocket nozzle that had to work (and no LM to escape into, as the Apollo 13 astronauts had to do), basing their faith in trajectory mechanics which hadn't been tested that far out
The ejection seats on Gemini were a joke, and there's an anecdote Gene Kranz tells in his book about Gemini 9 where he thought it was too risky for them to cut away the shroud on the thing they were going to dock with (the Agena having blown up on launch) but NASA was this close to overriding him and doing it anyway (they were saved by the astronauts vetoing it, which was good because the EVA, separately, that Gene Cernan did was incredibly harrowing. he was sweating, way overworked, could barely see)
"As of 1 April 2026, there have been five incidents in which a spacecraft in flight suffered crew fatalities, killing a total of 15 astronauts and 4 cosmonauts.[2][how?] Of these, two had reached the internationally recognized edge of space (100 km or 62mi above sea level) when or before the incident occurred, one had reached the U.S. definition of space at 266,000 ft, and one was planned to do so. In each of these accidents, the entire crew was killed. As of April 2026, a total of 791 people have flown into space and 19 of them have died in related incidents. This sets the current statistical fatality rate at 2.4 percent."
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 planets might be much more massive than Earth. On one with 3X our gravity a space program might never get going.
I suspect that it is NOT a weaker system than before, it is more accurate about the mortality rate. In other words, there are fewer "unknown unknowns" than there were in the 60s and 80s, partially because of explosions that took out previous astronauts.
(Some would snidely say as long as they don't put seven people on the rocket they'll be fine.)
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.
A lot of advancement is multipurpose. CNCs are more accurate than machinists, computers are faster. And we have a lot of the technical knowledge written down.
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.
That was the fair estimate for the Shuttle program. NASA caught hell in public, justifiably, for pretending otherwise. But astronaut memoirs such as Mullane's excellent Riding Rockets paint a much more nuanced picture.
I waited until splashdown to permit my emotions to get involved, and I'm glad I did. It was really something earlier, to hear my whole neighborhood bar set up a cheer for an American mission to the Moon.
Astronauts are, as a group, extremely risk loving. Every single person who signs up to go into space knows what they’re signing up for - they’ve spent their entire life working for the opportunity to be put in a tin can and shot into orbit atop a million pounds of explosives. There’s a very valid critique that NASA has become far too risk averse - we owe it to the astronauts to give them the best possible chance to complete the mission and make it back safely, but every single person who signs up for a space mission wants to take that risk, and we don’t do anyone any favors by pretending that space can be safe, that accidents are avoidable, or that the astronauts themselves don’t know what they’re signing up for. A mission that fails should not be considered a failure unless it fails because we didn’t try hard enough.
My father, who flew combat missions for the Navy in Vietnam and then became a test pilot, told me after the loss of Columbia that if he had had a chance to make that flight and spend 7 days in Earth orbit, even knowing that he'd burn up on reentry, he'd have done it.
1) Eventually you will die, no matter what. It can be the most mundane thing. Slipping on a ketchup splatter can cause great damage for example.
2) It's a profession where you intentionally kill people, so, that changes the calculation for your own risk.
3) It's a unique opportunity.
(and potentially)
4) Gives a sense of living / be in history books for his family.
So you have a possibility of a guaranteed exciting life for a death that you anyway will have, but doing something you love, it's not too bad.
> Artemis acceptable crew mortality rate is 1 in 30.
How did they arrive at that number?
(Eg. Did they arbitrily establish the target at the outset? Or did it evolve by gauging the projected failure rate of their core mechanical etc. systems as those began to take shape, then establishing a universal minimum in line with that, to achieve some level of uniformity and avoid drastically under/over-engineering subsequent systems?)
I mean it's the first space crew on an anti-science mission, right?
The point of them being there isn't discovery, it's to try to discourage anyone who wants try to understand and protect the planet that we all rely on for life
The craft has aerodynamics and speed. It might be figuratively true "unrecoverable" but if it takes e.g. 2 weeks to complete a return, their oxygen and food and batteries ran out. Alternatively if it enters too fast they return ... in pieces.
I think you're being a pedant, if your point is a grazing entry causing rebound skip ultimately returns to some orbital path downward.
You seem to intentionally be ignoring the original quote that any error may have caused them to be flung into space. This is patently false unless the one math error is pumping in hundreds of pounds more propellant and burning far longer than the scheduled burns. NASA would need to make a significant series of mistakes beyond orbital math for the "flung out into space" statement to be true.
They certainly could've gotten the return wrong but with a perigee of 119 miles they arent even in a stable orbit and likely could deorbit themselves using only rcs thrusters at apogee, or by just waiting a few orbits.
This is underselling the risks. On top of the many trajectories which push them into unrecoverable situations, leaving them stranded in orbit, there can be trajectories where the moon gives a gravity assist strong enough to fling the spacecraft into escape velocity, fulfilling the OP.
In fact, the trajectory they chose for this mission exploited the opposite effect to yield a free return without propellant expense.
In the modern day, the chance of a math error being the root cause behind this failure mode are vanishingly small, but minor burn execution mistakes that do not require hundreds of extra pounds of propellant are definitely plausible. They were extremely common in the early days of spaceflight and plagued most of the very first moon exploration attempts. Again, with modern RCS this is unlikely. But reentry is still incredibly tight and dangerous. Apollo famously had a +-1° safe entry corridor, and Orion is way heavier and coming in even faster. If their perigee was off they could’ve easily burned up or doubled their mission time, which they may not have been able to survive.
The amount of things that would have to go wrong for the craft to get an accidental gravity boost and be ejected would be significant.
I feel like the original claim paints the whole thing as on a knife edge and barely achieved by virtue of not making a single mistake. In today's age with so many moon landing deniers and worse I feel like we should be specific about where the actual dangers challenges and unknowns there were here. In reality, the orbital mechanics are one of the simplest parts of the entire problem, at least when we're talking about a moon flyby
The moon's gravity turns out to be "lumpy" because its density is not constant. This was detected by the Apollo missions and caused them to make errors in orbit calculations. This source of error could have influenced the flyby.
Yes, this is a fair point. I agree that orbital mechanics is trivially easy compared to everything else. The chances of a math mistake in particular are null, these trajectories have all been calculated years in advance.
I’ll agree, it seems crazy that it left earth, made it to the moon, and never really left earth orbit at all. That the furthest we’ve been away is still destined to return on its own.
I’d bet a million dollars that Orion will win every safety metric compared to the shuttle once it is retired. NASA deluded itself in thinking the Shuttle was safe. The reality is that the Shuttle was the most dangerous spaceship anyone ever built.
That's physically not possible due to the distances and energies involved. Even with the Commercial Cargo and Crew Program (C3P), NASA has set the acceptable mortality threshold at 1 in 270 over the entire mission and 1 in 1000 on ascent / descent. If they could set it higher by gaming the math, they would. They can't.
We're a very primitive species, and the forces involved here are genuinely new. And no, Apollo wasn't much better either, at least 10 astronauts were killed in training or burned alive (8 NASA, 2 sister MIL programs), as well as (far worse, because astronauts sign up for the risk) one member of ground staff.
People love to hate the Shuttle, and it ended up being subpar / fail expectations due to the political constraints NASA was under, but the Shuttle was a genuine advance for its time – a nonsensical, economically insane advance, but still an advance. If you look at the Shuttle alternative proposals / initial proposals as well as stuff like Dynasoar and Star Raker, you'll see NASA iterating through Starship style ideas. But those were rejected due to higher up front capital investment at the time.
The Shuttle is an odd franken-turduckling, because it was designed for one mission and one mission only. And that mission never happened. That cargo bay existed to capture certain Soviet assets and deploy + task certain American space assets and then bring them back to Earth.
And that's the bit that's hard to emphasize. The fact that the Shuttle could put a satellite up there, watch it fail, then go back up, grab it, bring it back, repair it, then launch again was an insane capability.
Was the program a giant fuck up at the end? Yes. But does that mean Artemis will be safer than the Shuttle? No. That's not how the energetics, time from civilization, acceptable risk profiles etc. work out.
How could a comparison between such dissimilar programs ever be meaningful? NASA flew 135 Shuttle missions over the course of 30 years; Orion will be doing well to approach a tenth of that number.
Yes, and the four RS-25 main engines on the SLS rocket (Space Launch System) are literally SSME's harvested from the shuttles (Space Shuttle Main Engine). Of course that means they are re-usable. So sad to see them plummet to the ocean floor. Perversely Rocketdyne is building cheaper non-reusable versions of the RS-25 for future missions.
Yes, Challenger - although program management knew they were violating a launch constraint (temperature), and it was the low temperature that produced the conditions necessary for SRB failure.
As with any aerospace mishap, it's a chain of events, not just one cause.
The Artemis SRBs incorporate design changes to address the causes of the Challenger failure. Specifically they changed the joint design, added another o-ring, and they have electric joint heaters to keep the seals warm.
I think we are a long way along from digging out Dr Feynman to look into why a shuttle exploded.
Unless you happen to have some deep links into NASA, in which case please elucidate us all, then why not celebrate a happy and safe return from a sodding dangerous mission that involved things like >25,000 mph relative velocity and some remarkable navigation.
When you depart earth (close quarters gravity, air resistance, things in the way), everything moves really fast, really fast and any acceleration becomes an issue really ... fast!
The moon moves, the earth moves: both famously in some sort of weird dance around each other and both orbit around the sun. Obviously the moon affects the earth way less than vice versa but it still complicates things.
I think that NASA did a remarkable job of making Artemis II look almost routine and I don't think that was down to behaving as they did in the past.
> I think that NASA did a remarkable job of making Artemis II look almost routine and I don't think that was down to behaving as they did in the past.
I have been excited for Artemis--yes it's big and expensive and late, but look how it has brought out the best of what humans can be--but, despite all that, the heat shield situation was textbook "normalization of deviance." Just as the O-rings were not designed to have any damage but they retroactively justified it was okay, just as there was not supposed to be any foam or tile damage but they retroactively justified it was okay, so too was the Artemis I heat shield not supposed to come back with damage, but they...
I'm not trying to be negative, and risks are inevitable, but the resemblance to me was uncanny. The lesson with normalization of deviance is that a successful result does not inherently mean a safe decision. After all, most of the time that you play Russian Roulette you will escape unharmed.
There will always be issues on something a mad as putting some people on a firework and shooting them at a moving target 100,000 miles away from a moving platform.
The heat shield failure was a test and the result was a working heat shield, when it counted. That's the point of tests. NASA already had several working heat shields from the old missions but the new one needed testing - for the shape of the craft etc. They already had a lot of data from the old efforts (that worked).
I think that exit and re-entry are almost routine now, provided your rocket doesn't explode. The tricky bit is out there in space and trying to make the moon a resource of some sort.
The new one failed in ways it was not designed to fail. In C-compiler terms it was "undefined behavior." In Donald Rumsfeld terms it was an "unknown unknown."
The mere fact that the outcome was successful does not inherently indicate that the decision-making was safe: the O-rings "worked" for 24 missions and the foam/tiles "worked" for 111. Nevertheless there were ample warnings and close calls.
Reentry from the Moon is not routine. Re-entry speed was about 40% faster than from low earth orbit, and kinetic energy goes up by the square, so about double.
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 knew how to prioritize curiosity and innovation.
Feeling like a bit of a "vibe" post which is everything wrong lately but I can't help but feel some satisfaction that we're still able to accomplish something like this in our space endeavors.
I think especially online there's a lot of emphasis on "everything is wrong". A mission like this is hard to ignore and highlights the bias. On the whole, despite setbacks, we continue.
If you want to dispel a bit more of the ever-pervasive online pessimism bias, read up on global rates of hunger the last time we flew to the moon (1972) vs now. The reality is, for all the problems we face today, there's no sane answer other than today to the question "when would you prefer to be born as a random person on earth"
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.
Ahh yes, I need a space mission to make me feel proud to be American and forget about how my country is being ran by genocidal maniacs with millions of bloodthirsty followers.
I feel so much more American because the 4th Reich sent some members of its military into space in NASA uniforms. The people on that ship are contributing to an Empire who's sole purpose is making as much money for the elites as possible no matter how many children have to die in the process.
What is coming into view from the top center at 08:26:25 [0], right after the commentator says, "the weather conditions remain go"? It stays visible for more than seven minutes before disappearing behind the horizon.
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 the way to do something this unbelievably complex.
The analogies for these things like "hitting a golf ball into a hole in one 5,000 miles away" are always fun.
I like starting from the fact that Ptolemy was able to get the accuracy of the "motions of the heavens" down so well that it took more than a thousand years to get observations that showed discrepancies. The math, it maths.
I feel like it’s “easier” with space math because there’s so little to interfere with the course. With a golf ball, the basic math is easy, but the slightest bit of wind throws it off way beyond the acceptable error, and you can’t model all the wind perfectly.
The first-order approximations are easy. When you start adding up all the other factors, it gets complicated fast. The solar wind, which isn't constant, affects trajectories. Earth's atmosphere is neither homogenous nor perfectly predictable along many dimensions: upper-level wind speeds and directions, air density, and temperatures, to name a few. The Moon's gravitational field is very lumpy. Earth's gravitational field, while relatively smooth compared to the Moon, also isn't perfectly uniform. Propulsion systems have tolerances. Same with parachutes. The location of the vehicle's center of gravity affects everything.
All of these factors and more have to be taken into account if you want your predictions to be accurate. Aside from telemetry processing, most of the computing power on the ground during a space mission is used for churning out navigation solutions.
Fun info: The NASA orbital codes include things like photon pressure... from sunlight reflected off of other planets in the solar system. At some point, I think they are just showing off :)
Wild that they manage to fly to the moon but still seem to be having those comms problems. Asking the astronauts if they’re really pressing the PTT button is wild.
My friends and I have been deriving much amusement from the comms issues. We can fly people around the moon, talk with them, send back high res video, but talk to the boat that’s close enough to swim to? Forget about it!
i was thinking maybe astronauts can be disoriented when splashing down and that's why they figured they should ask if the right buttons were being pushed?
It’s been amazing - and inspirational - watching the live stream of Mission Control and the capsule over the last ten days. Or at least having it as background audio. I’m going to miss all these folks I’ve grown to know.
This whole mission was amazing, and the most positive and hopeful thing I have seen as a global event in the last 5 years at least. Bravo and cheers to everyone involved :)
Watching this, I can only describe it as holy. An incredible reminder of what humanity can do, and the beauty of our curiosity and the universe around us. I grew up learning that my great uncle was in Mission Control for Apollo; missions like this are what inspired me to pursue engineering in the first place.
1 hour 29 minutes seems excessive to extract the astronauts; if any of them _did_ have a medical issue they'd be in for a long wait.
The commentary said that the initial problems with the boats approaching Integrity was due to an unexpected swell. Unexpected, in the Pacific?
Edit: all of the Apollo missions, except 8, had their stabilization collars inflated in under 20 minutes. With Integrity today it took nearly an hour more.
I also like how they waffled on about how winching them up to a helicopter was the fastest option, when they obviously could have shaved an hour off the recovery time by simply having them step out onto the waiting boats!
Having worked for various government agencies for a while I've learned to recognise the signs of the "We're following the procedure whether it makes sense or not, dammit!" attitude you get with large bureaucracies.
I’ll note, since it is supremely interesting to me, that Starship is able to communicate with the ground during its whole reentry due to its sheer size and ability to connect with Starlink satellites. I assumed loss of signal due to reentry was a given for any spaceship!
Shuttle in its last days had antennas that protruded outside the plasma just enough for telemetry. Apollo and Artemis reentry are also direct entry from Lunar-Earth transfer orbit using ablative heat shields, so the plasma would be hotter and thicker than suborbital Starship shots with Shuttle style ceramic tiles.
Would this capsule had been been able to communicate if it was integrated with starlink or is the size more important? I'd imagine if they could have achieved communication via Starlink they would have done it, but just curious.
It's a function of the shape. On a capsule-sized spacecraft, the ionized plasma completely surrounds the craft, so no radio communications can get in or out. For an oblong-shaped spacecraft, like the Space Shuttle or Starship, the descent tends to be angled such that you have a "hole" in the plasma you can get a signal through.
No, the plasma forms a teardrop shape around small craft like Orion, completely cutting off radio comms. Larger craft like starship or the shuttle which have a roughly cylindrical shape (vs Orion’s circular cross section) aren’t fully enclosed by the plasma. The shuttle had a transmitter attached to its tail for later flights, which could send back telemetry during re-entry.
Awesome, thank you! I wonder if some kind of very long-tethered deployed antenna could enable this for the capsule or if the ratio of long-enough-to-work vs thick-enough-to-not-burn-off-completely just doesn't work. Time to read about the shuttle.
Also Orion and other capsules fall like a rock (steep reentry profile ) compared to shuttle/starship, which intentionally slow down the reentry and kinda glide (ballpark 10min with capsules compared to 30min with shuttle/starship).
tl;dr: capsules get fully enveloped in plasma due to their shape, size and reentry profile
The space shuttle, too, was able to communicate. I imagine the smaller the craft the smaller the angle you can "speak" out of and, below a certain size, it just doesn't work.
I was wondering about that, so I looked up the heat shield issues. It seems like their solution was very defensible and there was every reason to believe it would work out just fine. The plan that did not work as they wanted had a new idea, a double re-entry, and when the results were concerning they backed off to using a traditional single re-entry. That seems like a legitimate fix?
Scott Manley went into the details in a recent video.
The reason the heat shield failed was due to gas buildup inside the ablative material.
This was due to the skip reentry profile they used, where the craft does a single skip (as in skipping stones) during reentry. The high bounce caused the shield to be heated enough that the heat penetrated the material causing gas release but not enough that the material ablated. Thus gas would build up deep inside up until it caused large chunks to break off. They could reproduce this in tests.
The fix was two-fold. First they lowered the bounce height, so a much less pronounced skip, avoiding the lowered heating of the shield. And they tweaked the material formula a bit so it was more porous, allowing subsurface gas to escape rather than build up.
If we're going to have a surveillance state, let's use it for superlative control - one dollar in taxes for every superlative you use in personal life; $0.01/viewer for each one you use in any live televised event.
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 fuel just to slow down, plus fuel for the weight of the wings themselves, plus fuel to carry all this extra fuel to the right place, etc.
The space shuttle landed like something resembling a plane, but it is more accurate to say it landed like a concrete brick traveling faster than the speed of sound.
Splashdown-style landings are the simplest and safest, parachutes are always good but adding water makes for another layer of safety (and of risk, to be fair, it could sink).
A Space Planes is needed to land at a runway like a plane.
Space Planes are not only much more dangerous, but are not ideal for this type of mission. They carry a lot of extra weight (wings) that would affect how much fuel is needed to launch them to the Moon.
Capsules are safer and more lean in terms of weight.
The Shuttle was not ideal in many ways. It was used so long not because it was the best option, but because Congress wanted it to keep it going for jobs.
So why do they need to use helicopters and a risky airlift to return the astronauts to the main vessel? Why not just use the speedboats to take them back? Seems really odd and I can’t find any reasonable explanation.
Helicopter -> large boat is much easier, and much faster, than small boat -> large boat. And it's not riskier. I know the inherent risk in flight is greater, but it's also much more managed, so the actual risk is less.
>Why not just use the speedboats to take them back?
They actually covered this in the broadcast: Helicopters are faster to get the astronauts to medical, smoother in rough seas, and there's less risk of being swamped by a rogue wave. Plus, since the astronauts might have fatigue/muscle atrophy/whatever, it complicates potential boat transfers.
The public information sheet implies that in poor weather/rough seas they would do crew recovery in the well deck, sort of like how Dragon works. [1]
From the broadcast, they made it sound like a big factor is the 2 hour program requirement to get the crew out of the capsule. Maybe they can't reliably hit that mark with a well deck recovery?
>Buoyancy is an easier equation to solve than lift.
That's a snappy one-liner but it doesn't address the real concerns.
First of all, subsonic lift is well understood and has been for decades. The answer is much more mundane: The Artemis mission profile does not require payload doors that open, no Canadarm, no requirement to service, launch, and/or capture satellites in orbit, and so like good engineers they designed the minimum vehicle that satisfies the requirements.
Also, the Shuttle was actually much more expensive to reuse than originally predicted.
> 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.
>Piloting a boat is easier and more forgiving. Hence, splashdown.
At no point were the astronauts piloting a boat. The reasons they splash down into the ocean has nothing to do with buoyancy being easier to solve, and even less to do with the ease of piloting a boat.
>It’s also hyperbole to suggest we understand lift. We don’t.
Maybe you personally do not understand lift, but "we" do in fact understand it. Please educate yourself before continuing this discussion any further.
Too fast. The space shuttle used to reenter sometimes over us in California. I remember in elementary school the entire building shook, and that was just one building! The amount of energy being dissipated is literally astronomical! If you've never experienced the sonic boom of reentry it is something to marvel at. It literally feels like an earthquake!
Aerospace engineer here: The simple answer is that the Shuttle form factor is unnecessarily complex for this mission.
A small Apollo-style capsule that parachutes into the ocean has a simpler mission profile, which allows for simpler technical and operational requirements, which in turn reduces program cost.
Watching that capsule fall out of the sky at high speed from the teaching cameras was nerve wracking! Awesome footage, exciting to watch it live in such detail.
For All Mankind aired an episode today that movingly commemorated the fictional lead character Ed Baldwin's Apollo 10-like in-universe mission on the same day that the real world Artemis II mission which also strongly resembles Apollo 10 landed safely. A strange and moving coincidence.
It's hard to know who was right. All of these things can be true: it made it back ok; it had a high chance of making it back ok; it should've had a much higher chance of making it back ok. Most of the concerned people were stressing this last point, that it should've been safer than it was. They still thought it had a quite high chance of making it back ok. It took a lot of shuttle missions before Columbia failed.
We'll need a post mortem to know what the margin of failure was. This said they had made changes since the first flight so we'd expect less to no damage this time.
I get that there are people who think the moon landing was staged, but are there really people who think rocket launches are staged? Because it's pretty easy to go witness one yourself.
More than that, people today seem to be saturated with sarcasm.
It's especially tragic with younger people who seem to have no experience with handling genuine sincerity. They laugh nervously at it, as if they're unfamiliar with how to handle someone saying what they actually think and feel.
The questions from the news agencies and their responses are not scripted. I encourage you to listen to the Q&As the astronauts and ground crew had during the mission and judge their character on that. You won't find any public figure / politician with any amount of media training that even comes close to their level of genuine humanism, humility, and professionalism.
This almost brought tears to my eyes. I can only imagine how people felt when the first astronauts got to the Moon, and then when they got back to Earth in one piece.
As I've said before. This is a huge achievement. And also is the most effective political propaganda ever. Bravo to everyone involved .
This is not sarcastic. This is very much meant. I love that America does this. We still get to evoke an awe which previous empires awesome as they may be, could never match. American superlatives are amazing. God bless America
I noticed a delay between video and audio - the announcer on the NASA official live broadcast said splashdown before the the capsule splashed down on video. Was it intentional (in case something happened)?
Also, what were these puffs on thermal camera after the main chutes were deployed?
My suspicion was they were burning excess propellant, rather than attitude adjustment while under the parachutes. Though who knows how much propellant remained. It could be quite a bit more than it appears was used.
Not just excess - excess and toxic. Hydrazine derivatives and nitrogen tetroxide, IIRC. They are hypergolic, too, so the easiest way to vent them is just to run the engines until empty. However, to prevent moving the craft too much, you do short bursts.
There are opposed thrusters, but I assume that in atmosphere and under parachute canopy it’s harder to make sure they are perfectly opposed.
Heating likely plays a role as well.
I am not a rocket engineer, but I have read How Apollo Flew to the Moon and Ignition!: an informal history of liquid rocket propellants, both of which cover these issues. Highly recommended.
I was wondering about that too, I assume maybe there was some additional adjustments needed to land in the right spot, but they didn't mention it on the stream.
How? I struggle with this. It all seems like a fearful waste of money and resources. We can't live on the moon. We can't live on Mars. It is a fantasy. We have so many problems here on Earth that are more important to solve than sending a handful of men to the moon (again).
All those countries are essentially American vassals. No shade to them, just stating the reality, and not really sure why we need to keep pretending. There's no shame in that. It's often the smartest move to join forces with the big guy in the block!
I don't know how to describe the feeling but it feels like a bad movie remake. Maybe I am just a sucker for practical effects and not 2020s CGI to stick with the metaphor and conspiracy...
As a long time space nerd, I'm not sure what this accomplishes by repeating the previous stunts that failed to usher in the promised space frontier.
Apollo was, IMO, not successful at changing the course of human history. A really cool footnote, sure, but everything else that was to follow, nope, just a bunch of neat, interesting but ultimately meh science missions.
An exciting change would be more like Delta-V/Critical Mass, but NASA is not going to deliver that, at least not in any form it has taken thus far.
The guidelines ask us to avoid being curmudgeonly. I'm sure you didn't mean to come across that way, but could you try not to make Hacker News the kind of place that responds with “meh” to a successful space mission?
Why this was such a big deal? Haven't people reach the moon so many years ago? By this time we should have lunar bases, not cheer so much that we got past the moon at a few thousands miles away.
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 is a world where they don't make it back home.
I am grateful that they did. And I'm grateful that we're going to go even further. I can't wait to see what Jared's cooking up (for those who don't know, he made his own version of the Gemini program in Polaris and funded it out of pocket).
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?
But if I'm allowed to repeat myself from elsewhere in the thread and the meat of the above thing,
It's physically not possible at our current level of technology to make this "safer" due to the distances and energies involved. Even with the Commercial Cargo and Crew Program (C3P), NASA has set the acceptable mortality threshold at 1 in 270 over the entire mission and 1 in 1000 on ascent / descent. If they could set it higher by gaming the math, they would. They can't.
We're a very primitive species, and the forces involved here are genuinely new. And no, Apollo wasn't much better either, at least 10 astronauts were killed in training or burned alive, as well as (far worse, because astronauts sign up for the risk) one member of ground staff.
People love to hate the Shuttle, and it ended up being subpar / fail expectations due to the political constraints NASA was under, but the Shuttle was a genuine advance for its time – a nonsensical, economically insane advance, but still an advance. If you look at the Shuttle alternative proposals / initial proposals as well as stuff like Dynasoar and Star Raker, you'll see NASA iterating through Starship style ideas. But those were rejected due to higher up front capital investment at the time.
The Shuttle is an odd franken-turduckling, because it was designed for one mission and one mission only. And that mission never happened. That cargo bay existed to capture certain Soviet assets and deploy + task certain American space assets and then bring them back to Earth.
And that's the bit that's hard to emphasize. The fact that the Shuttle could put a satellite up there, watch it fail, then go back up, grab it, bring it back, repair it, then launch again was an insane capability.
Was the program a giant fuck up at the end? Yes. But does that mean Artemis will be safer than the Shuttle? No. That's not how the energetics, time from civilization, acceptable risk profiles etc. work out.
Adding to it - Apollo 13 was a mission where 3 men should have died, but somehow didn't. If it had happened while the LM was on the moon, you would have had the CSM lose power, and then two men on the moon would have had no way to return home.
(And for the shuttle design mission - my understanding is it was likely the ability to do a HEXAGON-style film return mission in a single orbit, before the Soviets knew what was happeneing.)
note - I can't verify any of the following, it's more - for lack of a better term - aerospace nerd fan theory at this point.
Post-collapse, people think that the Buran justification was paranoia. But based on what I've read / seen (though this is getting hard to source, so I might be just good ol' hallucinating here), they weren't entirely wrong. The subtext around that large payload bay had to do with the Soviet pursuit of systems like Fractional Orbital Bombardment System (FOBS) https://en.wikipedia.org/wiki/Fractional_Orbital_Bombardment... that weaponized space.
Again, there's a reason for those ASAT tests. There's a reason for the weird specifications set in the early 1970s for the Shuttle. And I don't think deploying a spy satellite alone is it. But this is speculation. AFAICT, nothing was put on paper.
It would have been an incendiary WW3 starting act to capture a Soviet asset. But I think it is understandable if certain people within the American blob wanted that capability at hand.
I wish I was immortal. I'd drop everything for a decade and try to find people from the time who're still alive (and some still are!) and ask them these questions directly - on the record – for posterity's sake. I suspect, we came much closer to war via space than most people think. And because we didn't, we'll eventually repeat these mistakes.
---
Oh and then there was the documented attempt to capture Salyut-7 https://www.thespacereview.com/article/2554/1
Somehow all the numbers just happened to line right up. :)
This isn’t true. The same article even explains that.
From that article: “It takes only some basic fact checking to debunk all the preposterous allegations…”
Read Payne Harrison's 1989 novel Storming Intrepid, followed by NASA publication SP-4221, "The Space Shuttle Decision," from 1999. [1] The first is a pretty good depiction of what you're imagining, and the second explains why the imagination of a technothriller author is where that idea went to die. Then maybe give your head a shake. If Reagan had violated the Outer Space Treaty - via NASA of all agencies! - how do you imagine it'd have stayed secret over these forty years just past?
[1] https://web.archive.org/web/20241229052235/https://ntrs.nasa...
> There’s a reason why there wasn’t an Apollo 18, or 19 and 20. Even though funding had been secured, an executive decision was made to kill the program early, because LoC was inevitable.
Was funding really secure? I believe that was the main sticking point; a quick search [0] seems to confirm this, and the John Young quote below backs it up: "Even if they’d had the money..." Not to say the risk wasn't a factor too of course, but it doesn't look like funding was otherwise guaranteed.
Anyway, I think what sets the risk of the Shuttle apart from Apollo is summed up nicely in one of the quotes (in reference to the Apollo program): "The awareness of risk led to intense focus on reducing risk." In the Apollo program, there was a pattern of rigorously hunting down and eliminating any possible known risks, leaving unknowns as the primary source of risk; on the other hand, the Shuttle program let known risks accumulate continuously until crews paid the price for a bad draw.
When debris hit Atlantis on STS-27 [1] and the shuttle only survived on a one in a million stroke of luck -- the completely broken tile happened to be over an aluminum mounting plate -- it should have been taken as a free lesson on one more known source of risk to eliminate. Instead, it led to seven people dying completely preventable and unnecessary deaths a few years later.
Spaceflight is inherently risky, it's true. That's why things like the Orion heat shield are so worrisome; because it is physically possible at our current level of technology to make it safer, and yet for political / funding / etc. reasons we're not doing the best we can.
[0] https://airandspace.si.edu/stories/editorial/why-did-we-stop...
[1] https://en.wikipedia.org/wiki/STS-27
How could they have eliminated that risk?
I am stunned to see that LoC risk assessment.
I kept wondering to myself over the past week, “will this be the last USA-supported human space travel if these astronauts don’t survive?”
I’d have a hard time imagining the general public would support any future missions if they hadn’t survived.
These astronauts are some elite humans. My respect for them is even greater now that I’ve seen the risk quantified.
Obviously I realise the shuttle program was pretty far away from being able to head out to the Earth-Sun L2(AB, and wasn't even working towards it. But man, it would be nice to have that ability.
The ejection seats on Gemini were a joke, and there's an anecdote Gene Kranz tells in his book about Gemini 9 where he thought it was too risky for them to cut away the shroud on the thing they were going to dock with (the Agena having blown up on launch) but NASA was this close to overriding him and doing it anyway (they were saved by the astronauts vetoing it, which was good because the EVA, separately, that Gene Cernan did was incredibly harrowing. he was sweating, way overworked, could barely see)
[wiki link](https://en.wikipedia.org/wiki/List_of_spaceflight-related_ac...).-,During%20spaceflight,fatality%20rate%20at%202.4%20percent.)
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 planets might be much more massive than Earth. On one with 3X our gravity a space program might never get going.
(Some would snidely say as long as they don't put seven people on the rocket they'll be fine.)
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.
I’d say we’re doing better!
how do you keep past performance while stop performing it for XY decades?
I waited until splashdown to permit my emotions to get involved, and I'm glad I did. It was really something earlier, to hear my whole neighborhood bar set up a cheer for an American mission to the Moon.
How did they arrive at that number?
(Eg. Did they arbitrily establish the target at the outset? Or did it evolve by gauging the projected failure rate of their core mechanical etc. systems as those began to take shape, then establishing a universal minimum in line with that, to achieve some level of uniformity and avoid drastically under/over-engineering subsequent systems?)
The point of them being there isn't discovery, it's to try to discourage anyone who wants try to understand and protect the planet that we all rely on for life
I think you're being a pedant, if your point is a grazing entry causing rebound skip ultimately returns to some orbital path downward.
They certainly could've gotten the return wrong but with a perigee of 119 miles they arent even in a stable orbit and likely could deorbit themselves using only rcs thrusters at apogee, or by just waiting a few orbits.
In fact, the trajectory they chose for this mission exploited the opposite effect to yield a free return without propellant expense.
In the modern day, the chance of a math error being the root cause behind this failure mode are vanishingly small, but minor burn execution mistakes that do not require hundreds of extra pounds of propellant are definitely plausible. They were extremely common in the early days of spaceflight and plagued most of the very first moon exploration attempts. Again, with modern RCS this is unlikely. But reentry is still incredibly tight and dangerous. Apollo famously had a +-1° safe entry corridor, and Orion is way heavier and coming in even faster. If their perigee was off they could’ve easily burned up or doubled their mission time, which they may not have been able to survive.
I feel like the original claim paints the whole thing as on a knife edge and barely achieved by virtue of not making a single mistake. In today's age with so many moon landing deniers and worse I feel like we should be specific about where the actual dangers challenges and unknowns there were here. In reality, the orbital mechanics are one of the simplest parts of the entire problem, at least when we're talking about a moon flyby
Artemis II never escaped Earth’s pull.
That video that NASA put out where the craft did a sling shop around the moon is extremely deceptive. The pull of the moon had very little effect.
If they had missed, they would have eventually crashed back to earth in the worst case, and best case just re-adjusted and returned a little bummed.
No, it had a very significant effect: it's what made possible the free return trajectory while observing the far side of the moon.
Like I said, the gif you saw makes it look that way.
Here is a link that explains it very well. https://youtu.be/MF8IbYbVIA0?t=269
I’ll agree, it seems crazy that it left earth, made it to the moon, and never really left earth orbit at all. That the furthest we’ve been away is still destined to return on its own.
We're a very primitive species, and the forces involved here are genuinely new. And no, Apollo wasn't much better either, at least 10 astronauts were killed in training or burned alive (8 NASA, 2 sister MIL programs), as well as (far worse, because astronauts sign up for the risk) one member of ground staff.
People love to hate the Shuttle, and it ended up being subpar / fail expectations due to the political constraints NASA was under, but the Shuttle was a genuine advance for its time – a nonsensical, economically insane advance, but still an advance. If you look at the Shuttle alternative proposals / initial proposals as well as stuff like Dynasoar and Star Raker, you'll see NASA iterating through Starship style ideas. But those were rejected due to higher up front capital investment at the time.
The Shuttle is an odd franken-turduckling, because it was designed for one mission and one mission only. And that mission never happened. That cargo bay existed to capture certain Soviet assets and deploy + task certain American space assets and then bring them back to Earth.
And that's the bit that's hard to emphasize. The fact that the Shuttle could put a satellite up there, watch it fail, then go back up, grab it, bring it back, repair it, then launch again was an insane capability.
Was the program a giant fuck up at the end? Yes. But does that mean Artemis will be safer than the Shuttle? No. That's not how the energetics, time from civilization, acceptable risk profiles etc. work out.
Shameless plug, wrote a bit about the Apollo hagiography, Artemis and risk here – https://1517.substack.com/p/1-in-30-artemis-greatness-and-ri...
https://en.wikipedia.org/wiki/Texas_sharpshooter_fallacy
As with any aerospace mishap, it's a chain of events, not just one cause.
Unless you happen to have some deep links into NASA, in which case please elucidate us all, then why not celebrate a happy and safe return from a sodding dangerous mission that involved things like >25,000 mph relative velocity and some remarkable navigation.
When you depart earth (close quarters gravity, air resistance, things in the way), everything moves really fast, really fast and any acceleration becomes an issue really ... fast!
The moon moves, the earth moves: both famously in some sort of weird dance around each other and both orbit around the sun. Obviously the moon affects the earth way less than vice versa but it still complicates things.
I think that NASA did a remarkable job of making Artemis II look almost routine and I don't think that was down to behaving as they did in the past.
I have been excited for Artemis--yes it's big and expensive and late, but look how it has brought out the best of what humans can be--but, despite all that, the heat shield situation was textbook "normalization of deviance." Just as the O-rings were not designed to have any damage but they retroactively justified it was okay, just as there was not supposed to be any foam or tile damage but they retroactively justified it was okay, so too was the Artemis I heat shield not supposed to come back with damage, but they...
I'm not trying to be negative, and risks are inevitable, but the resemblance to me was uncanny. The lesson with normalization of deviance is that a successful result does not inherently mean a safe decision. After all, most of the time that you play Russian Roulette you will escape unharmed.
The heat shield failure was a test and the result was a working heat shield, when it counted. That's the point of tests. NASA already had several working heat shields from the old missions but the new one needed testing - for the shape of the craft etc. They already had a lot of data from the old efforts (that worked).
I think that exit and re-entry are almost routine now, provided your rocket doesn't explode. The tricky bit is out there in space and trying to make the moon a resource of some sort.
The mere fact that the outcome was successful does not inherently indicate that the decision-making was safe: the O-rings "worked" for 24 missions and the foam/tiles "worked" for 111. Nevertheless there were ample warnings and close calls.
Reentry from the Moon is not routine. Re-entry speed was about 40% faster than from low earth orbit, and kinetic energy goes up by the square, so about double.
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 knew how to prioritize curiosity and innovation.
Feeling like a bit of a "vibe" post which is everything wrong lately but I can't help but feel some satisfaction that we're still able to accomplish something like this in our space endeavors.
I definitely don’t envy kids that are born nowadays.
Civil Rights Activists protested against Apollo 11 at the Kennedy Space Center in 1969, and "Whitey on the Moon" was released in 1970.
Not to say it's the best of times, nor to say it's the worst of times, mind you. Just that it's really hard to objectively compare.
I feel so much more American because the 4th Reich sent some members of its military into space in NASA uniforms. The people on that ship are contributing to an Empire who's sole purpose is making as much money for the elites as possible no matter how many children have to die in the process.
[0] https://youtu.be/X9Miy8ngusQ?t=30382
It all boils down to equations that describe the world accurately, and a way of experimentation, iteration, thinking that gets us all the way to do something this unbelievably complex.
I like starting from the fact that Ptolemy was able to get the accuracy of the "motions of the heavens" down so well that it took more than a thousand years to get observations that showed discrepancies. The math, it maths.
All of these factors and more have to be taken into account if you want your predictions to be accurate. Aside from telemetry processing, most of the computing power on the ground during a space mission is used for churning out navigation solutions.
Fun info: The NASA orbital codes include things like photon pressure... from sunlight reflected off of other planets in the solar system. At some point, I think they are just showing off :)
Note: next time, pack a walkie talkie. ;-)
grrr
Bring on Artemis III and IV!
The commentary said that the initial problems with the boats approaching Integrity was due to an unexpected swell. Unexpected, in the Pacific?
Edit: all of the Apollo missions, except 8, had their stabilization collars inflated in under 20 minutes. With Integrity today it took nearly an hour more.
Having worked for various government agencies for a while I've learned to recognise the signs of the "We're following the procedure whether it makes sense or not, dammit!" attitude you get with large bureaucracies.
Bravo, Artemis team for an exceptional return to extra-orbital space travel.
Also Orion and other capsules fall like a rock (steep reentry profile ) compared to shuttle/starship, which intentionally slow down the reentry and kinda glide (ballpark 10min with capsules compared to 30min with shuttle/starship).
tl;dr: capsules get fully enveloped in plasma due to their shape, size and reentry profile
The reason the heat shield failed was due to gas buildup inside the ablative material. This was due to the skip reentry profile they used, where the craft does a single skip (as in skipping stones) during reentry. The high bounce caused the shield to be heated enough that the heat penetrated the material causing gas release but not enough that the material ablated. Thus gas would build up deep inside up until it caused large chunks to break off. They could reproduce this in tests.
The fix was two-fold. First they lowered the bounce height, so a much less pronounced skip, avoiding the lowered heating of the shield. And they tweaked the material formula a bit so it was more porous, allowing subsurface gas to escape rather than build up.
control: "i guess we'll have to go back".
(paraphrased from memory)
I think that audio stream was designed to be POTUS safe.
It's becoming a public hazard, we must act!
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 fuel just to slow down, plus fuel for the weight of the wings themselves, plus fuel to carry all this extra fuel to the right place, etc.
Splashdown-style landings are the simplest and safest, parachutes are always good but adding water makes for another layer of safety (and of risk, to be fair, it could sink).
Space Planes are not only much more dangerous, but are not ideal for this type of mission. They carry a lot of extra weight (wings) that would affect how much fuel is needed to launch them to the Moon.
Capsules are safer and more lean in terms of weight.
The Shuttle was not ideal in many ways. It was used so long not because it was the best option, but because Congress wanted it to keep it going for jobs.
They actually covered this in the broadcast: Helicopters are faster to get the astronauts to medical, smoother in rough seas, and there's less risk of being swamped by a rogue wave. Plus, since the astronauts might have fatigue/muscle atrophy/whatever, it complicates potential boat transfers.
From the broadcast, they made it sound like a big factor is the 2 hour program requirement to get the crew out of the capsule. Maybe they can't reliably hit that mark with a well deck recovery?
[1] https://www3.nasa.gov/sites/default/files/files/orion-recove...
That's a snappy one-liner but it doesn't address the real concerns.
First of all, subsonic lift is well understood and has been for decades. The answer is much more mundane: The Artemis mission profile does not require payload doors that open, no Canadarm, no requirement to service, launch, and/or capture satellites in orbit, and so like good engineers they designed the minimum vehicle that satisfies the requirements.
Also, the Shuttle was actually much more expensive to reuse than originally predicted.
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.
At no point were the astronauts piloting a boat. The reasons they splash down into the ocean has nothing to do with buoyancy being easier to solve, and even less to do with the ease of piloting a boat.
>It’s also hyperbole to suggest we understand lift. We don’t.
Maybe you personally do not understand lift, but "we" do in fact understand it. Please educate yourself before continuing this discussion any further.
A small Apollo-style capsule that parachutes into the ocean has a simpler mission profile, which allows for simpler technical and operational requirements, which in turn reduces program cost.
https://www.youtube.com/watch?v=jG6NNnoNC80
OP: "I'm happy they didn't die."
Response: "You're going to be less happy when they turn into the Fantastic Four and Dr. Doom shows up."
It's especially tragic with younger people who seem to have no experience with handling genuine sincerity. They laugh nervously at it, as if they're unfamiliar with how to handle someone saying what they actually think and feel.
I’d pay to see Shaq on broadway.
I'd refuse the mission just to avoid that meeting.
Missaved their version 2 Excel spreadsheet using the wrong file name causing confusion about this version was the latest.
Nearly missed a cell in their burn sheet had multiple lines of text until mission control reminded them to resize the cell.
This is not sarcastic. This is very much meant. I love that America does this. We still get to evoke an awe which previous empires awesome as they may be, could never match. American superlatives are amazing. God bless America
Also, what were these puffs on thermal camera after the main chutes were deployed?
https://www.youtube.com/live/m3kR2KK8TEs
Heating likely plays a role as well.
I am not a rocket engineer, but I have read How Apollo Flew to the Moon and Ignition!: an informal history of liquid rocket propellants, both of which cover these issues. Highly recommended.
Apollo was, IMO, not successful at changing the course of human history. A really cool footnote, sure, but everything else that was to follow, nope, just a bunch of neat, interesting but ultimately meh science missions.
An exciting change would be more like Delta-V/Critical Mass, but NASA is not going to deliver that, at least not in any form it has taken thus far.
Because we stopped, we get to do everything over again with hardware from this century.
Imagine if your employer wanted to start using a software system it retired in 1972. What would you do?