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Artemis II safely splashes down

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Re: Artemis II safely splashes down

#91

Post by rufo »

llbbdd wrote: post #52
philistine wrote: post #18

Earlier quoted context omitted.

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!

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.

Re: Artemis II safely splashes down

#92

Post by rootusrootus »

eqmvii wrote: post #2

Held my breath the whole time after all the heat shield warnings. Very glad it all worked, or that there was enough margin!

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?

Re: Artemis II safely splashes down

#93

Post by trothamel »

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

Earlier quoted context omitted.

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

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

That was a great article.

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.)

Re: Artemis II safely splashes down

#94

Post by paulgerhardt »

mackman wrote: post #78
irjustin wrote: post #51

Earlier quoted context omitted.

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

You are comparing orbiting earth in a shuttle to a lunar flyby in a pod. Very different risk profiles.

First couple of crews to orbit the earth at 0’ AGL had mortality rate of 9 in 10.

I’d say we’re doing better!

Re: Artemis II safely splashes down

#95

Post by Ifkaluva »

sho_hn wrote: post #77
echoangle wrote: post #20

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.

Just like in the year 3000, we will still ask "Can you hear me?" in video meetings.

And the printer will be perpetually broken

Re: Artemis II safely splashes down

#96

Post by rootusrootus »

mgfist wrote: post #74
ggm wrote: post #60

Dear NASA. Please dial back the poetics and rhetoric. Be more like ATC than Shakspear.

I think we've all become to numb and jaded. This is the first moon mission in 50 years and the furthest any human has ever been from Earth.

Indeed, the world is so grim these days that I welcome even a little bit of relief, a little bit of hope for a better future.

Re: Artemis II safely splashes down

#97

Post by thegrim33 »

rootusrootus wrote: post #92
eqmvii wrote: post #2

Held my breath the whole time after all the heat shield warnings. Very glad it all worked, or that there was enough margin!

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?

Yes, but it was the biggest opening for propagandists to latch on to for demoralizing and spreading fear/uncertainty/doubt about the mission.
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