131–140 of 475 posts
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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,…
> 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 hav…
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.
Glad that they're safe and sound. It's worth pointing out that this is the first extremely public, widely acknowledged high risk mission NASA has done in over 50 years. The Shuttle was risky, but it wasn't thought of or acknowledged by NASA as being risky until very late in its lifecycle. According to NASA's OIG, Artemis acceptable crew mortality rate is 1 in 30. Roughly 3x riskier than the shuttle. There genuinely i…
Announcer just said “we just reenacted” the last Apollo mission. So, yep. That’ll be used as proof-text that this was all staged.
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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 should be an opposite thruster for each axis. I wonder if the short bursts were due to heating limits.
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 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 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.
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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.
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.