Andrew Dalke's Comments

That's ... one way to slant it.
Sure, we don't have access to the same materials. (We're not going to use asbestos now.) And we don't have people with the same skills.
But we also have better materials and alternative skills. 10 years ago, Pratt & Whitney Aerodyne designed the F-1B (see https://en.wikipedia.org/wiki/Rocketdyne_F-1#F-1B_booster ) based on the F-1 engine, but using a better design and more advanced construction techniques. The design estimate was an engine 15% more powerful than the most advanced Apollo-era engine, cheaper to build, and more reliable.
See https://www.youtube.com/watch?v=ovD0aLdRUs0 for the slant I prefer.
The reason why we don't send people to the moon is there's no good reason which justifies the cost, both in human lives and financial.
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Looks like I could stick my hand through the bottom and be able to catch a falling plate.
Maybe I should go there and try! Checking ... Err, no. At almost $5,000 and 30 hours of travel to fly to Xi'an it's rather out of my league. (I honestly didn't expect it to be *that* expensive.)
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The characterization "the first computer bug was quite literally a bug" isn't quite correct. "Bug" was used in the Mark I, before the famous bug mentioned here. See https://chsi.harvard.edu/harvard-ibm-mark-1-language. Also, Hopper's oral account at https://archive.org/details/podcast_from-archives_grace-hopper-howard-aiken-th_1000425230042 says it was a man who taped the moth into the computer’s logbook. ("the operator got a pair of tweezers ... and below it he wrote “First actual case of bug being found.”)
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There are plenty of people on Earth who want a sustainable city for inhospitable climates. Why not start there? Argentina pays a lot of money to keep their Antarctic colony going, for example. There's plenty of cheap land in our cold deserts, shipping is a lot cheaper, and survivability is rather higher, so I would expect sustainable cities here first, But of course, this is link is more marketecture than anything else. Sigh, I'm getting old and blasé.
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A problem with that interpretation of Giovanni Stanchi's picture is that Giuseppe Recco's Still-Life with Fruit and Flowers (ca. 1670, so essentially the same time as Stanchi) shows a much more normal looking watermelon. Stanchi's watermelon looks more like modern "hollow heart" watermelons, likely due to impropert pollination. (Of course I nearly only buy mass-produced store-bought fruit and veg so have little experience with produce outside of that conformity. I'm basing my opinion here on what I've read elsewhere, not personal experience.)
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The article says the proposed vehicle uses nuclear thermal propulsion, not nuclear pulse propulsion. I used the average distance to Mars, because the link refers to it as "on average around 140 million miles away". Mars 2020 is using low-energy Hohmann transfer orbit. A three month transit requires a higher-energy orbit, resulting in a shorter travel distance than a low-energy orbit. I don't know how much shorter. My goal was to show that the overall g-force could be very low, though I made the wrong assumption about how the engine operates. A longer trip needs less energy and less (integrated) g-force.
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No much. Figure average distance to Mars is 229 million km, and ignore the solar well delta V so it's acceleration 1/2 way and deceleration the other half, or 115 million km in 60 days. 115 million km / (60 days)2 = 0.0043 m/s2 or about 0.00043 g. Assuming it were slow and gradual like an ion thruster ... and I see now that I'm completely wrong about that. Reading https://en.wikipedia.org/wiki/Nuclear_thermal_rocket now, and I still can't figure it out. :( My guess is, slow and steady rather than a high-g force, in order to keep the operating temperatures cool.
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Firefox's "Private Window" page says: "While this doesn’t make you anonymous to websites or your internet service provider, it makes it easier to keep what you do online private from anyone else who uses this computer." 'Course, we all know that most people don't read things like that.
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Profile for Andrew Dalke

  • Member Since 2012/08/04


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