311–320 of 365 posts
Wholly cow. In that 2nd photo, the rover looks like it just missed landing on a ridgeline. ref: https://ichef.bbci.co.uk/news/976/cpsprodpb/58BB/production/...
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A couple of thousand years ago is the peak of the Romans, so you're way off on your 'height' of technology at that time. Using bows and arrows as an example when you've got wonders of pretty advanced engineering like the Parthenon, plus they also had ballistae, chariots and catapults, so not the peak at all. Not only that, but even the bows were more advanced, composite bows much more powerful than simple ones made o…
The most complex machine of the Roman era was perhaps a water organ. (I would guess that for long historical periods the most complex machines were keyboard-controlled musical instruments.)
I'll start: https://en.wikipedia.org/wiki/Aeolipile
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Yep, that’s the same reason why it runs on a PowerPC750 chip. They cost $200k+ for under 200Mhz on a 150-250 nm process, but can withstand up to 1,000,000 rads of radiation and function within extreme temperature ranges for decades. They have been proven to work in the harshest environments on prior missions, and the risk of an unproven processor is giant; a CPU failure could jeopardize the mission just as much as a…
Could you explain why such a processor is 1000x more expensive than a non-rugged one ? I mean, considering the future of earth, I'd certainly welcome a processor that could withstand a lifespan of decades (including the harsh "I'm going to unsolder it to put it in another device" environment).
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The most complex machine of the Roman era was perhaps a water organ. (I would guess that for long historical periods the most complex machines were keyboard-controlled musical instruments.)
Oh see you did it now - opened up a vacuum about ancient tech. I'll start: https://en.wikipedia.org/wiki/Aeolipile
Wholly cow. In that 2nd photo, the rover looks like it just missed landing on a ridgeline. ref: https://ichef.bbci.co.uk/news/976/cpsprodpb/58BB/production/...
iirc the "landing crane" was doing autonomous live analysis of the terrain and making the necessary last minute adjustments to avoid problematic areas.
The bottom of this page says: "All images copyright Nasa/JPL-Caltech" But I thought all works created by the US federal government are public domain and not protected by copyright? Famously the "Blue Marble" photo is not under copyright and reproduced all over the place: https://en.wikipedia.org/wiki/The_Blue_Marble
That's probably just a mistake from the BBC. The original source [1] just says "image credit" NASA/JPL-Caltech, not copyright. [1] https://mars.nasa.gov/mars2020/multimedia/raw-images/
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Part of it is low demand, so you don't benefit from economies of scale. Also the customers buying this type of equipment are able to bear such costs. They aren't gonna haggle over $100k on a critical component to a $3B mission.
a $100k here, a $100k there, suddenly, we're talking real money.
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Maybe a stupid question, but couldn’t they put there something “cutting-edge” next to the existing system? Then if that fails then whatever, the rest of the system is still functional as expected, but at least they know that in the future what they would need to change to be able to use the new technologies in that environment. Although I can imagine that even the smallest weight increase could cause issues, so proba…
Scott Manley mentioned in one of his recent videos about Perserverance that they have an FPGA on board the rad hardened PPC main cpu can offload tasks to, such computer vision based navigation during landing. Not sure what the long term plan is for that hardware - I guess they can just do stuff more slowly on the main CPU if it gets fried by radiation. Or maybe being an FPGA the can just isolate the radiation affecte…
Radiation Performance
> RTG4 FPGAs are immune to radiation-induced changes in configuration, due to the robustness of the flash cells used to connect and configure logic resources and routing tracks. No background scrubbing or reconfiguration of the FPGA is needed in order to mitigate changes in configuration due to radiation effects. Data errors, due to radiation, are mitigated by hardwired SEU resistant flip-flops in the logic cells and in the mathblocks. Single Error Correct Double Error Detect (SECDED) protection is optional for the embedded SRAM (LSRAM and uSRAM) and the DDR memory controllers. This means that if a one-bit error is detected, it will be corrected. Errors of more than one bit are detected only and not corrected. SECDED error signals are brought to the FPGA fabric to allow the user to monitor the status of these protected internal memories.
https://www.microsemi.com/product-directory/rad-tolerant-fpg...
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Very low bandwidth, very low power, very long distance comms are really cool. The limiting factor tends to be the clock frequency precision - if you have precise enough clocks at both ends, there isn't anywhere in the universe you couldn't communicate with, as long as you're happy to go slow enough.
> there isn't anywhere in the universe you couldn't communicate with Right, assuming you are emitting infinite amount of photons, there are no obstructions, black holes and you ignore universe expansion and GR which can make your precise enough clocks go out of sync.
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Why though, if you're not going to make a difference? Why bother? The reality is that the reason we do these things is to make ourselves feel better. Ah, yes, my daily shot of endorphins from recycling. Ah yes, my bumper sticker makes sure everyone knows I'm one of the good ones -- my social standing is safe. This philosophy is why middle class first world kids pay thousands of dollars to go on missionary trips to bu…
> The reality is that the reason we do these things is to make ourselves feel better. Ah, yes, my daily shot of endorphins from recycling. Ah yes, my bumper sticker makes sure everyone knows I'm one of the good ones -- my social standing is safe Speak for yourself my friend. The idea that people only make changes, even little ones entirely out of self service is extraordinarily cynical and a very negative and sad vie…
You keep saying that. It's subjective, and it's not an argument. George Bernard Shaw said, The power of accurate observation is commonly called cynicism by those who have not got it.
Say I tell my friend and they decide to do the same thing, now it's 1000 pieces of litter. They tell 2 of their friends, now it's 2000 pieces of litter. Then I decide to make it 2 pieces of litter, and I tell my friend and they pass it on. Now it's 4000 pieces. They start telling their friend
Well that's imaginative but it seems highly unlikely. After all, if everyone is so highly primed to change in this way, and all it takes is one person to spark the fire... chances are enormously likely it would have happened already, and it would have happened without you needing to spark it.
This idea that you're at the center of a movement to change the world is just more subconscious ego feeding. If you want to be at the center of a movement that changes the world... it's going to take a lot of hard work.
what change do you think you're making by stomping on the idea that multiple little changes can lead to positive effects
Humans enjoy conversation, and some of them enjoy trying to figure out truth from fiction. No more, no less.
personally I choose to be optimistic because why waste my life
Whatever floats your boat. We "cynics" are enjoying the ride as much as anyone. We just think we're doing it in a clear-eyed way.