91–100 of 231 posts
"molecules from the rocket exhaust produce photons at a wavelength of 6300 Å – the same color as red auroras." Anyone else have this use of Ångström trigger an exception in their brain? The unit of default for wavelength is nm, not Å… (1nm=10Å)
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Good point. Deserves some numbers. California's area is about 500 thousand km^2, and the Earth's is about 500 million, which means the side facing the Sun is about 250 million, so we're talking about 0.2% of the area facing the sun. Suppose the hole takes six hours to heal (the article makes it sound like it takes much less), and suppose there's a launch every month (since launches have in the past carried 600 satell…
Another way of putting it is that it could potentially affect 40 million people.
But on the other hand, you typically don't launch rockets there.
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> One famous example occured on August 25, 2017, when a Falcon 9 rocket carrying Taiwan’s FORMOSAT-5 satellite created a hole four times bigger than the state of California. Doesn't sound too local to me.
Good point. Deserves some numbers. California's area is about 500 thousand km^2, and the Earth's is about 500 million, which means the side facing the Sun is about 250 million, so we're talking about 0.2% of the area facing the sun. Suppose the hole takes six hours to heal (the article makes it sound like it takes much less), and suppose there's a launch every month (since launches have in the past carried 600 satell…
Earth's radius: 6,371 km Ionosphere: 60-300km
... If we use the inner edge of the ionosphere we get about 2% more surface area whereas the outer edge gives us 9.6%. Probably the right number to use is somewhere in between.
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We had similar anomalies with tri-bands gnss drone before (L1, L2, and L5) with multi constellations support, I even remember before we had similar issues with an RTK enabled system. It is puzzling because the next day we would bring the sane drone and systems, and as of nothing happened, and since the problem solve itself we never bothered to investigate more.
That seems like ground based interference. Today a lot of stuff, including components of the drone itself, can be unintentional L-band radiators. Getting what is probably the cheapest tier of spectrum analyzer and investigating that behavior seems somewhat prudent.
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They sort of do though. Cars, for the most part, follow the road and the direction they're already going. They (usually) signal if they're about to make changes. And to be safe, we've built an arrangement that they only travel on these specific paths at specific speeds, modifying their speed to match the other cars they might hit. The challenge with satellites is that steering is hard and very limited. And they don't…
Cool thing about satellites is if you're on the same path, you must also be going the same speed. Collision avoidance in LEO is quite elegant. When two satellites are predicted to pass uncomfortably close to one another, one satellite will fire its station keeping thrusters to raise its orbit above the other. No brakes or swerving needed, just a slight push well ahead of time. Starlink sats do this over 1000 times pe…
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just because I appreciate it when people do it for me waste -> vast https://www.merriam-webster.com/dictionary/vast
Thank you for this. Is 'waste' used in a specific vernacular? I've never heard of someone saying waste instead of vast before.
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Yes that's right, also known as shortwave radio. https://spectrum.ieee.org/amp/wall-street-tries-shortwave-ra...
Well, the article itself does a pretty good job of describing why it is not an exactly good idea. What it does not say (and what probably nobody suggesting that ever though about) is that the sky-wave propagation mode is either about reflection off the ionosphere or refraction effects of the ionosphere, both of which means that the propagation path is significantly longer and in the refraction case over “slower” medi…
That's where the high-frequency traders should put their fibers ;)
"molecules from the rocket exhaust produce photons at a wavelength of 6300 Å – the same color as red auroras." Anyone else have this use of Ångström trigger an exception in their brain? The unit of default for wavelength is nm, not Å… (1nm=10Å)