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Comment: Re:Good (Score 4, Insightful) 361

Me too. It's a hell of a lot harder to bug every man, woman, and child in the west than it is to intercept and crawl their communications. Having them have to actually spend time, effort, and money and risk discovery to obtain information makes it far far less likely that they will collect it just because they are able to. It's a check on their power that's sorely needed.

I came here for this exact sentiment. Spying has always had a component of risk of exposure, and that is needed to keep spying at a small scale. Drift net sieving of all our communications is the abuse.

Comment: Re:Lift? (Score 1) 83

by dougmc (#48902447) Attached to: NASA Considers Autonomous Martian Helicopter To Augment Future Rovers

So make them larger -- as large as you can get with the tips not quite going supersonic. (The speed of sound on Mars (probably around 540 mph at ground level) is a bit lower than it it is on Earth thanks to the low pressure, low temperatures and mostly CO2 atmosphere, so that's an even bigger problem.)

More blades as well -- not just 2, but 3, 4, 5, 6, whatever. There's diminishing returns past two (well, one!) but it can help when you don't mind using a lot more power for a little more thrust.

Go for fatter blades and higher pitches as well -- more diminishing returns, but it could still help.

If you're thinking of a multicopter as I imagine they are, go with more than four propellers. Putting propellers on top of other propellers could help as well, but again ... diminishing returns.

It's not trivial, but it should be doable.

Or maybe they could even let the tips go supersonic ... it might be less of a problem with such a thin atmosphere than it would be here. I'm not so sure about this.

so simply applying a scaling law like that isn't very accurate.

It's a good "back of the napkin" first order approximation. I'd expect NASA to take everything into consideration, model it exactly, and then actually build it and fly it in a chamber that approximates the atmosphere of Mars.

It doesn't need high performance or duration -- just enough to go almost straight up and pan around and take pictures and then land back and charge up again.

Comment: Re:Lift? (Score 3, Insightful) 83

by dougmc (#48899323) Attached to: NASA Considers Autonomous Martian Helicopter To Augment Future Rovers

Atmospheric pressure on Mars is 1% that of Earth. How're you going to get any lift?

if you rotate the blades 10x as fast as you do on Earth, you'll get the same lift.

That said, gravity on Mars is 1/3rd as much as Earth, so you only need 1/3rd the lift. So rotating the blades at 6x the rate you'd rotate them on Earth would be sufficient.

Or you could go with much larger blades.

Either way ... it's doable. It would require more power than it would on Earth, but it's certainly doable.

This is a pretty interesting discussion of how we'd fly on Mars, done in the context of the X-Plane simulator. It's written with fixed wing planes in mind rather than helicopters, but most of it still applies.

Comment: Re:To Protect and Serve Cancer (Score 1) 290

by plover (#48863013) Attached to: Police Nation-Wide Use Wall-Penetrating Radars To Peer Into Homes

That's even cooler than I thought. I knew high power radar was responsible for some bird deaths, but they were directly exposed to very high power radiation. I didn't know about the army tech statistics, so thanks! (And would you happen to have a citation to it I could use?)

Comment: Re:To Protect and Serve Cancer (Score 2) 290

by plover (#48858341) Attached to: Police Nation-Wide Use Wall-Penetrating Radars To Peer Into Homes

Highly concentrated beams of radio waves are known to cause cold pizza to become hot.


It takes a lot of RF exposure over a very, very long time to increase your chances of getting cancer by a statistically detectable amount. Despite decades of data, (and several very poor quality, highly-biased studies) there is still not a clear correlation between cell phone exposure and brain cancer*. During the course of a police action, the device will likely be on for a few seconds while they recon the inside of the building. For that to cause harm over that short amount of time, it would have to be emitting many kilowatts or even a megawatt of energy; and not only would the resulting burns be ridiculously painful, your heart would short circuit and your eyes would probably boil and explode. Cancer would be the least of your worries.

* If there was a link, cell phone usage is so prevalent across the globe that we should be able to trace a perfect curve that matches cell phone usage to brain cancer mortality statistics. But there isn't even a hint that brain cancer rates are changing due to phones. Toxins? Pollution? Asbestos? Smoking? Volatile Organic Compounds? All those have traceable curves that map exposure to human diseases. Cell phone exposure? Zero.

Comment: Re:Didn't we have this discussion... (Score 1) 290

by plover (#48858083) Attached to: Police Nation-Wide Use Wall-Penetrating Radars To Peer Into Homes

Agreed, it's clear the use of these without a warrant provides inadmissible evidence today.

So if an open source version becomes available, and people can just print one on their 3D printer so lots of people start using them, that somehow makes warrantless use of these legal for evidence gathering tomorrow? Go, Open Source, go!! ??

Comment: Re:Let's be blunt (Score 2) 359

by plover (#48842029) Attached to: Linus On Diversity and Niceness In Open Source

I'm not saying Linus doesn't have talent, or that he's not "nearly always correct", but I am saying that he goes beyond stripping away sugar-coating, and resorts to name calling (I believe the phrase I once read was "unevolved chimpanzee"), and public (not private) belittling of people who makes mistakes. That's not simply "correcting you", that's not straddling the line in any way. That's fully crossing the line to being an asshole, and it's completely unnecessary. And here he is, talking about it again. Being an asshole has embroiled him in side debates about the correctness of it, and all of this effort and stupid side chatter is now nothing but a waste of his time.

There's a very-not-gray area of being blunt: "This code is too abstract and isn't efficient, it wastes cycles with all this dereferencing, and is not acceptable in the kernel." It's not nice, but it's not mean. It's actually easy to stay in that area. It takes no more or less effort than calling someone an insulting name, and it provides a not-hostile work environment that might bring extra talent to the table.

Sorry to poke at the god-like bubble people try to wrap Linus in, but I never see talent as an excuse for a prima donna getting away with unwarranted hostility.

Comment: Re:Let's be blunt (Score 1) 359

by plover (#48839123) Attached to: Linus On Diversity and Niceness In Open Source

There is not a reason that talent and asshole must always be coupled in the same person. And very few people who aren't assholes like to work in an abusive environment. Therefore, this kind of environment excludes people who have talent but who are not assholes. Of course, a "nice" environment excludes assholes for very similar reasons.

So what we need is what we've got: two distinct environments. One is where assholes with talent build one set of components, and nice people build other components. Occasionally they spit at each other from across the divide, but overall, it works. Yes, people will complain if they find they ended up working for the wrong team, and they may be appalled at the working environment of the other side, but those seem to be individual preferences.

Is one side better or more talented than the other? Probably, but they would unquestionably be better than they are today if they could draw from the full talent pool, instead of restricting themselves to just like-minded assholes or nice guys.

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