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Comment: Re:Lift? (Score 2) 64

by Immerman (#48899173) Attached to: NASA Considers Autonomous Martian Helicopter To Augment Future Rovers

It's still a periscope - you can use it to see over hills, but not to scout ahead.

You'll also get piss-poor lift with a hot air balloon - Martian air density is only 0.02kg/m^3, compared to the 1.2+kg/m^3 on Earth. The colder temperatures will help somewhat, offering a better density gradient with temperature, but you're still talking about a lift of maybe 20% of the displaced air mass, versus 90% for a helium balloon. Even with helium, a balloon 2m across could lift under 80g, minus it's own weight. A hot air balloon of similar size could lift a paltry 16g - scarcely more than the mass of a rubber party balloon. That would have to be a pretty insanely thin skin just to be able to get off the ground.

Comment: Re:Lift? (Score 1) 64

by Immerman (#48899045) Attached to: NASA Considers Autonomous Martian Helicopter To Augment Future Rovers

Actually it would lift closer to 20 grams - CO2 is denser at the same pressure, and Mars' atmosphere has a density of 0.020kg/m^3 at the surface.

Your point remains though, your average rubber party balloon is 12g, and would be stretched pretty thin if inflated to the 1.5m diameter needed to displace 1m^3 of air.

Which is the reason blimps tend to be built large - the lift-to-surface-area ratio increases linearly with size: 2x the (linear) size requires 4x the skin and gives 8x the lift. 10x the size needs 100x the skin for 1000x the lift.

Of course the bigger it gets the more power it needs to fight those Martian winds, and since a blimp can't land, to stay near the rover it would have to have a power source strong enough to to fly directly into the wind at 20-60mph, 24.37 hours a day, as well as dealing with the gusts in the 100-300+mph range. Probably not realistic, though it might make for an interesting atmospheric rover in it's own right.

Comment: Re:Lift? (Score 2) 64

by Immerman (#48898813) Attached to: NASA Considers Autonomous Martian Helicopter To Augment Future Rovers

Well, the prototypes might be using plastic for ease-of-revision, but my guess would be molded carbon fiber, at least for later prototypes and the final product - I don't think there's anything competitive in terms of durability and strength-to-weight ratio, and the cost is peanuts by NASA budget standards. Hell, once shipping costs to Mars are factored in it's probably cheaper.

Hmm, come to think of it, I wonder why we see so much metal used in the current rovers.

Comment: Re:Lift? (Score 2) 64

by Immerman (#48898759) Attached to: NASA Considers Autonomous Martian Helicopter To Augment Future Rovers

A tethered blimp isn't a scouting drone, it's a periscope. And given those winds an untethered blimp would likely never see the rover again, so still no good for scouting.

It might be interesting as an independent, largely unsteerable, low-altitude survey drone to study wind patterns and look for interesting target regions for the next mission, but at that point we've changed the mission parameters so drastically that it's no longer relevant to the original discussion

Comment: Re:Space Administrators Wanted (Sr. level) (Score 1) 64

by Immerman (#48898423) Attached to: NASA Considers Autonomous Martian Helicopter To Augment Future Rovers

Well, I suppose with awesome ion drives that might be feasible - but that's still going to have to be a pretty large and/or expensive satellite to justify sending a person + life support system halfway across the solar system instead of just sending a replacement satellite.

Especially since with a person on board you probably aren't going to take an efficient route, instead consuming hundreds of times the fuel to get there in weeks or months instead of years. Plus there's that hazard pay - which presumably you're charging from the moment of launch, rather than just for the three hours of work you do on-site.

Comment: Re:Nope (Score 1) 293

by Immerman (#48898027) Attached to: UHD Spec Stomps on Current Blu-ray Spec, But Will Consumers Notice?

The distance from the TV is not about being able to see the image - it's about filling your field of view to make the experience more immersive. If you sit the recommended two screen diagonals away from your TV, the diagonal will always have an angular size of 28 degrees, regardless of physical size. If I want to do some more immersive gaming, or really get "into" a movie, and have the diagonal span 90* of my field of view then that requires that I sit half a diagonal away. And that isn't necessarily a problem - it's recommended that you sit one arms-length away from a computer monitor to minimize eye strain, so get a TV with a two arms-length diagonal and you're golden.

Comment: Re:Not programmable? (Score 1) 389

by Immerman (#48896847) Attached to: Ask Slashdot: Where Can You Get a Good 3-Button Mouse Today?

A "normal" mouse has three buttons, pus maybe four more pseudo-buttons for the scroll and tilt functionality, depending on how you count them. The g600 apparently has at least 20, the 12-key thumbpad is numbered G9 through G20. In that context "the primary buttons" pretty clearly refers to the normal mouse buttons.

Comment: Middle click maps to... (Score 1) 389

by Immerman (#48896817) Attached to: Ask Slashdot: Where Can You Get a Good 3-Button Mouse Today?

"Open link in new tab" in most web browsers

Panning the view in many graphics editors (don't even talk to me about tilt-wheels - I want to be able to scroll in whatever arbitrary direction is appropriate to whatever I'm doing at the moment)

Lots of different stuff in 3D modeling software.

Lots of advanced functionality in multi-clickable interfaces where, generally speaking, left-click=most common action, right-click = context menu, and middle click is usually a moderately common alternate action, often user-configurable. For just normal Window GUI stuff it's not uncommon to middle click the title bar and widgets to roll-up to window shade view, send to back or make always on top, minimize to the tray, or various other options. It often takes a 3rd-party extension, but power users have the option to do such things on all the major OSes

Comment: Re:Interstellar missions... (Score 1) 202

by Immerman (#48896747) Attached to: At Oxford, a Battery That's Lasted 175 Years -- So Far

That makes no sense - an object much smaller than the sun must by necessity be *much* hotter than the sun to be able to radiate away the same amount of energy. Unless I'm very much mistaken a blackbody will radiate a fairly specific amount of energy per unit area at a given temperature.

Comment: Re:Nope (Score 1) 293

by Immerman (#48896725) Attached to: UHD Spec Stomps on Current Blu-ray Spec, But Will Consumers Notice?

Yeah, at 28" the difference probably isn't *that* dramatic unless you have really good eyes, or frequently rest your nose on the screen. There's also the question of the relative quality of the two monitors, not to mention how well you calibrated them. I've also heard that Samsung's TV quality has become far less consistent, even within a single model number - no idea if they're any better with monitors. As for 8k - I think that's likely to remain primarily the domain of home theater enthusiasts and VR helmets - and might not be enough for really good VR. Then again, with a 40" or 60" monitor it would probably be well worth it. 1080p on a 40" monitor leaves me almost able to see the subpixels

Comment: Re: No way! (Score 1) 506

by Immerman (#48896675) Attached to: Senator Who Calls STEM Shortage a Hoax Appointed To Head Immigration

Well now, I could certainly see a ban on handguns - it makes far more sense than a ban on assault rifles - they're both generally semi-automatic weapons, and nobody is discretely tucking an assault rifle into their waistband in preparation for an attack, much less "just in case".

As for Japan's violent crime rate, the culture is so different, especially in terms of the presumed relationship between individuals and society, that I really doubt you can honestly credit that to gun policies. Tell me this - why would gun policies have any effect on non-gun violent crimes, other than potentially raising them? (Due to both less fear of armed victims, and violent people that might prefer guns choosing another weapon instead)

Utility is when you have one telephone, luxury is when you have two, opulence is when you have three -- and paradise is when you have none. -- Doug Larson

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