Catch up on stories from the past week (and beyond) at the Slashdot story archive


Forgot your password?

Comment Solar Perhaps (Score 1, Interesting) 111

The only thing it's missing is a small solar panel to keep the battery charged. That way, no one has to climb those tanks of deadly radioactive water unless hardware has actually failed. Some of those Arduino boards already have battery chargers on them, but if not, a small regulated LiPo or NiCad battery charger is what you need. Then you just need a solar panel that is small and has the right output voltage. seems to sell a 10 watt, 12 volt panel for $15. No big deal, and that's more than enough juice. Size the panel right, and you can do the monitoring continuously for a measurement every minute or so. (not that this really matters, but why not overdeliver?)

The Media

The Register: 4 Ways the Guardian Could Have Protected Snowden 233

Frosty Piss writes with this excerpt from The Register: "The Guardian's editor-in-chief Alan Rusbridger fears journalists – and, by extension, everyone – will be reduced to using pen and paper to avoid prying American and British spooks online. And his reporters must fly around the world to hold face-to-face meetings with sources ('Not good for the environment, but increasingly the only way to operate') because they believe all their internet and phone chatter will be eavesdropped on by the NSA and GCHQ. 'It would be highly unadvisable for any journalist to regard any electronic means of communication as safe,' he wrote. El Reg would like to save The Guardian a few bob, and reduce the jet-setting lefty paper's carbon footprint, by suggesting some handy tips – most of them based on the NSA's own guidance."

Comment Self Consistency Canon (Score 5, Interesting) 401

I would greatly prefer if the writers for this series, in the unlikely event it takes off, focused on being self consistent.

Don't show the "time police" one episode, complete with an enforcement vessel called the USS Relativity, that ruthlessly polices the timeline, then magically resolve all the outstanding problems by having your captain come back from the future with cheat-technology in a later episode. (because if the time police let this stand, why don't they simply give the Federation the best tech of all time from day 1?)

Don't show a space station next to earth one movie, with a massive infrastructure, then show the Enterprise and another ship have their illegal fight between Federation warships right next to earth, so close that the Enterprises crashes into the earth in the same movie!

If you establish that maximum warp has a speed, don't show a ship getting from the border of the Klingon neutral zone to Earth in 5 minutes of warp.

If you establish that Bones is the medical officer on the ship, aka the only qualified doctor, and you then show the Enterprise taking massive damage with mass casualties, don't have him quietly standing on the bridge lecturing Kirk instead of getting his ass to sickbay to treat the critically wounded.

Comment Re:Extraordinary claims (Score 1) 254

Cryonics, when performed properly, is done at the point of LEGAL death, not biological death. The trick is, the very moment a person's heart stops, they are legally dead. Ideally, a cryonics team gives them CPR and bypass, and a drug that prevents their heart from restarting (even though it very well might if the CPR and bypass are done well). They are biologically quite alive at this point. And, agents are given that make their cells resistant to the freezing, ideally, non toxic agents that don't kill cells in samples. (the frost inhibitors are a special molecular that stops ice crystal growth in modern solutions)

  And the basic technique - freezing in liquid nitrogen - can preserve smaller organisms perfectly, such that they can be thawed out and revived decades later.

That's the idea. For many reasons, it often does not go this well. But, done right, it isn't freezing a dead body, it is pausing a living one.

Comment Re:Extraordinary claims (Score 1) 254

The last point is arguable. The nanorobotics would be permanent nanoscale fixtures built into a large machine, they would not wander around freely like in science fiction. Given that micromachined parts work today (a common example is the mirror array in certain kinds of projectors), nanomachined parts seem probable in the future.

Furthermore, your brain has an awful lot of redundant circuits and connections. If you were rebuilt atom by atom, it is possible that the person revived would be "close enough" to the original to satisfy people who knew the original.

Comment Re:Slashvertisement (Score 1) 254

To some extent, experiments have been done that provide some fairly convincing evidence for #1-4.

1. Electrical measurements of brain activity during anesthesia pretty much disprove this one. During heavy anesthetic, the neurons stop communicating and become fairly quite electrically. They become even quieter if you cool the blood.

2. This is a mostly guess, based on electron micrographs of frozen specimens. When the freezing is done perfectly, the details seem to still be visible. Also, an experiment has been done where a slice of brain tissue was frozen under exotic conditions (by exotic, I mean conditions that can't be reached for an entire brain with existing tech), and the cells came back online and started communicating again upon thawing the slice.

3. This one is a major problem. It is hoped that the current procedures are fast enough, but faster would be better.

4. This is based upon a set of assumptions that are fairly solid. Assuming no civilization ending catastrophes, the tools that will be capable of fixing you are almost certainly possible in a technical sense. One caution : the kind of tools that will probably work would be able to "fix" your body from a technical level, but philosophically it is hard to argue if you survived. See, the way to fix it is to slice your brain into many small slices, and to scan these slices at extremely high resolution. Software would reverse most of the freezing damage, and construct a graph in memory of the state of your neural network at death. A hardware emulator would be loaded with this graph, and that's what you'd be - a very good emulation.

5. This one's just a gamble. No one can predict the future with certainty. One thing that IS absolute, however, is your fate if you don't pay the $100k. Not a penny of that money will do you any good anyway, so...

Comment Re:DOA (Score 1) 240

6 kps is faster than escape velocity for Mars. So if you don't have a way to slow down, won't the spacecraft just hurtle past Mars (or slam into it at high speed)

I understand sorta what you're talking about regarding an elliptical orbit, it makes sense via conservation of energy, and it works that way in KSP. :)

In any case, from an engineering prospective, to land on Mars with a big heavy lander full of people and supplies is a difficult problem. I *think* that a similar approach to that used by the MSL may work, that a capsule the size of SpaceX dragon can slow down using it's heat shield, then deploy parachutes, then use rocket engines for a soft touchdown.

But it's by no means guaranteed and is extremely dangerous. Also, there doesn't seem like there is any room at all for aborts or error. When the spacecraft comes screaming in at 6kps towards Mars, they gotta either land or die, right? No way to go into orbit around Mars without it costing a lot of fuel.

Comment Re:Magnetic fields for passengers (Score 1) 533

Yeah, it's supposed to either use "reaction thrusters" (basically it would send out little puffs of compressed air from the same onboard supply the skis use) or control moment gyroscopes.

What I'm proposing is you embed some magnets in the walls of the tunnel a mile or so before the stator slot to force the stator into the correct position.

OR, you could have a "guide" made of light plastic a few thousand meters before the actual metal stator. The capsule control systems try to line up the rotor with the stator slot, such that it fits within this plastic "guide". If it fails to do this, the jerk as the rotor cuts through the plastic would trigger an emergency breaking.

Comment Re:How do you breathe in it? (Score 2) 533

The actual PDF with his plans does mention this briefly. It has a massive air compressor in the front, and the air that's in the hyperloop tubes is just ordinary air that leaked in. There's compressed air tanks inside the front of the car, and so basically some of that compressed air gets injected through tiny holes in the skies, and some of that air is pumped into the cabin, with the exhaust air pumped out the back.

If the car loses pressure, those exact same plastic masks that fall from the ceiling they use on airliners would come down, and the oxygen would come from those chemical oxygen generators that they also use on airliners.

Comment Re:Magnetic fields for passengers (Score 1) 533

If you read the actual article, you'll find out that the "rotor" of the linear electric motors is an aluminum blade that sticks out below the capsule. This is one tricky bit - it has to neatly slide into narrow track of the the stators of the linear motor when it reaches that part of the track at 800 mph. I'm thinking that external stabilizing electromagnets located in the tube itself might be needed to make sure this happens even if the capsule has system failures.

In any case, I don't think the magnetic fields impinging on the cabin should be any worse than if you sat a few feet above a conventional electric motor. (admittedly a several thousand horsepower motor, but still)

Comment Sigh, this is why NASA doesn't get anything done (Score 1) 545

"tall order" to build it in 150 years. Does this NASA director know what the world was like 150 years ago? Virtually all of the technology and all of the thing we have built today did not exist then, nor did the people to build them.

Step 0 to build something like the Elysium is to build large scale, fully automated factories that can churn out the parts to build such a station. Bonus points if those factories can also build many of the components used to build more factories, because you're going to need a lot of them.

Step 1 is to build a set of superconducting quench guns that you would use to actually put those parts into space.

Step 2 is to build more of these automated factories on the moon, since there's no environmental laws against strip mining, and plenty of real estate. Also no atmosphere to slow down your quench gun launches, and a fraction of the velocity needed.

Step 3 is to assemble all that shit together in space.

Now, building a single monolithic ring that rotates for centrifugal pseudo-gravity - THAT's hard to do and probably a bad idea (since if the ring fails, you lose the whole station). I'd much rather see several thousand smaller "hab modules" that spin opposite one another on big cables. You'd take transit cars or small spacecraft to move between the hubs of different modules (and ride an elevator down the cable to each distinct module)

If a cable snaps, you can send a recovery spacecraft to recovery them individual modules - if they didn't crash into anything, the occupants would probably be uninjured.

Comment Re:DOA (Score 1) 240

Not true. At the end of the trip using a transfer orbit, you're still going about 6 kps. That's what the MSL mission control video mentioned on reentry.

The expensive (and completely impractical way) to slow down from 6 kps to under 1 is to bring enough rocket fuel and an engine to make that kind of velocity change. However, you'd need to have a lander almost as big as the rocket that launched the mission.

Or you can try to skim the atmosphere and use a really great heat-shield. That's what MSL did. I understand there's problems with bigger spacecraft doing this, however. That's why landing methods are in doubt.

Comment Re:You're ignorant (Score 1) 285

That's fine, but consider the relative mass ratios of human crew mass to space station mass. The ISS weighs 419,455 kilograms, while it only has maybe 300 kilograms of crewmembers onboard. That means that more than 99.9% of the mass is things that might be able to withstand the acceleration you mentioned.

Now, of course this is optimistic, none of the ISS's assembled modules can withstand 360G of acceleration. But all kinds of raw materials, basic components, supplies, and so forth can. If we had a big quenchgun launcher we could probably send at least 90% of the stuff needed in space as disassembled components that can survive the Gs.

Slashdot Top Deals

"Spock, did you see the looks on their faces?" "Yes, Captain, a sort of vacant contentment."