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Comment Re:"Clock parts" wired together in an adhoc fashio (Score 1) 815

Is the Moon a hoax bomb? If I claim it is a bomb, about to go off, is that now a suspected hoax bomb? Give me a break.

Anyone can suspect anything or anyone of anything. That doesn't make it a justified belief.

In real life we want justified beliefs.

The complete lack of anything resembling an explosive or detonator makes anyone suspecting it to be a bomb very stupid.

Comment Re:"Clock parts" wired together in an adhoc fashio (Score 1) 815

Yes, but to be a hoax *bomb* there would have to be a hoax *explosive*.

Where's the fake explosive in any picture of this device???

There isn't one.

Did he even claim it was a fake bomb at any time??? The answer seems to be: no.

It's all a load of rubbish, and the police knew that, which is why they let him go.

Comment Re:Not so fast (Score 1) 226

> Their tech works and they built it.

LOL, I don't think so.

This is the tech that keeps lithobraking and exploding when it's supposed to be landing on a barge. They've been trying to pin a landing since the first flight of Falcon 1. They're currently on Falcon 9.

Maybe they'll succeed one day, but the very high performance rockets they build are obviously *very* fragile.

And that's the problem with their approach, pure rocket reusables have to be super lightly built, and then it's very difficult to make it back down to the ground.

Comment Re:the interesting part (Score 1) 63

> Even the most devoutly religious would not actively wager money to put their faith to the test.

People do this kind of stuff all the time.

Many people wager their lives on their belief in a God, and... usually die.

George R. Price famously gave all his possessions to the poor; got evicted, fell into depression and then killed himself.

Comment Re:Not so fast (Score 1) 226

Actually, I once did a computer model of SpaceX-style reusability, and that's actually what my model showed me, that it would be extremely hard for SpaceX to get it to work.

But my modelling shows that Skylon ought to make orbit, and return and land safety with comparative ease, Their design is very insensitive to weight growth; and they actually have spare mass built into their design in case things are harder than they look.

But yeah, I do agree with you pretty much on the economics, that's the worst part of their design. But compared to the economics of the Space Shuttle... ;)

Comment Re:Not so fast (Score 1) 226

> Sure, at this stage of any project it's easy to be "looking at" very low costs. They haven't done anything yet. The nature of these kinds of projects is there are a whole bunch of costs, technical an regulatory, that aren't apparent until you actually start building something.

I don't agree. For example, the Space Shuttle estimates were about on the money. As in they said, the cost estimate is $X, but we'll need $1.2 X, to allow for obvious contingencies. President Nixon went: we don't budget contingencies, we'll give you X and then fund the overrun later. NASA: OK boss.

So actually, it cost what they said, but it looked to the rest of the world like an overrun.

And the Space Shuttle main engine was about as complicated as SABRE looks like it will be, maybe more so, it was an unreasonably complicated design.

And Reaction Engines actually have a careful design, with computer modelling of everything. That bodes well for a relatively straightforward detailed design and build. The X-33 had none of that, and when they got around to it, they found the horizontal stabilisation was total shit.

And the engine is particularly clever in that it works almost the same at all speeds; the precooler means that it doesn't care whether it's at ground level or Mach 5, the air behind the cooler is at the same temperature. That means, like a rocket engine, they can do almost complete testing when stationary. And the precooler also, they've already tested the precooler; it works fine. And the precooler was the most challenging bit of the whole system; it's something like half a gigawatt per tonne of cooling.

The take-home message is not that it's not a clever design, it's that most of the clever bits are easy to ground test. About the only bit they can't totally test on the ground is the aerodynamics of the aeroshell- but that was basically the same problem that the Space Shuttle faced and dealt with.

Comment Re:Not so fast (Score 3, Informative) 226

Actually, the Skylon group predicted that the X--33 wouldn't work. They said that the X-33 was too tail heavy. And fixing it would mess up the payload fraction. And they were right.

It's difficult to get your head around just how far ahead these guys have been for about 20 years.

The ultimate reason is that they built a computer model of launch vehicles, which they fiddled with until they got a plausible vehicle. Then they did a back-back comparison with a pure-rocket vehicle, and found that there was no big advantage. Then they fiddled around more, and out popped Skylon, and then they found it *seriously* beats pure-rocket vehicles; it's not even close.

Skylon is looking at costs starting around $500/kg and then going lower. SpaceX won't be able to get down to that.

Comment Re:Green Movement opposition to Nuclear (Score 2) 173

Brownouts aren't likely; but grids of all and any design do sometimes brown or black out.

Up to about 20-30% wind/solar, brownouts are largely a non issue- the backup power already built into the network is enough to fill in the extra power.

Going forward, as the existing generating plant wears out, much of the coal plant on many networks is being converted to gas, which has a lower carbon footprint, and is somewhat more flexible, the plant is otherwise mostly paid-off, and hence cheap. It's still wearing out, but it will run less because the wind and solar will fill in, but the grid will have to run on even gas less and less because of climate change.

Past about 2017, brownouts are looking like they will gradually become non issues, because grid-level storage is looking like it will become ridiculously cheap, and because more and more solar and wind will be coming on line; they are both growing exponentially, and are likely to continue for the foreseeable future.

I see no major role for nuclear power, and the amount of power generated from nuclear will reduce over time. This is a combination of its inherent relatively high cost, the fact that people don't trust it, its reliance on (mostly fresh) water, and the long lead times that new reactors require.

Yes, we will be going to OSI, Mars, and Pluto, but not necessarily in that order. -- Jeffrey Honig