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Comment: Re:Hmm (Score 1) 78

by Rei (#48623175) Attached to: SpaceX To Attempt Falcon 9 Landing On Autonomous Spaceport Drone Ship

That's not all that different from how he got started with Tesla. He had no intention of starting a car company (he already had SpaceX), he just wanted AC Propulsion to build him a copy of their t-zero - but they had no interest, even for a small fortune. But then they pointed him to this guy named Martin Eberhard who had this wild idea to commercialize the t-zero's tech base on a Lotus Elise body and was looking for funding... and thus Tesla was born.

Comment: Re:Why not push toward collapse? (Score 1) 321

by cheesybagel (#48620941) Attached to: In Breakthrough, US and Cuba To Resume Diplomatic Relations

You can hardly call the invasion of Iraq a conquest. It was a successful expeditionary incursion but the stated goals by the PNAC for the war were the stabilization of the Persian Gulf oil producing region and the demobilization of the troops stationed in the border since the first Gulf War. The demobilization did happen but the Persian Gulf was not stabilized at all. So in that sense the war failed to meet their objectives.

The PNAC also intended to invade North Korea at the same time but I guess the Afghan war precluded that from happening.

Comment: Re:Wildly premature question (Score 1) 78

by Bruce Perens (#48620117) Attached to: SpaceX To Attempt Falcon 9 Landing On Autonomous Spaceport Drone Ship

If we look at jet aircraft, wear depends on the airframe and the engines, and the airframe seems to be the number of pressurize/depressurize cycles as well as the running hours. Engines get swapped out routinely but when the airframe has enough stress it's time to retire the aircraft lest it suffer catastrophic failure. Rockets are different in scale (much greater stresses) but we can expect the failure points due to age to be those two, with the addition of one main rocket-specific failure point: cryogenic tanks.

How long each will be reliable can be established using ground-based environmental testing. Nobody has the numbers for Falcon 9R yet.

Weight vs. reusable life will become a design decision in rocket design.

Comment: Re:Pretty sad (Score 1) 151

by Rei (#48619997) Attached to: Dr. Dobb's 38-Year Run Comes To an End

g++ supports it with __restrict__. And if you're writing high performance code but not having support for the features of modern compilers, you're an idiot. In appropriate situations, the performance difference for using restrict or not is huge. Array-heavy tasks like image processing often get a 2-fold or more benefit with using restrict. There's very few places in the coding word where a single keyword can raise your performance that much.

Comment: Re:As with all space missions: (Score 1) 179

by Rei (#48619855) Attached to: NASA Study Proposes Airships, Cloud Cities For Venus Exploration

I'll begin by stating that I I don't support such a mission, as I prefer robotic exploration. But this proposal isn't as extreme as it may sound - it's probably a heck of a lot easier than landing on a planet and taking off. It's only 640 m/s from earth escape to Venus (3/5ths that of Mars). Transit time is less and launch windows a lot more frequent. Venus offers very easy aerocapture. You don't have to deal with the randomness of the surface - your "landing" is a lot more forgiving. Your habitat is probably simpler, not having to deal with a surface (although there's a few potential complications that need to be studied, such as storms, and I don know the radiation level at the desired altitude). Keeping it aloft is easy - even normal earth air is a lifting gas on Venus. Solar energy arriving at Venus is double that of Earth. Nearly earth's gravity eliminates a lot of the uncertanties about skeletal and muscular wasting.

One of the neat things is that a person could potentially step outside without any sort of special suit, just an oxygen mask. It's a "maybe", though, as there's a few complicating factors. It's 37C (100F) at the same sort of heights that it's about 600mb; for US analogies, it's Phoenix temperatures at Mount Whitney air pressures (lower or higher for both, depending on your exact altitude - you can choose). So it's not a perfect match - but probably tolerable. But there's two potential complicating gases: SO2/sulfuric acid and carbon monoxide. Breathing them is right out, but even long-term (hours at a time) skin exposure might be problematic at the given concentrations; it's not certain whether at these altitudes they'd be prohibitive. They would however make eye protection a must at the very least, the eyes are more sensitive to both CO and SO2 than the skin.

Manned or not, the main advantage of a Venus blimp would be the lower altitude it would provide to scientific equipment versus satellites. So you'll get a lot more information on the atmosphere, which could help answer questions about Venus's evolution (and how other worlds in other systems might be). You'll get higher resolution radar imaging of the surface. You simplify to some extent sample return missions from the surface, as each sample collection doesn't have to be a self contained return mission. Etc.

One thing on Venus I'd love to see studied more is the super-reflective radar surfaces. It's now believed to be due to a "galena snow", snow made of shiny, electrically conductive lead sulfide. I'd really love to know more about the surface minerology of Venus in general.

Comment: Re:Hmm (Score 1) 78

by Rei (#48616615) Attached to: SpaceX To Attempt Falcon 9 Landing On Autonomous Spaceport Drone Ship

I'm not talking about ideals, or tourism, or saving the world, or finding anything "up there", or anything of that nature (did you even read what I wrote?). I'm talking about the sheer awesomeness of, at your whim, shooting up a 1500 tonne rocket into orbit then landing it on an automated oceanic platform. It's like playing Kerbal with a real-life 70-meter tall rocket. Why don't more billionaires do stuff like that if only just for the fun of it?

But clearly you have an axe to grind against something for some reason, so I'll let you get back to that wheel.

Comment: Hmm (Score 4, Interesting) 78

by Rei (#48616227) Attached to: SpaceX To Attempt Falcon 9 Landing On Autonomous Spaceport Drone Ship

Why don't more billionaires do stuff like this?

I'm not saying do it "for the benefit of humanity", or even "for a profit". Just simply.... if you have billions of dollars, and you want to spend it on something, what can you possibly spend it on that wins in a sheer awesomeness category as "shooting a gigantic rocket up into orbit and then landing it on a robot boat in the middle of the ocean"? That's like a freaking video game, played with 1500 tonnes of aluminum and highly combustible fuel.

Comment: Re:Pretty sad (Score 1) 151

by Rei (#48615965) Attached to: Dr. Dobb's 38-Year Run Comes To an End

Back in the day, Dr. Dobbs was giving the world invaluable stuff like Mode X. Your average programmer had to be a lot more connected with the hardware, and working with the hardware was somewhat of a black art. Nowadays there's still some black art stuff out there for getting good performance (even a lot of simple, important stuff is inexplicably obscure... I bet you that 90% of C/C++ programmers don't even know what the restrict keyword does, for example), and you still see the occasional inner loop of some high performance code use assembly, but that's not the general case.

Comment: Re:Anti-Aging is a Fraud Magnet (Score 4, Informative) 165

by Rei (#48615927) Attached to: Researchers Accidentally Discover How To Turn Off Skin Aging Gene

Usually most aging-preventing discoveries cause cancer. For example, the p21 knockout mice that gained almost salamander-like regeneration also gained a high tumor rate. Usually processes in your body involving the stopping of growth and areas dying off are things that help prevent cancer from forming or growing.

"You don't go out and kick a mad dog. If you have a mad dog with rabies, you take a gun and shoot him." -- Pat Robertson, TV Evangelist, about Muammar Kadhafy

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