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Comment Re:certified materials (Score 3) 220

You think having the part designed to handle five times the load it actually experienced to not be "with sufficient margin"? How much of a margin do you want them to put, 100x?

RTFA. They were doing statistical-sampling quality control testing of struts. The problem was that most of them were just fine, but there were a very small number which were totally defective and broke at a tiny fraction of their rated value. And no, SpaceX did not make the parts, it was an outside supplier. And yes, SpaceX A) will now be testing 100% of them, and B) is ditching the supplier.

Comment Re:Transparency (Score 1) 220

It's not just about the cost of a failed launch, there's also a huge cost to a company's reputation if a rocket fails. And to their schedule.

Out of curiosity, is there any lightweight way to sense how close a part is to failure *in use*? I mean, finding defects on the ground is great, no question. But what if something would doom a mission not due to a part having a manufacturing defect, but due to an oversight somewhere in the rocket design process, or assembly, or transportation, or launch setup, or unexpected weather conditions, or whatnot? It seems to me it could be a massive boost to launch reliability if one knew that a part was about to fail - for example, in this case, the computers could automatically have throttled back to the rocket to reduce stresses, at the cost of expending more propellant, and possibly been able to salvage the mission. And then the problem could be remedied for future missions, without having to have a launch failure first.

To pick a random, for example, would there potentially be a change in resistance or capacitance or other electrical properties when a strut nears its breaking point?

Obviously, though, if adding sensing hardware would add a high weight or cost penalty, that would be unrealistic.

Comment Re:Futile search? (Score 1) 208

Funny ;) But the main point is that its surface is high radiation and very oxidizing; and as far as we know there's no liquids anywhere on Mars except for possible transients or extremely perchlorate-rich brines (aka, something you'd use to sterilize a rock of life).

On the other hand, subsurface water oceans are common elsewhere in the solar system, and colder bodies are known and/or theorized to have a wide range of alternative liquids.

Comment Re:Holy Jebus (Score 5, Interesting) 220

Also, maybe it's just because I've never worked in that industry before, maybe it's common practice in rocketry, but is anyone else impressed with the use of sound triangulation to figure out which part broke? I've never heard of that being done before.

Sad that the Falcon Heavy won't be launched until next spring, I've been really looking forward to that. Oh well...

Comment Re:Holy Jebus (Score 4, Insightful) 220

Elon is surely really fuming about this one, as I know from past interviews with him that he really doesn't like having to source hardware from outside suppliers. He has the old "robber baron" mindset of wanting to get the whole production chain start-to-finish in house, and it's one of the things that really frustrated him when he started Tesla: at the time of the last interview I read on the subject (something like 3 or 4 years ago), he had gotten SpaceX up to 80% in-house, but Tesla was only up to 20% in-house. Car manufacture has long been all about sourcing parts from a wide range of outside suppliers.

But even at 80% in-house at SpaceX, looks like that remaining 20% still bit them : Seriously, failing at 1/5th the rated failure value? The vendor might as well have given them a cardboard cutout with the word "strut" written on it in sharpie.

Comment Re:Futile search? (Score 5, Interesting) 208

The speed of light also comes into play in the Fermi Paradox. It's quite possible that for a billion years there's been a vast galactic scale civilization in the universe emitting copious amounts of readily-identifiable radiation. But if that galaxy is more than a billion light years away, it would be physically impossible for us to see them.

There's lots of things about the universe that would make it hard for advanced lifeforms to spot each other unless they're close.

And I fully agree about our own solar system (although I personally think Mars is a terrible place to look and Europa is overrated). There's so many "worlds" in our solar system with fluids (including water, although I wouldn't be so bold as to say that it's a requirement for all life) and energy sources to harness. Organic chemicals seem very common too, even complex ones.

Of all of the bodies in the solar system, I think Enceladus has the best potential payoff in terms of "dollars vs. chance of finding evidence of life". Namely because you don't even have to land on it to do a sample return (but if you do want to land on it for better sample collection, it takes little energy to take off again). And because it emits its internal sea straight up into space. And its internal sea has interesting properties - namely, it's a hyperbasic sea caused by serpentinization of its rocky core, which is a process that also releases hydrogen, giving a potential fuel source to hydrogen-metabolizing life.

That said, my dream mission is still a Titan sample collection/return mission using an RTG-powered rotary nacelle craft to fly in hops all across the planet over the course of a year, recharging its flight batteries overnight on the surface and taking small samples from every potential terrain - dune fields, rivers, the various seas, cryovolcanoes, etc. It would then re-dock with its ascent stage (single solid stage similar to a small Pegasus stage), lift the ascent stage out of the atmosphere (to reduce drag) and as fast as possible until it's drained its flight batteries (which would happen quickly with the added load), ditch all unneeded weight and fire the ascent stage to re-dock with the ion-powered orbiter that got it there. The orbiter, having spent the past year skimming the outer layers of Titan's atmosphere for return propellant that doubles as an atmospheric sample return, would then return to Earth, possibly skimming Enceladus's plumes and Saturn's atmosphere on the way for more sample returns.

No question that would be a flagship mission, though, requiring two RTGs and three stages. An Enceladus-only return could probably be done on Discovery or New Frontiers budget (probably the latter).

Comment Re:100 million quest to waste 100 million (Score 5, Interesting) 208

It's a serious point. Our own radio signals are probably indistinguishable from background noise from Alpha Centauri, and they're actually reducing with time, not increasing.

Rather than than looking for "stray radio communication" (you really think an advanced society is going to lose lots of energy to stray communications?), we should either be striving for extreme optical / UV resolution (satellite-based interferometer telescope) so that we can spatially resolve surface spectra on extrasolar planets in our area to look for signs of life; and in general look for signs of energy release that might be associated with interstellar travel, such as antimatter annihilation, directed thrust, solar sail reflection, etc.

IMHO.

Comment eDiversity (Score 4, Funny) 398

About Us:

eDiversity was founded in 2015 by Ayotunde Okonjo, a self-taught Pakistani refugee of African descent. Spending her teenage years in Ecuador facing discrimination as a lesbian of colour, Ayotunde overcame the challenges of her muscular dystrophy and moved to Silicon Valley where she met Kiri Chey, a survivor of the Cambodian genocide and Heba Mohammad, a Yemen-born teacher of the Chemehuevi Uto-Aztecan language, and together their shared interest of underground Soviet-era outsider art and Haitian folk dancing brought them together to form eDiversity.

At eDiversity, we utilize crowdsourced design and 3d printing to provide innovative solutions to underprivileged children as a solution to the global energy crisis. In addition to our LEED platinum-certified central office, we operate five international branches in Kiribati, Nepal, Sri Lanka, Uganda, and the South Sandwich Islands, the latter of which also qualifies as an internationally recognized penguin reserve.

We seek $5,5m in seed funding for 2.5% of the company.

Comment Re:Before and after (Score 4, Interesting) 132

That's controlled for by the randomness of the counties involved - both changes before and after drilling, and with no-drilling areas in the same region as controls (the control county had a drilling ban because it was in the Delaware River watershed). The admissions were largely not due to accidents - cardiology admissions were the strongest correlated. However, the authors don't identify the particular causative factors. They speculate, for example, that it might be diesel exhaust from all of the work vehicles that could be a causative agent. Another speculation is that the development of the industry has changed the demographics of drilling areas.

We really shouldn't be surprised that living next to industry in general isn't good for one's health, just from these sort of factors alone. Exhaust from heavy work vehicles, noise, dust, etc aren't famously conducive to good health. Even living next to a busy road is correlated with negative health effects.

A real problem with the study is, as they wrote, "Given that our modeling approach cannot account for within zip code demographic changes over the study period,". Curiously, while there were positive correlations between wells and health problems in most fields, there were negative correlations in gynecology and orthopedics. They remark "However, within the medical categories of gynecology and orthopedics, inpatient prevalence rates are expected to decrease each year by around 13–14% and 3–4%, respectively. Despite this surprising result, it is unclear why gynecology and orthopedics inpatient prevalence rates are decreasing each year. It is unlikely that these decreasing rates are related to the increased hydro-fracking activity." I'm surprised that they were allowed to get away with this - you shouldn't be allowed to credit increases to an industrial effect while just dismissing data (quite significant data) that doesn't match your hypothesis. There could be actually very useful information about the validity of their overall study and their conclusions in the reason for why gynecological inpatient cases are declining. For example, perhaps the demographics are changing to a lower percentage of women due to the arrival of the drilling industry. Men have shorter average lifespans and in particular a higher rate of cardiovascular disease.

To me, this is a really big hole in their study, and again I'm surprised it passed peer review with it there. But apart from that, I see no problem with the study, so long as people don't overinterpret the results. It's a very broad, generalized study focused entirely on correlation and not causation.

Comment Re:Fundamentally flawed (Score 1) 188

I find it amazing how much people obsess over the cost of production and disposal of a couple hundred pounds of the mass of an EV, and ignore the environmental cost of production and disposal of the rest of the bloody vehicle, both in the case of gasoline cars and EVs. Really, you think that ICE just popped out of the ground preformed? You think mining platinum for a catalytic converter or lead for a lead-acid starter battery is a harmless process? Lead is far more toxic than lithium.

Comment Re:as always no mention of lithium mining (Score 1) 188

1) Most lithium isn't "mined". It's produced from playas where you have a salt crust with briny water underneath. Evaporation ponds are set up on the surface (where it should be added no life more complicated than extremophile bacteria live, and whose surface is identical over vast stretches of land). The brine is pumped into the evaporation ponds to concentrate it and then the lithium salts are selectively crystalized out. The playas are seasonally flooded so there's no year-to-year water loss, and on some the entire top surface gets flooded out, resurfacing it. If you took down your hardware one year, all signs that you were ever there would be gone the next.

2) Lithium salts are relatively nontoxic. Some places actually bottle natural lithium-rich mineral waters and sell them as a health drink. The symptoms of consumption of lithium at below a toxic (high) level are feelings of calm and a reduced risk of suicide. Long-term consumption of lithium-rich water has been linked in one study to longer lifespan.

3) Contrary to popular myth, there are many places on Earth to get lithium. Afghanistan is not a major player, and is not likely to become a major player for a long, long time.

4) Contrary to popular myth, lithium salts are not expensive. They're so cheap that among the biggest consumers of lithium are glassware/glazing and greases.

5) Contrary to the name, lithium is not the largest, nor most expensive, component of lithium-ion batteries.

6) That "it's better not to junk an old guzzler" car is - you guessed it - also a myth. Which you should be able to figure out just from some extremely rudimentary analysis. The average US driver drives over 12k miles per year. If your car gets 24mpg then that's 500 gallons of gasoline, or 1400kg per year. Forget that most of a car's mass gets recycled at end of life, forget about the consequences of all of the oil leaks and the like caused by old decrepid cars - you burn your car's weight in gasoline every year. And the average car on the road is about 10 years old, meaning an average lifespan of 20 years.

Comment Re:Exactly I've made this point here many times (Score 3, Informative) 188

I don't know where you're getting your "59-62%" figure from, it's usually higher than that. The US grid is about 93% efficient, generator-to-socket. Grid losses are far lower than most people give them credit for. Chargers are typically 92-94% efficient, depending on how fast the charge is. beyond the charger, charging is usually 90-99% efficient, depending on how fast the charge is and what sort of pack the vehicle has and pack management the vehicle does. Powertrains during operation (including battery losses) are usually 65-95% efficient, depending on torque and RPM conditions and the vehicle, with a usual operational average of 85%-ish. A small portion of the energy, depending on the type of driving, is returned via regenerative braking, which on li-ion EVs is usually 60-70% round trip efficiency (lower on NiMH hybrids). Ignoring regen, the whole picture is usually 70%-ish.

You're right about the efficiency of gasoline cars, but to be clear, it's not that the engine can't achieve higher - it's that maximum efficiency (usually 35%-ish) is confined to a narrow torque / rpm band. Gearshifting helps you pick your RPM / torque combination but you don't have control over power (the combination of the two) - that's dictated by the driving conditions. And then of course on top of that you have idling and no regen potential.

Concerning the production of electricity, it's important to note trends. Electricity is in most countries in the world, including the US, trending toward cleaner, both in regards to CO2 and to health-related pollutants. Gasoline, however, is trending toward dirtier - it involves more energy to extract and/or refine. There's no reason to expect these trends to reverse in the forseable future.

Comment Re:Exactly I've made this point here many times (Score 1) 188

Haven't found a copy of the study yet but I did find this map supposedly from the paper, which already right there doesn't just wave red flags, it applies for a zoning permit to make a factory for automated red-flag-waving robots. Compare it to a map of coal power generation - they don't match up at all.

Without having the paper, I don't know what screwy thing they're doing with the data, but there's clearly something they're doing screwy with the data.

Comment Re:I see theyre using the Step 2 profit model (Score 4, Insightful) 188

Why are we dignifying it by calling it a "study"? It's not published in a journal. It's not undergone peer-review. It's a "working paper" on the NBER website. It's not the same thing. If it was legitimate, they would have submitted it to a legitimate journal and gotten it published. They have not, as it stands.

How long is it going to take for news sources to bother to check whether something has undergone peer-review before they start citing it as "science"? Let alone the "most comprehensive study yet"?

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