People have to keep renewing the contract to pay for those copies though. Afaik there's nothing that guarantees people will maintain them indefinitely after the contract expires.
Yeah that's right, I'm not sure how you could possibly value or incentivize indefinite storage. All storage mediums are consumable and require upkeep, a "one time" pricing model doesn't really make sense.
I would assume that eventually the cost of "old storage" will be too much and new payments wouldn't be able to subsidize it anymore (sort of like a failing Ponzi scheme) but to be fair I haven't heard of this. Thanks for the link!
You're welcome! I have some questions about how the network is going to play out over time wrt mining centralization and access incentivization, but their overall funding model seems sound to me. It's based an endowment that pays out over time to fund storage mining. Their yellow paper (https://www.arweave.org/yellow-paper.pdf) is worth a read if you want to learn about all the details.
How do you think this would play out? My intuition is that the not-for-profits wouldn't even be close to sustainable (even with cost cutting). Are you anticipating a huge influx of funding for them or do you think they could cut costs that drastically?
In SLS, if we are not talking about Orion, not really.
So, the engines is the same as the SpaceX Shuttle (RS-25). This is a great engine but nobody would build it today. It uses a fuel-rich design and almost universally people are now building Oxidizer-rich staged cycles. BlueOrigin BE-4 being a good example.
Second these RS-25 use hydrogen but currently everybody is building methane based engines. Building a new hydrogen engine would maybe make sense for upper stages in some situation but then you would probably copy the RL-10 or the new BE-3U that BlueOrigin is working on.
So I don't think that any modern project will try the same route as the RS-25 did.
The SLS is using new solid boosters that are not worth copying unless you want to build gigantic nukes. Solid fuel just does not make sense in space flight currently (outside a few specialised applications).
On the upper stage they will use very good but old and expensive engines (both in Block 1 and Block 1b).
Structurally the SLS is also behind the times. I don't think anybody would design something like it, they were just forced to use old stuff they had from the Space Shuttle.
So I don't think anybody would still copy SLS. Yes, SpaceX uses much of the old US and Russian ideas but in there current design, Falcon 9 they have already improved on pretty much everything. Their next Rocket, BFR, will go way beyond anything done in any other rocket. From the engines, to the structure, to the control, to cold gas thruster, fuel integration and so on.
Yes; much of the SLS requirements were forced by a certain bloc of congress who, since the 1970's have been directing pork-barrel $ at a few contractors' business. (in particular, Lockheed's Michaud facility in Louisiana, and Thiokol/ATK..now OrbitalATK, in the case of the solid rocket fuel). A lot of the original STS requirements were driven by this congressional delegation.
Good riddance to this form of "engineering".
That said: I'm not super bullish on the outcome of Blue Origin's efforts. The have not impressed me. SpaceX has; very much. And I do believe that Lockheed, Boeing, and even OrbitalATK will be very important players in the future. They're all continuing to do great work, but the government's got to start spending their money much smarter than they had been. (And perhaps the worst example was the cancellation of the X-33 Program).
There aren't many new components. The tech in the Orion capsule is new, but the capsule design is very similar to previous capsules (aerodynamics don't change). All the rest is basically re-used tech from the shuttle.
I may be wrong in this case about the upper stage. I don't know what they plan on using for those engines. If they're new engines (which I haven't heard of development regarding them), then that could be interesting, but they're likely reused OM engines from the shuttle or something like that.
FYI, I was able to add the Pebble 2 to my cart and get to the order confirmation page (I didn't click confirm though; still deciding if I want to buy it).
Thanks! I tried pretty much all of the sellers for the black watch, but none of them would ship to me. This one did. Not my preferred colour, but oh well.
Well, good for him. I'd like to see him stand in a pool of dirty water in contact with a 400V DC power system trying to remove someone who might be hurt from the car. If you've ever seen what things look like around a serious car crash you know what I am talking about.
Here, pick one and let's "use large amounts of water" as the emergency response manual recommends.
If the water is flooding the battery compartment and basically shorting between every positive and negative terminal of every cell simultaneously inside the armored battery compartment, I very much doubt this puts someone walking near the car at risk of themselves becoming a short circuit.
Please think a little about the geometry of the situation.
EDIT: Okay, physics challenged people out there: electricity tries to take the shortest route of least resistance. Please use reasoning more sophisticated than: "Water! Electricity! Oh Noes!"
Please think a little bit about (a) not being condescending and (b) that the scenario you painted is ONE in a range of scenarios for a 400 VDC system with enough energy to propel a 4,000 pound vehicle a few hundred miles. I am not going to get into hypotheticals. All I am saying is that elecric cars have inherent dangers not found in gasoline cars. You can stand in a puddle of gasoline and you'll be OK.
Please think a little bit about (a) not being condescending
Please think about physics and use specifics in your reasoning. If you have better logic in your head, please relate it. What you have posted is indistinguishable from spin doctoring and therefore receives appropriate treatment.
I am not going to get into hypotheticals.
Because they'd sound pretty stupid if you came out with specifics. Remember, the context here is dealing with batteries encased in 1/4" thick aluminum armor. Scenarios that can expose dangers in the wreckage for one type of vehicle would also be dangerous for the other type.
All I am saying is that elecric cars have inherent dangers not found in gasoline cars.
Gasoline cars have inherent dangers not found in electric vehicles. See how hazy statements like that are?
You can stand in a puddle of gasoline and you'll be OK.
And you'd be much more foolish for doing that than standing in a puddle of water near a Tesla S whose battery compartments have been breached, but are mostly intact and are being inundated by fire fighters.
EDIT: "Water, electricity! Oh noes!" was directed at my downvoters, not you.
> Please think about physics and use specifics in your reasoning.
What do you imagine I was thinking about? Underwater basket-weaving? Please look at my profile on HN. I think I get it, and not just from a college course on physics theory.
Specifics? You are asking for hypothetical scenarios. Severe crash damage is random. It cannot be predicted. Not to a deterministic degree at least. We recently had a horrific crash in our neighborhood. An 18 year old decided it would be OK to drive his car at 100 miles per hour down an avenue.
He lost control at a turn and plowed into a bunch of cars on the side of the road. We heard the impact from over two blocks away and went to investigate. He destroyed FIVE cars. His car and an SUV were mangled into a ball of twisted metal to such an extent that it was hard to tell the two cars apart. He was severely injured. Nearly died. It took them OVER TWO HOURS to get him out. They had to cut the two cars apart from each other and used a crane to separate them. They they had to cut his car to pieces just to get him out. When his car crashed into the SUV the resulting ball of metal demolished another four cars. They were all mangled to an unbelievable degree, a couple of them on top of each other.
There was lots of gasoline everywhere. His tank and the SUV's ruptured. No fire. The firemen sprayed a foam and water over areas and just kept everyone away. There were probably a dozen rescue workers and two ambulances working on this ball of metal to get this kid out.
Now. Stop for a moment. Don't be defensive about Tesla. Think about that wreck. Try to picture what I described in your mind. Picture at least two cars mangled into a ball to such an extent that you have trouble telling them apart. Picture one or more people in there who are in desperate need for help. Now replace the gas-powered cars with electrics with fully charged 85 kW battery packs. Think about powerful super-hot fires. Think about a variety of conduction paths. Think about more than the battery packs but also about the high voltage cables going from the battery packs under the car to the motor controller and motor. Think about any number of potential random arrangements and damage scenarios for these components. Think about a hefty high voltage and high current cable from the battery pack to the motor controller becoming severed and making contact with the body metal. I ask you to think in terms of a severely damaged system, not a battery pack full of water. Now think about the people in there and the rescue workers trying to get to them.
Surely somewhere in there there has to be something that might cause you to take pause and realize there are issues with electrics that we have not yet experienced because electrics are truly rare in a population of over 250 million gasoline vehicles.
This idea that gasoline powered cars are more dangerous is a huge fallacy that is being used to try and protect the reputation of electrics. I get it. I get what they are trying to --and have to- do. That's far from the truth though. If you really want to compare electrics to gasoline vehicles look at the entire history of gas powered vehicles from the 1800's until today. You have over 200 years of history on various designs. The number of gasoline powered cars in the world today easily exceeds a BILLION units. Sorry partner, I have to say that gasoline, as much as you and I hate it --and I do-- is pretty damn safe stuff. The data on Tesla's causing fires due to collisions isn't statistically significant yet. If you were to do the math with this imperfect data today you'd find that Tesla's are six times more likely to catch fire in a collision when compared to gasoline cars. Again, this is based on insufficient data, so it's nonsense. Don't waste any time on it at this point.
I am rooting for Tesla. I truly am. My comments about electric car safety are more about the general issues with electrics rather than Tesla specifically. For all I know Tesla's designs are the safest around. Without detailed engineering data this is pretty difficult to evaluate. I'll take their word. I think it is a cool company.
My concern is that the entire electric "dream" could easily be damaged if we have one or two horrific electrocution or high energy fire incidents. I've purposely blown up LiPo batteries in order to learn more about their failure modes (we use them for our RC planes and helicopters). They produce explosive high energy fires. I don't even want to imagine what a large pack could do.
This, to me, is THE area that requires the most intense work in electrics. Forget range. Forget increased capacity. Safety is the number one consideration. Imagine, if you will, if we had the technology to make electric cars with packs that could take you a thousand miles. Maybe that's a couple of hundred thousand kW. How do you deal with these things in serious accidents? You can't discharge them quickly enough. The fires could be unimaginably hot and violent with electrical systems capable of delivering hundreds of volts and probably thousands of amps in an instant. This is dangerous stuff. Combine such a vehicle colliding with a gasoline powered vehicle and, well, now things are even scarier.
All that is needed for the electric car industry to suffer a serious setback is for an event to occur that would plant fear in the minds of buyers. I don't care how much of a proponent of electrics anyone might be. If a mother is in fear of her kids being electrocuted or burned to death in a horrible way you lost that buyer forever. No amount of reason or statistics is going to fix that problem. That's the scenario I am concerned about. Tesla and the entire electrics industry could be destroyed overnight if something horrible happened. Panic is a powerful force. That's the plain truth.
No disrespect. I am not trying to diminish you. I am simply not sure you've thought this through. If you are coming to this conversation from a perspective of having taken a usual dose of physics courses in high-school and college and without a reasonably amount of experience with high-power/high-voltage systems I will respectfully suggest you might not be equipped to fully grasp the gravity of the situation. Again, this is not a personal attack. I am just stating facts. I am not a doctor and would not be equipped to fully grasp a range of medical issues. That's just a fact.
Yes, understanding the theory is important. However, as the saying goes, in theory, theory and practice are the same, in practice, they are not. I've dealt with a wide range of high voltage and high power systems throughout my engineering career. High voltage is dangerous. Very dangerous. Period. I could not imagine any reasonably experienced electrical engineer not agreeing with me on this one. You don't want to be anywhere near an uncontrolled system with several hundred volts and lots of available energy, much less be in it, wet and injured. Not fear-mongering. This is as real as it gets.
Try to picture what I described in your mind. Picture at least two cars mangled into a ball to such an extent that you have trouble telling them apart. Picture one or more people in there who are in desperate need for help.
This situation is going to suck, no matter what. It's also a sure bet that this sort of situation sucked worse while it was still relatively new and experience was being gained by emergency responders and procedures were being worked out.
This, to me, is THE area that requires the most intense work in electrics. Forget range. Forget increased capacity. Safety is the number one consideration.
You make a lot of good points, and you do seem to have the background to know what you are talking about. It would seem that what's needed is a way to reliably disconnect every cell from every other cell, lowering the voltage to around 4 volts. If one can do this in response to the high g from a collision, this would go a long way towards making these things safer.
> It would seem that what's needed is a way to reliably disconnect every cell from every other cell, lowering the voltage to around 4 volts.
Yes, absolutely. Something along those lines will probably be essential as we move forward. Maybe not to 4 Volts. That's probably not necessary. Somewhere in the range of 20 to 50 V there's a good safe spot. I am not up to speed on where safety levels lie for different circumstances. I's more about current through your body than absolute voltages. Of course, a higher voltage makes producing high currents that much easier.
High voltage and current circuits are not the easiest to interrupt mechanically. They tend to make such things as mechanical contacts explode with molten metal flying all over the place. The arcs produced when trying to mechanically interrupt high current circuits can be massively destructive. That's why most high power mechanical contactors are very large, loud and fast. More here:
