I don't understand exactly how these tires work, but having wheels with integrated rollers so that you can move sideways is a pretty old idea, see for example this forklift (video from 2006!).
Somewhat related: also the diary of Anne Frank is now in the public domain under the same rules, since she died about 2 months before Hitler. This is disputed by the Anne Frank Foundation, who claims that her father was co-author and that the work should thus remain under copyright for at least another 15 years. As a protest, the Dutch original text is now put online by several French politicians.
Exactly this. What you are describing is the economic equivalent of Amdahl's law for speedup of using parallel computing: even with infinite parallelism (infinite reuse), theoretical minimal costs are dominated by non-parallelizable computation (per launch costs). Elon keeps repeating the talking point that fuel is cheap so launches can be 100x cheaper. This ignores recurring costs of launch operations, manpower, non recoverable 2nd stage, inspections and repairs. Still, lowering costs by a factor 2-3 would probably be enough to kill competition...
They want to re-use this Dragon for an in-flight-abort test, using a Falcon 9 first stage launched from Vandenberg, so purposely introducing mechanical flaws seems risky. If it were a deliberate test, I would be simplest to just set the throttle to one of the motors to zero in software close to the end of the burn (to not ruin the overall test in case of problems), and then see if the control system can recover using the remaining 7 engines. Let's hope that Elon comments on this in the next days...
No, OP's remark was correct, he is not discussing the planned pitch over towards the sea after half a second, but a visible puff of smoke around the 4 second mark and some subsequent 'wobble', as if one of the 8 thrusters is switched of. See the zoomed video here. This proves the effectiveness of having 8 redundant thrusters, instead of having only 4. It is still not clear if this was a real engine failure (which might be verified via post-mortem examination of the motor), or if this was a deliberate, unannounced test of the 'engine out' capability. Credit: the discussion in the forum over at nasaspaceflight.com.
Indeed, they would need some mechanism like this, which is implemented using several heterogeneous processes. Triple hardware redundancy is useless if they all have a common mode software bug. Same thing happened to the first flight of Ariane 5, where all 3 controllers crashed within milliseconds.
[Mod parent informative] Indeed, this seems exactly the same issue. For Boeing, it might either be a signed integer being incremented at 100 Hz, or an unsigned one at 200 Hz.
Easy workaround: dual-booted laptop, one partition with WindowsXP and weak password, full with celebrity porn, 9/11 conspiracy documents and spyware to keep them busy for a while. Fully encrypted Linux partition for everything else.
I am neutral to mandatory voting. I believe they have this in Belgium, but it is not strictly enforced with sanctians, so the polical system works similar to neighboring countries. America has bigger political issues: 1) too large influence on politics of big money: by rich people via superPacs and by corporations via lobbying or outricht corruption. 2) Effective two party system, where everything is decided on a single left-right axis, so that non-issues like gun rights and being patriotic or christian enough decide all national politics. Fix these two issues first., then we can discuss mandatory voting.
I am not sure if we will get some personal answers out of this guy, I guess he will just forware every single question into one of these websites that claim to know everything. Serioudly, though, what do you think of Elon Musk's fear of A.I., and when do you think that Wolfram Alpha will become self aware?
I completely disagree. I have worked extensively both with Matlab and Numpy, and I much prefer Python's 0-based indexing and half-open intervals over Matlab's 1-based indexing and closed intervals. Edsger Dijkstra, the famous computer scientist, explained why this is a good idea. E.g. splitting the first n items off an array in Matlab is head = x(1:n); tail = x(n+1:end), while in Python it is head = x[:n]; tail = x[n:]. Even worse is when doing some computation over blocks within an array, in Matlab you do for i=1:n; y(i) = fun(x((i-1)*m+1:i*m)); end, while in Python it is for i in range(n): y[i] = fun(x[i*m:i*m+m]). In Matlab, you always have to think careful about the extra +-1, which causes many off-by-one errors, while in Python you just write it down intuitively.
The fact that he can make this claim only half a day after the fact (so I assume they had no time to piece together the debris) means that they did recover the most valuable part: the telemetry. Overall, they achieved probably 95% of the required challenges. With around 5 successful retro burns, 1 low-level flame out due to loss of roll control, 2 soft water landings, 1 bullseye impact on a boat and around ten successful low altitude tests with grasshopper, only extremely bad luck can stop them from making a good landing in the next few attempts.
Some years ago, an advertisement for a Dutch insurance company made fun of some Stalinist dictator, without mentioning North Korea by name. As far as I know, this did not cause any large-scale hacking warfare against the involved company, but Korean diplomats were not amused. Watch it here while you still can. This regime cannot be ridiculed enough, Sony should just release the whole movie for free.
With 50 euro for a power supply, 100 for a sensor conditioning module (without the sensors!), 300 for a base station and 800 for a complete starter pack, I don't care if it is open source or not, it is way out of budget for the casual hobbyist. There are already enoughdifferentalternatives, most of which appear to be vapourware. Home automation seems easy enough that many people who follow the IoT hype start their own project.
But we don't need more standards, we need less. The best would be if one of the existing protocols (not necessary that one) would win, so that people could mix and match their own components, which don't have to be more fancy than some arduinos and RPis thrown together.
No, the 'x wings' are not passive, but they are just as steerable as normal fins. See this video of SpaceX where they used them for roll control on a test flight in Texas. And the software to control these is pretty standard.
Can some aerospace engineer enlighten me about the advantage of these tennis-racket shaped x-wings over some standard steerable fins which you see e.g. on a guided missile? I could imagine that the grid-shaped 'louvers' could be seen as many small fins in parallel, but intuitively I would think that one big fin would have more effect. Is it something related to hyper-sonic aerodynamics? Or is it mechanically stronger?
For a decent debunking go to the Bellingcat blog. Also saw some graphic somewhere that clearly showed that the perspective was wrong by an order of magnitude, either the plane was 1 km wide or the satellie was orbiting at 20 km or so. This fake is so bad, that I think the only target audience is the Russian public, most of whom believe everything that Putin's propaganda machine feeds them. I have a Russian colleague, whom I normally regard reasonably high, that believes some really strange facts about this incident. She probably gets all her info from Russian websites.
NASA obviously thought about this possibility, so yes, the event will be observed by at least 3 satellites orbiting currently around Mars, 2 rovers on Mars, the Hubble telescope and probably plenty of earth-based telescopes.
I am afraid I am feeding a troll, but that is complete BS. It is a shitty job, since you have to get up at 5:30 in the morning and get paid very little for beginning crew, but it is not useless. Flight crew is needed to evacuate 200 people within 90 seconds in case of fire. They are needed to extinquish fires on board, if you don't everyone is dead (lithium laptop batteries are extremely nasty). They are neede to calm down drunk and annoying people, the legal limit is 1 crew per 50 passengers, so this requires a lot of social skills. They know how to handle a potential hijack situation. They are needed to serve you drinks, clean up people and toilets when someone throws up. They are fully trained to perform first aid to keep you alive until the plane can land. Source: a good friend flew for 8 years herself and now trains 18-20 year olds in 6 weeks to become a fully qualified cabin crew member.
I am not so worried about the patents. Vertically landing a rocket has been described in the TinTin comic ''Objectif Lune in 1953, has been demonstrated on the moon in 1969, with the Delta Clipper in 1993 and more recently with the X-prize in 2009. The patent by Blue Origin (sponsored by your purchases on Amazon) is from 2009, and is being challenged. I didn't read the patent and I am not a patent attorny, but the 'on a boat' part seems very much like the 'on a mobile device' part that gets slapped onto old ideas.
This time, they launched without the landing legs, but since they are still testing above water that does not matter a lot. Deploying the legs and soft landing on water have been tried successfully already, so I imagine they could test other things like partially flying back to the launching site, fuel permitting. The twitters are silent, so far, however.
There is currently an enormous discussion going on at python-ideas (see various large threads towards the bottom). Guido himself seems to be in favor of including something like MyPy into Python's standard library, which is allows for optional specification of arguments and return types using function annotation. The main use would be for static/offline code analysis/linting.
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I don't understand exactly how these tires work, but having wheels with integrated rollers so that you can move sideways is a pretty old idea, see for example this forklift (video from 2006!).
Somewhat related: also the diary of Anne Frank is now in the public domain under the same rules, since she died about 2 months before Hitler. This is disputed by the Anne Frank Foundation, who claims that her father was co-author and that the work should thus remain under copyright for at least another 15 years. As a protest, the Dutch original text is now put online by several French politicians.
Exactly this. What you are describing is the economic equivalent of Amdahl's law for speedup of using parallel computing: even with infinite parallelism (infinite reuse), theoretical minimal costs are dominated by non-parallelizable computation (per launch costs). Elon keeps repeating the talking point that fuel is cheap so launches can be 100x cheaper. This ignores recurring costs of launch operations, manpower, non recoverable 2nd stage, inspections and repairs. Still, lowering costs by a factor 2-3 would probably be enough to kill competition ...
They want to re-use this Dragon for an in-flight-abort test, using a Falcon 9 first stage launched from Vandenberg, so purposely introducing mechanical flaws seems risky. If it were a deliberate test, I would be simplest to just set the throttle to one of the motors to zero in software close to the end of the burn (to not ruin the overall test in case of problems), and then see if the control system can recover using the remaining 7 engines. Let's hope that Elon comments on this in the next days ...
No, OP's remark was correct, he is not discussing the planned pitch over towards the sea after half a second, but a visible puff of smoke around the 4 second mark and some subsequent 'wobble', as if one of the 8 thrusters is switched of. See the zoomed video here. This proves the effectiveness of having 8 redundant thrusters, instead of having only 4. It is still not clear if this was a real engine failure (which might be verified via post-mortem examination of the motor), or if this was a deliberate, unannounced test of the 'engine out' capability. Credit: the discussion in the forum over at nasaspaceflight.com.
Indeed, they would need some mechanism like this, which is implemented using several heterogeneous processes. Triple hardware redundancy is useless if they all have a common mode software bug. Same thing happened to the first flight of Ariane 5, where all 3 controllers crashed within milliseconds.
[Mod parent informative] Indeed, this seems exactly the same issue. For Boeing, it might either be a signed integer being incremented at 100 Hz, or an unsigned one at 200 Hz.
I guess this might be due to a 32-bit signed integer being incremented at 100 Hz: 2^31 / 24 / 3600 / 100 = 248.5 days.
Easy workaround: dual-booted laptop, one partition with WindowsXP and weak password, full with celebrity porn, 9/11 conspiracy documents and spyware to keep them busy for a while. Fully encrypted Linux partition for everything else.
I am neutral to mandatory voting. I believe they have this in Belgium, but it is not strictly enforced with sanctians, so the polical system works similar to neighboring countries. America has bigger political issues: 1) too large influence on politics of big money: by rich people via superPacs and by corporations via lobbying or outricht corruption. 2) Effective two party system, where everything is decided on a single left-right axis, so that non-issues like gun rights and being patriotic or christian enough decide all national politics. Fix these two issues first., then we can discuss mandatory voting.
Hmm, seems it will still take a while ...
I am not sure if we will get some personal answers out of this guy, I guess he will just forware every single question into one of these websites that claim to know everything. Serioudly, though, what do you think of Elon Musk's fear of A.I., and when do you think that Wolfram Alpha will become self aware?
I completely disagree. I have worked extensively both with Matlab and Numpy, and I much prefer Python's 0-based indexing and half-open intervals over Matlab's 1-based indexing and closed intervals. Edsger Dijkstra, the famous computer scientist, explained why this is a good idea. E.g. splitting the first n items off an array in Matlab is head = x(1:n); tail = x(n+1:end) , while in Python it is head = x[:n]; tail = x[n:] . Even worse is when doing some computation over blocks within an array, in Matlab you do for i=1:n; y(i) = fun(x((i-1)*m+1:i*m)); end , while in Python it is for i in range(n): y[i] = fun(x[i*m:i*m+m]) . In Matlab, you always have to think careful about the extra +-1, which causes many off-by-one errors, while in Python you just write it down intuitively.
The fact that he can make this claim only half a day after the fact (so I assume they had no time to piece together the debris) means that they did recover the most valuable part: the telemetry. Overall, they achieved probably 95% of the required challenges. With around 5 successful retro burns, 1 low-level flame out due to loss of roll control, 2 soft water landings, 1 bullseye impact on a boat and around ten successful low altitude tests with grasshopper, only extremely bad luck can stop them from making a good landing in the next few attempts.
Some years ago, an advertisement for a Dutch insurance company made fun of some Stalinist dictator, without mentioning North Korea by name. As far as I know, this did not cause any large-scale hacking warfare against the involved company, but Korean diplomats were not amused. Watch it here while you still can. This regime cannot be ridiculed enough, Sony should just release the whole movie for free.
With 50 euro for a power supply, 100 for a sensor conditioning module (without the sensors!), 300 for a base station and 800 for a complete starter pack, I don't care if it is open source or not, it is way out of budget for the casual hobbyist. There are already enough different alternatives, most of which appear to be vapourware. Home automation seems easy enough that many people who follow the IoT hype start their own project. But we don't need more standards, we need less. The best would be if one of the existing protocols (not necessary that one) would win, so that people could mix and match their own components, which don't have to be more fancy than some arduinos and RPis thrown together.
No, the 'x wings' are not passive, but they are just as steerable as normal fins. See this video of SpaceX where they used them for roll control on a test flight in Texas. And the software to control these is pretty standard.
Can some aerospace engineer enlighten me about the advantage of these tennis-racket shaped x-wings over some standard steerable fins which you see e.g. on a guided missile? I could imagine that the grid-shaped 'louvers' could be seen as many small fins in parallel, but intuitively I would think that one big fin would have more effect. Is it something related to hyper-sonic aerodynamics? Or is it mechanically stronger?
For a decent debunking go to the Bellingcat blog. Also saw some graphic somewhere that clearly showed that the perspective was wrong by an order of magnitude, either the plane was 1 km wide or the satellie was orbiting at 20 km or so. This fake is so bad, that I think the only target audience is the Russian public, most of whom believe everything that Putin's propaganda machine feeds them. I have a Russian colleague, whom I normally regard reasonably high, that believes some really strange facts about this incident. She probably gets all her info from Russian websites.
NASA obviously thought about this possibility, so yes, the event will be observed by at least 3 satellites orbiting currently around Mars, 2 rovers on Mars, the Hubble telescope and probably plenty of earth-based telescopes.
I am afraid I am feeding a troll, but that is complete BS. It is a shitty job, since you have to get up at 5:30 in the morning and get paid very little for beginning crew, but it is not useless. Flight crew is needed to evacuate 200 people within 90 seconds in case of fire. They are needed to extinquish fires on board, if you don't everyone is dead (lithium laptop batteries are extremely nasty). They are neede to calm down drunk and annoying people, the legal limit is 1 crew per 50 passengers, so this requires a lot of social skills. They know how to handle a potential hijack situation. They are needed to serve you drinks, clean up people and toilets when someone throws up. They are fully trained to perform first aid to keep you alive until the plane can land. Source: a good friend flew for 8 years herself and now trains 18-20 year olds in 6 weeks to become a fully qualified cabin crew member.
Apparently, fiction does count as prior art in some cases. I guess the requirement that a patent must be 'non-obvious according to the state of the art" is greatly undermined if some artists already had the same idea before. This might depend on if the patent just describes the crazy idea (in which case the artist could have filed the same patent), or if the patent describes a new technical solution to an otherwise old idea. The famous example is that a crazy idea to raise a sunken boat with pingpong balls was rejected because the exact same idea was featured in a Donald Duck story 15 years earlier.
I am not so worried about the patents. Vertically landing a rocket has been described in the TinTin comic ''Objectif Lune in 1953, has been demonstrated on the moon in 1969, with the Delta Clipper in 1993 and more recently with the X-prize in 2009. The patent by Blue Origin (sponsored by your purchases on Amazon) is from 2009, and is being challenged. I didn't read the patent and I am not a patent attorny, but the 'on a boat' part seems very much like the 'on a mobile device' part that gets slapped onto old ideas.
This time, they launched without the landing legs, but since they are still testing above water that does not matter a lot. Deploying the legs and soft landing on water have been tried successfully already, so I imagine they could test other things like partially flying back to the launching site, fuel permitting. The twitters are silent, so far, however.
There is currently an enormous discussion going on at python-ideas (see various large threads towards the bottom). Guido himself seems to be in favor of including something like MyPy into Python's standard library, which is allows for optional specification of arguments and return types using function annotation. The main use would be for static/offline code analysis/linting.