Comments by "ke6gwf - Ben Blackburn" (@ke6gwf) on "Scott Manley" channel.

  1. Some observations from someone who enjoys working with metal. The base section is completely structural. It is using welded heavy wall stainless steel pipe for a bulletproof internal support frame and landing legs, heavy enough to withstand "slight miscalculations" on the suicide burns and punch holes in the concrete if needed. This looks like it was designed by an engineer familiar with building bridges and roller coasters and other such durable structures, and I see signs of very good workmanship in the welds and little details like the contoured gusset plates and such. It really looks like it's designed to support a bridge rather than fly. But considering that Elon probably wants something close to actual weight, overbuilding this is not a problem, and makes it more likely to survive heavy grasshopper testing without needing repairs. (landing pad is more likely to need repairs lol) The shell of the base section is heavy gauge SS as well, and was all bent in large probably CNC plate rolls making perfect curves that fit and weld together. And it is heavy enough not to distort from the welding. I assume that this will all be polished up to a mirror finish, and was built by a structural engineering team. The upper sections are built totally different, and I suspect by a different team or company. They seem to be an open framework with thin sheet metal panels fastened over it. It makes sense that it is a water tank company, because they would have experience doing such things. Now the difference is that they normally aren't trying to do compound shapes with thin sheets on water tanks, and it is nearly impossible to do it with flat sheets without lots of wrinkles and divots, just like of you put a sheet of paper over a basketball. They may have some trick to use heat to stretch the sheet metal and smooth it out after the structure is finished, it's pretty much black magic, but it is used by good sheet metal workers, so I say wait a little while and see what they are able to do. I also will not be surprised if the company that bid to do it had never done anything quite like this before, and are finding that they are fighting the metal, and it is winning lol So this may turn out to be a total failure on their part of being able to get a good looking result. Elon may be fuming about how ugly it is looking as we speak. On the other hand, as long as it is all attached properly, it is totally flyable as a grasshopper, and once the polishing is done it will be hard to see the surface shape. So it is possible that Elon decided he wanted something of the right size and shape and shiny to be in the air asap, and so is using his preferred fail fast prototyping method to knock together something that can hop, even if the appearance is wanting. If that is his goal, this is the way to do it. If you have seen the videos of that NASA guy who worked with SpaceX, and helped develop the Pica heatshield, (can't remember his name, but it was a series of short interviews), you are familiar with the culture there of being able to order stuff up from McMaster Carr, and put a test prototype together the next day to see what happens, and this seems to fit that profile. Though they probably didn't get the metal from McMaster lol So whether Elon is angry at how it looks, or this was the expectation, it is the fastest and cheapest way to get a Starship prototype hopping, and the appearance really doesn't matter for the testing, since it won't be going fast enough to have any effect. And using stainless steel is just because he wants it to look shiny like the final version lol As far as tanks, he doesn't need large or super light tanks for this first prototype. For initial testing, he can probably just use umbilicals, or small tanks. In order to make this shape with stainless steel, you basically need to use the same method that car body panels use, and hydroform or press them, so each panel is already shaped properly for the location it needs to go. This however requires extensive time and work making the dies for each section, since the sheets change shape and size as it goes up, so this is a big investment, and I can totally see him saying to just wrap it in tin foil to get it flying. They very likely are currently working on building dies and such, and may replace the upper section as soon as they are done and some hydroformed panels are available. So let's see what they are able to do to smooth out the tin, and remember that as long as it is being moved around and welded on, any straightening they do will just get messed up again, so they may be waiting until it is stacked before smoothing it. Oh, and if they were building this for anything other than an actual test prototype, they would NOT be making the top to look like a steam punk Burning Man art installation. The very fact that it is ugly and utilitarian, for something that Elon is doing, tells me that it is for hard science quickly.
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  14.  @MillionFoul  the Max crashes are exactly the same root cause, arrogance and ignoring engineering testing practices to save a buck and speed things up. They had never tested the MCAS system in many different failure modes, including loss of AOA vane on takeoff with no AOA Disagree indicator. They did the paperwork and said that runaway trim procedures would take care of any issues, and most of the people who were looking at safety and testing were not even aware of how powerful the software had become, and the people who expressed concerns were shut down. And all the people like you who are saying that all the proper testing and certification had been done, are just saying that the process of testing and certification is broken, because it should never have let so many arrogant assumptions slip by without being verified. For instance, they discovered that even with US pilots, the assumption that the runaway trim procedures could be done in a certain length of time, which was an assumption that they have been making for decades, turned out not to be reliable, and not just for foreign pilots. Pilots are trained differently than they were when that standard assumption was made when most pilots had a military background, and hand flying was the only way to fly a plane. So when you hear "we tested everything and it all met the requirements" it doesn't mean that they didn't mess up, it means that the messing up was done in assumptions and shortcuts in the testing and verification process. And MCAS didn't get thoroughly tested, just as Starliner didn't get thoroughly tested.
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  29. I am surprised that no one is talking about using the ISS as a staging facility for space missions. It is easy to launch to, high weight capacities with low delta v needed so easy reusablility and heavier payloads. You basically send the empty Orion capsule up on whatever rocket works best, and berth it to the ISS. Then you send up whatever works best as a space tug to get it to the moon, and using the Canada Arm on the ISS, and a space walk if needed, you connect them. Then you send up fuel, and using the Canada Arm you fuel it. (if you don't want to fuel at the station, you just dock the tanker to the side of the moon assembly, connect the hoses using the arm, and then after it leaves the station and is a safe distance away, you start the fueling process). Then to get the crew on it, you send them up on Crew Dragon, and either transfer at the ISS, or if you want to do the off-station fueling and not have astronauts on board during the fueling, you dock the Dragon to the Orion after fueling is complete. Then you jettison the tanker, send the Dragon back to the ISS as a back up reentry vehicle in case Orion has issues, and blast off towards the moon. And while this is a lot of steps, it requires very little additional engineering, because instead of having to design special automatic in orbit docking systems, you just have to make sure that things can be bolted together by the astronauts, and add Canada Arm grapple points. You could probably send up the extra Falcon loads and do the extra engineering for less than a years budget for the SLS.
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  30.  @A.Lifecraft  put your hand through a hole it barely fits through, then spread your fingers out, grab a tennis ball, and duct tape your fingers around it, and then try to pull your hand back through the hole. It won't go lol There are styles of wedge sockets where the tension simply pulls a wedge in tighter, often used to terminate crane cables because it's easily removable, but the poured style are the ultimate termination for a cable. The cable wires are splayed out to evenly fill the cone of the socket, and then they are mechanically and chemically cleaned. The metal, zinc, or a zinc based alloy is then poured in, and it's like soldering or brazing to each individual wire strand. So there is no way for it to loosen around the wires or corrode inside the metal plug, any more than a proper solder joint will loosen around the wires. It tins the metal and forms a metallurgical bond, actually forming an alloy layer of a combination of the base metal and the solder metal. This is in addition to any mechanical or adhesion bonds. So the zinc is held to the base metal with as much force as its held to itself, as long as the formulation is correct to be able to wet the base metal. So now, we have a tapered plug of solid metal bonded to thousands of wires inside. When you apply tension to it, the taper wedges it deeper into the socket, which compresses the plug of metal, squeezing down on the wires inside it. Since the potting metal is a little bit soft, it does compress the tighter it is pulled on, creating a very tight wedging action on the cable strands. As long as it is done properly, you can't get corrosion inside the plug, and the wires can never slip out.
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  36.  @PistonAvatarGuy  as for the SLS being a completed design, why do you think they keep having delays? They are making iterative changes too, just using multi million dollar jigs that have to be scrapped, and having to rebuild custom buildings for the changes. The built a custom rolling gantry for the test unit, and will have to build another later for the full size SLS. It's working on the same process as SpaceX, just with massive overhead and slow bureaucracy. And the one they are almost done building now, which then has to go through months and months of testing after transporting it to a different congressional district, is just a test prototype which will be totally destroyed in the test process. As far as I know, they haven't even begun building the next one which will be prototype number 2, and they haven't started building the upper stages that are able to do the actual exploration missions. So no, it's not a final design, it's still in the prototype and testing phase. What SpaceX does differently is cut out all the pork, let the engineers build something, test it, build a better one, test it, and keep going until you get something that works right. That's how they got Falcon 1 reaching orbit on the 4th attempt, to Falcon Heavy with landing boosters, and then a flying water tank, and now this, in 10 years. And while you may have a bad opinion about it, their track record is pretty good at actually doing what they set out to do. And if one gets destroyed in the process of testing, well, every SLS built is going to be destroyed, so what's the problem? Lol And they will keep iterating until they get it right. And if Raptor has problems that haven't shown up in testing yet, they will work on it until they solve it. And by letting the engineers do what they know, and cutting out the bureaucracy, they can work through this process in days and months, instead of years like nasa and contractors do.
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  46.  @scottmanley  as someone who long lived in typical California terrain where underground would be most useful, and also worked in construction and underground utilities in those areas, the reason they don't do it is because it would be incredibly expensive, and require cutting swaths though the land about the same as putting an oil pipeline in. Most of the California hills are rock, and digging trenches of any size either requires a very long time with large hydraulic hammers on giant excavators, or blasting. Neither of which the neighbors would appreciate. In much of it the rock is too hard for breaking, and so would require blasting. And don't be picturing a 1 foot wide trench a couple of feet deep, if you are installing anything high voltage, you are going to be looking at a 3 to 4 foot wide trench, probably 8 or 10 feet deep, and all the material removed gets trucked away, and then it's backfilled with imported sand and capped with cement. There is no way they would be given the permits to do this, with the required extensive clearing and road building that it would require, and would take decades just to work through the environmental impact studies and deal with fish protection plans etc. If this were soft and level ground, it's only several times more expensive, but those aren't the places where the fire danger is high, which is the mountains and canyons and high places where the wind is highest, and where you are on shallow bedrock. Many of the lines currently at risk are installed using helicopters, and since there would be no way to install a oil pipeline through the same terrain, they would have to be routed miles out of the way, increasing the costs many fold again. When you look at the places that do underground utilities, you will find that they are mostly on dirt, and don't have much shallow bedrock to deal with, and also that they have much smaller areas, and so they aren't dealing with a 200 mile run through rugged mountains. There are places where it makes sense, and where they are putting it underground, but the majority of places where underground would be nice, it's not a practical option, and it's not just expensive, it's unbelievably expensive, and incredibly damaging to the environment. So I am not trying to defend pg&e, just giving my experience as someone who has done a lot of digging in those areas, and I watched a lot of pipelines being installed, and what they had to fight with. My little town up in the hills above the Napa Valley in many places has the road asphalt directly on the rock surface, and it's common for the water line and the gas line to be in a trench scraped into the bedrock barely below the asphalt, sometimes with the asphalt directly on it. (leading to frequent leaks lol) In order to put the power lines underground you would have to blast trenches through this everywhere....
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  51.  @guidedmeditation2396  you are correct that NASA used experienced seamstresses to sew the gloves and fine details on the Apollo suits, and some of them were probably grandmothers, but the key was that they were the best seamstresses around, hired out of the garment industry because there was no aerospace industry at the time, and able to make the perfectly fitted suits accurately. But you have to remember that the suits had many layers of different materials, for comfort against the skin, insulation, debris protection, ventilation, bellows for mobility, etc, and then they had a pressure layer over the top of it. In addition, are you unaware that you can seam seal stitches? Between stitching through wet sealant, applying flexible sealants over the top of the stitches, applying seam sealant tapes over the seams, dipping the entire thing in liquid latex, etc etc, there are countless ways to seal needle holes and prevent leaks. And the Apollo suits didn't function flawlessly for a long period of time, they were each used once and then replaced. No Apollo suit went to the moon twice, because they wore out too fast. The part that you don't seem to understand is that while the seamstresses may have been sewing the suits together, the materials they were using were all custom designed and manufactured by teams across the country developing and testing new materials, and then after the ladies would sew a suit up, it would be sent to a giant lab and extensive testing done on it. Then the life support systems would have to be designed and built and tested, because these aren't just some fancy set of pajamas they are sewing up, it's a self contained miniature space ship, and the ladies were only responsible for assembling the soft parts of it, not building the entire thing. So if you think that they could build another one by getting done grannies in a sewing circle, you are missing the thousands of workers in labs and factories across the country that it took to make each suit, and so don't understand how expensive the Apollo suits were, or why new ones are so expensive.
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  75.  @A.Lifecraft  you seem to think that because you "studied physics" that you are smarter than 100 years plus of engineers and scientists and and end users finding every possible way to make one of these terminations fail. There are only two ways to terminate a wire rope where the termination is stronger than the rope itself, and doesn't derate the cable due to bending it etc. You 100%of the cable strength with pressure swaged ferrules and fittings, and with Spelter poured ends like this (using either a special epoxy or zinc/white metal/Babbitt metal, etc). Since hydraulic ferrule presses are a newer invention, and a major investment, Spelter sockets are one of the most common methods to terminate cables, including bridges, crane support cables, rigging slings, barge tow lines, etc, and it's been that way for a very long time. Tug boats will carry the stuff on board so if one of their giant tow lines gets damaged, they can easily cut off the bad end and put the Spelter socket back on the end. They have been extensively tested and studied, by people with actual degrees, and the physics of how they work are well understood. I went to Crosby and did some reading on their research, and I was wrong on one point. It's almost entirely the wedging action of the tapered zinc or epoxy plug that holds the cable in. Using epoxy for instance, when it cures you have two forces acting on the wires, adhesion and friction. They found that either the adhesion or the friction by itself was adequate to seat the plug and create enough wedging action to break the cable. However, if the plug didn't seat, the adhesion was not enough to hold the wires in, so these fittings are always proof tested after installation to ensure it seats the plug. So they found that even if the wires were oiled so it would seem that they could slip out easily, there was still enough friction to pull the wedge in and exceed the breaking strength of the cable. And that's the key point of this termination method, it holds the cable securely enough that the cable will break before it pulls out of the potting material, because of the wedge shape squeezing tighter the more load you add to it. You also seem to think that zinc is a lubricant, which makes me wonder if you understood how Babbitt bearings worked, and I also suspect that the bearings you referred to are actually Babbitt metal, which is tin based, and not zinc. Babbitt works by having hard crystals in a soft matrix, providing a low coefficient of friction when used with a polished harder shaft. And it requires oil to make that happen. If you run steel directly on babbitt, or zinc, it will tear it up, because it's not a lubricant. And crimped wire rope wires are not a smooth surface, and so will not easily slide out of metal poured around it. The fact that it has held for 30 years indicates that it was a proper joint, or it would have failed when originally loaded. Also, the fact it failed after 30 years points to the likelihood of corrosion outside the potted section, which is a known and likely issue. So instead of saying that one of the best and most thoroughly tested cable termination methods is a bad idea, maybe we wait for more data on the actual failure.
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  110. What many are missing is that the "minor software issue" is actually a serious ground up design problem that needs to be completely redesigned with different assumptions and criteria. They designed the system in a way where a single point of failure would cause the capsule to blindly do things regardless of any other inputs. It was simply responding to a fixed sequence based on the clock, and that means that we won't find out what else has zero fault tolerance or error checking, until it's actually put to use. I do industrial automation, so I am familiar with making large machines perform actions automatically, and you always want to verify your inputs and have some form of error checking or redundancy. For instance, the easiest one. If the clock says 11, before you do the step for 11, you verify that the previous steps have been completed. Or, before changing the orientation of the craft, you check the star trackers and GPS and verify where you are supposed to be with where you actually are. You can also compare SECO/deployment with the download clock time and verify that they match the schedule. But, just like with MCAS, it is a system with lots of power and no way to verify or error check what it's doing, so one input is all it needs to jump off the bridge blindly. And you can say that it could be overridden by the crew and everything would be fine, but since they obviously failed in basic design and ground testing, designing a system that could fail so confidently, and not testing it adequately to discover this problem, but that is not a valid assumption, because the rest of the system is designed and tested by the same team, and so it would be surprising if this blind and Fail Dangerous system didn't have other similar flaws and bad assumptions and improperly tested aspects, that could have terrible consequences without a review as detailed as the MCAS is receiving.
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  119.  @MillionFoul  you just described for me WHY they need to do actual testing, because the systems are so interrelated, actually testing different failure modes is the only way to verify that a new system is safe! You are talking about a plane or rocket system like its a phone app, where you can just test it in the simulator, and then publish it, and then fix the bugs that show up, rather than testing it with different model phones and different OS versions. It's fine for an app, not for a plane. In addition, it was because of lack of testing and verification that they decided that MCAS wasn't a Catastrophic level system, because if they had looked at the more powerful version that shipped, they would have realized that it was capable of catastrophic failures. But because they had very low levels of oversight and were happy to ship stuff with minimal verification and testing, it never got looked at after it was strengthened. If they had been paying attention, they would have realized as soon as they discovered that they screwed up on the AOA disagree indicator, that the lack of it would leave the flight crew with no way to recognize an MCAS issue, especially considering that no one even knew MCAS existed, and someone would have realized that maybe they should alert the customers that the feature they were training for, didn't actually function. But they decided that it wasn't needed, and so were going to include it quietly in a future update, which never came... As to your claim that the crashes were mostly pilot error, you are assuming that the procedures and memory items are infallible and accurate, and they aren't. They attempted to follow the runaway trim procedure, but they were unable to, because the manual trim wheels are not able to be cranked with the control surface at that high an angle, because the aerodynamic forces are too high to overcome manually, and they were too low altitude to be able to dive while they cranked it to take load off of it. So when that didn't work, they re-engaged the trim cutouts, and were able to use the trim switch to recover. Now, if Boeing/FAA had actually told anyone about MCAS, the procedure would be that if the AOA disagree indicator was on, and you had runaway trim, to use the yoke trim switches to get the proper trim, and then turn the trim cutout switches off. And everything would have been fine. But because they decided not to tell anyone, and instead rely on a 50 year old procedure that hadn't been tested under extreme conditions, and that made their untested software unable to be overridden, causing hundreds of deaths. And claiming that the pilots didn't follow procedures that wouldn't work under those circumstances, in a failure mode that they had no training for, because a company shipped untested and unverified software without telling anyone, shows that you have bought into their culture, that not testing extensively is all right, because it costs too much to do proper testing. And it's rich that you make this claim after all the other stuff has come out and the Max failures, both of internal and external oversight, and now seeing the same thing play out with Starliner, with major lack of testing, as well as lack of internal and oversight. The whole system is broken if a company is this lax about testing their actual product, and the supposed oversight agency lets them do whatever they want, to save some time and money. Hopefully this tragedy, and the Starliner comedy (since no one was on it) will get NASA to put Boeing back on the leash, and get the world airline regulators to get involved in making sure that the planes are safe, even if it costs more money.
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  135.  @A.Lifecraft  it sounds like maybe you have also heard of trapping monkeys by putting chunks of salt etc into bulb shaped holes? Lol The reasons that they don't just solder the wires around the edges is, 1, you would be relying entirely on the shear strength of the solder to hold the load, and 2, the cables are giant, and you would have to have a very large ring to be able to terminate every strand to the anchor ring. Instead, the cable end is simply expanded, like the sticks on a witches broom, and unlike my analogy with your hand, the center is also full of strands, all evenly spaced apart. So basically you are forming the end of the cable into a wedge shape, and then filling it in with the potting metal to hold that shape. It doesn't rely on the sheer strength of the metal, which is why it's a tapered shape, so that the tension increases the gripping force on the wires much like a wedge and socket, but it's even stronger, because instead of simply using friction to hold the wires, it also uses the intermetallic bonds to make the wires become part of the wedge. In addition, and very important for such a large cable, it evenly distributes the load across all the strands and compresses them all evenly. In a wedge socket design, the friction is only on the outer strands, and it loads the core unevenly, while relying on bends in the cable to transfer force, leading to high stress points, cable, bundle, and strand deformation, and thus loss of strength. This method protects each strand, does not require any bending or deformation, and equalizes the compression forces and friction and actual metallic bonds across all the wires.
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  142.  @travcollier  in other words, Peter is trying to make his decision not to copy SX sound reasonable. Same as ULA dismissing reusablity. But you have to look at two other factors as well. The reason Peter ate his hat is because he realized that if they were able to reuse rockets they could save money, by reducing the number of rockets they had to build. In other words, reusablity was cheaper than building a second factory. So the recovery plan used a parachute and a helicopter, which is cheaper than a barge landing, for a tiny rocket. It's not an option for SpaceX, because the Falcon 9 is MUCH too large to catch with a helicopter. So Peter's new bigger rocket design is designed to do propulsive landing, and he is talking about how much money he saves by not using a barge, but at what cost? SpaceX doesn't need a barge, they have RTLS pads right next to the launch pads, and they can save so much money. But at what cost? RTLS takes away a lot of performance from the rocket, so less payload to orbit. So while Peter might be saving money with no barge, he's also reducing the maximum payload he can carry for every flight, unless he goes full disposable. So basically SpaceX has to look at each payload and flight and decide if it's cheaper to run the barge out there, or just dispose of the rocket. And so far, between the actual cost savings of reuse, combined with the increased launch cadence allowed without building a new factory, the barges are a good investment. But then, you have to remember that SpaceX wants to get away from the barges as well, which is where you need Starship, because it's large enough to RTLS with any size payload, so you are not limiting your largest payload by RTLS. You can launch an actual big yellow bulldozer to the moon with it! And if someone made a large enough payload, they could do fully expendable and only be out a few million dollars in stainless steel lol So Peter is talking up his personal choices, but not presenting the full picture, such as how much RTLS limits his payloads. Falcon 9 ride share with that 3rd party custom space tug to deliver small sats to exact orbits will be cheaper than Neutron anyway, so it's only benefits are a little more scheduling customization. And then Starship should be even cheaper still. But, I suspect there are enough customers who don't want to give Elon money that Rocket Lab has a chance at survival lol
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  147.  @Bourinos02  a single bus line was not an option at the Las Vegas convention center, because there is no room for it. Otherwise they would have simply bought a couple of busses. And the reason so many casinos want the system to go to their casino is because traffic is already so bad that the busses that run the Strip can take an hour to get down it. Even 30 mph is several times faster than the options. You then compare some early concept art with the early prototype system, and don't see that the design matured since that early artwork, and also that the current system of human driven cars is only temporary. As the demand increases, higher capacity pods specifically designed for tunnel operation will get built, but I don't expect to see that until after Giga Texas gets finished, since Fremont doesn't have the capacity to build any new designs. And as the FSD software improves, it will be able to take a greater role in the driving. And as longer straight tunnels are made, such as down the Strip, speeds can increase as well. So all of your current complaints are that it's not all happening instantly right at the start, and so doesn't yet look like the end goal. When Elon says "next year", he's saying that he thinks something can be achieved in that period of time, but he makes clear that he is speaking of the goals he has, and that there are often delays and setbacks. Look at the Crew Dragon system. Years of delays, lots of "vapor ware" accusations, but now working beautifully. Same with Starlink and Model 3 and countless other projects that he has worked on that were delayed and called impossible, and are now part of daily life. And I was extrapolating that Starlink is probably over 2 hundred thousand users by now as they continue shipping dishes as fast as possible, but my point is that it's in daily use across the globe, so can't really call it vapor ware any more.
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  164.  Joe Chang , yes, like I said, gravity and magnetism were similar in that they both decay with distance, and I used magnetism as an example because it is something that we can feel and experiment with instead of just being an abstract theory. As far as long distance radio data transmission, yes! I am a Ham Radio operator, and also spent a few years in broadcast radio, including installing and tuning towers and the antennas on them, so I know a few things about the subject. You need 2 things you need to get a signal that far. A high gain antenna at each end, and an error correcting data format for when interference overpowers the signal briefly. If you take 23 watts and put it into a standard whip antenna (like a car radio antenna for instance), that power is going to radiate in all directions equally, and so any one direction is only going to get a tiny fraction of that energy. That is a zero gain antenna. But if you modify they antenna a little bit, such as putting reflector elements behind it, or the ultimate, using a dish antenna, you can point all that energy in one direction, giving it "gain". An old rooftop TV antenna is an example, having reflector elements behind the main element. A parabolic dish antenna is the highest gain you can have basically, which is why it it used for satellite dishes and microwave telecommunications links etc. So what they do for the deep space missions is have a parabolic dish antenna that is kept aimed back at earth, and then since the atmosphere attenuates radio waves, and there is a lot of rf interference on earth, they have a network of satellites called the Deep Space Network or something like that, and they have even bigger dish antennas pointed back, and the combination is enough to allow communication at those distances. It is extremely slow, because the data rate has to be kept very low at those distances, but the signal gets through, and if some drops out, it gets resent. Then the Deep Space Network satellite relays it back to the earth ground station.
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  167. Scott, one thing I think you misunderstood is the radio communication issue. On the teleconference they really tried to talk around the issue, but finally got asked enough times what the problem was that they very reluctantly said more than just "an elevated background noise floor in certain geographical areas". From what I heard on the teleconference, they said it was a loss of communication with TDRS, probably because of cell towers. Now, I am a radio guy, and I don't know exactly what system they had set up, but if it involved the TDRS satellite network, then it would either be a ground station uplink to TDRS, or a connection to a NASA TDRS ground station. If they are communicating directly with the capsule, they wouldn't need TDRS, so I am guessing that it was a TDRS uplink site, probably something Boeing built especially for Starliner. And didn't test... Cell towers broadcast relatively low power, and directed out horizontally, so they don't waste power aiming for the sky. Ever try to send a text from a plane? Lol You don't get reception even directly over a tower usually, because the lobe is horizontal. So there's no way that a cell tower would reach a signal to LEO. It's just not powerful enough. So, if a cell tower caused interference, it was with ground based equipment, not space based. And that means that they probably didn't design proper filters and interference rejection into the ground systems, which is standard practice for any radio system installed near possible interference sources. In addition, if it was a ground station connecting to TDRS, then they could test it ahead of time, to verify it connected. Oh, and certainly they would have known that they were using the same frequency band (or near harmonics of) the nearby cell towers, because that's part of a basic site survey, and that's all in the public FCC database. So if cell towers indeed causes this interference, unless one of the cell transmitters had just gone nuclear and was pumping out highly elevated levels of noise and hadn't shut down yet, then it means that they didn't do a proper site survey, they didn't design the system with intermod and interference rejection and protection and filtration, they didn't test the system to see if there was a lot of noise from nearby frequencies, and didn't test the link to TDRS to make sure it was stable. And if they messed up THAT badly, I understand why they REALLY didn't want to admit that cell towers had messed up their TDRS uplink lol
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  172.  @hawkdsl  haters by their very nature get all the facts wrong. He was not kicked out of PayPal, he was replaced as CEO just before it was sold to eBay. I agree that SpaceX works so well because of Shotwell, which is exactly why Elon gave her the job, because they work well together, she keeps the company working smoothly so he can focus on developing new technologies. Without both of them SpaceX would not be what it is today. And if you think that SpaceX could push technology so far without Elon, how come no one else is doing so well, and how come before Elon hired her, Shotwell was just a regular engineer and manager at her previous jobs, and didn't make any amazing progress on anything before joining Elon? Elon certainly has a cult of personality, but acting like that's all he is shows a deep level of denial of the accomplishments he's made and how integral he is to the companies he starts and runs. And countless engineers and scientists have testified how in awe they are at his grasp of engineering and science, and how quickly he learns new things. People who have spent a lifetime studying a particular subject, and they are in a meeting with Elon deciding how to proceed on a project, and he asks the right questions to be able to understand the situation, and then makes a decision that turns out to be the right one. There's a reason SpaceX and Tesla are the most popular places for engineers to work, because Elon has created an environment where engineers can shine and develop amazing things, and with few exceptions, the ones who have worked with Elon say he's a great engineer. You seem not to understand what the T Mobile service is, or how it compares to Starlink broadband internet. They will use the same satellite buss, but nothing else will be the same. It's literally an expansion pack bolted to the Starlink satellite. Different antennas, different frequencies, different power levels, and different ground based hardware. The T-mobile service will only work for slow low bandwidth text message transmission, and possibly eventually phone calls, literally turning the satellite into a cell tower in space as far as the phone knows. Starlink broadband internet service on the other hand is a high bandwidth that provides faster internet service than most cable internet today, and works everywhere in the world (when the laser links are fully rolled out anyway.) If you consider that must of the cruise lines and airlines working on using Starlink for data connections as a "niche" service, that's on you lol Already it's what people across every country are clamoring to get if they live in the country, or half a mile past the end of the cable company internet cable that wants $30k to extend broadband to the house. And as they expand converge to places like Africa and Australia and South America, where internet infrastructure is not built out to most of the country, they will become the primary or only provider of internet access to great swaths of the world. I know lots of people up in Canada for instance that are snapping up Starlink because all they had before was slow access, or Direct TV type internet access which is nearly useless, and now they can have stable and high speed access for about the same price. But the Starlink service is totally different from what T-mobile is talking about, because it requires a large antenna and receiver on the ground, and uses completely different frequencies than cell phones, so the T-mobile deal doesn't give SpaceX more or less access to customers, because the orbital cell tower will be accessed through the cell phone carrier, while the internet service will be through SpaceX directly. So anyway, do your research if you want to sound like you know what you are talking about!
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  196. I remember my dad talking about seeing the Echo satellite go overhead. He went on to program for and operate a couple of the early tube and transistor computers including the ERMA at BofA in LA, basically the original Online Banking, and what made the magnetic ink on checks a thing so it could read them automatically. One fun story he told was that the computer developed a glitch, some circuit was going out and it would lock some board on the back end of the computer up, and the operator would have to get up from the control console and walk all the way around the racks, open a panel and flip a momentary reset toggle switch. The GE technicians had looked at it and just gave the instructions to keep flipping the switch as needed, and didn't seem to be in a hurry to repair it, so late one night when my dad was working alone processing checks, the thing kept locking up, and he would have to walk around to the other side of the racks and flip the switch, then walk back to the console and hit Continue, and it was wasting a lot of time, so he grabbed a roll of string from the secretary's desk, tied one end on the reset switch, through a vent slot in the cover panel, and then ran it over the top of the racks and tied it to the console, so every time it froze up he could just pull the string and hit the restart button and lose very little processing time. The next morning the manager gets into work and yells at him for the string dangling over the room, and my dad tells him how many minutes of processing time it saved that night by not having to walk back every time, and the manager simmered down. Then the manager went and called GE, and very soon the tech came over a little red around the ears and replaced the faulty board!
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  200.  @sunside79334 , lightweight linear position sensor hydraulic cylinders are a very common off-the-shelf product, as are the linear sensor components for inclusion in a custom cylinder design. It is one of the most preferred means to measure position, because it is completely protected from external interference or damage, unlike rotary shaft encoders or external scales. Since this is being controlled by a computer, all you have to do is tell the computer what angle of grid fin equals what cylinder position. If you did a rotary encoder on the shaft, you have to find space for it, add complexity to the shaft, either a disk mounted to the shaft, gears to operate a parallel axis rotary encoder, or try to fit 4 of them in the center between the end bearings and the shafts and the stage seperation cylinder, protect it from damage (it would need to be a high precision encoder, which means very tiny slits which are susceptible to debris clogging them leading to an incorrect reading), and adding additional components to the system. Then you would have to put that data into the computer, which would have to count pulses and then calculate rotary position. The linear approach prevents calibration errors or position error, because instead of counting clicks, it can tell what part of the sensor the piston is at. No, having it built in to an existing component that very possibly is an off the shelf part, where it is protected from space and heat and debris is a very smart thing. Also, if they wanted pressure sensors, they would need to have 2, one for each end of the cylinder since it is a double acting cylinder. These would probably be mounted flanking the valve if they needed them, but they aren't dealing with high forces here, so they don't really need pressure sensing. As for the plumbing, it is really simple. On the lower left side, 2 metal lines come from the hydraulic pump. One is Pressure and one is Return. (the smaller one is Pressure) They connect to 2 square manifold loops, a larger and a smaller, and then there are 4 sets of red hydraulic hoses coming off the 4 sides of the manifolds to the valves, which are mounted on the cylinders. The reason for the square loop manifolds took me a second to figure out, but it is to smooth hydraulic flow and prevent pressure drops. Each valve and cylinder is separately controlled, and as they cycle, the hydraulic flow needs vary widely, but since they tend to move in opposed pairs, with one extending while the other retracts, and it takes a lot more fluid to extend a cylinder then to retract it, by allowing fluid to go either direction around the loop, it allows fluid to bypass lower flow cylinders to get to the higher flow cylinders. If it only went 3/4 of the way around, then the cylinder on the far end would be starved if 2 cylinders before it were in high flow demands. So by adding a few inches of pipe and closing the loop, they were able to reduce the size of the manifold pipe, and avoid pressure drop issues. I call that genius! There is no need to try to hydraulically synchronize cylinder pairs, because that is done through positive position feedback through the computer, and since it is flying the rocket with the fins, it does not always want them synchronized. If they were hydraulically synchronized, you would see lines going directly between the cylinders. So, I am also quite impressed with this design, because it is simple, and uses standard parts and systems that are well understood and reliable, except maybe for the hydraulic pump, which is probably some special helium driven gas over hydraulic unit, which always have problems lol
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  201.  @firesculpturevideo  a servo hydraulic valve is a specific part. It is designed so that the valve can be opened part way, rather than the normal valves that are either all the way open or all the way shut. It is normally only used on larger valves, but it is used when the continuous speed of operation of a cylinder or motor is needed, rather than just position. So to position grid fins, you don't need smooth gentle variable speed motion, you can pulse the valve to get the fin to the needed position, and so the valve just needs to be on or off. If you are dealing with a larger device with a lot of inertia, then you might need a servo valve, so you can command it to 20 percent to start the load moving, then to 50 percent, then to 80 percent, and finally fully open, etc. The servo in the name refers to the valve operating mechanism being something other than on or off. I have worked with these types of valves using either direct magnetic core designs, or rotary motors operating the valve. Now maybe in some fields some people refer to position controlled hydraulics as "servos" because it reminds them of electric servos from airplanes or radio controllers, but that isn't the normal name for having motion controlled hydraulics, because other than occasionally using a servo valve, it isn't really the same thing as a servo. Oh, and the reason servo hydraulic valves are not very common is because they generate lots of heat, and heat kills hydraulics. Normally if you need to control the speed of a cylinder, you use some form of pressure control or variable output pump, etc. Anything that uses friction to control flow is like using the brakes to control the speed on your car, instead of taking your foot off the gas. Not a good idea, unless it is only occasionally needed lol
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  218. 4:44 - Run. Do not walk, RUN AWAY! I am a rigger, and that cable makes me weak in the knees... Death waiting to happen. In regards to hanging guys below helicopter, when a cable snaps, it can recoil UP and take out the helicopter too. The only safe way to deal with this is to set charges where the cable stays from the top of the towers attach to the outer ring of ground anchors, and sever all the cables at once so that the weight of the truss pulls the now unsupported towers inwards. This keeps people as far from the danger zone as possible (unless one of the cable stays snaps at the top of the tower and recoils back to the ground anchor). Basically getting closer than the length of the cables is dangerous. The only safe way I can see to salvage it is to get someone like Mammoet (just the best heavy move company in the world) to come in with either an unlimited budget, or donating their services, and set up giant crane towers around the outer perimeter, and then snake giant cables across underneath the truss, and then winch them up to cradle under the truss, removing the weight from the existing cables without having to get any workers underneath it. Once it was supported in the cable basket, then you could start replacing the cables. But this dish is in the middle of the jungle, and getting the massive amount of giant equipment up there would probably require building new roads, new ports, and take months getting billions of dollars of specialized equipment, designed, fabricated, shipped from across the world, and hauled up into the jungle. Building a new one is probably cheaper....
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  252.  @DC2022  what you and Scott are missing is that the "minor software issue" is actually a serious ground up design problem that needs to be completely redesigned with different assumptions and criteria. They designed the system in a way where a single point of failure would cause the capsule to blindly do things regardless of any other inputs. It was simply responding to a fixed sequence based on the clock, and that means that we won't find out what else has zero fault tolerance or error checking, until it's actually put to use. I do industrial automation, so I am familiar with making large machines perform actions automatically, and you always want to verify your inputs and have some form of error checking or redundancy. For instance, the easiest one. If the clock says 11, before you do the step for 11, you verify that the previous steps have been completed. Or, before changing the orientation of the craft, you check the star trackers and GPS and verify where you are supposed to be with where you actually are. You can also compare SECO/deployment with the clock time and verify that they match the schedule. But, just like with MCAS, it is a system with lots of power, and no way to verify or error check what it's doing, so one input is all it needs to jump off the bridge blindly. And you can say that it could be overridden by the crew and everything would be fine, but since they obviously failed in basic design and ground testing, designing a system that could fail so confidently, and not testing it adequately to discover this problem, but that is not a valid assumption, because the rest of the system is designed and tested by the same team, and so it would be surprising if this blind and Fail Dangerous system didn't have other similar flaws and bad assumptions and improperly tested aspects, that could have terrible consequences without a review as detailed as the MCAS is receiving.
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  325.  @spacedout5692  you know that what they mean by "they lost the technology" is that they designed amazing things and kept all the blueprints, but because it was a bunch of young guys operating in skunk works/startup mode at the time, the team actually building the engines and such were having to solve problems on the fly, and having to develop new techniques to build things, and making tweaks to the blueprint design to get it to work right, and since it was the same team that continued building them, no one thought to document and preserve the techniques and specialized skills they had developed, and so when those guys retired and died, the knowledge of how to make it work reliably went with them. Teams since have built engines based on the blueprints, and found that they differed slightly from the remaining engines they compared them to, and without knowing the exact techniques used to build the pieces, they were not able to exactly recreate it, and decided that the amount of time and money to try all the different techniques until they figured out the right one, and how to apply it, would be more expensive than designing a new engine. So it isn't so much that the technology was lost, it is that they relied on human craftsmanship rather than technology, and the craftsmanship wasn't passed down, as the programs were canceled and new ways of doing things were developed. It's just like we don't know how the Egyptians built the pyramids, but we could achieve the same results now, just using different technologies.
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  383. ​ @maskie4189 the pad got damaged on the first launch because Elon didn't want to wait for the water deluge system which was already under construction, and they knew it would sustain some damage, it was just more than expected. But they installed the deluge system and it works fine now. The second launch had upgraded quite a few things that they learned from the first launch, and then they found several other issues that they improved on the third launch. And all the issues are related to it being fully reusable, because the entire rocket is designed differently to achieve this goal. If they weren't going for reusability, the rocket would use composite tanks and simple engines and not need all this extra complexity. And if they were not working on reusability, then the third launch would have been a success, because it launched and reached orbit just fine, it was on the reentry that it burned up, but guess what? Every other orbital class rocket before Falcon 9 also burned up on reentry! And every second stage, even for F9, has also burned up, so it's only a failure to successfully reenter, the launch was a success. In any case, SpaceX is pushing the envelope with the sole focus on making a reusable rocket, and they are doing it by launching rockets to test them, not waiting until they are positive it won't blow up, which is why they haven't bothered putting a payload on yet. This lets them move faster because they aren't afraid to break things. But the most important part of this, is that none of the failures have been identical, and each flight they have gone further and made more progress, and if they continue that trend, they will be reliably going to orbit before BO, and then start getting success recovering the rocket as well. Remember, people were saying the exact same things about Falcon 9 when it started flying and blowing up, and now it's the only Human rated rocket in the US, and they are using reused rockets to launch astronauts, so while you may not like their design and testing methods, they are effective and they have a proven track record of being able to pull off things that people say are impossible.
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