[HN Gopher] The big automotive semiconductor problem
___________________________________________________________________
The big automotive semiconductor problem
Author : picture
Score : 50 points
Date : 2022-03-30 17:23 UTC (1 days ago)
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| chmod600 wrote:
| What devices are left that are fairly normal (that normal people
| might interact with in a given week), mechanical or
| electromechanical, have at least modest complexity, and have no
| microchips?
|
| Locks? Guns? What else?
|
| EDIT: perhaps an extra requirement that it's fairly durable, i.e.
| easily lasts ten years of normal use.
|
| EDIT2: maybe it should also fit the requirement that it's a
| current model in production and that you don't have to go out of
| your way to find a non-semiconductor version.
| TacticalCoder wrote:
| > EDIT: perhaps an extra requirement that it's fairly durable,
| i.e. easily lasts ten years of normal use.
|
| Moka pot / press to do coffee. Lasts ten years easily.
|
| All my tools and powertools. Some of them are old, really,
| really old (I've got my "favorite" screwdriver which is 30
| years old). Some are manual, some require electricity.
|
| Using daily my mechanical watch and my floorstanding
| loudspeakers which others mentioned. The loudspeakers are
| hooked to an amp to DAC to computer, so the "chain" is not
| exactly microchip free though.
|
| EDIT: also various types of chimneys and stoves are still
| microchips free. Although there's a move towards freaking
| "smart" pellets stove that require electricity, WiFi, that are
| noisy but, hey, they're _programmable_. Thanks but no thanks.
| Good old chimney for me.
| takk309 wrote:
| Tools for sure, power and hand. Aside from a voltage
| regulating circuit most power tools are super simple, make a
| thing spin to cut other things. I also love using proper hand
| tools like a plane or hand saw.
| aimor wrote:
| A lot of musical instruments come to mind.
|
| Also many plumbing related things in a house such as faucets,
| temperature shutoff valves, toilets.
|
| Manual kitchen gadgets are usually pretty simple but still
| interesting. Peelers and slicers, pasta machines, oil expeller,
| scales.
| HeyLaughingBoy wrote:
| Interesting question.
|
| * it's surprising how many dishwashers still use spring-loaded
| timers to sequence their operations. Although at this point
| mine is 19 years old so maybe that doesn't count.
|
| * Likewise, my iron filter is sequenced by a mechanical timer
| (run off an electric motor), but my water softener's controller
| is fully electronic.
|
| * A lot of houses still have mechanical mercury thermostats.
|
| * The flush valve in your toilet tank is completely mechanical
| and surprisingly complex. Once you take it completely apart you
| realize that there's more to it than just a float that shuts
| off a valve.
|
| * I'm always amazed by the centrifugal clutches in weed
| whackers and small gas-powered lawn appliances.
|
| Should be more things I can come up with...
| chmod600 wrote:
| Toilets are a great example, thank you.
| takk309 wrote:
| Older clothes washing machines, maybe? Though, they are getting
| replaced by machines with ic type controllers too.
| selectronics wrote:
| Mechanical watches fit the bill here. Not everyone has them,
| but they are common enough
| pas wrote:
| I'm still mesmerized by microwave ovens. Sure, all of them now
| come with a chip, but that part is guaranteed 100% shit (I mean
| who the fuck designs these unergonomic monsters anyway!?)
|
| But the magnetron in them is complex, has to be machined to a
| high precision, yet they are a pretty old piece of completely
| analog technology.
| frosted-flakes wrote:
| Regarding microwave oven ergonomics, the best one I've seen
| doesn't have old-school dials, but a touch-sensitive slider
| bar. You may think this is bad, but it works very, very well.
| The front of the microwave has the time display, the time
| slider bar, and two buttons: stop/cancel and start/+30sec.
| Open the door and there are a few auto cook options and power
| level options. There is no number keypad at all; the slider
| bar gives you both very fine and coarse-grained control,
| depending on how fast you slide across it. It's all very
| intuitive, and I was very impressed with it.
|
| https://www.lg.com/us/cooking-appliances/lg-LMC0975ST-
| counte...
| frosted-flakes wrote:
| Push lawnmowers, dirtbikes, or chainsaws typically do not have
| microchips, and they are all quite complex. Also, old elevators
| often had purely relay logic, and I've heard that it is often
| more cost-effective to repair old elevators than to replace
| them outright, so if you live in a really old building the
| elevator might still be click-clacking away.
|
| Then there are washing machines and dryers. Most new models are
| stuffed to the guts with computer chips, but older styles are
| still available, new (Speed Queen) or used (appliance
| refurbishment shops). Old ones are purely electro-mechanical,
| with some rather ingenious timer boards that do a lot with only
| a few contacts, a tiny motor, and a large resistor.
|
| (I helped repair an old dryer a few months ago: the large
| resistor is for the dryer's auto dry mode. The wetter the
| clothes, the more power the heating coils will draw through the
| resistor, which lowers the voltage of the power the timer motor
| receives, slowing it down. Once the clothes start getting dry,
| the voltage goes back up and the timer speeds up again.)
| chmod600 wrote:
| "dirtbikes, or chainsaws typically do not have microchips"
|
| Interesting, good examples.
|
| "The wetter the clothes, the more power the heating coils
| will draw through the resistor, which lowers the voltage of
| the power the timer motor receives, slowing it down. Once the
| clothes start getting dry, the voltage goes back up and the
| timer speeds up again."
|
| Sounds like this kind of ingenuity is on its way out, though.
| I expect the vast majority of washers/dryers have
| semiconductors in today.
| sidpatil wrote:
| > Push lawnmowers, dirtbikes, or chainsaws typically do not
| have microchips, and they are all quite complex.
|
| Is this still the case for the newer battery electric
| variants of these tools? The battery itself will have
| microchips for the BMS, and if those tools are using BLDC
| motors, those motors will contain a controller likely
| implemented with microchips.
| frosted-flakes wrote:
| Obviously battery-powered tools will have chips. But at
| this time those are mostly still gas-powered.
| [deleted]
| pySSK wrote:
| Obligatory Sunbeam Radiant Control toaster video since you
| mentioned old appliances: https://www.youtube.com/watch?v=1Of
| xlSG6q5Y&ab_channel=Techn...
| aidenn0 wrote:
| Can opener
|
| Stapler
|
| Loud-speakers
|
| Shop vac
| chmod600 wrote:
| "Loud speaker" surprises me. Are you sure they don't use
| semiconductors for amplification?
| frosted-flakes wrote:
| Speakers? Definitely not. The amplifier will, but not the
| loudspeakers. That's basically a magnet, a coil, and a
| paper cone.
| renw0rp wrote:
| And, as someone mentioned above, usually a RLC filter
| michaelt wrote:
| Cheap loudspeaker products, like [1] often have built-in
| amplifiers.
|
| [1] https://www.amazon.co.uk/AmazonBasics-Computer-
| Speakers-Desk...
| HeyLaughingBoy wrote:
| There's nothing mechanically or electrically complex about a
| speaker. It's a coil and a magnet attached to a bit of
| paper/plastic.
| aidenn0 wrote:
| High-order crossover filter?
| HeyLaughingBoy wrote:
| Well, if we're going there, we might as well just delve
| into the whole Active Speaker thing and get into the
| amplifiers.
|
| But a basic speaker (driver) that's been around for
| decades is essentially a small linear motor: one moving
| part and very simple in operation.
| aidenn0 wrote:
| 2-way and 3-way speakers have been around for longer than
| I've been alive.
| stevenwoo wrote:
| Is gas water heater complex enough?
| frosted-flakes wrote:
| Gas water heaters often have control boards and displays with
| buttons. The only type that might not are the low-efficiency
| type with a pilot flame and room air intakes--but even those
| usually have forced exhaust fans that require some sort of
| smarts to know when to turn on.
| throwaway0a5e wrote:
| Your typical $400-$500 tank style gas water heater has none
| of those things. It has a PCB with some analog circuitry to
| do sparky magic to light the pilot light. A gas/propane
| heater or stovetop is basically the same thing in a
| different form factor.
|
| Tankless water heaters are necessarily much more fancy.
| frosted-flakes wrote:
| AKA low-efficiency water heaters.
| chmod600 wrote:
| Can you explain? Are you talking about inline water
| heaters as the efficient ones?
|
| I have only seen the tank style in the U.S. So it seems
| to fit, though I guess you are implying those will get
| replaced by something better.
| frosted-flakes wrote:
| High efficiency condensing water heaters still have a
| tank.
| froh wrote:
| My personal pet peeve theory is that automotive engineering
| missed the memo that the hard part of software based systems is
| integration and remote dependencies.
|
| All their engineering and supply structures have evolved from
| mass producing mechanical marvels which happen to have a few
| electrical and electronic E/E components, marvels and components
| which are hard to manufacture but simple to integrate ("plug
| together", essentially).
|
| At the core, their thinking goes "Creating components is
| expensive. Putting components together is cheap. Also minimize
| prototype scrap with extensive planning and scrupulous list
| checking processes. If parts don't work together you didn't plan
| well enough."
|
| And that leads to a culture that is the exact opposite of CI/CD,
| fail early, fail often, rebase or reintegrate continuously.
|
| Thus in the automotive SPICE and six sigma world it takes 2-3
| years to replace an ECU with another one with sufficiently
| similar specs.
|
| Also, they prioritize "economies of scale" over flexibility and
| time to market.
|
| For example a "gateway controller", a router and switch, routing
| and switching between ethernet and CAN, with some spare CPU
| cycles for centralized functions? 2-3 years. Now let's say you
| need 3 million of these devices per year (Volkswagen group,
| Toyota, Stellantis each make ~10 million vehicles y/y), and
| you'll produce cars with that same device for 5 years? Then cost
| savings of 10$ per device are equal to 150 Mio bucks. As a
| supplier you'll happily put 20 people on saving those 10 bucks on
| the "bill of materials" --- not adding cool features, no, saving
| some RAM, CPU, ... the boring and non-innovative side of
| "economies of scale"
|
| Now the device is cheaper but maxed out. So your OEM won't ship
| new functions. the OEM is also later to market. And the OEM can't
| replace the part as easily because the spare would have to be as
| damn dirt cheap as the original. Not alone would you have to redo
| all these micro optimizations --- the savings from the previous
| design wouldn't materialize against the lower volume any more.
|
| And that is, in a nutshell, imnsho, why automotive asks for more
| of the old parts instead of switching to a new board design with
| a next-gen CPU...
|
| To summarize: automotive deals time to market and flexibility for
| "economies of scale" and "automotive grade quality processes".
|
| Contrast that to an OEM who thinks like a software CEO... the
| software CEO understands that the secret to high quality is in
| CI/CD with outstanding test and validation pipelines. You seek to
| change any part of your system just at marginal cost. And then
| you can replace some ECU within 6 months.
| dclowd9901 wrote:
| > It would be a misconception to look at your standard internal
| combustion car as a fundamentally mechanical device. Today's cars
| are some of the most complex electronic systems mankind has ever
| made.
|
| As a car restorer, mechanic and enthusiast, yes. This is also why
| bringing a car in for service has ballooned in cost over recent
| years. Oddly, it's become remarkably _easy_ to chase down a
| problem in a car because the systems will just tell you exactly
| what's wrong. Now it's just a huge time sink to actually fix the
| problem because it's probably buried deep in the gubbins of the
| car and the parts are very costly.
| JKCalhoun wrote:
| > Automakers found that mechanical, hydraulic or pneumatic
| controls failed to achieve enough accuracy and consistency over
| each vehicle's usage life to meet these emissions tests. This was
| especially the case as the car aged.
|
| Decades ago, I owned an old Alfa Romeo that incorporated a
| complicated cam system to control the oxygen ratio to the fuel
| injection system. More complex than your typical 1-dimensional
| function of a cam, this cam was "two-dimensional" in its output.
| The cam follower was able to slide along the axis of the cam
| based on something or another (RPM? temperature?) and the profile
| of the cam varied from one end to the other. Now there's a pretty
| wild "mechanical computer".
|
| A mechanic though told me that over time the middle of the cam
| would wear -- a kind of "saddling" -- and engine performance (and
| probably emissions) would suffer.
| dclowd9901 wrote:
| Sounds a bit like BMW's VANOS or Honda's Vtec. Variable cam
| timing is super cool tech and a huge reason newer cars are so
| much faster than old cars.
| unregistereddev wrote:
| If described correctly, it is a different concept. Variable
| cam timing in the context of VANOS / Vtec / VVT refers to
| variable timing on the camshaft that controls valves.
|
| This sounds different, and I think it refers to mechanical
| fuel injection. Several automakers experimented with
| mechanical fuel injection in the 80's and early 90's, but I
| think the concept died pretty quickly. It was rather complex,
| failure prone, and less efficient than EFI.
| saiya-jin wrote:
| Every car engine loses gradually power with wear. Top gear
| famously showed this multiple times with their older car
| episodes. Usually it was in 20-30% range.
|
| Basically new car is a 100% system and from first kilometer /
| month of ageing and exposition to elements various items go
| down the hill. Each car type had its own set of reasons for
| that, but result was +-same.
| throwaway0a5e wrote:
| >Decades ago, I owned an old Alfa Romeo that incorporated a
| complicated cam system to control the oxygen ratio to the fuel
| injection system. More complex than your typical 1-dimensional
| function of a cam, this cam was "two-dimensional" in its
| output. The cam follower was able to slide along the axis of
| the cam based on something or another (RPM? temperature?) and
| the profile of the cam varied from one end to the other.
|
| V-tech, yo.
| bayindirh wrote:
| From the article:
|
| > Mobile phone SOCs integrate a substantial amount of function
| right onto the chip. Why hasn't that been the case for the car?
|
| Because your mobile phone SoC is not certified for -20/+80
| degrees Celsius, copious amount of vibration, error-free
| operation on many environments (incl. inputs with wrong voltages,
| shorts, etc.), and have a lifetime of 10+ years with the same
| performance characteristics.
|
| Your car is running a real-time simulation of your engine to keep
| itself operational, and it's a much serious business than running
| Android or iOS.
|
| More information:
| https://media.ccc.de/v/32c3-7331-the_exhaust_emissions_scand...
| shadowpho wrote:
| Also... mobile phone SoC are made in much higher quantities
| then car chips: there are much more phones shipped then cars.
| Therefore R&D costs per unit are significantly lower with phone
| chips and you can spend more.
| pySSK wrote:
| They do however use SoCs for HMI/head-units/carputers now
| however.
|
| The bigger reason is just the nature of automotive development.
| Every part is developed by a specced or sourced by different
| teams and outsourced to a different Tier 1/2/3. Things are
| designed to be modular, so if you pick Option A for something,
| it might use ECU A, and if you pick Option B, they might pack a
| whole different ECU B. Also, every ECU is costed down to only
| support the intended application, so ECU A likely doesn't have
| the extra bandwidth to add on extra features for Option B.
|
| Also, none of this is decided or developed at the same time, so
| you have all the different features and ECUs developed
| throughout. Some things are changed mid program. Some things
| carry over from previous programs, so it's usually just easier
| to go your own way and not work with other teams on combining
| features.
|
| Every automotive OEM has a person who comes up with the
| brilliant and cost saving idea of combining ECUs. I know 4 such
| people from different OEMs but they have all failed for some of
| the reasons mentioned above.
| nudgeee wrote:
| SoCs in head-units would still be automotive qualified
| variants (temperature grade, etc).
| ryanobjc wrote:
| When you buy semiconductors on digikey or whatever, there are
| several different 'classes' of performance. Everyone imagines
| milspec being the top one, and it's true, but for most people
| the ideal class is 'automotive'... Because precisely of what
| the parent said: tolerances of temperatures to 140F or more.
| Think of a car sitting in a baking parking lot in Phoenix, no
| shade.
|
| You don't build semiconductors for that purpose by using 10nm
| process then adding a lot more redundancies when all you need
| is a simple opamp. You instead build the thing beefy and
| resistant to the environment.
|
| And all the excitement over new chip plants by TSMC etc, won't
| do a thing for these automotive applications.
| xyzzy21 wrote:
| There are classes ABOVE mil-spec. These are several "Space
| grade" classes above mil-spec which have far wider
| temperature and radiation ranges.
| turbinerneiter wrote:
| How does functional integration interfere with robustness?
| JRKrause wrote:
| One method of making a chip 'tougher' is to physically
| increase the size of the semiconductor elements (e.g.
| transistors, FETs). This would seem incompatible with highly-
| integrated ICs.
| xyzzy21 wrote:
| This is true. For radiation hardening for space, this is
| exactly what is required for anything more harsh than LEO.
| And as a consequence, the generation of processors and
| memory typically used are 10-20 years behind the current
| state of the art. That's simply the price of reliability in
| harsh environments!
| bayindirh wrote:
| The discrete components are designed, tested and verified
| after a long stint and their specs are frozen. It's a bit
| like space hardware. You verify an older CPU design can work
| reliably in space, and certify that processor. Then, you use
| the same foundation for a decade or so.
|
| It's same with automotive industry. You have a well defined
| and certified stack from Delco, Bosch, Delphi, etc. and you
| can trust that hardware. Integration makes you return back to
| square one.
|
| I remember Toyota tried unifying some control units into a
| single box, and 5-6 years considered realistic if not a
| little optimistic.
| pySSK wrote:
| To add to that, some of these features are extremely
| specialized, and for each feature, 1-2 of the big players
| might have a huge technical advantage and economies of
| scale in production and in supplying. This leads to higher
| barrier to entry and not enough margin for other players to
| replicate the feature.
| foobarian wrote:
| Funny, this sounds exactly like why microservices have an
| advantage over monoliths in big organizations.
| Isinlor wrote:
| SpaceX works around that by using consumer grade stuff and
| just replicating it 3 times. Tesla also managed to handle
| issues with supply shortages very well.
|
| The old practices are just not good enough.
| pas wrote:
| > The old practices are just not good enough.
|
| True, but also think about the path dependence of the old
| companies. They have withered a lot of ups and downs,
| they are not the innovators, they are the very slow
| incrementalists that despite this release a new boring
| model every few years dressed up as the new best thing
| ever. (If you have seen a car from one manufacturer you
| have seen them all from them for the past decades too.)
|
| The whole car industry is a relatively high volume & low
| margin & medium risk business. (The unit economics is
| great, but any risk kills profitability, so there was a
| lot of consolidation and convergence.)
|
| Basically the car industry is like the "iphone industry"
| except there's some actual price competition and worse
| fundamentals, plus Apple is relatively young (and Steve
| set up a pretty high pace, and expectations, plus the
| fundamentals of the components - eg. semi industry,
| radios, displays - are really moving forward, whereas
| internal combustion engines, and the material science of
| other car components are not).
| JumpCrisscross wrote:
| > _SpaceX works around that by using consumer grade stuff
| and just replicating it 3 times_
|
| Falcons get refurbished after short flights. That reduces
| the emphasis on durability. Redundancy defends against
| random errors, reducing the need for radiation hardening.
| It does less against wear and tear.
| hulitu wrote:
| Tesla is not a car. It looks like one, it might behave a
| bit like one but i would not touch such a thing even with
| a 9 m pole. I heard too many horror stories about Tesla
| requirements.
| hulitu wrote:
| -20 deg C - + 80 degC is for keyfobs. For ECUs in the passenger
| compartment is -40degC - 85 degC and for ECUs in the engine
| compartment is -40 degC - 105 degC.
| sandworm101 wrote:
| >> SoC is not certified for -20/+80 degrees Celsius
|
| That is basically the operating range of the average graphics
| card these days. Not many people go sub-ambient with their
| cooling but no graphics card would complain if they did. The
| actual silicon is perfectly fine with such temperatures. The
| only real issue is the external cooling rig, a classic
| engineering problem that any car company shouldn't have a
| problem solving. A water cooler tied to the vehicle's coolant
| loop would easily cap the upper temperature range at water
| boiling points. A car engine has plenty of power available for
| fans or even air conditioning if necessary. Hide the controller
| chips somewhere in the passenger compartment and the humans
| will die of heat before the silicon.
| ptsneves wrote:
| In low temperatures you start having issues with moisture
| saturating the air. Things get wet out of nowhere. There are
| also electrolytic capacitors which are water based so these
| need to be ruled out as well. Given air has at any given time
| a lot of water and water goes through a phase change at sub
| zero i find the comparison quite invalid.
| sandworm101 wrote:
| That's a difference with automotive/aviation products. They
| will all be in sealed containers and then the actual
| circuitry will all be covered in plastic. There shouldn't
| be any exposed metal that could possibly short, even if
| immersed in water. Pouring buckets of water on a running
| engine (ie a gap in the hood closure on a rainy day) or
| even into the passenger compartment (ie sunroof left open)
| shouldn't do much of anything to a car's electrical
| systems.
|
| (This is also done for fire safety reasons. Any metal that
| could possibly short if wet could also ignite a fire
| during/after a crash.)
| bayindirh wrote:
| I'm not talking about processor temperatures. The
| temperatures I'm talking about are ambient/enclosure
| temperatures. So, the board, and all integrated components
| will be at least that ambient temperature, and they'll work
| without any transient errors.
|
| Also this means, no solder joints or any other component
| won't act funky.
|
| A transient error in your GPU is a one pixel blip. In an ECU,
| that's a power loss event in best case.
| geocrasher wrote:
| This article does a good job outlining why these systems can't
| just be replaced with a Raspberry Pi or an Arduino: Durability.
| At one point I was interested in replacing the ECU in my old '88
| Suburban. The ECU is probably the only "real" bit of electronics
| in the whole vehicle. And yet after almost 35 years it's still
| doing fine. The Arduino based ECU I was looking into, as it turns
| out, is a great hobby project, but not so good for reliability
| due to the harsh conditions.
|
| Still, I think electronics in modern vehicles are completely over
| the top, but then again... I drive a 30+ year old Suburban. I'm
| prone to thinking that way :D
| technothrasher wrote:
| I designed a drop in replacement ignition ECU for Ferrari 308
| cars from the 1980's (the Magnum PI model), as after almost 40
| years a lot of them are now failing. When I started the
| project, I had no idea how miserable an environment the car
| actually was. It wasn't hard to get a prototype that basically
| worked, but I had to go through quite a few revisions before I
| got something that could withstand the torture of everyday use
| (and things like electrically dirty jump starters that would
| completely fry my units until I put a protective power supply
| in it against +/-100VDC surges.)
| dylan604 wrote:
| The space shuttle used a hardened 386 (or something similar)
| that cost a bazillion dollars. The drone currently on Mars used
| commidity off the shelf chips (snapdragon IIRC). The harsh
| conditions thing is not something to laugh at, but I also think
| we might have over-engineered somethings a bit.
| tablespoon wrote:
| > The space shuttle used a hardened 386 (or something
| similar) that cost a bazillion dollars.
|
| Their main computers were a custom variant of the IBM 360
| mainframe. They _also_ duplicated it _5x_ : 4x with majority
| vote for error correction, plus a backup running separately-
| developed software.
|
| https://en.wikipedia.org/wiki/IBM_System/4_Pi
|
| > The drone currently on Mars used commidity off the shelf
| chips (snapdragon IIRC). The harsh conditions thing is not
| something to laugh at, but I also think we might have over-
| engineered somethings a bit.
|
| It should be noted that drone is 1) an engineering experiment
| and 2) no one will die if it malfunctions, so they can afford
| to be a bit sloppier.
| Isinlor wrote:
| SpaceX is also using commodity hardware, but they duplicate
| it 3x with majority vote for error correction.
| froh wrote:
| do you happen to have pointers evidencing this handy? IS
| this also true for Dragon?
| TrainedMonkey wrote:
| It is, see https://stackoverflow.blog/2021/12/27/dont-
| push-that-button-...
| xyzzy21 wrote:
| Some of it is classified but you can often find info on
| certain open sites at NASA or SNL.
| Retric wrote:
| The surface of Mars being further from the sun and inside an
| atmosphere has vastly fewer issues with radiation.
| geerlingguy wrote:
| But more issues with temperature swings--ideally radiation
| wouldn't be the main concern here in Earth's atmosphere.
| Retric wrote:
| Rovers regulate internal temperatures to keep electronics
| happy. Ex:
| https://mars.nasa.gov/mer/mission/rover/temperature/
| temp0826 wrote:
| Biggest difference is the lack of risk to human life, tbh
| Symmetry wrote:
| In both cases you're well protected against the solar wind
| by distance and atmosphere in the case of the Mars rover
| and by the Van Allen belts in the case of the Space
| Shuttle. But both still have to worry about cosmic rays.
| Mars's thin atmosphere helps a bit with that but not nearly
| as much as you'd like.
|
| EDIT: I suspect a lot of what lets you use Snapdragons in
| the rover is the idea of making error resistant systems
| rather than error resistent devices. The same thing that
| let us replace a single $10,000 hard driver with ten $100
| hard drives in a RAID with the same performance and
| reliability despite the individual drives being much worse.
| Retric wrote:
| That's not really accurate the sun causes real issues in
| LEO. See chapter 2 starting on page 9 here:
|
| https://commons.erau.edu/cgi/viewcontent.cgi?article=1101
| &co...
| dylan604 wrote:
| As an anecdotal bit of support, I seem to recall recently
| SpacX loosing a number of satellites in their LEO
| constellation because of sun activity
| mschuster91 wrote:
| Yes, but that was not due to EM activity, it was because
| the solar activity made the atmosphere go up higher than
| usual which meant that the atmospheric drag was too
| strong for the engines to overcome.
| addingnumbers wrote:
| We can't teleport something from one atmosphere to another,
| though. It's a long trip.
| Retric wrote:
| That's a risk, but the chip is off for the trip which
| makes a significant difference. Fail safe is much easier
| if you can run diagnostics without needing the system to
| be doing it's job.
| dclowd9901 wrote:
| Also, human lives aren't at stake if things go awry.
| [deleted]
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