Gyros, reaction wheels, seem to be a chronic problem in satellites. I have a friend who designs cubesats, and he says that the gyros are the most expensive and unreliable parts. They should be redundant, or redesigned, or something.
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Another friend, a Fellow of a giant areospace conglomerate, tells me that they have a new CEO. The old one was big on outsourcing, and they did stuff like using contract programmers in India, and things went to hell. They will be hiring 8000 engineers in the next few years, so they can start learning how to do stuff again.
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This is a cool part:
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John Larkin Highland Technology, Inc
picosecond timing precision measurement
jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
... which suggests that this is a Hard Problem. I don't find that surprising. Gyro bearings are a "moving part" (unlike a lot of what's in satellites). Almost by definition they have to take a big torque load on the bearing surfaces when they operate, since part of their job is to twist the satellite around into a new orientation. They often have to operate over an extreme temperature range (cold-of- eclipse to heat-of-full-sun) with the range going back and forth multiple times per day (for a LEO satellite at least). And, there's no opportunity to replace, or relubricate the bearings once the sat is in service, in most cases.
I don't know what material they use in the bearings for those gyros, but suspect that they're probably frightfully expensive.
If you don't use gyros, you need some other way to maintain and change orientation... and reaction-thruster fuel is an expensive resource!
Each time I've heard stories about gyros on a satellite failing, the information in the story has made it clear that the satellite in question did contain redundant gyros. They always seem to have at least an N+1 set, with N+2 being not unusual.
I imagine that the decision about adding additional gyros (for an additional level of robustnes) comes with the usual problems... they're heavy, they take up space, so if you add another one, either something else has to go or the sat gets bigger/heavier/ more-expensive.
My naiive concept is that things don't need bearings in zero G and hard vacuum. Just a little magnetic suspension. Of course, a zero-G maglev (spherical?) gyro would be hard to test on the ground; maybe we have finally found a use for the ISS, manufacturing gyros.
MAGA?
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John Larkin Highland Technology, Inc
picosecond timing precision measurement
jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
I want to say a lot of terrestrial gyros are air-bearing supported, of course that literally doesn't "fly" so well in space. I suppose it could be a pressurized module. Maybe that's not a good way to go overall, say because of precession rate.
The recent spate of reaction wheel failures apparently is an ESD phenomenon. Radiation causes photoemission on the bearing surfaces, accumulating charge, which eventually discharges through the grease, pitting the bearing balls and races, causing rising power consumption until the ratings are met and the thing grinds to a halt.
Sure, He's set his sights on Moog, a local (mostly) defense contractor. He's stuck in NY for his first 4-5 years, after college, (well the current plan is some state univ., and NYS picks up the tuition if you work in the state after college. That's about $8k/yr. If you get a job out of state you have to pay off the ~$32k right away... I'm not sure if you owe interest or not?
I know some guys at Moog, I should see if there are some summer internships. He's more of a motor head than I am, and might interview well.
Now they retired the shuttle no way to send a repair crew up there...
The Russian mission to the ISS also failed, crew made an emergency landing and is safe.
Statistics...
Software made elsewhere, hardware made elsewhere, that leaves the US with nothing... Can the trend be reversed? I think not in the short run.
The empire is over the hill, and as all empires before it, will vanish. Climate change will accelerate things. large migration, population changes..
A reality show host closing the borders for trade will cause the US dollar to be replaced by some other currency, Chinese, European.. Starting an other war will not work as the 'enemy' has as many nukes as US, even if you could get people to fight, they won't, they will sit down in protest, unity lost. Mr Xi will be visiting my country soon, and Dutch Chinese relations are the best ever now.
The markets took a big hit recently, US people lost a lot of money.. The high tech you need, the factories you need, the workers you need are not there. And you will not be able to buy those with a dollar that is no longer accepted. The expertise is not there, the milking of the taxpayer for military nonsense projects like for example the F35 has made a farce of US defense. Alienating your allies with tariffs and a gun to their head to sell your inferior weapons, creating wars to sell your weapons. some other power will do that has the resources now. Breaking promises, stepping gout of international treaties, claiming to be a capitalist state and being against free trade at the same time, not a good thing. Evolution, things change, stars are born and stars die.
Success with finding 8000 engineers with any experience. Where would they have gained experience? Everything is made in China.
Yes, nano nano, higher switching frequencies, short wave is already 100% polluted, next GPS goes out due to interference of switchers, next .. chips emit light.... mm satellite TV interference better stop here. Does not sound all that optimistic now does it ;-)
They need bearings or magnetic suspension that can handle the forces that occur when the satellite is being rotated by using the gyros. If they could avoid using mechanical bearings they would do so.
Almost all sensor gyros are counter rotating laser beams these days. It is only the devices that have to provide real forces that move.
The moving parts with serious kinetic energy and high torque are always by far the most unreliable components especially in spacecraft.
We had maglev turbopumps for a while on our kit. It was wonderful in earthquake free zones but one day the entire of Tokyo moved an inch to the left and every damn one of the things was written off in an instant. We even had an earthquake in our factory which did in a couple and the UK is not known as a hotbed of earthquake activity. After that they went back to traditional bearings for almost all customer sites.
You have clearly never sat on a swivel chair and played with a spinning lead rimmed bicycle wheel. It is quite fun to try and the forces on the bearings are distinctly non-trivial when you use it to move a mass.
Cubesats are light and fly in low orbits, so drag is serious. They only last a year or two. I'll ask my friend, but I'd expect that the drag on the surfaces sort of zero-bases the orientation. I don't think he uses any sort of thrusters to zero out the gyros. He does complain about the gyro-based orientation package that they buy.
Some satellites apparently use magnets to align with Earth's field. That sounds complicated. I guess you could use stepper motors to move magnets around, to get orientation and damping. Some cubesats apparently use electromagnets or microthrusters. I'll ask M what they do.
He owes me; I taught him the value of a rum-and-coke as a skiing enhancement.
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He's from Sweden, skiied all his life, and missed this fundamental component. Now he has two.
There are two cubesat companies within a 15 minute walk of our place, and soon to be a third. I wonder if they will survive. The satellites don't last long, so have to be continuously replaced, so there has to be an ongoing revenue model.
google cubesat layoffs
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John Larkin Highland Technology, Inc
lunatic fringe electronics
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