Reliability?

BobC

Voyager 1 was launched over 40 years ago and is still sending data back to earth. It is the only man made object to exit the solar system and is now considered to be in interstellar space. In Nov of 2017 they wanted to make a minute correction and needed to fire it's thrusters for a very short burst. The last time they had been fired was 37 years ago when Voyager was flying buy Jupiter and Saturn.

They fired those thrusters a few months ago and they worked just fine, good thing - a service call would be tough considering Voyager is 13.153 billion miles from earth and moving at 38,000 miles an hour.

Nasa's Voyager Mission Status https://voyager.jpl.nasa.gov/mission/status/

Youtube video on thrusters https://www.youtube.com/watch?v=z62Y_H15Eos

It's humbling to think people designed and sent this probe all those years ago and it's still doing it's jon.

Bob

Jamie Hall

Zero Defects and 5 nines reliability... We CAN Do It! USA!

BobC

@Jamie Hall We had a poster in engineering that read "Zero Defekts" that we got from EDN magazine.

Another good one was 'Remember the budget" That had a picture of an Atlas rocket with the third stage replaced with a biplane.

That is back when we did things right.

Bob

NY_Rob

Amazing stuff, especially considering the tech available at that time!

The Apollo command modules used "core rope memory" for the rom portion of the guidance computer.
It was hand sewn by female workers in factories. Amazing tech from engineers who would not accept "no" as an answer!
https://en.wikipedia.org/wiki/Core_rope_memory

Mark Eatherton

They don't make em like they used to...

I never in my wildest dreams thought I'd ever see the day that they were LANDING their booster rockets for reuse. Only in the movies did we ever see that stuff...

ME

JUGHNE

IIRC that was one reason the Star Trek "transporter" was developed.
Less special effects needed than landing any type of craft on the surface.

KC_Jones

Mark Eatherton said:

They don't make em like they used to...

I never in my wildest dreams thought I'd ever see the day that they were LANDING their booster rockets for reuse. Only in the movies did we ever see that stuff...

ME

It's funny, I watched it over and over again. It was so hard for my brain to believe, that it looked computer generated. If it wasn't for all the people watching live I am not sure if I would have believed it.

NY_Rob

Even up to just a few years ago we used to laugh at the 50's sci-fi movies where the iconic bullet shaped- finned tail- 100ft tall rocket landed upright on Mars, the Moon, etc....

Time to stop laughing I guess...

nicholas bonham-carter

This says it all:

Jamie Hall

I was, and am, proud to have been a very very minor part of all that, @nicholas bonham-carter .

For reference, the computing power for the LM had a whopping 16,000 bytes of memory, all told, and the CM had two 16K byte memory computers. Whee!

There still seem to be a few daring folks out there -- SpaceX must have some to do what they are doing.

Perhaps it's just because I am old... perhaps... I don't know. But what has happened to the nation which went to the moon? Which listened proudly to MLK Jr. dream his dream? Which earlier got into their wagons and forged on beyond the Blue Ridge? Where five men could herd a thousand cattle from Texas to Abilene? Where earlier they could get into cockleshell boats and head out into an unknown sea with uncharted dreams, or take a canoe voyaging into the wilderness? Or even earlier could cross from Siberia into Alaska? All "to boldly go where no man has gone before".

No safe spaces then. No microagressions. No regulations and codes from a distant and uncaring government (in fact, some of those folks threw one of those out, once upon a time, driven by a dream of freedom, personal responsibility and liberty).

I am too old and frail now to do that, but I can still dream, and I hope that there are still young men and women who are not afraid of their shadows who will carry on...

Eastman

@Jamie Hall

What are microagressions?

ChrisJ

Yes, but we have guys afraid to use anything but 1930s technology because it could be unreliable. Meanwhile their simple vaporstats are failing.

Jamie Hall

You know, @ChrisJ , a vapourstat -- or the closely related old style T87 -- is an excellent case in point. For some 5 decades, at least, Honeywell manufactured the original vapourstat. It had a large diaphragm which flexed well within its fatigue limits, and caused, through a simple linkage with very little resistance, a mercury switch to tilt. When the switch tilted far enough, the mercury went to the other end and opened one circuit (and in some, closed another). Then as the pressure dropped the diaphragm contracted and eventually overcame the unbalanced mercury switch and it flopped back. All this assisted by a pair of simple compression springs which could be adjusted. All it had to be was level, and the life was almost unlimited (the limit was fatigue in the diaphragm, which was minimal provided it was never overpressured. The life of a mercury switch is unlimited). All it had to be was level...

Then some bright individual got scared that somehow the mercury in the switch was going to kill all known forms of life on the planet, or something like that, and banned its use. The design had to be changed to a microswitch (life limited) which has much higher actuating forces (more stress on the diaphragm, shorter life) which are variable (much harder to calibrate) and this is referred to as progress.

Sometimes the old and proven is better for an application than the new and untried. Sometimes the other way around. The art comes in balancing the varying needs and the related risks to achieve the goal. I personally believe that we, as a society, have gone much too far in our efforts to achieve a zero risk life style -- while at the same time placing far too much faith in appallingly unreliable technology to help us get there.

And just to go back to that poster -- had we attempted to use technology with the reliability of a modern home computer or smartphone to reach the moon, we'd never ever have made it.

the_donut

You know what always gets me about mercury? There’s more in the air from burning coal or people breaking their cfl bulbs than in those switches. Heck there’s a youtuber who does all kinds of work with it.

I can’t understand why fear monger if exists when knowledge is literally second away. Instead of learning, people seek out information to support their own version of reality.

Jamie Hall

And another ramble. This time on what 5 nines reliability really means -- it's hard to visualize. But just a few examples.

Your car. If your car's starting system were rated at 5 nines, you could start it 4 times a day for 70 years and it would never fail or need service.

Putting a steam system together with 100 fittings. If you did those fittings to 5 nines, you could assemble 1,000 systems and none of them would ever leak.

Your smartphone. If we redefine 5 nines in terms of a failure in any given hour out of all hours, you could leave your smartphone on for 12 years straight, and it would never crash or drop a call.

Do we need 5 nines in everyday life? Certainly not. Which is why, for instance, a Chevy costs $30,000 instead of $3,000,000. Or a smartphone $1,000 instead of $10,000,000. One has to balance the risk of failure with the cost of performance, and it's a different balance for every application, every client, every job.

JUGHNE

Wasn't the Eagle landed without a computer, but with a by guess and by golly joy stick.

I commented here a few years ago that we hadn't returned to the moon since we quit using slide rules.......I believe there was a pause by some and then agreement, hum, you are right.

Jamie Hall

JUGHNE said:

Wasn't the Eagle landed without a computer, but with a by guess and by golly joy stick....

Yes it was. The computer was trying to land in a boulder field. Neil Armstrong was one of the very best of the very best!

Fred

Save your keystrokes and your time @Jamie Hall . @ChrisJ has a 1934 monitor top in his kitchen for refrigeration and the regular old fashioned Pressuretrol on his boiler as his safety control. I think he just enjoys being an aggravation.

ChrisJ

> @Fred said:
> Save your keystrokes and your time @Jamie Hall . @ChrisJ has a 1934 monitor top in his kitchen for refrigeration and the regular old fashioned Pressuretrol on his boiler as his safety control. I think he just enjoys being an aggravation.

@Fred My 1933 Monitor Top is far more complicated than a modern refrigerator.

Monitor Tops have a pressurized oil system, unloader, mechanical thermostat with capillary tube, solderpot overload, a float valve and an injector setup with an oil skimmer in the evaporator. And let's not forget about the crank case heater. There may be more I'm not thinking of yet, it's early.


There are no such animals in modern refrigerators aside from a much simpler medicinal thermostat.


But thank you @Fred the Monitor Top is the perfect example of how something quite a bit more complicated can be more reliable than a simpler counterpart when engineered better and built better than the simpler one.

Gordy

Mark Eatherton said:

They don't make em like they used to...

I never in my wildest dreams thought I'd ever see the day that they were LANDING their booster rockets for reuse. Only in the movies did we ever see that stuff...

ME

That was the only part of the falcon heavy lift that impressed me, landing the boosters. Also synchronizing that many separate rocket engines which was the beginning of the end for the soviet moon program the N1, it had thirty for the first stage.

Other than that the Falcon heavy lift doesn’t hold a candle to the Saturn V that was made in the mid 60’s. It could carry over twice the payload.

NY_Rob

Jamie Hall said:

JUGHNE said:

Wasn't the Eagle landed without a computer, but with a by guess and by golly joy stick....

Yes it was. The computer was trying to land in a boulder field. Neil Armstrong was one of the very best of the very best!

It was later discovered that the LEM landing computer crashes and subsequent reboots (called reset/restarts back then) were caused by human error.
Buzz had failed to turn off the docking radar after undocking from the CSM and left it on during the whole decent to the lunar surface. The extra input from that radar overloaded the simple landing computer and caused the reset/restarts which necessitated Armstrong landing without the aid of the landing computer. It was proved out in simulators after the mission and Buzz even admitted he failed to turn off the docking radar as was in the pre-landing checklist.
On later missions, using the same computer system- the landing computer functioned correctly since the docking radar had been turned off before the decent.

Gsmith

Jumping back to the elimination of mercury switches earlier. Often these changes are mandated by well intentioned but not well informed knuckleheads in our state and federal regulatory apparati.

EPA a few years ago decided that small gasoline cans (really plastic containers now) were causing too many emissions of volatile organic compounds to the air and mandated an EPA approved design for the gas spout to shut off gas when the receiving container is full. DId anyone at EPA actually use these devices before approving them? In my experience it is impossible to use the new spouts without spilling gas all over the ground, and usually my hands--much worse than the little vapor that escaped when the small plastic cap was off while pouring gas. Reliable and environmentally protective on paper, in real life not so much.

ratio

A common theme that I've noticed lately is a denial of unintended or unexpected consequences.

Don't get me started on how much forethought would be necessary to foresee those "unexpected" consequences.

ChrisJ

> @Gary Smith said:
> Jumping back to the elimination of mercury switches earlier. Often these changes are mandated by well intentioned but not well informed knuckleheads in our state and federal regulatory apparati.
>
> EPA a few years ago decided that small gasoline cans (really plastic containers now) were causing too many emissions of volatile organic compounds to the air and mandated an EPA approved design for the gas spout to shut off gas when the receiving container is full. DId anyone at EPA actually use these devices before approving them? In my experience it is impossible to use the new spouts without spilling gas all over the ground, and usually my hands--much worse than the little vapor that escaped when the small plastic cap was off while pouring gas. Reliable and environmentally protective on paper, in real life not so much.

I bought a steel Safety || can with flex spout because of this. It's awesome though.

I refuse to use the new cheap cans. They're awful.

Steamhead

nicholas bonham-carter said:

This says it all:

This.

Fred

ChrisJ said:Yes, but we have guys afraid to use anything but 1930s technology because it could be unreliable. Meanwhile their simple vaporstats are failing.

@ChrisJ , I need to remind you of your original comment. I thought we were talking about reliability, not complexity.

ChrisJ

> @Fred said:
> Yes, but we have guys afraid to use anything but 1930s technology because it could be unreliable. Meanwhile their simple vaporstats are failing.
>
> @ChrisJ , I need to remind you of your original comment. I thought we were talking about reliability, not complexity.

I'll pm you in a bit about it. No reason to need this thread up.

Gordy

ChrisJ said:

> @Gary Smith said:

> Jumping back to the elimination of mercury switches earlier. Often these changes are mandated by well intentioned but not well informed knuckleheads in our state and federal regulatory apparati.

>

> EPA a few years ago decided that small gasoline cans (really plastic containers now) were causing too many emissions of volatile organic compounds to the air and mandated an EPA approved design for the gas spout to shut off gas when the receiving container is full. DId anyone at EPA actually use these devices before approving them? In my experience it is impossible to use the new spouts without spilling gas all over the ground, and usually my hands--much worse than the little vapor that escaped when the small plastic cap was off while pouring gas. Reliable and environmentally protective on paper, in real life not so much.



I bought a steel Safety || can with flex spout because of this. It's awesome though.



I refuse to use the new cheap cans. They're awful.

Those are all that's allowed on construction sites by OSHA requirements. They are expensive, but will last a long time when treated well. Filling them can be a pain kicks off the pump, unless you remove the strainer.