The Space Shuttle used 6502S OH YEAH!!!

[tokafondo]

Altough I've already opened new threads with several findings amongst NASA documents, related to the use of the 6502 microprocessor based systems, I will also tell here that the Apple II, the AIM 65, the Jolt / SuperJolt and KIM-1 systems were extensively used in NASA projects, or external projects in univerisities backed by NASA. It could be said that it was the microprocessor of choice in NASA in the '80s.

[BigEd]

Interesting to hear. I'll post some thoughts on those threads of yours - thanks for starting them. Just one request: could you put NASA in the title (which is to say, the subject line of the head post) to make it easier to find?

Edit: for convenience

• NASA: A FUNCTIONAL VIDEO-BASED ANTHROPOMETRIC MEASURING SYSTEM
  NASA: In 1983, the 6502 powered a Loran-C navigation system

Edit: updated those titles - thanks!

[tokafondo]

BigEd wrote:

Interesting to hear. I'll post some thoughts on those threads of yours - thanks for starting them. Just one request: could you put NASA in the title (which is to say, the subject line of the head post) to make it easier to find?

Edit: for convenience

• A FUNCTIONAL VIDEO-BASED ANTHROPOMETRIC MEASURING SYSTEM
  In 1983, the 6502 powered a Loran-C navigation system

Done. Thanks.

[Sheep64]

Quote:

All EVA batteries will be converted to Lithium technology by 2016 and the existing BCM is not capable of charging them, has numerous fault issues and will be expiring in 2016.

Much of my knowledge about spacesuits comes from fictional asteriod mining and much of my knowledge about battery charging comes from a Dallas Semiconductor data-book. Regardless, this looks like a boondoggle to me unless lithium batteries are vastly different lead acid or nickel cadmium. Dallas fast charging chips may be pre-programmed for different battery compositions and one variant allows user programming over one of the incompatible Dallas 1/2/3 wire schemes. This pre-dated lithium charging but any device could charge any battery. The only difference is that charging speed and efficiency would be sub-optimal.

With lithium chargers, they typically seem to stop short of a full charge on alternate cycles. I presume this is to reduce a lithium memory effect. With nickel cadmium, the memory effect occurred around the 40% level. This could create a succession of false bottoms until a battery was unless. With lithium, I presume a memory effect occurs near the top. That would prevent a good old, lead acid style, linear regulator hooked to the mains, over-night trickle charge. Regardless, 6502 charging in potential fatal environment would be heavily logged and analyzed.

I am surprised that NASA would not make modification to a system which is mostly tested. From They Write The Right Stuff, a highly productive NASA programmer writes four lines of software per year and when they find an error, they attempt to eliminate the whole class of errors. Furthermore, this is NASA which first isolated a (lead free) tin whisker on a Toyota accelerator pedal. If necessary, they'd slice and dissect a questionable battery.

Is it correct that, in 2016, NASA, who were mad about 6502/Am9511 FPU systems, dumped a reliable, stateful, 6502 battery charging system because it didn't stop short on alternate charge cycles? After exploding lithium batteries in laptops, exploding lithium batteries in phones, an almost fatal incident in a Boeing 787, exploding lithium batteries in scooters, exploding lithium batteries in cars (not including the Tesla which caught fire three times), NASA said "Yeah, we want some of that. We haven't had any exploding astronauts, lately."

[tmr4]

Sheep64 wrote:

Is it correct that, in 2016, NASA, who were mad about 6502/Am9511 FPU systems, dumped a reliable, stateful, 6502 battery charging system because it didn't stop short on alternate charge cycles?

It could be as simple as the manufacturer of the off the shelf unit that NASA stripped down for part of the BCM didn't certify it for lithium-ion.

[AndersNielsen]

Sheep64 wrote:

Quote:

All EVA batteries will be converted to Lithium technology by 2016 and the existing BCM is not capable of charging them, has numerous fault issues and will be expiring in 2016.

Much of my knowledge about spacesuits comes from fictional asteriod mining and much of my knowledge about battery charging comes from a Dallas Semiconductor data-book. Regardless, this looks like a boondoggle to me unless lithium batteries are vastly different lead acid or nickel cadmium. Dallas fast charging chips may be pre-programmed for different battery compositions and one variant allows user programming over one of the incompatible Dallas 1/2/3 wire schemes. This pre-dated lithium charging but any device could charge any battery. The only difference is that charging speed and efficiency would be sub-optimal.

With lithium chargers, they typically seem to stop short of a full charge on alternate cycles. I presume this is to reduce a lithium memory effect. With nickel cadmium, the memory effect occurred around the 40% level. This could create a succession of false bottoms until a battery was unless. With lithium, I presume a memory effect occurs near the top. That would prevent a good old, lead acid style, linear regulator hooked to the mains, over-night trickle charge. Regardless, 6502 charging in potential fatal environment would be heavily logged and analyzed.

I am surprised that NASA would not make modification to a system which is mostly tested. From They Write The Right Stuff, a highly productive NASA programmer writes four lines of software per year and when they find an error, they attempt to eliminate the whole class of errors. Furthermore, this is NASA which first isolated a (lead free) tin whisker on a Toyota accelerator pedal. If necessary, they'd slice and dissect a questionable battery.

Is it correct that, in 2016, NASA, who were mad about 6502/Am9511 FPU systems, dumped a reliable, stateful, 6502 battery charging system because it didn't stop short on alternate charge cycles? After exploding lithium batteries in laptops, exploding lithium batteries in phones, an almost fatal incident in a Boeing 787, exploding lithium batteries in scooters, exploding lithium batteries in cars (not including the Tesla which caught fire three times), NASA said "Yeah, we want some of that. We haven't had any exploding astronauts, lately."

Li-ion charging IS vastly different than lead acid or NiCd. Li-batteries go through two distinct phases in a charging cycle, a constant current variable voltage phase followed by a constant voltage variable current phase.
They do not suffer from memory effects, however hydrogen gasses develop inside the batteries which typically exit through a valve - the closer to maximum capacity the cell is charged the more gasses develop. This is why modern laptops typically cycle between 97% and 100% capacity to reduce the time at 100%. And why Apple has implemented the “only charge beyond 80% if you usually need it mode”.
Optimal charge state for a Li-ion cell is 40-60% capacity - which you might have noticed if you turned on a new phone without charging it first, as they are typically charged to that level for storage.
A cell discharged below ~2.5 volts will also start to develop dendrites in the electrolyte, potentially causing a short circuit during recharge and explosion - which is why you should never recharge a deeply discharged cell.

TL;DR
Lithium batteries need a dedicated charging circuit and a dedicated battery protection circuit from over and undervoltage.