Somewhat OT: Long term design
in [Design]
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From: Sylvia Else on 13 Jan 2010 21:31 A recent episode of Stargate Atlantis prompted me to think about how would could design equipment that's intended to function far into the future. The episode required stuff to function 48,000 years after construction, but perhaps we could be less optimistic. Say 1000 years. Note, the requirement is not that the equipment function *for* 1000 years, but that when it is turned on, 1000 years from now, that it will work. It seems to me that semiconductors are out due to effects of difusion and radiation. But how about thermionic valves? They're not very reliable, but do they age when not in use? Would they hold a vacuum over that time? Obviously electrolytic capacitors are a no-no, but can resistors and capacitors be made stable enough that they'd work? Would it help to enclose the entire circuit in a vacuum tube? Again, could the tube sustain the vacuum over such a period? An energy source is a problem. Perhaps a cell where acid is added (how?) at the appropriate time? Sylvia.
From: George Herold on 13 Jan 2010 21:48 On Jan 13, 9:31 pm, Sylvia Else <syl...(a)not.at.this.address> wrote: > A recent episode of Stargate Atlantis prompted me to think about how > would could design equipment that's intended to function far into the > future. The episode required stuff to function 48,000 years after > construction, but perhaps we could be less optimistic. > > Say 1000 years. > > Note, the requirement is not that the equipment function *for* 1000 > years, but that when it is turned on, 1000 years from now, that it will > work. > > It seems to me that semiconductors are out due to effects of difusion > and radiation. > > But how about thermionic valves? They're not very reliable, but do they > age when not in use? Would they hold a vacuum over that time? > > Obviously electrolytic capacitors are a no-no, but can resistors and > capacitors be made stable enough that they'd work? > > Would it help to enclose the entire circuit in a vacuum tube? Again, > could the tube sustain the vacuum over such a period? > > An energy source is a problem. Perhaps a cell where acid is added (how?) > at the appropriate time? > > Sylvia. What does the machine have to do? Mechanical stuff (gears, cams, punch cards) lasts a long time. It could be powered by gravity. George H.
From: John Larkin on 13 Jan 2010 22:06 On Thu, 14 Jan 2010 13:31:08 +1100, Sylvia Else <sylvia(a)not.at.this.address> wrote: >A recent episode of Stargate Atlantis prompted me to think about how >would could design equipment that's intended to function far into the >future. The episode required stuff to function 48,000 years after >construction, but perhaps we could be less optimistic. > >Say 1000 years. > >Note, the requirement is not that the equipment function *for* 1000 >years, but that when it is turned on, 1000 years from now, that it will >work. > >It seems to me that semiconductors are out due to effects of difusion >and radiation. > >But how about thermionic valves? They're not very reliable, but do they >age when not in use? Would they hold a vacuum over that time? > >Obviously electrolytic capacitors are a no-no, but can resistors and >capacitors be made stable enough that they'd work? > >Would it help to enclose the entire circuit in a vacuum tube? Again, >could the tube sustain the vacuum over such a period? > >An energy source is a problem. Perhaps a cell where acid is added (how?) > at the appropriate time? > >Sylvia. I'd expect that most semiconductors and passives would last 1000 years, given a conservative design. There's not much radiation around at sea level. The gadget could be stored in vacuum or dry nitrogen to prevent corrosion and wiskers and such. It shouldn't be hard to keep a vacuum tight for 1000 years. A decent flange-sealed vacuum vessel hardly leaks at all. If it can do 1e-12 torr for a minute, it leaks to atmosphere in (linear extrapolation) 2 billion years. I think solar cells would stand up well. I bet that a Casio solar calculator will work 1000 years from now if properly stored. The biggest hazard would probably be polymerization of the plastics in the keypad, or maybe leakage from a poorly sealed LCD. I still use my original HP35 calculator, purchased in 1972. John
From: Joerg on 13 Jan 2010 23:41 John Larkin wrote: > On Thu, 14 Jan 2010 13:31:08 +1100, Sylvia Else > <sylvia(a)not.at.this.address> wrote: > >> A recent episode of Stargate Atlantis prompted me to think about how >> would could design equipment that's intended to function far into the >> future. The episode required stuff to function 48,000 years after >> construction, but perhaps we could be less optimistic. >> >> Say 1000 years. >> >> Note, the requirement is not that the equipment function *for* 1000 >> years, but that when it is turned on, 1000 years from now, that it will >> work. >> >> It seems to me that semiconductors are out due to effects of difusion >> and radiation. >> >> But how about thermionic valves? They're not very reliable, but do they >> age when not in use? Would they hold a vacuum over that time? >> >> Obviously electrolytic capacitors are a no-no, but can resistors and >> capacitors be made stable enough that they'd work? >> >> Would it help to enclose the entire circuit in a vacuum tube? Again, >> could the tube sustain the vacuum over such a period? >> >> An energy source is a problem. Perhaps a cell where acid is added (how?) >> at the appropriate time? >> >> Sylvia. > > I'd expect that most semiconductors and passives would last 1000 > years, given a conservative design. There's not much radiation around > at sea level. The gadget could be stored in vacuum or dry nitrogen to > prevent corrosion and wiskers and such. > > It shouldn't be hard to keep a vacuum tight for 1000 years. A decent > flange-sealed vacuum vessel hardly leaks at all. If it can do 1e-12 > torr for a minute, it leaks to atmosphere in (linear extrapolation) 2 > billion years. > > I think solar cells would stand up well. I bet that a Casio solar > calculator will work 1000 years from now if properly stored. The > biggest hazard would probably be polymerization of the plastics in the > keypad, or maybe leakage from a poorly sealed LCD. > > I still use my original HP35 calculator, purchased in 1972. > HP11C over here. I still use my grandpa's drill from around the 1920's. Works fine. You just have to keep the grease reservoirs packed by tightening the caps once in a while and refilling when at the peg. Oh, and the church we were married at goes back about 1200 years, the organ in there is probably well past 500 years. I guess a pipe organ fulfills the definition of "equipment". It can be done. -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Sylvia Else on 13 Jan 2010 23:51
Joerg wrote: > John Larkin wrote: >> On Thu, 14 Jan 2010 13:31:08 +1100, Sylvia Else >> <sylvia(a)not.at.this.address> wrote: >> >>> A recent episode of Stargate Atlantis prompted me to think about how >>> would could design equipment that's intended to function far into the >>> future. The episode required stuff to function 48,000 years after >>> construction, but perhaps we could be less optimistic. >>> >>> Say 1000 years. >>> >>> Note, the requirement is not that the equipment function *for* 1000 >>> years, but that when it is turned on, 1000 years from now, that it >>> will work. >>> >>> It seems to me that semiconductors are out due to effects of difusion >>> and radiation. >>> >>> But how about thermionic valves? They're not very reliable, but do >>> they age when not in use? Would they hold a vacuum over that time? >>> >>> Obviously electrolytic capacitors are a no-no, but can resistors and >>> capacitors be made stable enough that they'd work? >>> >>> Would it help to enclose the entire circuit in a vacuum tube? Again, >>> could the tube sustain the vacuum over such a period? >>> >>> An energy source is a problem. Perhaps a cell where acid is added >>> (how?) at the appropriate time? >>> >>> Sylvia. >> >> I'd expect that most semiconductors and passives would last 1000 >> years, given a conservative design. There's not much radiation around >> at sea level. The gadget could be stored in vacuum or dry nitrogen to >> prevent corrosion and wiskers and such. >> >> It shouldn't be hard to keep a vacuum tight for 1000 years. A decent >> flange-sealed vacuum vessel hardly leaks at all. If it can do 1e-12 >> torr for a minute, it leaks to atmosphere in (linear extrapolation) 2 >> billion years. >> >> I think solar cells would stand up well. I bet that a Casio solar >> calculator will work 1000 years from now if properly stored. The >> biggest hazard would probably be polymerization of the plastics in the >> keypad, or maybe leakage from a poorly sealed LCD. >> >> I still use my original HP35 calculator, purchased in 1972. >> > > HP11C over here. I still use my grandpa's drill from around the 1920's. > Works fine. You just have to keep the grease reservoirs packed by > tightening the caps once in a while and refilling when at the peg. > > Oh, and the church we were married at goes back about 1200 years, the > organ in there is probably well past 500 years. I guess a pipe organ > fulfills the definition of "equipment". It can be done. > Well, I'm not sure the organ qualifies, even if it reaches 1000 years. Has it never been repaired? The requirement is that the equipment be built, be left untouched for 1000 years, and then work. Sylvia. |