[X] My Assistant

[dtolman]

(MOD NOTE: Started a new topic for this discussion to continue. Please remember the 'no sci-fi engineering' provision of rule 1.9. Have fun!)


Also, since I'm thinking about surface operations on Venus, the state-of-the-art in high temperature electronics has advanced quite far in the past decade.
Its now possible to buy off the shelf chips from vendors designed to operate at the 250-300 C range.

Meanwhile basic functionality has been tested at and beyond the temperatures needed for long-term surface operations on Venus:
http://www.grc.nasa.gov/WWW/SiC/
http://www.gizmag.com/extreme-silicon-carb...ctronics/16410/
http://www.grc.nasa.gov/WWW/SiC/publicatio...Contact2010.pdf

Another decade or so and a long-term Venus lander could be possible with (practically) off the shelf electronics!

[nprev]

I'm officially your distant relative now, Dan, and I got a few bills...

Seriously, this is not a trivial problem. A Venus lander of any sort either requires a VERY well-controlled temperature environment for its electronics (which IIRC was the Venera strategy) or not only electronic components that can survive extreme temp swings during the cruise phase but also the same for all required electrical connections.

The latter are obviously quite vulnerable to materiel expansion/contraction cycles, which ultimately loosen connections over time and introduce either spurious or high-resistance interface points which can do all sorts of nasty things to signal flow. (For example, MIL-STD-1553 data buses really don't like impedance changes; tends to turn perfectly good data words into gibberish.)

How I see this playing out is a loosening of environmental control constraints over time for the silicon itself but capability bounded by a hard constraint on connection methods unless suitable (and workable, as Dan pointed out) connection/wiring alloys of some sort can be developed that are extraordinarily resistant to thermal cycling. That's a rather daunting challenge in metallurgy.

[ElkGroveDan]

Seriously, this is not a trivial problem. A Venus lander of any sort either requires a VERY well-controlled temperature environment for its electronics (which IIRC was the Venera strategy) or not only electronic components that can survive extreme temp swings during the cruise phase but also the same for all required electrical connections.

It's a real problem but I'm confident that existent materials technology can solve it -- especially the problem of conductive connections. I would imagine a mechanically secure solution such as clamping or spiral threading which is secondarily secured by a high temperature polymer. (If I were building it in my garage I'd be using RTV silicon or two part-epoxy which are reliable to 600F. I'm sure the JPL toolbox has even better stuff in it).

The electronic components are another story but frankly I'm pretty certain there are already temperature rated ICs and such in use in military and industrial applications which offer a starting point for this kind of high-temperature electronic circuit design -- probably servos, relays and optical applications as well.

[mcaplinger]

(If I were building it in my garage I'd be using RTV silicon or two part-epoxy which are reliable to 600F.... frankly I'm pretty certain there are already temperature rated ICs and such in use in military and industrial applications which offer a starting point for this kind of high-temperature electronic circuit design...

Venus ambient is around 450C or almost 900F. There are no ICs I'm aware of that get anywhere close. Most mil-spec parts go to 150C or maybe 200C in a few cases (junction temps, not ambient.)