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I don't know why Gizmodo says NASA's Latest Venus Probe Concept Looks Like a Tim Burton Creation, because it looks far more like a Theo Jansen creation! Compare videos below as well.

I can understand looking into wind to power strictly mechanical instead of electromechanical locomotion, but I don't see how meaningful computing could be done mechanically. Roughly, what kind of mechanical computing hardware is being considered for a future Venusian rover? Is it like 1 FLOP and 1 kilobit, or something small and dense or even MEMS-like?

I'm interested because the 10,000 year satellite could really benefit from non-electronic computers to survive in space that long!

See also NASA's Automaton Rover for Extreme Environments (AREE).

enter image description here

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  • $\begingroup$ I'd be reasonably sure that AREE will contain a more or less conventional, electronic microprocessor. Since these can be made so tiny and low-power nowadays, it wouldn't be a big problem to keep it at sufficiently low temperature. $\endgroup$ – leftaroundabout Aug 29 '17 at 22:12
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Don't underestimate what you can do with mechanical components. In the 1840s, Charles Babbage worked on a programmable general-purpose computer (the Analytical Engine). Sadly, it was never completed, although the idea is sound. An earlier design of his, the Difference Engine (which was not Turing-complete), was built in the 1990s.

That said, the AREE study hasn't advanced to the point of designing hardware. From page 19, the study summarizes the possible solutions (mechanical, pneumatics/fluidics, vacuum tubes and other electronics), then shows some possible implementations for elements like power storage, and navigation using a method for obstacle avoidance that does not need computation.

While Phase 1 demonstrated feasibility, a number of areas remain that require further refinement and demonstration to establish concept credibility. Continued work on a Venus rover concept that does not require yet to be developed technologies with unknown costs and timescales significantly changes the conversation with regards to Venus missions and achievable science.

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  • $\begingroup$ I think this is absolutely fascinating! Thank you for the links, I'll take a look :-) $\endgroup$ – uhoh Aug 29 '17 at 17:44
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    $\begingroup$ Not only Babbage worked on a computer with mechanical components, Konrad Zuse's first Z1 used a lot of mechanics too. See en.wikipedia.org/wiki/Z1_(computer) But both Babbage and Zuse had problems with insufficient mechanical precision. $\endgroup$ – Uwe Aug 29 '17 at 17:54
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This isn't a computer as the term is usually understood today, and it certainly isn't using morse code.

What the system is actually doing is taking the output of an instrument, probably a low voltage electrical signal, amplifying it to something mechanically usable, and converting it into rotation of the four disks on top of the rover (with 4 positions each, it's the equivalent of an 8 bit signal).

The value shown on those disks can be seen from an orbiter or high altitude baloon that can use conventional computers for all the more complex tasks.

Physically, the 'computer' part would be a bunch of gears that move the disks.

As shown in the previous answers, you can calculate a surprising with such systems, but due to weight concerns the complexity would probably be kept to a minimum - for example using relative positioning of the disks rather than resetting to an absolute value because the orbiter can easily subtract the previous value with no weight penalty.

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  • $\begingroup$ But how do you amplify a low voltage electric signal without electronics to something mechanically usable? The question was about mechanical computing hardware, therefore no electronic amplifiers. $\endgroup$ – Uwe Aug 29 '17 at 21:14
  • $\begingroup$ @Uwe True, that part can't be just gears. However, it is more part of the instrument than the computer (you probably can't make a camera purely mechanical anyway), and it can use heavy electrical components rather than easily melted silicon chips. $\endgroup$ – Quentin Clarkson Aug 29 '17 at 21:36
  • $\begingroup$ @QuentinClarkson Making a purely mechanical camera isn't that difficult if you've got nearly two centuries of experience making them, but I suppose getting the image back to Earth might pose a bit of a challenge. $\endgroup$ – 8bittree Aug 29 '17 at 22:41
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    $\begingroup$ @8bittree That isn't mechanical, it's a chemical process - and the important part is having a way to transmit the image (or other data using similar sensors, like measuring the exact color flame produced when a sample is heated). Retrieving film capsules has been done from LEO, but isn't really practical for all the data from a year long mission. $\endgroup$ – Quentin Clarkson Aug 29 '17 at 23:57
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    $\begingroup$ @uhoh Yes, that's a much closer analogy. The image in the gizmodo article labels the disks as radar targets - the clouds are only opaque if you are limited to visible light. $\endgroup$ – Quentin Clarkson Aug 30 '17 at 3:10
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Also don't forget that we don't have to do everything digitally. Analog computers were common until fading out in the 60's and 70's, but can be useful in some areas.

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  • $\begingroup$ That's a good point; I've assumed the mechanical computers were digital but that was just a reflex, thanks! But I think this is more of a comment than an actual stackexchange answer; I've asked about a particular NASA plan, "...how does it work?" not just ideas of what might work. $\endgroup$ – uhoh Aug 29 '17 at 17:58
  • $\begingroup$ But the analog computers of the 60's and 70's were to more than 90 % fully semiconductor electronic. In the 40's and 50's there were also electronic anlog computers equipped with vacuum tubes. $\endgroup$ – Uwe Aug 29 '17 at 21:03
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    $\begingroup$ You can do a lot with pure analog mechanical designs. EX the fire control systems on battleships. youtube.com/watch?v=s1i-dnAH9Y4 $\endgroup$ – Dan Neely Aug 29 '17 at 21:17

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