
Electronics robust enough for Venus - sohkamyung
http://physicstoday.scitation.org/do/10.1063/PT.5.7345/full/
======
simonbarker87
Nice to see this area is still evolving, my PhD was in SiC-related tech,
specifically how would you power a device embedded in a hostile environment so
I was researching SiC-based photovoltaics, temperature response of
piezoelectrics, high-temperature DC-DC converters and a very light touch
effort on high-temperature storage.

As soon as you start heating electronics up to these sorts of temperatures the
things we already take for granted become problematic. As highlighted already,
solder joints become a huge pain, wire bonds pop off, even just building the
test rigs to test these devices is usually a pretty interesting problem - I
built a high-temperature photovoltaic characterization rig and a high-
temperature vibration rig, which was involved enough but the true monster was
the gas-sensor characterisation lab which had evolved over many years that
could do gas, high pressure and temperature up to 700 degC (I think).

All good fun, if someone is looking at a PhD in electronics I would recommend
this area if even vaguely interested as it's a good mix of practical and
theory and when you can't even bank on your solder joints holding, let alone a
dielectric surviving then it makes for some interesting problems away from the
pure electronics.

------
rabboRubble
I recall a story from a Russian aerospace engineer describing a Russian
unmanned probe to Venus. They mounted a camera and arm to the probe to take
pictures and to measure the chemical composition of the planet's surface. He
said the camera cover popped off at the appropriate moment to land exactly
where the arm hit the ground. They got a very good measurement of the camera
cap's chemical composition. I'll see if I can dig up a link.

Found it... actually the arm was to measure the compress-ability of the
Venusian soil

[https://en.wikipedia.org/wiki/Venera_14#Landing](https://en.wikipedia.org/wiki/Venera_14#Landing)

~~~
westbywest
Actually, the camera was embedded deep inside the probe's pressure vessel. The
aperture on the probe's surface was glazed with a quartz window, and the image
projected through a long periscope arrangement to the sensor inside.

------
ChuckMcM
Wonderfully the paper is available:
[http://aip.scitation.org/doi/10.1063/1.4973429](http://aip.scitation.org/doi/10.1063/1.4973429)
consider swapping the link for this one.

Reading through the paper I have to admit those are some really impressive
numbers. A typical soldering station might run at 343C (650F) while Venus is
460C (860F) hotter than a reflow oven to be sure.

~~~
WaxProlix
To clarify for anyone as dim as I - Venus is 460C (860F) and is hotter to be
sure than a typical soldering station, which runs at around 340C (or 650F) -
it's not the case that Venus is 460C hotter than a reflow oven.

~~~
logfromblammo
This is where a grammar enthusiast might extol the virtues of the em dash.

> _...while Venus is 460C (860F)--hotter than a reflow oven, to be sure._

------
Robotbeat
Interestingly, with a few hundred gates you can produce the circuitry needed
to digitize data from a seismometer (one of the main reasons you'd want a
long-duration lander on Venus), do some basic forward error correction, and
transmit to a relay satellite. You'd have basically no memory, since memory is
extremely expensive energy-wise and consumes a lot of gates, so you would just
transmit the data as it is received. Just a few hundred gates is not
unreasonable to make out of these relatively primitive high temperature
circuits. A full computer with memory is not feasible, but neither is it
required to accomplish the mission. Here is a paper describing a Venus mission
operating entirely at high temperature using the kinds of digital circuits I
described:

[https://www.researchgate.net/publication/272522839_Venus_hig...](https://www.researchgate.net/publication/272522839_Venus_high_temperature_atmospheric_dropsonde_and_extreme-
environment_seismometer_HADES)

------
Jun8
The thing that struck me was the Glenn Extreme Environments Rig (GEER),
([https://geer.grc.nasa.gov/geer-overview/overview-of-
geer/](https://geer.grc.nasa.gov/geer-overview/overview-of-geer/)). That thing
is a beast! Operating 24 days with 470 C and 1400 psia gas mixture (including
acids) sounds like an amazing feat.

~~~
Robotbeat
I think I have some pictures of it that I took while I was an intern there.
It's basically an autoclave with fancy gases.

------
curtis
Electronics aren't the only problem for a Venus probe. You also need some way
to power the thing. One interesting possibility is that lithium will combust
in a carbon dioxide atmosphere, and it is also, conveniently, liquid at Venus
surface temperature.

[http://www.bbc.com/future/story/20160705-the-toughest-
spaces...](http://www.bbc.com/future/story/20160705-the-toughest-spaceship-
weve-ever-built)

~~~
TeMPOraL
Idea: put a good insulator under the surface of the probe to keep as much of
it as cool as possible (first making sure it cools off in space). Ship it with
a thermoelectric generator. I'm not sure how much useful power you'd get from
the spacy-cool - Venus hell temperature gradient, so maybe it's a stupid idea.

~~~
masklinn
> first making sure it cools off in space

Heat dissipation is actually a gigantic problem in space: you can only radiate
heat away (and try to reflectively shield against the sun) since you're in
hard vacuum which is a fantastic insulator.

~~~
logfromblammo
Basically, you need a sun-facing shield that is perfectly reflective, and
diamond fins with a perfectly black surface coating, forever in its shadow.

An effective radiator is an equally effective absorber, so management of light
and shadow is critical.

But it's still sort of moot when you consider atmospheric friction on the way
down.

You're not going to get much power out of the gradient. Even if you cooled an
object in space to near absolute zero, space probes must necessarily be low
mass to get into orbit from Earth. The low mass of the whole object, and the
low heat capacity of most space-grade building materials combines to make it a
really awful cold sink. You would essentially need to harvest water and
ammonia from somewhere outside of a gravity well, use your radiator to cool it
off as much as possible, and then drop it in the heat well. That's an awful
lot of trouble to go to for the amount of power you will then get out of it.

------
Animats
Finally! We need more info about Venus. Mars is a boring desert. Venus has
more action. So when do we see a Venus rover?

~~~
Sir_Cmpwn
Certainly not any time soon. A rover has a lot of complicated moving parts
that will have to be exposed to work properly, and will almost certainly fail
after a short time on the surface. All of the sensors will also have to be
exposed, and the interface between the sensors and the enclosure will be
vulnerable. A lander may work for some time, but a rover would be very
difficult. Venus is a very, very harsh place.

~~~
Animats
So is the drilling end of an oil well, but there are sensors and motors for
that.[1] "The heavy duty motor range is designed to withstand temperatures
over 240°C at pressures up to 1,733 atmospheres. They can withstand vibrations
to 25 Grms, impacts to 100 G." A 2005 study indicates how to get motors to run
at up to 500°C, which is above what's needed for Venus.[2]

Power systems for a Venus lander have been studied by NASA.[2] Sodium-sulfur
batteries, which need to be hot to work at all, were considered.

[1]
[http://www.maxonmotorusa.com/maxon/view/application/Brushles...](http://www.maxonmotorusa.com/maxon/view/application/Brushless-
DC-motors-for-down-hole-and-directional-drilling) [2]
[https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/201400...](https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140017762.pdf)
[2]
[http://www.firstmarkaerospace.com/pdf/vhtmotors.pdf](http://www.firstmarkaerospace.com/pdf/vhtmotors.pdf)

~~~
masklinn
> The heavy duty motor range is designed to withstand temperatures over 240°C

Venus is twice that, and the atmosphere is highly corrosive, though I guess
you get the benefit of lower pressure (~90 atm).

~~~
gene-h
NASA has successfully tested electric motors at venusian ambient
conditions[0]. Also, the atmosphere isn't corrosive at the surface. It's much
too hot for sulfuric acid there.

[0][http://www.techbriefs.com/component/content/article/ntb/tech...](http://www.techbriefs.com/component/content/article/ntb/tech-
briefs/mechanics-and-machinery/2241)

------
th0ma5
The is intense. I've often thought about the Russian Venus lander. In the same
vein I occasionally think about what could survive deep within the Earth. Of
course I then immediately get tripped up wondering if any useful satellite
could be made to work within the Sun, and that's where I realize I should just
think about something else.

~~~
mirimir
In _The Killing Star_ by Charles Pellegrino and George Zebrowski, one group of
survivors orbits a ship around the Sun, just below the chromosphere. There's
also a story about "distilling antihydrogen" near the Sun, in Vernor Vinge's
_Marooned in Realtime_.

~~~
masklinn
David Brin's Uplift series had mechanised lifeforms "floating" on the sun to
collect matter, and IIRC Sundiver has life forms floating in the chromosphere.

~~~
pavel_lishin
As I recall, Sundiver used a laser to beam away the accumulated heat into
space faster than it was absorbed.

------
imglorp
A closely related subject is radiation. If you want to explore Jupiter,
Saturn, or Fukushima you have some new challenges.

In the latter case, they're talking only a few hours of lifetime for ROV's
going into the 500+ Sv/hr environment. I bet the military has a bunch of
research on rad-hard equipment they're not keen to share.

[http://www.smithsonianmag.com/smart-news/fukushima-
reactor-s...](http://www.smithsonianmag.com/smart-news/fukushima-reactor-
shows-highest-radiation-level-initial-meltdown-180962050/)

------
avian
Some sources claim that in the 1980s USSR already developed instruments that
were capable of operating at surface environment of Venus as part of their
Venera program. From [1]:

While never deployed, a seismometer and thermopile battery were developed and
tested, capable of operating indefinitely on the surface of Venus.

[1]
[http://mentallandscape.com/V_Venera11.htm](http://mentallandscape.com/V_Venera11.htm)

------
SticksAndBreaks
Could some genetic engineered plants survive the upper layers of the
atmosphere if they where able to fly/float?

~~~
runholm
"While Venus’s surface is awful, its upper atmosphere is surprisingly
Earthlike. 55 kilometers up, a human could survive with an oxygen mask and a
protective wetsuit; the air is room temperature and the pressure is similar to
that on Earth mountains. You need the wetsuit, though, to protect you from the
sulfuric acid."

[https://what-if.xkcd.com/30/](https://what-if.xkcd.com/30/) (not quite a
scientific source, so make what you want of it)

Maybe if your plants can deal with the acid you might be able to do it. (I am
not a biologist, chemist or anything relevant to answer this question, this is
just my best guess).

~~~
sohkamyung
Exploring the atmosphere of Venus has been considered. Here's an article on it
[1]

[1] "NASA Study Proposes Airships, Cloud Cities for Venus Exploration"
[http://spectrum.ieee.org/aerospace/space-flight/nasa-
study-p...](http://spectrum.ieee.org/aerospace/space-flight/nasa-study-
proposes-airships-cloud-cities-for-venus-exploration)

------
jeff_vader
Has anyone ever bumped into similar articles about electronics longevity?
Sayyy.. Could we build a simple Voyager like probe that can last 1000 years?
10000?

~~~
jerf
Given the challenges involved in making a 10,000 year clock, a 10,000 year
space probe seems currently infeasible:
[http://longnow.org/clock/](http://longnow.org/clock/)

Putting it in space opens up some advantages, though that comes with its own
whackload of disadvantages, too. Perhaps you could stick something in
permanent shade on the moon to avoid 10,000 years of thermal stress, for
instance, but you've got a decent chance of something hitting you hard enough
to break something over that time span, too.

------
general_ai
It just blows my mind that Soviet Venera landers were sending digital (!)
images back from the surface of Venus in early 80s. This would be a heck of an
achievement even today some 35 years later.

~~~
tmsldd
Yeah, amazing achievement... there are many applications scenarios where the
old vacuum tubes are still unbeatable ..

