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#1 2020-02-24 19:18:10

SpaceNut
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NASA wants your help designing a Venus rover concept

The future is bright for mans exploration by robotics and soon for man on the moon and mars. Though we should not forget about Venus as its a world that could be when we conquer it.
NASA wants your help designing a Venus rover concept

venus-wind-powered-concept-rover-hg.jpg

What a wonderfull chance.

NASA's Jet Propulsion Laboratory in Pasadena, California, under a grant from the NASA Innovative Advanced Concepts program, is running a public challenge to develop an obstacle avoidance sensor for a possible future Venus rover. The "Exploring Hell: Avoiding Obstacles on a Clockwork Rover" challenge is seeking the public's designs for a sensor that could be incorporated into the design concept.

Venus is an extreme world. With a surface temperature in excess of 840 degrees Fahrenheit and a surface pressure 90 times that of Earth, Venus can turn lead into a puddle and crush a nuclear-powered submarine with ease. While many missions have visited our sister planet, only about a dozen have made contact with the surface of Venus before quickly succumbing to the oppressive heat and pressure.

The last spacecraft to touch the planet's surface, the Soviet Vega 2, landed in 1985. Now, engineers and scientists at JPL are studying mission designs that can survive the hellish landscape.

"Earth and Venus are basically sibling planets, but Venus took a turn at one point and became inhospitable to life as we know it," said Jonathan Sauder, a senior mechatronics engineer at JPL and principal investigator for the Automaton Rover for Extreme Environments (AREE) concept. "By getting on the ground and exploring Venus, we can understand what caused Earth and Venus to diverge on wildly different paths and can explore a foreign world right in our own backyard."

Exploring and studying different geologic units across the surface of Venus could help us understand the planet's evolution, and could contribute to a better understanding of Earth's climate.

Powered by wind, AREE is intended to spend months, not minutes, exploring the Venus landscape. AREE could collect valuable, long-term longitudinal scientific data. As the rover explores the planet, it must also detect obstacles in its path, such as rocks, crevices and steep terrain. And NASA is crowdsourcing help for that sensor design. The challenge's winning sensor will be incorporated into the rover concept and could potentially one day be the mechanism by which a rover detects and navigates around obstructions.

The difficulty of this challenge is in designing a sensor that does not rely on electronic systems. Current state-of-the-art electronics fail at just over 250 degrees Fahrenheit and would easily succumb to the extreme Venus environment. That is why NASA is turning to the global community of innovators and inventors for a solution.

"This is an exciting opportunity for the public to design a component that could one day end up on another celestial body," said Ryon Stewart, challenge coordinator for the NASA Tournament Lab at the agency's Johnson Space Center in Houston. "NASA recognizes that good ideas can come from anywhere and that prize competitions are a great way to engage the public's interest and ingenuity and make space exploration possible for everyone."

Participants will have an opportunity to win a first-place prize of $15,000. Second place wins $10,000; and third place, $5,000. JPL is working with the NASA Tournament Lab to execute the challenge on the heroX crowdsourcing platform. Submissions will be accepted through May 29, 2020.

"When faced with navigating one of the most challenging terrestrial environments in the solar system, we need to think outside the box," Sauder said. "That is why we need the creativity of makers and garage inventors to help solve this challenge."

https://www.herox.com/VenusRover
"Exploring Hell: Avoiding Obstacles on a Clockwork Rover"

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#2 2020-02-24 19:49:26

tahanson43206
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Re: NASA wants your help designing a Venus rover concept

Thanks for creating this new topic, SpaceNut .... it should have legs! 

This is (to me) a surprising direction for NASA to be looking, because ideas for blimps or dirigibles have been under development for some time.

However, solving the challenge of operating on the surface of Venus would be an impressive achievement, so I'll bet there'll be International teams at work in short order! 

(th)

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#3 2020-02-24 20:05:08

SpaceNut
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Re: NASA wants your help designing a Venus rover concept

The big issue is how to communicate from the surface with out semiconductor parts as the temperature will not allow for them to last but for only a short period of time.
I am thinking of transmitting like spark gap morse code but the power source will need to be quite protected but how would you recieve in that manner and actually perform a function based on decode of the command.
One could think of a power source as being mechanical motion such as the old watches that kept time by winding them up. It could generate power via magnets moving accross coils but how to store its energy as well how long could we concievably make it last?

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#4 2020-02-24 20:31:27

tahanson43206
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Re: NASA wants your help designing a Venus rover concept

For SpaceNut re #3 ...

Congratulations for being the first person in the NewMars community to suggest Morse Code for a lander.

Your concept of using Morse Code for communication at Venus has occurred to at least one other person in recent times.  A recent issue of Analog contains a story  about an attempted floating expedition on Venus.  What I noticed was that the author thought that it might make sense to use Morse Code to communicate with  equipment (of some kind) on the surface.

The current issue of Analog also contains a piece about the trials and tribulations of trying to live in a colony based upon balloons.

Now that you have brought this up in the forum, I will pay a bit more attention to the story, to see what the author did with it.

Please see post dated 2020/02/25

(th)

Last edited by tahanson43206 (2020-02-25 13:01:33)

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#5 2020-02-24 21:12:36

SpaceNut
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Re: NASA wants your help designing a Venus rover concept

Decoder ring comes to mind that turns and when a hit from the recieving pulse forces the mechanic lock to force a function to occur. I am reminded of an old metal tag typewriter unit that when a key is hit the motion of the hammers stamp the letter onto the metal tag made from a revolving head. This is an electric motor driven machine so something simular could make the coding to transmit messages back for temperature and other such details from a preprogrammed response to the quiry of recieved tranmissions.

5e177b7b904c4.image.jpg
vintage World War II era Graphotype platemaker machine

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#6 2020-02-25 12:58:51

tahanson43206
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Re: NASA wants your help designing a Venus rover concept

For SpaceNut re #3 (continuation of #4)

The story containing a reference to Morse Code on Venus may have itself been inspired in part by NASA planning documents.

The author is Wendy Nikel, the story title is "Around the World in Ninety-Six Hours" and the organizing theme for the story is a competition between teams exploring Mars and Venus simultaneously.  The issue of Analog is January/February 2020.

From page 146:

"All that, using nineteenth-century technology: flying balloons and rovers that transmit in Morse code. Jules Verne would have been very proud."

later:

And on the surface below, where the temperatures were hot enough to melt lead, their wind-powered mechanical rovers, propelled forward on their treads by a series of gears and levers, transmitted information back to the balloon via Morse code.

And here is a sliver of a clue about the technical basis for the story.  It may be totally fictional, or it might be based upon something that has actually been published:

"Cloud Nine" was one of the HAVOC (High Altitude Venus Operational Concept) balloons sent into Venus's atmosphere

(th)

Last edited by tahanson43206 (2020-02-25 18:28:16)

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#7 2020-02-25 19:19:27

SpaceNut
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Re: NASA wants your help designing a Venus rover concept

Making the landing do science that can be reported and commanded is the issue for no electronics and old school is the way to get around that high technolgy being defeated by the pressure and heat. That a on the machines surface can not take let allong an internal computer that can not be cooled.
I was thinking about the heat and how would you cool the insides to make electronics function and wondered if a heatpump system could be adapted. The systems on earth make use of the air temperature and a gound source of the other in order to circulate a fluid to make a cooling or heating unit for the inside of the home. Depending on the fluid flow you can creat heat or cooling in the area of the home as desired.
I think that an RTG produces heat and electrical of which is we use the heat in the place of the earth constant and the air as the dumping location we are making the potential to cool based on the function of the difference of the 2  points on the loop. Now to do some research...

https://theengineeringmindset.com/heat- … sign-data/

This crosses into the heat cause refridgeration effect or https://en.wikipedia.org/wiki/Absorption_refrigerator

https://en.wikipedia.org/wiki/Heat_pump … tion_cycle

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#8 2020-02-25 21:38:15

tahanson43206
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Re: NASA wants your help designing a Venus rover concept

For SpaceNut re topic...

In thinking about your post #7, I found an article about Venus that seems like a good fit for this topic.

https://www.space.com/44-venus-second-p … ystem.html

In recent years, NASA has funded several extremely early-stage mission concepts that could look at Venus in the coming decades, under the NASA Innovative Advanced Concepts Program. This includes a "steampunk" rover that would use old-school levers instead of electronics (which would fry in Venus' atmosphere), and a balloon that would check out Venus from low altitudes. Separately, some NASA researchers have been investigating the possibility of using airships to explore the more temperate regions of Venus' atmosphere.

I was looking for any information there might be about the interior of Venus, to see if the material under the surface might be cooler than the surface, but the indications are not encouraging.  Volcanoes appear to be active to this day.

If the material under the surface WERE cooler, then potentially your heat pump idea might have a place to dump heat to achieve cooling.

Another possibility is a real long shot.  .... or maybe not .... When I first began learning about ham radio, ** everything ** we did was vacuum tube based.

Vacuum tubes (for those who are from a generation that never saw them) function by heating a hot filament inside a vacuum chamber (usually glass but can be other material) to release electrons, which then are free to travel towards a metal surface which is deprived of electrons. The motion is caused by electrostatic force rather than magnetism.  The electrons may be forced to pass through metal grids which can influence the rate of movement of the electrons depending upon their state of charge.  Amplification of an input signal occurs if it is applied to a grid to control the flow of electrons which are greater in number than the input signal.  The result is that for a small change of polarity at the grid, a large change will be observed at the plate.

Good Grief! Google doesn't seem to know what vacuum tubes are!

I finally found citations by looking for "electronic" vacuum tubes.

https://www.nutsvolts.com/magazine/article/vacuum-tubes

I know who I can ask!  The gent who contributed to Calliban's discussion is ** very ** knowledgeable about electronics in general and "ancient" electronics in particular.

My guess is that ceramic vacuum tubes can operate happily at the temperatures found on Venus.

(th)

Last edited by tahanson43206 (2020-02-25 21:39:38)

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#9 2020-02-25 21:52:16

SpaceNut
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Re: NASA wants your help designing a Venus rover concept

We have a balloon topic for venus and cloud cities as well so thinking of how a balloon could operate the rover via remot cable connection to the computer that is in the balloon which would have solar cells to power it would not seem to far fetched but its not a direct drive rover on the ground being able to do anything other than drive around as we still need a means to get sensors to it that can work.
I remember the old tube tv's with the color tubes swapping to fix them but also of the tube audio amplifier sound that had a fuzz component that just made it sound better than sicky sweet when playing rock songs. The modern day FET replaced them as they could do the same with less voltage and achive near the same sound with them. But when it came to the need for more power its the tube that was the champion output stage that was needed to get the kilowatt sound power out of the stage setups of Marshalls, Ampegs and so many more....

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#10 2020-02-25 22:17:55

tahanson43206
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Re: NASA wants your help designing a Venus rover concept

For SpaceNut re topic ... I went looking for signs someone has considered air conditioning that would work on Venus.

I found a quora post that addresses that, and reports on some innovative ideas that might be of interest to readers of this topic.

https://www.quora.com/Is-it-feasible-to … pply-power

Elizabeth Greene, I am not an expert.
Answered Jan 15, 2018 · Author has 2.4k answers and 5.1m answer views

It is feasible, and some thought has gone into the concept. The presentation is here: A Venus Rover capable of long life surface operations (Michael Evans, James Shirley, Robert Abelson JPL/California Institute of Technology)

The proposed rover would have a surface lifespan of weeks to months, and it has some unique design features for dealing with Venus’ balmy conditions.

First, all of the electronics, even the drive motors, are inside a pressure hull. This hull is at vacuum like a thermos to help reduce heat transfer to the interior by convection. Developing the seals for this vacuum chamber would be an interesting engineering problem.

Next, they propose a Stirling engine as both the “air conditioner” and electric generator. Building an engine with moving parts that can survive on Venus is extraordinarily difficult. The proposal overcomes this challenge using a Thermoacoustic heat engine that doesn’t have any moving parts. This is the key (hard) engineering problem that would have to be solved for this mission.

Last but not least, they do something particularly clever with the rover’s batteries. Molten-salt batteries are an old technology that aren’t particularly practical for Earth. They are fantastic batteries in that they can be stored charged for a long time and have excellent rechargability. The unfortunate thing about these is that you have to get them hot enough to melt the salt to a liquid before they work. The proposed rover uses molten salt batteries and stores them outside the pressure/insulating hull so Venus herself can do the work of keeping them toasty warm.

Wikipedia has an article on acoustic heat pumps:
https://en.wikipedia.org/wiki/Thermoaco … eat_engine

(th)

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#11 2020-02-26 04:27:07

kbd512
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Re: NASA wants your help designing a Venus rover concept

SpaceNut,

The important thing that all these materials and technologies should have in common is that they're specifically designed to function in very high temperature and pressure environments.  Apart from the camera enclosures, my rover design would not be a sealed pressure vessel of any kind, meaning it would be filled with hot CO2 extracted from Venus and use the rover structure and liquid metals as coolants.

Rover Chassis

AlBeMet® Technical Fact Sheet

Mechanical and Thermal Properties of Aluminum-Beryllium AM162

Applications of an Aluminum-Beryllium Composite for Structural Aerospace Components

Deformation of a Beryllium-Aluminum Composite

Beryllium & AlBeMet® Engineered Materials That Can’t Be Beat

Rover Electric Motors

The electric motors for this rover need conductors with superb conductivity due to the heat of the operating environment.  All of the permanent magnets I’m aware of would be useless at these temperatures, so AC output from a KiloPower reactor is required to supply the electromagnetic field.  These will just be high mass, low-output industrial motors.

Electrical Insulation for High-Temperature, Cryogenic, and Other Harsh Environments

Incidentally, that Boron Nitride NanoTube (BNNT) technology I've mentioned several times in the past has oxidation resistance to as high as 900C and is a superior electrical insulator yet surprisingly good thermal conductor.

GoodFellow - Boron Nitride Nanotubes

Elsevier - CNT's are old stuff. Make room for BNNT - it is stronger and can take the heat!

Running Gear

Most likely 304 series austenitic stainless steel.  Differential hardening could produce a hard abrasion-resistant skin with a ductile core.

Power Source

I think this is an excellent candidate for a KiloPower demo mission.

KiloPower fission reactor using an AlBeMet 162 reflector and radiator to reduce mass and improve thermal conductivity over conventional Aluminum alloys.  Initial testing would seem to indicate that AlBeMet 162 actually increases in tensile strength following exposure to high proton and neutron radiation and demonstrates no tendency to lose ductility.  It's also dimensionally stable over a very wide temperature range.  The entire body of the rover would serve as the coolant loop for the reactor, rather than using separate structures.  It’s never coming back to Earth and our vast stockpiles of HEU aren’t being used for anything else, so we may as well it for a worthwhile mission.

Page 33 - Aluminum-Beryllium Composite Trade Study for Space Nuclear Applications

Electronics

Diamond-based integrated circuits to cope with the operating temperature ranges and flexible ceramic circuit boards to withstand thermal cycling and the wide range of temperatures over which they must remain flexible.  They’re good to 900C or so.

ENrG Inc - Flexible Circuit Boards

These new flexible ceramics can withstand temperatures ranging from cryogenic to 1200C.  All of the electrical connections would have to be flexible, obviously.

Cameras

Sapphire or ALON optical lenses with diamond-based imaging chips.

Communications

The X-Ray communications system NASA is testing would provide high data rate communications for relaying images and video to an overhead orbital satellite.

NASA Set to Demonstrate X-ray Communications in Space

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#12 2020-02-26 08:29:53

tahanson43206
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Re: NASA wants your help designing a Venus rover concept

For kbd512 re #11

Impressive!  This is a competition, and your design seems (at first reading) far superior to other ideas I've seen so far.  I particularly like your embrace of the operating conditions, instead of trying to defeat them.

If you have the time to pursue this, the NewMars forum seems to be a useful place to offer and hone your design.  It seems doubtful to me the exposure to the outside world is going to make much of a difference on the down side.  It is the designer who will present to the NASA review board.

And! I like your recommendation of the kilopower system, which is a NASA project in any case, so there should be some interest there in finding a new and (perhaps unexpected) application for the system.

(th)

Last edited by tahanson43206 (2020-02-26 08:30:47)

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#13 2020-02-26 11:00:46

tahanson43206
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Re: NASA wants your help designing a Venus rover concept

For SpaceNut re topic ... here is another email from [Dayton engineer]:

For Calliban ... [Dayton engineer] is unaware (I presume) of your Kilowatt proposal.

Yes, vacuum tubes are a possibility on Venus, and I think some could be developed to run in the hellish environment on its surface.  By their thermionic nature, vacuum tubes like heat.  Tubes developed in the 50’s and 60’s include the ceramic transmitting type that you’ve seen at Roger Smith’s Tesla coil run.  His big tube coil is powered by an Eitel-McCulloch (“Eimac”) 3CX10,000 triode that can dissipate 10,000 watts of waste in its anode (plate).  It is used in medium wave (AM) broadcasting.

I always envisioned a Venus lander with a strong fission reactor to supply power for a refrigeration system to keep the instrument bays of the probe below 200 degrees F, but that won’t happen any time soon.  The irrational fear of nuclear fission power, and government strangling of research and development of nuclear power has stunted our space program and power generation industries for 75 years.

Back to practical reality: A simplistic Venus probe run by vacuum tube would still need a stout power supply to carry the filament and plate power requirements of the tubes.  Everything would have to be analog, but we did great things with analog space exploration before computers were made light enough to fly.  Everything before the Voyager probes were pretty simple, but we learned a lot from those machines.

Miniature versions of the ceramic transmitting tubes could be used for processing and control.  A traveling wave tube can de used to transmit to an orbiting relay, or directly to earth.  Circuitry could be welded instead of soldered, like the Apollo Guidance Computer.  If the scalding wind howls, a windmill or two may keep up with the load, but tubes require lots of power, so a fission reactor would be so much better!

Edit#1: Roger Smith has a presence on the Internet, which is why I left the reference in place.

Search for Roger Smith Tesla

(th)

Last edited by tahanson43206 (2020-02-26 11:03:40)

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#14 2020-02-26 17:31:51

SpaceNut
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Re: NASA wants your help designing a Venus rover concept

Venus is an extreme world. With a surface temperature in excess of 840 degrees Fahrenheit and a surface pressure 90 times that of Earth, Venus can turn lead into a puddle and crush a nuclear-powered submarine with ease.

Disapating to the ambient temperature of venus surface is not cooling and vaccumns do not stay vaccumns the moment you want to try to pass anything through the walls of it and expect the item to be able to turn as in an axel shaft for the moving let alone keep the venus acidic pressure out.

The chamber for the electronics will need to have wiring going out of the area through isolation connections to send out to the motor and all other extrenal devices. Until we decide on that chambers materials properties for conduction of ac signlas through it, structural pressure differential we really are not going to be able to make much progress for the design of the wheel motors as the wiring insolation will need to be high temperature and flexible at the surface temperatures that they will see.

One method would be to use the cellphone charging plates to pass power through the chamber walls as its creating a magnetic field of ac or rf which will be captured by the reciever plate on the outside before bringing it to the motor connections. Can it be inductive motor or are we forced to use brushes to the rotor fields?

Here is a chart for metals or alloys that will be possible for soldering the electrical connections for the circuit board connections since cooling is to ambient venus surface temperatures..
metal_melting_ranges.jpg

http://www.calqlata.com/productpages/00065-help.html
Pressure Vessel Calculator (ASME VIII)

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#15 2020-02-26 18:40:32

tahanson43206
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Re: NASA wants your help designing a Venus rover concept

For SpaceNut re #14

** Very ** nice!  The chart you provided gives support to a private email suggestion from [Dayton Engineer] that electronic circuits could be welded rather than soldered for service on Venus.  [Dayton Engineer] seems skeptical that vacuum tubes (which I'm advocating) can survive 90 atmospheres of pressure or (for that matter) 900 degrees Fahrenheit.

However, it seems quite likely to me that a serious impetus from NASA (which this competition seems to be) will stimulate creative thinking around the globe, and it seems likely (to me at least) that if solutions allowing modern electronics to not only exist but actually excel on Venus are available, they will show up in coming years.

Ceramic materials appear to be capable of serving as insulators.  Something I just thought of is the potential to create 3 dimensional electronics structures using 3D printing technology that exists today to lay beads of ceramic paste interwoven with metal paste in solids which can then be baked in ovens to whatever temperature is optimum.

Edit#1: Logic gates don't ** have ** to be electronic!  They can be mechanical.  Physical flaps can flip back and forth inside a ceramic circuit brick, to hold bits for computations. 

Let's GO! Inventors!

(th)

Last edited by tahanson43206 (2020-02-26 18:43:31)

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#16 2020-02-26 19:00:25

SpaceNut
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Re: NASA wants your help designing a Venus rover concept

The component leads them selfs can be crimped as well and not use any circuit boards but the vaccumn tube days for a computer would be super large and limited for memory types that could survive the heat.

Temperature and magnets as a general will lose the magnetic properties as temperatures rise to the curie point in which one can change the direction of the materials pole orientation. https://en.wikipedia.org/wiki/Curie_temperature
This is how a CD works as the laser heats a spot and the magnet sets the value for digital 1 from a zero on the media platter.

https://www.jobmastermagnets.com/how-do … nt-magnets

https://en.wikipedia.org/wiki/Magnetism_and_temperature

https://www.kjmagnetics.com/blog.asp?p= … um-magnets

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#17 2020-02-26 19:03:16

tahanson43206
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Re: NASA wants your help designing a Venus rover concept

SpaceNut re topic .... How soon we forget!

World War II had mechanical digital devices.  The combatants had thousands if not millions of them.

In the United States, the Hollerith card systems employed by the US government kept records of just about everything imaginable.

Huge buildings full of such machines were still hard at work in Indianapolis as late at 1964, doing payroll for the US Government.

Such machines (with slight adaptation for 900 degree operating temperatures) would (I feel confident) perform just ** fine ** on Venus.

Another candidate for a mechanical computing system, long set aside by society, is the original Babbage Difference Engine technology.

With modern manufacturing at the nano-scale, the Babbage designs could come into their own for the first time.

(th)

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#18 2020-02-26 22:11:29

kbd512
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Re: NASA wants your help designing a Venus rover concept

SpaceNut,

Everything built into the rover needs to be intrinsically capable of operating at the heat and pressure it will be subjected to.  We're not going to build absurdly strong and heavy pressure vessels because from numerous data points, admittedly most of it relating back to the Soviet Union's hard-won experience with Venus landers, that doesn't work.  Solids are not compressible and therefore everything will be solid and filled with solids or otherwise exposed to the environment.  The entire structure and all electronics will be thermally soaked, so all materials will be capable of operating at that temperature without oxidation.  There's no other practical solution for an extended duration mission.

We're not going to be soldering any connections onto anything because that won't work.  We're going to use spring-loaded pins to make electrical connections to deal with the thermal expansion and contraction that the rover will experience as it transitions from the cryogenic cold of deep space to the Lead melting heat of the surface of Venus.  Nearly everything on this rover needs to be permitted to flex or expand and materials must be matched for thermal expansion.  The mechanical connection points for electronics will be minimized and those will also have to be spring-loaded or loosely connected.

If electric motors with more massive conductors in their windings won't operate sufficiently well at those elevated temperatures because the electrical resistance becomes to great, then we'll resort to a secondary coolant loop to produce hydraulic pressure for motive power.  Power from the reactor could also potentially be used by MOXIE to split CO2 into O2/CO to burn in a small combustion engine that provides hydraulic pressure.  This secondary coolant loop would also be filled with incompressible liquid metal.  We could use Lead-Bismuth eutectic since that boils at 1,670C.

Given that KiloPower or some variant of NASA's MMRTG is producing a thermal delta roughly double the surface temperature of Venus (462C surface temperature versus 850C for KiloPower or 1,050C for Pu238 bricks; the temperature limitation for KiloPower is the materials selected for thermal power transfer, not the core- Dave Poston specifically said "we can go hotter if we need to"), the 90 atmospheres of pressure does become a very conductive heat sink and the entire AlBeMet (melting point between 644C and 1,180C, heat treatment near 592C, its surface is passivated / corrosion resistant up to 600C; tensile strength testing conducted between -195C and 500C) chassis of the rover is the heat sink and it conducts heat even better than Aluminum.  The sensor and electronics packages for vehicle control, communications, and scientific instruments make use of very high temperature components such as diamond-based semiconductors and flexible ceramic (circuit boards / ribbons) and BNNT insulators (wire wraps to prevent short circuits).  Since we do have sensors that operate inside of or are directly connected to the hot section of jet engines, this is not beyond our capabilities.

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#19 2020-02-27 10:09:53

tahanson43206
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Re: NASA wants your help designing a Venus rover concept

kbd512 re #18 and previous posts

Your example of embrace of the premise of the NASA competition is encouraging.

[Dayton Engineer] is about as committed to the "Olden Days way of doing things" as anyone I know, despite being of middle years.

Despite his reservations, he offers this update to the topic by email:

Turbopump grease can lubricate at 900 deg. F.  It’s expensive...

Oils used in the J58 and GE4 supersonic jet engines may qualify.

To [Dayton Engineer] ** everything ** is expensive! 

(th)

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#20 2020-02-27 10:48:29

tahanson43206
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Re: NASA wants your help designing a Venus rover concept

For SpaceNut re topic ...

[Dayton Engineer] is back with another email:

High pressure is used to force the gas to condense.

In normal refrigeration, Freon is compressed to about 180 psig or thereabouts so it will condense at ambient pressure.  It is then sprayed into an area of very low pressure, where it evaporates into a gas.  This state change requires energy, and that is pulled from the cold space, making it colder.

The low pressure gas is then compressed again to force it to condense.  The heat of compression. And heat from the cold space is rejected to the atmosphere via the condenser coil.

A “refrigerant” for a Venus cooling plant would have to be an exotic compound, possibly something like sulfur hexaflouride or a duke’s mixture of chemicals.

It is not necessary to use Morse code for communications.  8 bit ASCII can be run at 100 words per minute using mechanical teleprinter techniques.  The old Teletypes used mechanical distributors to perform serial to parallel conversion of bit streams.

I had asked for help understanding how a refrigeration system could work on Venus, if the heat sink temperature is well above the desired cool temperature. In combination with the reply above, and a bit of reflection, I realized that the routine production of liquid hydrogen and liquid oxygen (two of many examples) occurs under ** precisely ** those conditions.  The heat sink of the surface of the Earth, or even the oceans, is far HIGHER in temperature than the desired end state of the products.

On Venus, were a submarine to be constructed to explore there with human occupants, the heat sink temperatures would be higher than the ones we are used to on Earth, so the heat pump would need to operate at even higher temperatures in order to dump heat to the outside.

Both kbd512 and [Dayton Engineer] appear to be in agreement that atomic power is required to support safe operation of such a vehicle.

(th)

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#21 2020-02-27 18:11:02

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 23,096

Re: NASA wants your help designing a Venus rover concept

We currently has cutting edge technology, of which it is funny that Nasa would not know of these materials and that leads me to believe that either they do not know or the materials fail under testing...Old school mechanical can also fail I am sure with both as viable as the other that it will come down to building them and sending them to venus in order to see how well they will do.

Morse code is a serial data bit transmission as the ascii serial port would be its just a different coding and decoding to make it make sense to the person and machine that will recieve it. One where if you can not get components to survive the temperature leads to working in a different manner for technology versus mechanical.

Things we know that change with temperature for technology is the coil of wire for a motor when exposed to heat rises with its resistive value which will mean, that higher voltages will be required. The coils insulated materials will also burn off causing wire shorting for the magnetic field to form with in it as we apply ac power or pulsed dc. There must be higher temperature insulation out there but with thickness we will need more windings or voltage to make the field strong enought.

Working fluids will see higher pressures and temperatures that we would use in simular systems of earth for sure and that is why we prototype and test to assure the design and quality of operation.

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#22 2020-03-01 18:58:34

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,096

Re: NASA wants your help designing a Venus rover concept

I was reminded that the difference of a reactors temperature of a working fluid and the temperature of the surface temperatures could be used to generate power that could be used for making motion.

I had posted this in the steam use on mars when I was looking at the rotary engine and how if we used continuous heat from an RTG that would allow venus air to be used directly and use the output side to work as a step up compressor. As temperature rises the shaft would turn to create motion.

crossectiona.gif

Inject the mars air into the chamber where its heated by the fluid jacket to make the pressure rise in the chamber to make it move.

So multiple chambers would increase the amount of movement.

http://runingonair.blogspot.com/2008/12 … y-air.html

http://www.keelynet.com/minto/minto2.htm

Minto Wheel Based Heat Energy Recovery Systems

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#23 2020-03-01 20:22:15

tahanson43206
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Registered: 2018-04-27
Posts: 7,326

Re: NASA wants your help designing a Venus rover concept

For SpaceNut re topic

[Dayton Engineer] indicated that lubricants exist that will work above 450 Centrigrade.

I went looking today for examples that might be useful for the Venus rover problem.

https://www.machinerylubrication.com/Re … -lubricant

The article at the link above contains a table showing that most known lubricants fail before or at 370 degrees Centrigrade.

however, I found this note:

As you can see, the choices become very limited above 400 degrees C. There are lubricants that can be used well above this temperature range, but the problem with them is that they are solids at normal temperatures, which poses a huge problem for transferability.

While I can understand the objection for an Earth application, which might be expected to cycle from above 400 degrees C to well below, on Venus, that would NOT be the case!  Accordingly, if we (forum members) can find examples of lubricants that work well above 400 degrees C, we can anticipate they will be shipped to Venus as solids, but they will soften and liquefy as they descend closer to the surface of the planet, and come into their own there.

Setting aside the question of lubricants for a moment, I went looking for information about which metals or alloys perform well above 450 degrees C.

https://www.engineeringtoolbox.com/melt … d_860.html

The article at the link above contains a table of metals and alloys and their performance at various temperatures.

I was encouraged to see that a large number of the items listed perform well above 450 degrees C.

It would appear that a Babbage machine, or any of the electromechanical designs from the "age of Hollerith machines" would work well on Venus.

SpaceNut made the observation that resistance of conductors increases with temperature,

People also ask
What type of wire is used in very high temperature locations?
SRML high-temperature wire is motor lead wire for hazardous locations and may be used for internal wiring of equipment in high-temperature environments.

High Temperature Wire and Heat Resistant Wire | Allied Wire & Cable

Silver is known to be the element which is least resistive to flow of electric current of all the elements.

I would expect it to perform well at 450 degrees Centigrade if it does not melt.

Per the table of melting points at the engineering web site given above, it is shown that both Silver and Copper remain solid well above the temperature at the surface of Venus.

Edit#1: https://hypertextbook.com/facts/2004/GeorgeBauer.shtml

The article at the link above includes a section which lists the conductivity of Silver as affected by temperature.

Calvert, James. Copper, Silver, and Gold. University of Denver. 2002.     "The electrical resistivity of silver is 1.62 μΩ-cm and the temperature coefficient is 0.0038 per °C"     1.62 × 10−8 Ωm

450 degrees Centigrade is given as the temperature at the surface of Venus.
20 degrees Centigrade is given as the reference temperature for the resistivity of Silver
430 degrees is the difference.
430 times .0038 is 1.64

I ** think ** this result means that Silver will decrease in conductivity, or increase in resistivity, from 1.62 microOhms per centimeter to 2.66 microOhms per centimeter.

SpaceNut, if you have time, I'd appreciate your checking my figures here.  I think the result shows that Silver would work fine as a conductor of electrical current on Venus.

So far, no show stoppers have shown up that I've been able to find, to interfere with design of machinery that could function at the surface of Venus without cooling.  I'll admit that my exploration of the search space is quite limited, and much more work remains to be done.

Happily, without a doubt, people across the planet are diving into the challenge.

Edit #2: Firefox came up with this citation on its own ... It (or Google?) noticed I was looking for high temperature lubricants, so it showed this:

https://www.machinerylubrication.com/Re … -lubricant

As far as lubricant selection, there are many choices for temperatures below 100 degrees C, which makes the decision more difficult. However, for temperatures above 400 degrees C, only a small handful of lubricants are available, making the decision process much easier. The only lubricants with long life at these temperatures are liquid metals, liquid oxides, glasses and a few solid lubricants like molybdenum disulfide.

I was struck by the idea that glass in the molten condition would be a useful lubricant.

It would seem that thinking well outside the "Earth Box" will be called for.

(th)

Last edited by tahanson43206 (2020-03-01 20:49:10)

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#24 2020-03-01 21:07:28

kbd512
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Registered: 2015-01-02
Posts: 4,615

Re: NASA wants your help designing a Venus rover concept

If high temperature lubricants are solid at room temperature, then you wait until the rover has been thermally soaked before operations begin.  I don't think this would be an actual problem since the rover would be thermally soaked by the time it landed if the entire chassis was a highly conductive alloy like AlBeMet.  It's worth noting that some types of batteries operate at fairly high temperatures, so a rechargeable battery required to initiate startup of the reactor should be fine.  Certain types of Sodium-based batteries operate between 400C and 700C, with some of them achieving energy densities similar to Lithium-ion (150Wh/kg to 200Wh/kg).

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#25 2020-03-01 22:39:04

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 23,096

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