Author Topic: Clockwork Rover to Explore Venus - AREE  (Read 4779 times)

Offline savuporo

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Clockwork Rover to Explore Venus - AREE
« on: 08/09/2017 01:17 AM »
http://spectrum.ieee.org/automaton/robotics/space-robots/jpl-design-for-a-clockwork-rover-to-explore-venus

Quote
A conventional approach to a Venus rover like this is difficult, expensive, and potentially dangerous, but a team of engineers at NASA’s Jet Propulsion Laboratory (JPL), in Pasadena, Calif., have come up with an innovative new idea for exploring the surface of Venus. If the problem is the electronics, why not just get rid of them, and build a mechanical rover instead?

With funding from the NASA Innovative Advanced Concepts (NIAC) program, the JPL team wants to see whether it might be possible to build a Venus exploration rover without conventional sensors, computers, or power systems. The Automaton Rover for Extreme Environments (AREE) would use clockwork gears and springs and other mechanisms to provide the majority of the rover’s functionality, including power generation, power storage, sensing, locomotion, and even communication: no electronics required. Bring on the heat.



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Offline Norm38

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Re: Clockwork Rover to Explore Venus - AREE
« Reply #1 on: 08/09/2017 02:51 AM »
 Very steampunk. Can a spark transmitter reach an orbiter?  Bandwidth will be horrible but there probably won't be much to send.

Offline Zed_Noir

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Re: Clockwork Rover to Explore Venus - AREE
« Reply #2 on: 08/10/2017 10:46 AM »
More details on this from a FISO telecon presentation on May 24th, 2017 with Jonathan Sauder and Evan Hilgemann from JPL. Audio & slides links below.

Presentation Slides

MP3 Audio Presentation



Offline john smith 19

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Re: Clockwork Rover to Explore Venus - AREE
« Reply #3 on: 08/18/2017 09:09 AM »
Very steampunk. Can a spark transmitter reach an orbiter?  Bandwidth will be horrible but there probably won't be much to send.
In the early years of the 20th century spark transmitters could send across the Atlantic.

I think the issue is that Venus has a very active weather system so the challenge is picking the signal out of the static.  :(

Either serious processing power on the orbiter or record and relay to Earth for processing.
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline john smith 19

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Re: Clockwork Rover to Explore Venus - AREE
« Reply #4 on: 08/18/2017 11:35 AM »
More details on this from a FISO telecon presentation on May 24th, 2017 with Jonathan Sauder and Evan Hilgemann from JPL. Audio & slides links below.

Presentation Slides

MP3 Audio Presentation
I've now heard the sound and presentation.

Once you get past the reaction of "This is barking mad"  :) you start to appreciate it's benefits. There also seem to be a few disconnects between what mechanical  technology has achieved and what people think it can. A read through the annual proceedings of the NASA "Space Mechanisms" conference demonstrats some truly astonishing space rated gadgets. One of my favorites was the deployment system for the Trident missile "aerodisk," which pops up the spike during a trident launch to cut drag by 50%.

The rover is pretty big, which suggests it's going to need quite a lot of power. If power is roughly pressure X volume of fluid through the turbine that's going to be issue, despite the very high static pressure.  :(

Data transmission. I quite liked the reflection mode radar Aldis lamp concept  :) but I think people underestimate how much bandwidth you can get with physical movement, if it's small enough.
This device for example had a bandwidth of several KHz.

https://en.wikipedia.org/wiki/The_Thing_(listening_device)
http://www.cryptomuseum.com/covert/bugs/thing/index.htm

Likewise this device managed maths functions at 21Hz.

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

I liked the idea of multiple single function probes the rover could drop at different locations for long duration data on temp, pressure and seismic activity but they also said you'd only have site of the orbiter data relay for maybe 10mins at a time.

The big difference between analog and digital computing is the ability of the digital computer to change what it does based on on its inputs [EDIT including what it does with those inputs. ]  Actual analog computers compute basically a single function, or very small group of functions, which is nowhere near the "universal machine"

The question is really do you need that level of flexibility or is Venus so hostile that any data is better than none or do "hard wired" (there doesn't seem to be an equivalent term for a rigid function mechanical system) mechanical systems perform adequately enough?

I personally would love to see a mechanical digital computer but you have to address how is it powered? What does it use for RAM? What does it use for ROM (probably the simplest of all. I'd go with a "player piano" with either an endless loop of metal foil or an instruction to rewind and start at the beginning  ).
What does it use for long term data storage? Mechanical profileometers have been able to measure surface features in the micro inch range (IE 25.4 x 10^-9 m)

I note that they seem to want to use analog computing devices but the "subjunction" architecture is based on little FSMs. That implies a digital system of some sort.

Venus is a very hostile atmosphere. I suspect their biggest challenge will be (conceptually) their simplest. Actual movement. Driving the rover (and storing the power to drive it during a 58 day "night" if needed) . deciding when it's gone far enough, or found something "interesting" and what to do if it gets into difficulty ) although the "tank" geometry looks like a big help in this situation.

[EDIT Their presentation talks about using a "composite spring" for energy storage. These turn out to be available
http://www.abssac.co.uk/p/Wound+Springs/Carbon+Composite+Springs/141/#.WZdEirg6Vkh

and it turns out DuPonts "Vespel" polymers are listed as being stable up to 398c (although not in air).

This raises the question "how close to Venus ambient do you want to run the rover internals." Pressurizing the rover internals to Venus ambient (giving a near all mechanical system) means you no longer need a pressure vessel that survive a pressure difference of 90bar and does not have to be a sphere or cylinder.

It gets more tricky if you want to run the internals at near Venus ambient temperature, which you also probably want to do. That eliminates needing a cooling system but complicates managing friction, which is going to be a big part of any such design. Fortunately Silicon Oxide and Nitride bearings can run to very high temperatures and quite a lot of work has been done on oil free gas turbine designs, which have similar issues. Otherwise you're probably looking at solid high temperature lubricants like MoS. Again filling the vehicle with a high pressure inert gas (He,Ar, N2 or even CO2) is a good idea. Another question is if you're doing active cooling do you want the inside filling to be a good or a bad heat conductor?

One point with a mostly mechanical system is how do you transmit data between units? Shaft rotation? Shaft sliding? If you relax the restriction from "mechanical" to "non electrical" that would allow transmission using fluid pressure of some kind, which at this these temperatures could include anything up to using Lead as a hydraulic fluid, although you'd probably want to use some lower Mp alloy like a Gallium mix   :)   ]


Note. Just because such a system measures pressure with a Bourdon gauge, or temperature with a bimetallic strip or seismic activity with a lump of metal on an arm (devices from the 19th century or earlier) does not mean they have to be designed by methods from the 19th century.  :)

If you were trying to design a full size steam locomotive would you do without CFD for tube design and stress calculations? Would you rule out CNC for the plates, or FSW for the joining?

Once you implement such devices using 21st methods the results you can achieve may surprise people. [EDIT As KE Drexler noted at nanometre scale a computer based on mechanical motion could cycle at 1GHz.

Conventional (wet) photochemical machining can deliver line widths and foil thicknesses of a few thou IE 50micrometers. ]
« Last Edit: 08/18/2017 08:59 PM by john smith 19 »
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline Star One

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Re: Clockwork Rover to Explore Venus - AREE
« Reply #5 on: 08/28/2017 04:24 PM »
More here.

NASA goes Steampunk for its future Venus probes

Quote
"The NIAC program is designed to let technologists stretch and create concepts that have never been considered by NASA before," said NIAC program executive Jason Derleth, adding that ideas can come from universities, businesses or garage inventors. Still, proposals must be based on "solid scientific and engineer principals and to advance NASA's mission objectives," he adds. An example of that is Adrian Stoica's folding mirror probe, that would create a "solar oasis" on the moon, approved for fuding at a prior NIAC symposium.

The most interesting project is AREE (Automaton Rover for Extreme Environments), a Venus probe. Since our unfriendly neighbor of a planet can hit 842 degree F temperatures and 90 times Earth's atmospheric pressure, most electronics would be dead on arrival.

AREE would actually use Venus' conditions to its advantage by taking power from the wind and tapping a mechanical computer. A radar reflecting piston would move up and down to transmit surface "data" as morse code, which could be picked up by "repeater" balloons and transmitted to Earth from an orbiter.

https://www.engadget.com/2017/08/28/nasa-futuristic-probes-niac/

Offline john smith 19

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Re: Clockwork Rover to Explore Venus - AREE
« Reply #6 on: 08/29/2017 08:42 AM »
More here.
https://www.engadget.com/2017/08/28/nasa-futuristic-probes-niac/
The video's quite entertaining. It gives you an idea of how they move.

A good question is how wind speed compares when the medium is 90x denser than Earth?

Assuming the probe can see the Sun it is possible to perform passive spectroscopy of elements, given the orbiter would have a clear shot of the Sun from above the atmosphere through Differential Optical Absorption Spectroscopy.

Actual imaging would remain very difficult. The Viking lander cameras seem to have the (relatively) simplest electronic system, with 12 sensors (roughly broadband, 3 color, IR bands), because the motor drive signals for the casing slot and nodding mirror can be replaced by mechanical drive indexing.

A Focal Plane Array systems starts with the question can you get an FPA that doesn't need cooling? If  you can't can it survive at Venus ambient between images? If it can't then you're looking at a permanent cooling system.  :(

"line scan" (Viking) type sensors may also be temperature sensitive, but the smaller number should make it easier to deal with. Worst case may call for special sensors built to do the job in something like SiC. Easier to do with single sensors, rather than a complex scanned array.
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline A_M_Swallow

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Re: Clockwork Rover to Explore Venus - AREE
« Reply #7 on: 08/29/2017 11:25 AM »
More here.

NASA goes Steampunk for its future Venus probes

Quote
"The NIAC program is designed to let technologists stretch and create concepts that have never been considered by NASA before," said NIAC program executive Jason Derleth, adding that ideas can come from universities, businesses or garage inventors. Still, proposals must be based on "solid scientific and engineer principals and to advance NASA's mission objectives," he adds. An example of that is Adrian Stoica's folding mirror probe, that would create a "solar oasis" on the moon, approved for fuding at a prior NIAC symposium.

The most interesting project is AREE (Automaton Rover for Extreme Environments), a Venus probe. Since our unfriendly neighbor of a planet can hit 842 degree F temperatures and 90 times Earth's atmospheric pressure, most electronics would be dead on arrival.

AREE would actually use Venus' conditions to its advantage by taking power from the wind and tapping a mechanical computer. A radar reflecting piston would move up and down to transmit surface "data" as morse code, which could be picked up by "repeater" balloons and transmitted to Earth from an orbiter.

https://www.engadget.com/2017/08/28/nasa-futuristic-probes-niac/

Electronics made from silicon carbide (SiC) may work up to about 500°-600° C. Although NASA would have to pay for development of the technology and design of the chips.

http://www.analog.com/en/analog-dialogue/articles/high-temperature-electronic-pose-design-challenges.html

Edit
I found NASA Glenn was working on this in 2012
https://www.grc.nasa.gov/WWW/cdtb/aboutus/workshop2012/Presentations/Session%203.%20Distributed%20Engine%20Control/DEC_04_Beheim.pdf
« Last Edit: 08/29/2017 11:37 AM by A_M_Swallow »

Offline john smith 19

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Re: Clockwork Rover to Explore Venus - AREE
« Reply #8 on: 09/14/2017 09:53 AM »
Electronics made from silicon carbide (SiC) may work up to about 500°-600° C. Although NASA would have to pay for development of the technology and design of the chips.

http://www.analog.com/en/analog-dialogue/articles/high-temperature-electronic-pose-design-challenges.html

Edit
I found NASA Glenn was working on this in 2012
https://www.grc.nasa.gov/WWW/cdtb/aboutus/workshop2012/Presentations/Session%203.%20Distributed%20Engine%20Control/DEC_04_Beheim.pdf
Passive components IE non transistors, are not that big a problem.

What you're looking for is called Low Temperature Cofired Ceramic. This video was made when the technology was just being introduced, but it's now very mature.



BTW "Low Temperature" in this sense is relative to its cousin, High Temperature CC. LTCC is mfg at 850c. You can screen print inductors , resistors  and capacitors. You can mfg 20+ layer circuit boards (and their packages) in this stuff with good performance into the GHz range. People have even mfg HTP cubesat monopropellant thrusters in it. It's common in automotive and medical applications due to high reliability and very high inertness.

The jokers about electronics on Venus are a)Power supply and b) Transistors.

Power storage is difficult. Very few battery technologies are designed to operate at Venus surface temp. IIRC the only ones I know are Sodium / Sulfur and "thermal" batteries, designed as one-shot use primary cells for military equipment. With no self discharge paths (because they don't conduct at all below several 100c) they have (theoretically) unlimited shelf lives. But that also means no one's ever tried to find a rechargeable chemistry for them.

The other issue is transistors.
Silicon dies at about 150c. Silicon using SOI processes (as Analog Devices may do) can survive to 210c.
GaAs, SiC or SiN should do better but its a density question. Mostly you can't order them up in the 10s of 1000s you'd want for substantial modern electronic functionality. You could do RF amplification, but in principle you could do that with a small sized, hardened travelling wave tube (technically a vacuum tube, but very solid, all metal construction).
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline Blackstar

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Offline sanman

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Re: Clockwork Rover to Explore Venus - AREE
« Reply #10 on: 11/23/2017 01:40 AM »
Aww, and I was hoping we'd get to see a 32-bit Babbage machine.

Offline colbourne

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Re: Clockwork Rover to Explore Venus - AREE
« Reply #11 on: 11/23/2017 05:00 AM »
For the power source why not get the Venus temperature to work for you.

Using  a pressurised liquid (probably solid for most of the trip)  from Earth let the heat run a steam engine or turbine, which can drive a generator. The liquid does not have to be water, but the most suitable material for Venus, possibly  a metal or salt.
If well designed the steam engine will also be able to cool the lander at the same time.
« Last Edit: 11/23/2017 05:03 AM by colbourne »

Offline ChrisWilson68

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Re: Clockwork Rover to Explore Venus - AREE
« Reply #12 on: 11/23/2017 06:05 AM »
For the power source why not get the Venus temperature to work for you.

Using  a pressurised liquid (probably solid for most of the trip)  from Earth let the heat run a steam engine or turbine, which can drive a generator. The liquid does not have to be water, but the most suitable material for Venus, possibly  a metal or salt.
If well designed the steam engine will also be able to cool the lander at the same time.

It's not a high temperature you need to extract useful energy, it's a difference in temperature.  Steam engines work by extracting power from the movement of heat from the boiler to the outside world.

If you're sitting on the surface of Venus, everything around you is at the same high temperature.  So you can't extract any energy from it.  It's one of the fundamental principles of thermodynamics.

Offline john smith 19

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Re: Clockwork Rover to Explore Venus - AREE
« Reply #13 on: 11/23/2017 07:33 AM »

It's not a high temperature you need to extract useful energy, it's a difference in temperature.  Steam engines work by extracting power from the movement of heat from the boiler to the outside world.

If you're sitting on the surface of Venus, everything around you is at the same high temperature.  So you can't extract any energy from it.  It's one of the fundamental principles of thermodynamics.
True.

The question is what's the temperature of the heat sink you can dump it to?

TBH Electricity is not "bad" as such but it has 2 really big problems.
1) There are very few high temperature long term battery chemistries (IIRC Sodium/Sulfur using "Beta Aluminide" is a rechargeable battery tech that might work). Hypothetically the chemistry of "thermal batteries," that use thermite compositions for 1-shot applications (mostly in military systems) might be modified to be rechargeable, but I know of no one doing that. Their power density is meant to be impressive. Huge power, for a very short (hours at most) space of time.

If high temp chemistry is doubtful there are other storage mechanisms. Coiled springs, like a watch, can do the job, as could some kind of closed cycle gas pressurizing system (although using the atmosphere as the working gas would be tough). Compressed gas storage can be surprisingly effective. Early torpedoes were powered by it.  The joker (for electricity use) is the generator. I'm not sure what (if any) metals retain their magnetic properties at these temperatures. If they don't then it's just a lump of metal. [EDIT SmCo magnets are said to be workable up to 300c. Unfortunately Venus surface temp is listed as about 460c. I'm not sure if that's because no one's ever really needed an alloy that's magnetic to those temperatures (but it's just a question of whipping up a batch), or it's a "deep" physics problem, demanding detailed modelling and complex alloys to raise the maximum operating temperature to those levels ]

2) Semiconductors. You want a wide band gap so whereas the free electron density in Silicon at Earth room temperature is makes things work (and consequently performance drops with temperature) you basically want a material that sees Earth room temperature the way Silicon sees being dumped in a pool of liquid Helium IE about 250c below room temperature.

Semiconductor material design seems to be a bit like Thermal Protection System design. People have been so busy developing a "wonder" material they completely neglected any (and all?) side issues. In TPS this results in a material you could not bond to a normal vehicle structure without stressing it to failure (Shuttle tiles anyone?). In high temp semiconductors this seems to be people don't have good P & N dopants, or the material is inherently (like ZnO) one type, and no good dopants exist to get it to the other.

That's a pity because metal oxides (Titania is another) are very rugged materials with the kind of band gaps you need.

Assuming (and that's a big assumption) you can find alloys that retain magnetic properties at these temperatures solar cells might be an option.

Essentially you'd have a rover with Alzheimers. It stores power. When it's got enough it moves. If it hits a problem it goes in another direction. If it finds something interesting it analyses it. Data storage is possible, but computation is very difficult. Either it transmits what its found immediately (regardless of wheather an orbiter is there to receive it) or it records the data awaiting a replay command.

You are literally looking at a Turing machine at best. Some kind of tape driving minimal mechanical gates making decisions, at best.  :(
« Last Edit: 11/23/2017 07:50 PM by john smith 19 »
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline Zed_Noir

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Re: Clockwork Rover to Explore Venus - AREE
« Reply #14 on: 11/23/2017 09:17 AM »
For the power source why not get the Venus temperature to work for you.

Using  a pressurised liquid (probably solid for most of the trip)  from Earth let the heat run a steam engine or turbine, which can drive a generator. The liquid does not have to be water, but the most suitable material for Venus, possibly  a metal or salt.
If well designed the steam engine will also be able to cool the lander at the same time.

It's not a high temperature you need to extract useful energy, it's a difference in temperature.  Steam engines work by extracting power from the movement of heat from the boiler to the outside world.

If you're sitting on the surface of Venus, everything around you is at the same high temperature.  So you can't extract any energy from it.  It's one of the fundamental principles of thermodynamics.

There was a April 19, 2017 FISO Presentation for "An Air-Breathing Metal-Combustion Power Plant for Venus in situ Exploration" with Michael Paul from Johns Hopkins APL.  Audio & slides links below.

Presentation Slides

MP3 Audio Presentation

An internal combustion engine with Lithium as fuel and CO2 from the Venusian atmosphere as oxidizer. :o

Offline john smith 19

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Re: Clockwork Rover to Explore Venus - AREE
« Reply #15 on: 11/23/2017 03:14 PM »

There was a April 19, 2017 FISO Presentation for "An Air-Breathing Metal-Combustion Power Plant for Venus in situ Exploration" with Michael Paul from Johns Hopkins APL.  Audio & slides links below.

Presentation Slides

MP3 Audio Presentation

An internal combustion engine with Lithium as fuel and CO2 from the Venusian atmosphere as oxidizer. :o
This is another of those sounds-insane-but-is-actually-quite-logical concepts physicists come up with.  :)

[EDIT Conceptually their idea is in some ways simpler than current underwater power systems, which I think are probably being used as torpedo power system (high water density and speed requirements dictate systems that have always had astonishing power to weight ratios).  Current systems seem to rely on using a small pyro charge to vaporize the Lithium, massively increasing its reactive surface area, and hence power output, but cutting its operating life drastically.

In contrast their system is more of a Lithium "candle," burning from one end (and it is combustion, just not how most people are used to thinking of it).

What complicates matters is the completely different (and AFAIK very poorly explored) materials compatibility issues. Iodine vapor turbines are quite exotic but make sense when your "cold side" is Venus surface temperature.  Aside form the material issues does this engine need an engine management unit?   ]
« Last Edit: 11/23/2017 03:47 PM by john smith 19 »
"Solids are a branch of fireworks, not rocketry. :-) :-) ", Henry Spencer 1/28/11  Averse to bold? You must be in marketing."It's all in the sequencing" K. Mattingly.  STS-Keeping most of the stakeholders happy most of the time.

Offline A_M_Swallow

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Re: Clockwork Rover to Explore Venus - AREE
« Reply #16 on: 11/23/2017 03:49 PM »

It's not a high temperature you need to extract useful energy, it's a difference in temperature.  Steam engines work by extracting power from the movement of heat from the boiler to the outside world.

If you're sitting on the surface of Venus, everything around you is at the same high temperature.  So you can't extract any energy from it.  It's one of the fundamental principles of thermodynamics.


Stirling engines are normally designed to use large temperature differences but low temperature difference designs also exist. A 5°-10°C temperature difference between the top and bottom of the probe may be sufficient to power a few chips.
https://www.stirlingengine.co.uk/d.asp?product=KS160_BLA_ASS

Offline Arch Admiral

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Re: Clockwork Rover to Explore Venus - AREE
« Reply #17 on: 11/24/2017 04:41 AM »
JPL has a reputation for barking mad engineering ideas. Many years ago I saw a presentation for a long-lived Venus lander that would refrigerate itself using a massive RTG running about 3 times as hot as any current technology. At the time, Johns Hopkins Applied Physics Lab was making an attempt to break JPl's monopoly on planetary probes. They proposed a system where the Pu-238 would run a cooling system by direct heating, like the old gas-fired refrigerators that used an ammonia cycle. Of course ammonia wouldn't work on Venus, so they proposed to test several alternative fluids. This was proposed for this Discovery Program, which had a goal of 3 yrs from selection to launch!!!!

The problem with these proposals is that there is very little scientific interest in the surface of Venus which seems to be all basaltic rocks of about the same age.

Offline john smith 19

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Re: Clockwork Rover to Explore Venus - AREE
« Reply #18 on: 11/24/2017 06:26 AM »
JPL has a reputation for barking mad engineering ideas. Many years ago I saw a presentation for a long-lived Venus lander that would refrigerate itself using a massive RTG running about 3 times as hot as any current technology.
In the recording I think the PI says this is where they lifted the figures for instrument power and mass to size their power chemical power system from.
Quote from: Arch Admiral
At the time, Johns Hopkins Applied Physics Lab was making an attempt to break JPl's monopoly on planetary probes. They proposed a system where the Pu-238 would run a cooling system by direct heating, like the old gas-fired refrigerators that used an ammonia cycle. Of course ammonia wouldn't work on Venus, so they proposed to test several alternative fluids. This was proposed for this Discovery Program, which had a goal of 3 yrs from selection to launch!!!!
This project is also targeted at a "Discovery" class mission at about $450m. I did not realize there is also a schedule limit on them as well.  :(
I'd say that Iodine turbine sounds pretty challenging. Starting with the fact that at Earth pressures Iodine sublimates. You never see liquid Iodine.  Like all Halogens I'd guess it's also quite reactive so very hot, very aggressive vapor turns into high pressure, quite aggressive liquid after passing through a Venus temperature CO2 heat exchanger.

If they get funding Reaction Engines in Colorado should be interested.
Quote from: Arch Admiral
The problem with these proposals is that there is very little scientific interest in the surface of Venus which seems to be all basaltic rocks of about the same age.
I'm not so sure about that.  :(

Gravity and size wise Venus is a lot closer to Earth than Mars is. Apparently it get regularly "re-surfaced." Large areas of the whole planet just get flattened. It's volcanically active and clearly has suffered from a runaway greenhouse effect, obviously without any human intervention.

So there aren't reasons to go in person there but there are quite a lot of reasons to study it, including the surface. Unfortunately it's so hostile just building the structure for a lander is massive undertaking that kills interest. People say "Yes it's interesting, but it's just too damm tough to study."

This suggests innovative designs that side step those problems are needed for Venus in a way they aren't for most other bodies in the Solar System. Long FO tethers from orbiters and "passive circuit" or non electrical systems seem worth a shot.

What might be a good idea would be a "Venus environment simulator" chamber as a shared resource available between interested parties, rugged and big enough to accommodate a range of hardware on test, [EDIT as well as allowing data connections and various driving connections (pressurized fluid, mechanical rotation) so you can test a subsystem without needing the whole probe to be complete. ]
« Last Edit: 11/25/2017 08:24 AM by john smith 19 »
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Offline sanman

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Re: Clockwork Rover to Explore Venus - AREE
« Reply #19 on: 11/25/2017 06:41 PM »
For the power source why not get the Venus temperature to work for you.

Using  a pressurised liquid (probably solid for most of the trip)  from Earth let the heat run a steam engine or turbine, which can drive a generator. The liquid does not have to be water, but the most suitable material for Venus, possibly  a metal or salt.
If well designed the steam engine will also be able to cool the lander at the same time.

It's not a high temperature you need to extract useful energy, it's a difference in temperature.  Steam engines work by extracting power from the movement of heat from the boiler to the outside world.

If you're sitting on the surface of Venus, everything around you is at the same high temperature.  So you can't extract any energy from it.  It's one of the fundamental principles of thermodynamics.

And yet surface temperatures do produce electromagnetic waves - eg. infrared.
Would it be possible to harvest infrared spectrum along with solar energy that makes it through Venus' clouds, to then power a surface probe? And considering how dense Venus' atmosphere is, perhaps it might be possible to make use of buoyancy forces to reduce the effective weight of the probe and increase its mobility.

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