Ultra thin PV film

louis · 2019-07-18 18:04:49

Yes - you are "asserting".

A ball on hard ground keeps bouncing and breaking the ground. A ball in soft mud comes to an abrupt stop.

I've been looking for evidence either way - can't find it via Google. The makers of thin film stress its "durable" qualities. Not sure what that means.

Happy to look at any real evidence you have to support your assertion that thin film PV is more easily damaged by abrasion than glass.

kbd512 wrote:

Louis,
I'm asserting that fine dust abrades soft plastic.
You can believe it doesn't as much as you wish, but it won't change how that process works.
Regarding something harder being less subject to abrasion damage than something softer, I can't believe you need evidence of that.
Did you skip shop class in high school where you sanded both wood and metal with a piece of sand paper?
Unless my eyes and muscles deceived me, it took considerably more effort to sand the steel than it did the wood, to the point where the top of one of the tables I made from wood and steel was sanded by hand and I sanded the steel using a belt sander.
Why do you think we coat drill bits meant for high speed use with diamond?
The diamond is a hell of a lot harder than the metal, even a carbide, and will cut through the work material faster.

louis · 2019-07-18 18:06:09

Won't all the charging of batteries take place inside temperature-regulated habs or spacecraft?

kbd512 wrote:

SpaceNut,
I would suggest that a battery with a broader operating / charging temperature range (something that can actually take a charge at lower temperatures, rather than just putting something on the sticker that says it operates at a given temperature without expressing what the real performance would be at the extreme ends of the operating temperature range), that is not prone to exploding or rupturing when shorted, is probably a better idea.
FIAMM SoNick battery for Energy Storage Systems - FIAMM ST523 620 V 22.5 kWh
The SONICK Battery by FIAMM
Yes, it's heavier than Lithium-ion. It weighs 564lbs. However, look at the cycle life at 80% DoD and notice how little volume it occupies. Each ORU is 430lbs and the thermal regulation ("heater") plate is ~85lbs.
FIAMM ST523
Weight: 564lbs
Dimensions: 24.6" W x 40.2" L x 16" H
Capacity: 22.5kWh
Containment: Completely sealed
Aerojet-Rocketdyne ISS ORU
Weight: 435lbs (ORU) 85lbs (adapter plate); 520lbs (total)
Dimensions: 37" W x 41" L x 21" H
Adapter Plate: 36" W x 41" L x 15" H
Capacity: 15kWh
Containment: Open to preclude a cell rupture from destroying the other cells in the pack
ISS Lithium-ion ORU Test Data:
International Space Station Lithium-Ion Battery Status
Lithium-ion can work without catastrophic events from single cells, but it won't look much like a Tesla Power Wall when you're done and will definitely weigh quite a bit more:
Design Guidelines for Safe, High Performing Li-ion Batteries with 18650 cells
Assessment of International Space Station (ISS) Lithium-ion Battery Thermal Runaway (TR)
International Space Station Lithium-Ion Battery
ISS Thermal Management Systems:
Active Thermal Control System (ATCS) Overview

kbd512 · 2019-07-18 18:15:46

Louis,

Take some sand paper and try to scratch a piece of tempered glass. Then take the same piece of sand paper and try to scratch a piece of plastic lamination film. Tell me which one was easier to scratch. It might cost a few dollars to perform the experiment. Otherwise, you're just being deliberately obtuse about this. I think you already know what the answer is.

Regarding the batteries, tell me if you have a plan in place that doesn't involve killing the crew if one of those batteries catch fire inside their pressurized habitat module. They don't store the International Space Station's batteries inside the hull of the ISS. Neither Orion nor Dragon nor Starliner store their batteries inside the pressure vessel, either. Completely random coincidental design feature? A fire / explosion from a camera or laptop battery is nothing like a car battery, either. Can you try to imagine why that is?

SpaceNut · 2019-07-18 18:59:40

Post # 25 was a reminder by kbd512 on the favorite batteries to recycle from lots of stuff that makes up a battery pack using the 18650 cells which get used just about everywhere.

Louis you do know that an effect of charging is out gassing of usually hydrogen gas which is in a vapor form that is highly explosive....

Plastics that get scratched become not so clear and will attenuate the light trying to pass through it. Plus once it wears (since its paper thin) through to the cell it once protected will now be sand blasted into becoming defective....

louis · 2019-07-18 20:23:26

So you, like Kbd, can't quote a source for your opinion? If it's "so obvious" that glass is less susceptible to abrasion than thin film plastic then please give a reference to a relevant scientific paper or other evidence...

SpaceNut wrote:

Post # 25 was a reminder by kbd512 on the favorite batteries to recycle from lots of stuff that makes up a battery pack using the 18650 cells which get used just about everywhere.
Louis you do know that an effect of charging is out gassing of usually hydrogen gas which is in a vapor form that is highly explosive....
Plastics that get scratched become not so clear and will attenuate the light trying to pass through it. Plus once it wears (since its paper thin) through to the cell it once protected will now be sand blasted into becoming defective....

kbd512 · 2019-07-18 23:55:46

Louis,

Science Direct - Scratch Hardness

From the article:

The Mohs hardness scale, which is addressed in every mineralogical text such as that by Milovsky and Kononov, assigns numerical scratch hardness values to common minerals. Virtually every descriptive summary of minerals presents their Mohs hardness values. Mohs assigned a value of 10 to diamond, 9 to corundum, 8 to topaz, 7 to quartz, 6 to orthoclase (feldspar), 5 to apatite, 4 to fluorite, 3 to calcite, 2 to gypsum, and 1 to talc. Each of these minerals is familiar to geologists and also to most ceramic engineers. On this scale, most polymers are in the 2–4 range and metals vary from about 2 for very soft metals, such as tin and lead, to about 7 for hardened steels. A human fingernail is about 3 on the scale.

There's your source.

That stuff blowing in the wind on Mars isn't talc. It's volcanic ash and iron oxide. In other words, stuff that's a lot harder than polymer (plastic) and your fingernails.

Can we move on now?

louis · 2019-07-19 04:32:24

So you're saying in the real world lead gathers scratches more readily than steel? You see, that's where I think real world experience might well differ from what is a perfectly valid scale.

You link doesn't show that flexible thin film PV is more likely to suffer abrasion than glass encapsulated PV.

kbd512 wrote:

Louis,
Science Direct - Scratch Hardness
From the article:
The Mohs hardness scale, which is addressed in every mineralogical text such as that by Milovsky and Kononov, assigns numerical scratch hardness values to common minerals. Virtually every descriptive summary of minerals presents their Mohs hardness values. Mohs assigned a value of 10 to diamond, 9 to corundum, 8 to topaz, 7 to quartz, 6 to orthoclase (feldspar), 5 to apatite, 4 to fluorite, 3 to calcite, 2 to gypsum, and 1 to talc. Each of these minerals is familiar to geologists and also to most ceramic engineers. On this scale, most polymers are in the 2–4 range and metals vary from about 2 for very soft metals, such as tin and lead, to about 7 for hardened steels. A human fingernail is about 3 on the scale.
There's your source.
That stuff blowing in the wind on Mars isn't talc. It's volcanic ash and iron oxide. In other words, stuff that's a lot harder than polymer (plastic) and your fingernails.
Can we move on now?

SpaceNut · 2019-07-19 17:13:42

A leather strap is for fine polishing of an edge that is razor sharp and is done to maintain that edge. Simular to polishing fiber optics with tiny diamond grit for the glass end to make it smooth.

What we are talking about is simular to what happens to an automobiles head lense being pelleted by sand and salt...

louis · 2019-07-20 19:55:06

I don't think so - cars on Earth are ploughing through our thick atmosphere at 70 MPH!

The conditions on Mars are way more benign than that!! Average wind speed about 10 MPH but the force is much less because the atmosphere is so thin.

SpaceNut · 2019-07-21 09:05:14

The physics equation is the same for both the moving vehicle being pelleted and the moving dust/sand doing the blasting....the difference is which number goes where in the equation...

Are Martian Dust Storms Dangerous?

NASA’s Viking landers clocked them at 100 km/h during dust storm season. Which is a thing on Mars. The landers sheltered enough from the big storms that they probably didn’t experience the greatest winds they’re capable of.
When the wind is above 65 km/h, it’s fast enough to pick up dust particles and carry them into the atmosphere encasing the planet in a huge, swirling, shroud.

not as slow as you had thought

That momentum comes from air particle density and their velocity. Sadly, the density of the atmosphere on Mars is a delicate 1% of what we’re used to. It’s got the velocity, but it just doesn’t have the density.
It’s the difference between getting hit by a garden hose and a firehose with the same nozzle speed. One would gets you soaked, the other can push you down the street and give you bruises.
To feel a slight breeze on Mars similar to Earth, you multiply the wind speed by 10. So, if the wind was going about 15 km/h here, you’d need to be hit by winds going about 150 km/h there to have the same experience.

ouch!!!

Sandblasting winds shift Mars' landscape

"In our study area, sand-moving wind occurs almost daily" throughout much of the year, "Winds on Mars can be strong and can reach hurricane speed (more than 120 kilometres per hour or 75 miles per hour),"
Understanding the characteristics of Mars' winds would allow scientists to make predictions about the rate of erosion of the landscape and about the martian climate, which is heavily influenced by dust in the atmosphere.

tahanson43206 · 2019-07-21 10:19:08

For SpaceNut re #35

Thanks for the links about the movement of sand on Mars.

For Louis ... thanks for keeping this back-and-forth going ...

(th)

SpaceNut · 2019-09-15 19:54:49

Advantages and Disadvantages of Solar Energy

This does not change for mars as to tap into limitless energy from the sun without depleting the source to the advantages and disadvantages of solar energy. There are no Nonrenewable sources- coal, or oil and methane may be a possibility once there and drilling.

louis · 2019-09-16 06:06:55

Looking at the disadvantages:

1. Location and weather dependent.

On Mars we can land at or near the optimal zone (around 30 degrees north).

The weather on Mars is benign - no thunder, lightning, rain storms, snow storms, hailstones, hurricanes, tornadoes (of any strength) or other phenomena which might disrupt supply, except for one: dust storms. The effects of dust storms have been greatly overstated. llight still gets through. At the height of a dust storm you might see 20% of normal insolation...more likely it's going to be 40-60%. Duration is normally fairly short but of course we do have records of storms up to 9 months, so any Mars mission must plan for that worst case scenario.

2. Land monopoly

Of no concern on Mars.

3. Low access point for non-homeowners

Of no concern on Mars.

My conclusion: I think the energy supply for a Misson One to Mars is a unique challenge. It has to be failsafe (because of propellant production) and it needs to be sufficient to enable you to create a basic infrastructure on Mars.

I favour solar plus battery plus methane/oxygen production (for use in methane fuelled electrical generators). That way you can use residual fuel from the landed cargo starships and also have a back up supply of methane and oxygen that the human-passenger Starships take with them to Mars in the event you land in the middle of a worst case scenario dust storm.

Last edited by louis (2019-09-16 06:10:43)

SpaceNut · 2019-09-16 17:30:53

The thing to increase solar capability is to use reflective parabolic troughs that have the panels placed so that it recieves concentrated energy for the same array. Sure we need to bring more materials to build but you can use light weight maylar plastics to create the troughs. Even though the levels would raise the panels surface temperatures mars would naturally cool them so that we would not be lowering the wattage output or degrading there performance.

SpaceNut · 2019-09-20 20:37:54

The reality of mars solar array would have to be at Mars to match the power output of a 30-meter-square (approximately 100x100 ft) of solar cells in Earth orbit (LEO). While the array only needs to be 2.3 times larger in Mars orbit, it must be 4.5 times larger on the surface - and 7.7 to 15.4 times as large to accommodate cloudy days.

louis · 2019-09-21 02:53:22

Think you miscalculated there. 100 feet = 30.48 metres. So 100 feet x 100 feet = 929 sq. metres That sounds more plausible. Presumably this is to cover propellant production, life support and all other base requirements.

Previous analyses I've undertaken suggest to me that, in order to account for worst case dust storm scenarios, the area of a solar array on Mars (for Mission One) might need to be about 30% over and above the area otherwise sufficient to generate the required amount of electricity in the absence of dust storms. So rather than a multiplier of 4.5 for the Mars surface (compared to LEO), that would be a multiplier of 5.85 (to incorporate the "margin of safety" 30% addition).

So you then end up with a figure of 5435 sq metres or about 74 metres by 74 metres. That sounds about right to me, but it might be larger if one is using some sort of thin film PV product, for ease of deploymeny.

It is certainly deliverable with current technology and the size of Space X's mission to Mars.

SpaceNut wrote:

The reality of mars solar array would have to be at Mars to match the power output of a 30-meter-square (approximately 100x100 ft) of solar cells in Earth orbit (LEO). While the array only needs to be 2.3 times larger in Mars orbit, it must be 4.5 times larger on the surface - and 7.7 to 15.4 times as large to accommodate cloudy days.

GW Johnson · 2019-09-21 11:47:51

Louis:

I think your 30% extra capacity figure for solar arrays is not adequate.

That's the average dust storm, not the big events, which though rarer, do in fact occur with enough frequency to make encountering one a certainty.

During those events, there is no usable solar radiation, nothing, nada. For days-to-weeks-to-months at a time. Which is exactly why the Opportunity rover finally died from being unable to run its heaters.

Which is why you take enough nuclear power to get you through such an event, so that in the predominant "good" solar panel weather, you have an excess of power to use as desired, not just as required. It really does require a mix of power sources.

A combination of lots of solar plus some kilopower units sounds like a good mix to me. The nukes must run the lights and heat and keeping whatever cryogens you have still cryogenic while the big dust storm rages. When it is over, you can resume rover charging and propellant production using solar.

GW

kbd512 · 2019-09-21 15:09:23

The only way to assure the availability of solar power is to keep solar power satellites in orbit and use microwave power transmission to redirect that power to ground-based receivers, which are not egregiously affected by dust in the atmosphere. The only other realistic alternative is to use a mix of solar and nuclear power. Some people freak out at the mention of the word "nuclear", so as a practical person who still wants to execute the science mission, I'd support the other realistic alternative. If we don't do that, then people will die. That's not a personal belief, it's a virtual guarantee. Mars is far more inhospitable than the worst environments found on Earth and people need to respect that fact. I think solar power satellites for exploration and small outposts is a viable energy distribution method, which would also be useful for science conducted in other inner solar system locales, and therefore a multi-purpose solution that's generally useful to NASA.

For a large colony, this solar power provisioning scheme probably won't scale well, in either the economical or technological sense, assuming we're forever stuck with existing technology (highly unlikely), but we're nowhere close to having a large colony on Mars and we can cross that bridge when we get there and have a discussion about solar vs nuclear at that time. I base that supposition on the fact that solar power satellites reliably consume power from the Sun for decades on end, whereas Mars inevitably kills ground-based solar arrays significantly faster than satellites in orbit.

I'm not opposed to either solution, but I'm 100% opposed to sending anyone to Mars without a guaranteed source of power. Using current technology, a ground-based solar array is not a guaranteed source of power. So... Stop worrying about Hollyweird absurdities, as it pertains to nuclear accidents, and learn to live with the fission reactor, or develop small solar power satellites to provide guaranteed power.

NASA is currently developing fission reactors because they're cheaper and simpler to develop than solar power satellites. Solar / microwave power transmission is still an experimental technology, although it works quite well at a laboratory scale. I'd like to see solar power satellites developed, tested, and operationally deployed. Fission has been providing lots of electricity, with greater reliability than all other forms of power generation, for decades on end. If we don't need a fission reactor, then perhaps we can simply take a few as backups and only turn them on if the other power generation schemes have failed.

SpaceNut · 2019-09-21 16:24:45

The narrow beam microwave energy is deflected and diffused with the dust which is mostly iron oxide such that its not going to be any better.

kbd512 · 2019-09-21 17:23:22

SpaceNut,

That depends greatly on how many kilometers the dust storm particles are lofted into the atmosphere. You're obviously going to lose some power, but microwave beams are used to penetrate many meters below the surface of Mars, with or without dust in the atmosphere.

louis · 2019-09-21 17:38:04

I dispute your claims that dust storms will lead to 0% solar energy generation.

When I've looked into the matter I have never found any evidence of solar power systems dropping below 20% of normal during dust storms; importantly, the extreme low insolation lasts only a few days. For the rest of the dust storm you can be looking at levels between 40 and 80%. Furthermore, insolation levels during dust storms vary greatly across the planet. There are areas which are far less vulnerable to reduction in insolation (I'm wondering if that's one of the reasons why they are looking at the Amazonis plain).

This academic paper states:

"Based on the experience with the MER rovers, Marsglobal dust storms do not (my emphasis) present a significant challenge to photovoltaic power systems because even during these storms scattered sunlight still provides in excess of 10% of the insolation per surface area as during a clearMartian day."

http://systemarchitect.mit.edu/docs/cooper10.pdf

You shouldn't be misled by NASA's rovers closing down during dust storms. That, as I understand it is more a question of the whole machine going into hibernation to protecting their mechanisms from the dust. That doesn't apply to PV panels out on the surface. They won't need to be "closed down".

I thought the 10% figure was a bit low and found this other reference to optical depth which appears to be on a scale of 1 to 5:

"Values less than 1.0 correspond to clear days, where little sunlight is scattered, reflected, or absorbed in the atmosphere. Meanwhile, 5.0 is representative of a thick dust storm that reduces solar flux at the surface to ∼35% of the nominal value."

https://www.liebertpub.com/doi/full/10. … .2018.0019

I am a bit confused by that discrepancy between 10% and 35%. Possibly the former relates to solar panel power and the latter to available insolation. The lowest figure I can recall ever seeing was 20%, which might reflect dust accumulation on the solar panels, rather than recording actual available insolation. The good thing about a solar array on the surface during a human mission would be that we could deploy rovers to clean the panels, and so raise the power levels that way to some extent at least.

Dust storms may last for weeks or even months in some rare cases but they are seasonal and they don't maintain the extreme levels on the optical depth scale for more than a few days.

I think my overall expectation is that if you had a worst case dust storm scenario you might get 20% at least of nominal power for a few days, and then fluctuations between 40% and 80% for up to maybe three months.

If you've got anything that supports your "nada" claim I'd be interested to see it.

GW Johnson wrote:

Louis:
I think your 30% extra capacity figure for solar arrays is not adequate.
That's the average dust storm, not the big events, which though rarer, do in fact occur with enough frequency to make encountering one a certainty.
During those events, there is no usable solar radiation, nothing, nada. For days-to-weeks-to-months at a time. Which is exactly why the Opportunity rover finally died from being unable to run its heaters.
Which is why you take enough nuclear power to get you through such an event, so that in the predominant "good" solar panel weather, you have an excess of power to use as desired, not just as required. It really does require a mix of power sources.
A combination of lots of solar plus some kilopower units sounds like a good mix to me. The nukes must run the lights and heat and keeping whatever cryogens you have still cryogenic while the big dust storm rages. When it is over, you can resume rover charging and propellant production using solar.
GW

kbd512 · 2019-09-21 18:53:29

Louis,

If your life support systems require 10kW of power to function, but your solar array only provides 1kW of power in a dust storm, then whether you get "nada" or 1kW really doesn't matter in the slightest. The rover required power measured in terms of single digit Watts to stay alive, but it's as dead as any doornail ever was. It was fine before the dust storm and now its dead. When the power requirement is multiple orders of magnitude greater than what it was for that tiny rover, how would that not make the problem that much worse?

If only said rover had an array attached to it 10 times as big as it was, then maybe it would've survived the dust storm. How well would it have been able to drive around with an array like that attached to it? If it was just as simple as attaching an array 10 times as large to it, then why didn't NASA do that? Is it possible that the solution simply wasn't practical, much like a jet-engined powered car? Have you ever thought about the possibility that there are some ideas that won't work very well, if at all, and even if someone you personally like proposes them, that that still doesn't make them viable engineering solutions?

louis · 2019-09-21 19:02:10

We're talking about systems in the 400Kwe range, constant average. In terms of life support and so on at the base, you probably only need about 12Kwe. Even on a low 10% figure, you'd be generating 40Kwe - more than enough to supply everyone's need. The only problem in the worst of a major dust storm is your propellant production will be hampered.

The Mission will arrive with plenty of methane and oxygen that can be used to power generators when required to provide supplementary power if necessary. After a short while, there will of course be even more methane and oxygen available from the propellant production.

The rovers used by a human mission won't need solar arrays to power them directly. They will be powered by batteries or methane engines.

Lots of NASA's rovers have survived multiple dust storms. They shut down and hibernate for a while, that's all. Opportunity was way past its intended lifespan by a factor of about 10.

kbd512 wrote:

Louis,
If your life support systems require 10kW of power to function, but your solar array only provides 1kW of power in a dust storm, then whether you get "nada" or 1kW really doesn't matter in the slightest. The rover required power measured in terms of single digit Watts to stay alive, but it's as dead as any doornail ever was. It was fine before the dust storm and now its dead. When the power requirement is multiple orders of magnitude greater than what it was for that tiny rover, how would that not make the problem that much worse?
If only said rover had an array attached to it 10 times as big as it was, then maybe it would've survived the dust storm. How well would it have been able to drive around with an array like that attached to it? If it was just as simple as attaching an array 10 times as large to it, then why didn't NASA do that? Is it possible that the solution simply wasn't practical, much like a jet-engined powered car? Have you ever thought about the possibility that there are some ideas that won't work very well, if at all, and even if someone you personally like proposes them, that that still doesn't make them viable engineering solutions?

kbd512 · 2019-09-21 20:06:03

Louis,

If you have a plan that requires a constant average of 400kW, then you're talking about a solar system of the type that would supply a small town with electricity, but that's just to produce enough propellant to get the rocket back. For use on Mars, we're now talking about something with a nominal capacity rating well into the low MegaWatt range. In other words, the type of array that's built over the course of a year with unlimited labor and fossil fuel supplies of the type that don't need to be kept cryogenically cold, just to power the construction equipment that makes that possible.

Unlike robotic rovers, humans don't have a "temporary shutdown" or "hibernation" mode. They have a "permanent shut down" mode called "death". That's what this plan is really advocating for because it categorically refuses to acknowledge the limits of current solar panel and construction technology, which are well understood in engineering, substituting a personal fantasy you find pleasing for engineering reality.

SpaceNut · 2019-09-21 20:54:57

The batteries are why the rovers die as they can not take the cold of mars and must be kept warm. Even humans can not tolerate the cold of mars which will with reduced power happen as what must be continued is life support so as to not die from oxygen deprivation and with the drop in heat will be a bursting of water lines.....

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#26 2019-07-18 18:04:49

Re: Ultra thin PV film

#27 2019-07-18 18:06:09

Re: Ultra thin PV film

#28 2019-07-18 18:15:46

Re: Ultra thin PV film

#29 2019-07-18 18:59:40

Re: Ultra thin PV film

#30 2019-07-18 20:23:26

Re: Ultra thin PV film

#31 2019-07-18 23:55:46

Re: Ultra thin PV film

#32 2019-07-19 04:32:24

Re: Ultra thin PV film

#33 2019-07-19 17:13:42

Re: Ultra thin PV film

#34 2019-07-20 19:55:06

Re: Ultra thin PV film

#35 2019-07-21 09:05:14

Re: Ultra thin PV film

#36 2019-07-21 10:19:08

Re: Ultra thin PV film

#37 2019-09-15 19:54:49

Re: Ultra thin PV film

#38 2019-09-16 06:06:55

Re: Ultra thin PV film

#39 2019-09-16 17:30:53

Re: Ultra thin PV film

#40 2019-09-20 20:37:54

Re: Ultra thin PV film

#41 2019-09-21 02:53:22

Re: Ultra thin PV film

#42 2019-09-21 11:47:51

Re: Ultra thin PV film

#43 2019-09-21 15:09:23

Re: Ultra thin PV film

#44 2019-09-21 16:24:45

Re: Ultra thin PV film

#45 2019-09-21 17:23:22

Re: Ultra thin PV film

#46 2019-09-21 17:38:04

Re: Ultra thin PV film

#47 2019-09-21 18:53:29

Re: Ultra thin PV film

#48 2019-09-21 19:02:10

Re: Ultra thin PV film

#49 2019-09-21 20:06:03

Re: Ultra thin PV film

#50 2019-09-21 20:54:57

Re: Ultra thin PV film

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