Going Solar...the best solution for Mars.

SpaceNut · 2020-02-23 18:49:22

Here is the magical rollout solar panels

Solar tried at ISS but mostly failed as the rails got stuck
https://en.wikipedia.org/wiki/Roll_Out_Solar_Array
These would be way different than what louis has been discribing as the wonder panels for mars.

Roll-Up Solar Panels Could Fundamentally Alter How We Power the World Instantly deployable power with the potential to hasten relief in disaster-stricken areas.

Rollable and large-scale flexible Solar Panels, called Roll-Array, can be towed by any 4X4 car, like a Range Rover or Land Rover.
Ready to Roll Renovagen’s Rapid Roll solar panels
Flat Holm’s solar panels generate an average of 11KW of power, connected to batteries that can store 24KW/h. That’s roughly a day’s worth of energy for the island’s four inhabitants, as well as for the tourists who frequent Flat Holm. Best of all, the Rapid Roll solar panels can last up to 10 years.
The Rapid Roll panels are packed in 4×4 trailers, which carry enough solar panels to power a mobile clinic with 120 beds or to desalinate 25,000 liters of seawater daily, and is particularly suited for Flat Holm’s environmental and logistical needs. “Compared with traditional rigid panels, we can fit up to 10 times the power in this size container,”

103466723-Aerial_Feb_2016_2.1910x1000-1200x628.jpg

No range rovers or glrass to soften the rolling dragging process that will shred these panels on mars.

22 panels 6 cell structure is what I am seeing displayed of 11KW SIZE...

Rapid Roll "T"

The Rapid Roll “T” trailer/tactical version provides an extremely mobile solution which can be airlifted by a wide range of medium and heavy-lift helicopters (gross weight from 1,500 kg) but packs enough power for energy intensive operations. Easily mounted on an on-road or off-road trailer or flat-bed truck, the Rapid Roll “T” provides many options for deployment to practically any global location imaginable. With simple deployment in just a few minutes without needing solar engineers onsite, it provides a practical solution for humanitarian and disaster relief, military, mining, events, film production and other temporary power-hungry operations in remote places which require equipment mobility.
The size and weight of the Rapid Roll “T” when trailerised (2,000kg – 3,000kg total trailer weight) also makes it easy to tow with standard 4×4 vehicles and it fits on a number of commercial air freight pallets or 463L military pallet and so becomes extremely easy to transport internationally very quickly. Easy handling is facilitated with bi-directional forklift pockets and lifting rings.
Rapid Roll “T” models can be configured with independently variable solar and battery capacity. Models are designated, for example, RAPID ROLL 11\48 – indicating 11kWp solar capacity and 48kWh battery capacity. Rapid Roll “T” systems are available in single or 3-phase, 230V/400V 50Hz or 120V/208V 60Hz variants with grid-connect

Page table for the 11 kw for 33kwh gets and output of will get you an output of 6kw for a run time of 5 hours back up...
Mars we need that wattage 25 hrs a day continuous not just 5 hours for the roughly 3 hours of direct light when laying flat on the ground.

Rapid Roll "I" - Under Development

The integration of the Rapid Roll technology into a side-opening ISO shipping container, combined with inverters and a larger battery bank, creates an easily transportable self-sufficient solar power system capable of generating 10 times more power than competitive products. Deploying a huge solar array measuring 5 metres (20ft ISO) or 10 metres (40ft ISO) in width and up to 200 metres in length, this represents by far the largest containerised deployable solar array yet conceived.

Wind proof

The rollable solar field can also be easily staked to the ground so it can withstand winds up to 80 miles per hour.
Meanwhile, only two people are required to install the Roll-Array, which includes batteries and inverters.

Installing a solar field manually takes about 22 hours, according to Renovagen.

Simulated mars field

Not even close to the levels for a starship refueling

SpaceNut · 2020-02-23 19:24:14

louis wrote:

Of course they would last a year. We have experience of PV arrays in dusty deserts on Earth, so we know how they react. But bear in mind the wind force on Mars is about 1/20th of that on Earth, so dust particles are not being slammed against the surface with the same force as on Earth. In a dusty environment there will clearly be some abrasive degradation in the PV systems, but bear in mind we've had Rovers on Mars operating in those conditions for 12 years or more and they still functioned very well.
Also, remember that - as with the Apollo mission - for Mission One to Mars, cost is not a major consideration. If you have to spend $1 billion on your energy system, that's not a big issue in terms of the overall budget. So if that's what it costs to get a lightweight resistant surface on the PV array, so be it. Space X can afford $1 billion for the energy system.
How much power do we need to cover propellant production? I think the conservative (upper limit) figure is 1MW constant...probably translates into something like 8 MW solar capacity.
Calliban wrote:
Ultra-lightweight thin film PV presumably does not include any cover glass for abrasion and UV resistance. Under those conditions, what would be the effective lifetime of panels on Mars? Would they last a year?
It is also noteworthy that very thin semiconductor layers will have very low breakdown voltage. That is a problem, as very low voltage would lead to high resistance losses in long rolls of PV panels. The panels would need inverters and transformers at regular intervals. That adds extra weight to the PV system.
Realistic space PV systems achieve about 1kg/m2. On Mars, that would mean realistic power density of about 10W/kg. How much power does the Starship need for its return propellant provisions? How much for other things?

SpaceNut · 2020-02-23 19:33:40

Of course the plastics are not mars temperature tested and from all of the warm weather applications that makes un rolling problematic for becoming brittle as it rolls from the much colder temperatures that they could see on the surface at deployment.
I think the batteries will also suffer from that same cold getting into them causing them to freeze as well.

louis · 2020-02-23 19:37:35

The Rapid Roll "T" 11/120 clocks in at about 115 sq. metres. I estimate the average daily output power at 4 x 18 KwHs = 72 KwHs or an average of 3 Kws.

http://www.renovagen.com/products/rapid-roll-t/

So to produce an average of 1 Mw that would mean you need about 52,000 sq metres on Earth, or maybe 100,000 sq. metres on Mars.
That's an area of 316 x 316 metres...probably equivalent to an athletics sports stadium area. So definitely not unfeasible, given how easy it is to roll out the system.

That said, I am sure if we throw money at the problem we can get a more efficient flexible PV system, so reducing the area required. But on the other hand you need to plan for major dust storms and you have to account for battery storage loss as well, which requires you to over-design the PV system...so 100,000 sq metres is probably as good an estimate as you are going to get.

If you can unroll 155 sq metres in 2 minutes that means you could unroll 100,000 sq metres in just over 21 hours.
Allowing for breaks to reconnect robot rovers to the PV rolls and limited working hours (maybe only 6 hours per sol), I think that might be a 5 to 7 sol job - a very reasonable time allowance for such a crucial Mission system.

SpaceNut · 2020-02-23 20:43:38

The fully charged battery for that model is 96kwhrs of output but only at a load wattage of 1.5 kw for 64 hr period..
The invertor can supply 18kw at max but with that the run time drops like a rock...to just a shade over 5 hrs
The t 11/120 unit is 10.8 kw per roll and that times 3 hours is the stored energy from it that can be store in the battery.

First mars surface solar is at 43% that of earths 1,000 w or 1kw making it only 430 w on mars to be used by those panels.
The panels are 36 x 129 w each for the mars surface power of 4.644 kw for that units performance times the 3 hours is 13.6 kwhr of energy to be stored. The batteries are design to store 120kwhrs of energy so the panels do not match the storeage value. That said 9 roll out panel assembly units for 1 battery is the design required just to get the most energy to the battery capability as a 10 multiplier might be to much unless we are planning on days of difused light intensity.

each array is 2.2 m x 50 m long and we need 10 just for the 120kwhr of battery storage...

The brochure shows a green tarp under each section to allow for the abration of pulling across green grass and smoothened out sand with no rocks like mars sharp and jagged.

Found zero references to climate temperature of operation at this point...

edit

Our objective is to demonstrate performance in -40C to +50C during 2017, although field testing to date (Sept 2016) has included a range of 0C to +38C. Components are typically rated for -40C to +80C operation.

To not be confused with how low the temperature can be to unfurl without breaking it....as these were deployed while warm...

Indicated 10 year of use but there appears to be no UV protectant for the plastic of the cell or backing tarp materials which is problematic for the very high levels of UV due to thin atmospher.

http://www.renovagen.com/products/fast-fold/
Appears to be a very useful portable power system for quick setup and instant power.

Calliban · 2020-02-24 17:15:11

louis wrote:

The Rapid Roll "T" 11/120 clocks in at about 115 sq. metres. I estimate the average daily output power at 4 x 18 KwHs = 72 KwHs or an average of 3 Kws.
http://www.renovagen.com/products/rapid-roll-t/
So to produce an average of 1 Mw that would mean you need about 52,000 sq metres on Earth, or maybe 100,000 sq. metres on Mars.
That's an area of 316 x 316 metres...probably equivalent to an athletics sports stadium area. So definitely not unfeasible, given how easy it is to roll out the system.
That said, I am sure if we throw money at the problem we can get a more efficient flexible PV system, so reducing the area required. But on the other hand you need to plan for major dust storms and you have to account for battery storage loss as well, which requires you to over-design the PV system...so 100,000 sq metres is probably as good an estimate as you are going to get.
If you can unroll 155 sq metres in 2 minutes that means you could unroll 100,000 sq metres in just over 21 hours.
Allowing for breaks to reconnect robot rovers to the PV rolls and limited working hours (maybe only 6 hours per sol), I think that might be a 5 to 7 sol job - a very reasonable time allowance for such a crucial Mission system.

Impressive tech. But note, you have here a 10.8kW-peak system weighing 2.75 tonnes. To generate an average power of 1MW at the Martian equator, the system would weigh close to 1800 tonnes. You see the problem?

Of course, that includes a lot of battery storage that you may not need for propellant production. Let's look at Spacenut's example of folding cells.
http://www.renovagen.com/products/fast-fold/

A 1kW-peak panel weighs 35kg. It would generate average power of 143 watts on Mars at the equator. More in day; none at night. Power would vary sinusoidally during the day, peaking at noon. To generate average power of 1MW, you would need 244 tonnes of cells. Add in the inverters and transformers and you are talking substantially more. The 2.88kW inverter-transformer unit in the brochure weighs 125kg - about half of which is battery mass.

Maybe you should send a smaller propellant factory several years in advance. As new missions arrive, they can assemble an ISRU factory for solar power plants.

Last edited by Calliban (2020-02-24 17:22:57)

SpaceNut · 2020-02-24 17:44:10

Louis and Calliban,

I made an error in the last post as hidden in the specifications was a max wattage input for charging the batteries and with that the number of panel arrays can only be 4 to stay under that wattage limit for the rapid roll t units. It is 20.1 kw max of which 4 x 4.644 kw = 18.576 kw and if we get 4 hr ( 74.3 kwhr)- 6 hrs (111.456 kwhr) of charging at 70% of the total we can expect 53 kwhrs - 78.0 kwhrs stored each day in the batteries to make use of during the night as we do not get to use the total battery capacity from the invertor.

We are saving the basically most of the container mass with batteries of 3 units with a charger and invertor assembly to have the 3 extra rolls of these flexible arrays with a 440 sq m area (8.8m x 50m) total for the 4 arrays that is just charging the batteries for night use (roughly 13hr).

Using a second array set that feed supercapacitors and then to the 18 kw ac invertor you could supply the rough 6 hrs of power directly from that array for the days useage. This is where I would add the powerwall to the mix as it could save excess power that the invertor supplies but is not being drawn for feeding back into an artifical grid. I would say that its unknown as to howmany arrays or powerwalls would be needed to make this all work.

This leaves a gap to solve for out of the 25hr day for how to best make use of another set of the arrays with batteries, arrays with supercapacitors and solving the night time loading as well as day time use for just how many sets are needed to bring to mars. At this point this is just to solve for man's survival and nothing else.

louis · 2020-02-24 18:37:23

Yes, I wouldn't use Rapid Roll as a guide to tonnage, only really as a method of setting up an array.

From previous analysis, I think we can get the system under 150 tons, certainly under 200 tons. And yes, I would be looking to minimise chemical battery storage. Remember there will be pretty big batteries on board the six Starships in any case. They can be incorporated in the overall surface system. They are likely to be able to hold 2.4 MwHs. From memory, I think I was proposing something like 30 tons of additional chemical batteries for a Space X style mission which should produce another 7.5 MwHs of storage. That should ensure you can keep any propellant production process ticking over, during the hours of darkness.

Calliban wrote:

louis wrote:
The Rapid Roll "T" 11/120 clocks in at about 115 sq. metres. I estimate the average daily output power at 4 x 18 KwHs = 72 KwHs or an average of 3 Kws.
http://www.renovagen.com/products/rapid-roll-t/
So to produce an average of 1 Mw that would mean you need about 52,000 sq metres on Earth, or maybe 100,000 sq. metres on Mars.
That's an area of 316 x 316 metres...probably equivalent to an athletics sports stadium area. So definitely not unfeasible, given how easy it is to roll out the system.
That said, I am sure if we throw money at the problem we can get a more efficient flexible PV system, so reducing the area required. But on the other hand you need to plan for major dust storms and you have to account for battery storage loss as well, which requires you to over-design the PV system...so 100,000 sq metres is probably as good an estimate as you are going to get.
If you can unroll 155 sq metres in 2 minutes that means you could unroll 100,000 sq metres in just over 21 hours.
Allowing for breaks to reconnect robot rovers to the PV rolls and limited working hours (maybe only 6 hours per sol), I think that might be a 5 to 7 sol job - a very reasonable time allowance for such a crucial Mission system.
Impressive tech. But note, you have here a 10.8kW-peak system weighing 2.75 tonnes. To generate an average power of 1MW at the Martian equator, the system would weigh close to 1800 tonnes. You see the problem?
Of course, that includes a lot of battery storage that you may not need for propellant production. Let's look at Spacenut's example of folding cells.
http://www.renovagen.com/products/fast-fold/
A 1kW-peak panel weighs 35kg. It would generate average power of 143 watts on Mars at the equator. More in day; none at night. Power would vary sinusoidally during the day, peaking at noon. To generate average power of 1MW, you would need 244 tonnes of cells. Add in the inverters and transformers and you are talking substantially more. The 2.88kW inverter-transformer unit in the brochure weighs 125kg - about half of which is battery mass.
Maybe you should send a smaller propellant factory several years in advance. As new missions arrive, they can assemble an ISRU factory for solar power plants.

SpaceNut · 2020-02-24 20:15:36

louis wrote:

Yes, I wouldn't use Rapid Roll as a guide to tonnage, only really as a method of setting up an array.

I understand that the method is simple but the drawback of issues are not present here on earth that we will see on mars.

The issue is the back of the arrays are going to need more than a tarp protection for a backing pad to the abrasive nature of the sharp rocks of mars surface. We will need to prepare the surface area to allow for that dragging across it such that they are not damaged by it. The flat tent pegged down after is also a problem as they will be constantly dirty which will lower the output from them not to meantion its lower as its not aligned but that is only and issue under the more intense dust storms. The cold temperature may mean only a summer time roll out of the array for power system setup.

SpaceNut · 2020-03-03 19:55:57

Interesting that we are over the 500w size as the high efficiency panels are 300 to 400 typically.

Trina Solar launches 500W ultra-high-power modules

Trina Solar has formally unveiled its latest Duomax V bifacial double-glass modules and Tallmax V back sheet modules. Based on the 210mm large-size silicon wafer and monocrystalline PERC cell, the new modules come replete with several innovative design features allowing high power output of more than 500Wp and module efficiency up to 21%, consolidating the Company's leadership and embracing a new era of PV 5.0.
Based on its superior multi-busbar technology, Trina Solar's research and development team has introduced an innovative design that integrates advanced three-piece, non-destructive cutting and high-density packaging technologies. This further reduces the resistance loss and significantly improves the anti-cracking, anti-hot spot performance of the modules while maximizing space utilization.

http://www.trinasolar.com/

Need to see what the size of the panels are to computer efficiency.

louis · 2020-03-04 08:12:48

Double sided might work well on Mars where there is a lot of ambient light, owing to high dust levels.

SpaceNut wrote:

Interesting that we are over the 500w size as the high efficiency panels are 300 to 400 typically.
Trina Solar launches 500W ultra-high-power modules
Trina Solar has formally unveiled its latest Duomax V bifacial double-glass modules and Tallmax V back sheet modules. Based on the 210mm large-size silicon wafer and monocrystalline PERC cell, the new modules come replete with several innovative design features allowing high power output of more than 500Wp and module efficiency up to 21%, consolidating the Company's leadership and embracing a new era of PV 5.0.
Based on its superior multi-busbar technology, Trina Solar's research and development team has introduced an innovative design that integrates advanced three-piece, non-destructive cutting and high-density packaging technologies. This further reduces the resistance loss and significantly improves the anti-cracking, anti-hot spot performance of the modules while maximizing space utilization.
http://www.trinasolar.com/
Need to see what the size of the panels are to computer efficiency.

SpaceNut · 2020-03-04 17:31:13

Place the back side to collect power from reflected light that would boost the power to that side of the panel. It appears to me that this is a combined set of panels which are back to back so that the light recieving sides face outward.

That said the rollout flexible panels could be double sided and have dual reflecting parabolic dish trough to focus the light onto both sides of the assembly. This take advantage of the fact that a single battery system that requires multiple panel sets to make it work in the first place and the trough can serve to make hot water with a little glazing to cover part of the trough to isolate the mars cold from creating thermal heat for making it happen.
Depending on the size of the reflective surface we can bring the panels capability back to that of earths wattage output levels.

SpaceNut · 2020-07-11 15:06:50

HCPV Solar Parabolic Solar Concentrator Technology

We have talked about high temperature PV cells in a few topics and this companies seems to be where we need solar to be.

Concentrating photovoltaic (CPV) technology uses optics such as lenses or curved mirrors to concentrate a large amount of sunlight onto a small area of solar photovoltaic (PV) cells to generate electricity. CPV multi-junction solar cell efficiencies of 46% are being reached compared to conventional solar power tower steam engine efficiency of 14% and average PV panel efficiency of 15%. Solartron works with CPV manufacturers and solar power plant project developers and provides a state-of-the-art parabolic solar concentrator for use with CPV multi-junction solar cell modules.

Void · 2020-07-11 18:26:21

Spacenut I have enjoyed your materials supplied. Thanks.
I intend to appropriate a bit of it for the "Ice Slabs" topic under "Life Support". I do most certainly not want to mess up your topic here.
I think the two topics can be parallel, for this, but I will do mine there.

SpaceNut · 2020-07-11 19:12:27

So making solar concentrated would be possible

void wrote:

I think that due to low Martian gravity, and winds that are far less of a problem, it can be made from lighter materials. This Spacenut also suggested.
But for the parabolic mirror, I am thinking Styrofoam, with a reflective coating. The other surfaces may need a protective coating as well.
If Styrofoam, is not strong enough, then embed a wire mesh in it.
This then being lighter, the supporting structures can also be lighter. And of course that was obvious to the other members as well.
I am usually worried about the consumption of Copper and Aluminum, so I would like to avoid that when alternatives exist, or at least reduce the amount of consumption. We do have Chromium, Iron, and Titanium available in the sand dune materials, and of course from other sources.

Sounds like we could do this...

SpaceNut · 2020-07-25 16:59:41

tahanson43206 wrote:

Mars is approaching perihelion...
Mars' Calendar | The Planetary Society www.planetary.org › explore › space-topics › mars-cale...
The Mars dust storm season begins just after perihelion at around Ls = 260°. ... of this comparison, we use the solar longitude range 0°-360° to define a Mars ...
August 3, 2020
Mars' perihelion is a once-in-two-Earth-years event. Mars came to perihelion last on October 29, 2016. Its next perihelion will be August 3, 2020. None of the planets have exactly circular orbits, but most, like Earth, have orbits around the sun that are nearly circular.Sep 16, 2018
Per Google from: earthsky.org › mars-perihelion-closest-to-sun
I found a citation that Mars receives (about) 40% more Solar radiation at perihelion than it does at apohelion.
That increase of energy would account for the expected increase in weather.
(th)

That is why we design for the worsts levels for what we can receive each day....for the daily useage…..

https://www.firsttheseedfoundation.org/ … -tomatoes/

At local noon on Mars, with Sun directly overhead, the solar irradiance is 590W/m2 (590 watts per square metre). All the above measurements are taken with the incident light perpendicular to the absorbing surface. If the sunlight falls on the surface at an angle, less energy will be incident (per square metre) on the surface.

SpaceNut · 2020-10-12 08:08:57

I was reminded of this topic by the https://mars.nasa.gov/insight/weather/ page which is publishing a running pressure, Temperature and winds but what of the power levels received by the landers fixed location round fan panels?

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

Power is generated by two round solar panels, each 2.15 m (7.1 ft) in diameter when unfurled, and consisting of SolAero ZTJ triple-junction solar cells made of InGaP/InGaAs/Ge arranged on Orbital ATK UltraFlex arrays. After touchdown on the Martian surface, the arrays are deployed by opening like a folding fan.
Rechargeable batteries
Solar panels yielded 4.6 kilowatt-hours on Sol 1

With the highest Beginning-Of-Life (BOL) conversion efficiency of 32%, SolAero's industry-leading multi-junction solar cells provide the highest levels of performance

Side panel indicates Rechargeable batteries of 600 w but thats is in error as that is not ampere hour related.

https://www.eaglepicher.com/resources/n … ht-lander/

Two of EaglePicher’s 8-cell, 28 volt, 30 amp-hour batteries are mounted to InSight’s baseplate and will be used to store solar power that the lander collects.

https://www.eaglepicher.com/sites/defau … 112918.pdf

https://www.planetary.org/space-missions/insight

The battery is a lithium ion type with the two, 7-foot wide solar panels capable of as much as 700 watts on a clear day.

we know mars opacity varies quite a but assuming that first day was clear that would mean 6.5 hrs of daylight producing power...

SpaceNut · 2020-11-21 15:11:31

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

Power is generated by two round solar panels, each 2.15 m (7.1 ft) in diameter when unfurled, and consisting of SolAero ZTJ triple-junction solar cells made of InGaP/InGaAs/Ge arranged on Orbital ATK UltraFlex arrays. After touchdown on the Martian surface, the arrays are deployed by opening like a folding fan. Rechargeable batteries. Solar panels yielded 4.6 kilowatt-hours on Sol 1

PIA22835-MarsProbes-SingleSolGeneratedEnergy-20181130-corrected.png

https://www.jpl.nasa.gov/news/press_kit … pacecraft/

About 20 to 25 minutes after touchdown, the lander will deploy two nearly circular, 10-sided solar arrays, each 7.05 feet (2.15 meters) in diameter, extending from opposite sides of the lander. The two arrays combined have almost as much surface area as a pingpong table. Before landing, these are stowed in a radially folded configuration similar to a folded fan. After they have been deployed, the lander’s two arrays will together generate up to about 600 to 700 watts on a clear Martian day (or 200 to 300 watts on a dusty one). The UltraFlex panels are from Northrup Grumman Innovation Systems (formerly Orbital ATK-Goleta) in Goleta, California, with photovoltaic cells from SolAero.
A pair of rechargeable 28 volts, 25 amp-hour lithium-ion batteries located on the lander will provide energy storage. The lithium-ion batteries are from the Yardney Division of EaglePicher Technologies in East Greenwich, Rhode Island. In addition, a single-use, non-rechargeable thermal battery will supplement the main batteries during entry, descent and landing.

The batteries can hold just 16 hours of power for the lander to make use of until at the dead battery voltage level for a lithium ion battery pack.

The 18650 series cell is a 3.7 volt come in a variety of ampere hours from 1 a/hr to 3 a/hr delivery ratings these days. Lithium Ion cells are 3.7volts nominal, their safe operating voltage is ~3.5v-4.2v.

https://www.devonbuy.com/checking-batte … ge-levels/

Generally, a battery is considered dead when it has fallen to about 60% of its original as-new voltage.

Anything under 3 v is considered dead with below 2.5v is damaged.
https://insightsolutionsglobal.com/comm … -fix-them/

SpaceNut · 2020-11-21 22:45:21

Phoenix Mars lander also used the fan style 450 watt solar panel but it had different batteries.
-

Phoenix landed in the Green Valley of Vastitas Borealis on May 25, 2008, in the late Martian northern hemisphere spring (Ls=76.73), where the Sun shone on its solar panels the whole Martian day. By the Martian northern Summer solstice (June 25, 2008), the Sun appeared at its maximum elevation of 47.0 degrees. Phoenix experienced its first sunset at the start of September 2008

-
https://en.wikipedia.org/wiki/Phoenix_(spacecraft)

Power
Power for the cruise phase is generated using two gallium arsenide solar panels (total area 3.1 m2 (33 sq ft)) mounted to the cruise stage, and for the lander, via two gallium arsenide solar array panels (total area 7.0 m2 (75 sq ft)) deployed from the lander after touchdown on the Martian surface. NiH2 battery with a capacity of 16 A·h.

https://artisanelectricinc.com/mars-sol … eneration/
https://www.jpl.nasa.gov/nmp/st8/tech/solar_array3.html

SpaceNut · 2020-11-22 20:29:57

Going to mars with to few batteries or to few solar panels is a problem since we can not guarantee how much we will receive or use on a daily basis or hourly as is what happens when we want to eat or to shower. So power without a grid to take excess energy or alternative systems to turn off makes for a difficult time using just solar and batteries.
SURVIVING ON MARS WITHOUT NUCLEAR ENERGY

SpaceNut · 2020-12-21 19:59:43

Going to mars with a only solar requires the highest level of solar and right now the commercial industry is catching up Scientists have set a new efficiency record for perovskite-silicon solar cells with "proof of concept" milestone of 30 percent, clocking 29.15 percent in this experiment.

SpaceNut · 2021-04-10 23:00:32

The usual discontent has started once more for going solar only in another topic that Elon Musk can not be wrong.

Earth mars size comparison
55066main_earthmarst.jpe

The maximum solar irradiance on Mars is about 590 W/m2 compared to about 1000 W/m2 at the Earth’s surface.

The Sun’s intensity on a horizontal patch of the Earth’s surface of 590W/m2 occurs when the Sun is a mere 36 degrees above the horizon.

This is the climate zones on mars
Rcbc560d1503dd7e771e1fc8056d7a914?rik=E0ZYk1t3E2%2fSBA&riu=http%3a%2f%2fplanetary-science.org%2fwp-content%2fuploads%2f2014%2f12%2fMars_climate_zones.jpg&ehk=p3fKzpxVTeoosXQdLvITk9d7WIsUPjMtP8X1d2iMwvI%3d&risl=&pid=ImgRaw

Remember that Mars society chose to work on Devon Island as it had the same solar energy levels as Mars has at its equator.
Devon Island is the largest uninhabited island on Earth. It is found at 75oN and has surface characteristics that strongly resemble the surface of Mars. Being so far north, Devon Island has solar irradiance similar to the solar irradiation on the Martian Equator.

Except for a brief period in June, the intensity of the Sun on Devon Island never exceeds the solar intensity on Mars

The solar radiation intensity falling on a surface is called irradiance or insolation and is measured in W/m2 or kW/m2. The solar constant can be used to calculate the irradiance incident on a surface perpendicular to the Sun’s rays outside and the Earth’s atmosphere on any day of the year (i.e. as the distance between the Sun and Earth changes thought the year):

$latex.php?latex=I_0%3DI_%7BSC%7D%5Cleft+%5B+1%2B0.034%5Ccos+%5Cleft+%28+2%5Cpi%5C+%5Cdfrac+%7Bn%7D%7B265.25%7D%5Cright+%29+%5Cright+%5D&bg=T&fg=000000&s=1$

ISC = the solar constant

kbd512 · 2021-04-11 03:34:16

SpaceNut,

TSI at TOA on Earth is ~1,361W/m^2.

TSI at TOA on Mars is ~590W/m^2.

If an Earth-based PV panel is 25% efficient, then you can potentially obtain as much as 340.25 Watts of power.

To collect the same amount of power on Mars, your PV panel needs to be about 57.7% efficient.

340.25 / 590 = 0.576694915254237

Believe it or not, there is such a thing as a 57.7% efficient solar panel. However, you'd better have your wallet ready, because they don't merely cost twice as much as the 25% efficient panels. If your pockets are deep enough, then you can afford just about anything. However, your average Mars homesteader may not have enough scratch to cover the increased PV cost after they pay a quarter million dollars per person for their one-way ticket to energy poverty to go live like Ted Kaczynski did.

Would a 57.7% efficient panel help reduce the crazy amount of surface area that you have to cover? You betcha. Every little bit helps. The problem is that the PV array would still cover an area the size of a city, merely to supply a city of a million people, the size of a postage stamp by way of comparison, with power. Beyond that, you have to store that power for at least 16 hours per day, because even 100% efficient panels don't produce measurable power at night.

I'd bet almost anything that the PV panels in the Bhadla array are 20% efficient commercial panels; the cheapest stuff the Indian government could get their hands on. If the panels we use on Mars are more than double the efficiency of those used in Bhadla (46% efficient), then we're still talking about the biggest solar array ever constructed, with no other array on Earth even close to the same size, made from really expensive panels, with even more expensive lightweight backers like CFRP composite with a Nomex honeycomb core. Damaging a single panel is literally akin to throwing thousands of dollars into a bonfire. That's just to provide the air and water, but no food, no reserve power, and no power to make anything- despite the fact that construction in all active cities continues on into perpetuity.

Let's talk about weight, so that people who don't think we need to ship a million tons of cargo to Mars every year can begin to understand how ridiculous that idea truly is.

30% efficient GaAs cells from FullSuns:

4*8cm Triple Junction Gallium Arsenide Solar Cell

According to the documentation, each wafer weighs 3.8g +/- 0.2g. Since we don't entirely trust Chinese quality control, we're going to round that up to 4g per cell.

1m^2 = 10,000cm^2

Each cell is 30.15cm^2.

Average fill factor per m^2 is listed as 85%.

8,500cm^2 / 30.15cm^2 = 282 cells per m^2

282 cells per m^2 * 4g per cell = 1,128g/m^2

1km^2 = 1,000,000m^2

1,000,000 * 1.128kg = 1,128,000kg = 1,128t

1 Bhadla = 10km^2 of active area (actual solar panels)

1,128t per km^2 * 10km^2 = 11,280t of silicon per Bhadla

50 Bhadlas * 11,280t of silicon per Bhadla = 564,000t of silicon

Now I understand why Louis wanted to build a PV factory on Mars. Without it, this nonsense swiftly consumes every bit of a million ton cargo allotment.

If we have a 1kg/m^2 CFRP and Nomex honeycomb backer (4 plies of Toray T1000 cloth, two plies per side), then that adds another 500,000t.

Oh look, we've already used up more than 100% of our million ton cargo allotment. We haven't included one lousy dab of Silver solder to connect the bazillions of individual silicon cells together, not one lousy meter of wiring to take the power to the base from tens of kilometers away, not one lousy power inverter, not one lousy transformer, nor one lousy battery to store any power so everyone doesn't die at night when there's no more solar power to be had. Can anyone else do some simple math to figure out how much all of that wiring, the power inverters, transformers, and CFRP frames would weigh? How about the batteries that store / supply 59.2GWh when day turns into night?

Delivering 11,580t for 30 of those 258MWe ThorCon reactors (includes the first batch of fuel, BTW) doesn't look so bad now, does it?

Heck, we can probably afford to splurge on Titanium containment cans instead of the cheapest carbon steel available, in order to cut that weight in half again with all the money we just saved on transportation costs.

If we have to deliver 78.2925t of fuel per year for, oh, I don't know, seven thousand years, that's about how long it would take for the weight of the Uranium and Thorium fuel to equal the weight of the Silicon we'd have to deliver to keep a million people alive. Even if we transport it in special containers, we're still talking about several millennia of time for the weight of the fuel to equal the weight of the shiny sand.

Who else here thinks we might easily blow right past that 1,000,000t cargo allotment I proposed, by the time the weight of the rest of the machinery to keep everyone alive and healthy is included for construction of Mars City?

If anyone still wants to goof off with PV, then do it using locally-acquired resources AFTER we have a reliable power source in place that doesn't quit producing power every time the planet makes a half rotation.

louis · 2021-04-11 04:38:13

Why would you need a 57% efficient PV panel on Mars?

With 25% efficiency a figure of 0.5 KwH per sol per sq metre on Mars looks about right. With a 10 m by 10 m array you get 50Kwhes per sol on average. In the UK the cost of installing an array that size would be something like £25,000 (and that's with people clambering all over house roofs and fixing heavy struts etc). Maybe add on £15,000 for inverter and storage system. I am just giving those prices as context to show 100 sq metres of panelling is not a deal breaker.

kbd512 wrote:

SpaceNut,
TSI at TOA on Earth is ~1,361W/m^2.
TSI at TOA on Mars is ~590W/m^2.
If an Earth-based PV panel is 25% efficient, then you can potentially obtain as much as 340.25 Watts of power.
To collect the same amount of power on Mars, your PV panel needs to be about 57.7% efficient.
340.25 / 590 = 0.576694915254237
Believe it or not, there is such a thing as a 57.7% efficient solar panel. However, you'd better have your wallet ready, because they don't merely cost twice as much as the 25% efficient panels. If your pockets are deep enough, then you can afford just about anything. However, your average Mars homesteader may not have enough scratch to cover the increased PV cost after they pay a quarter million dollars per person for their one-way ticket to energy poverty to go live like Ted Kaczynski did.
Would a 57.7% efficient panel help reduce the crazy amount of surface area that you have to cover? You betcha. Every little bit helps. The problem is that the PV array would still cover an area the size of a city, merely to supply a city of a million people, the size of a postage stamp by way of comparison, with power. Beyond that, you have to store that power for at least 16 hours per day, because even 100% efficient panels don't produce measurable power at night.
I'd bet almost anything that the PV panels in the Bhadla array are 20% efficient commercial panels; the cheapest stuff the Indian government could get their hands on. If the panels we use on Mars are more than double the efficiency of those used in Bhadla (46% efficient), then we're still talking about the biggest solar array ever constructed, with no other array on Earth even close to the same size, made from really expensive panels, with even more expensive lightweight backers like CFRP composite with a Nomex honeycomb core. Damaging a single panel is literally akin to throwing thousands of dollars into a bonfire. That's just to provide the air and water, but no food, no reserve power, and no power to make anything- despite the fact that construction in all active cities continues on into perpetuity.
Let's talk about weight, so that people who don't think we need to ship a million tons of cargo to Mars every year can begin to understand how ridiculous that idea truly is.
30% efficient GaAs cells from FullSuns:
4*8cm Triple Junction Gallium Arsenide Solar Cell
According to the documentation, each wafer weighs 3.8g +/- 0.2g. Since we don't entirely trust Chinese quality control, we're going to round that up to 4g per cell.
1m^2 = 10,000cm^2
Each cell is 30.15cm^2.
Average fill factor per m^2 is listed as 85%.
8,500cm^2 / 30.15cm^2 = 282 cells per m^2
282 cells per m^2 * 4g per cell = 1,128g/m^2
1km^2 = 1,000,000m^2
1,000,000 * 1.128kg = 1,128,000kg = 1,128t
1 Bhadla = 10km^2 of active area (actual solar panels)
1,128t per km^2 * 10km^2 = 11,280t of silicon per Bhadla
50 Bhadlas * 11,280t of silicon per Bhadla = 564,000t of silicon
Now I understand why Louis wanted to build a PV factory on Mars. Without it, this nonsense swiftly consumes every bit of a million ton cargo allotment.
If we have a 1kg/m^2 CFRP and Nomex honeycomb backer (4 plies of Toray T1000 cloth, two plies per side), then that adds another 500,000t.
Oh look, we've already used up more than 100% of our million ton cargo allotment. We haven't included one lousy dab of Silver solder to connect the bazillions of individual silicon cells together, not one lousy meter of wiring to take the power to the base from tens of kilometers away, not one lousy power inverter, not one lousy transformer, nor one lousy battery to store any power so everyone doesn't die at night when there's no more solar power to be had. Can anyone else do some simple math to figure out how much all of that wiring, the power inverters, transformers, and CFRP frames would weigh? How about the batteries that store / supply 59.2GWh when day turns into night?
Delivering 11,580t for 30 of those 258MWe ThorCon reactors (includes the first batch of fuel, BTW) doesn't look so bad now, does it?
Heck, we can probably afford to splurge on Titanium containment cans instead of the cheapest carbon steel available, in order to cut that weight in half again with all the money we just saved on transportation costs.
If we have to deliver 78.2925t of fuel per year for, oh, I don't know, seven thousand years, that's about how long it would take for the weight of the Uranium and Thorium fuel to equal the weight of the Silicon we'd have to deliver to keep a million people alive. Even if we transport it in special containers, we're still talking about several millennia of time for the weight of the fuel to equal the weight of the shiny sand.
Who else here thinks we might easily blow right past that 1,000,000t cargo allotment I proposed, by the time the weight of the rest of the machinery to keep everyone alive and healthy is included for construction of Mars City?
If anyone still wants to goof off with PV, then do it using locally-acquired resources AFTER we have a reliable power source in place that doesn't quit producing power every time the planet makes a half rotation.

GW Johnson · 2021-04-11 10:18:24

The power requirement for a small base (or a large city) on Mars will be the power demand here on Earth, just much larger numbers. Why larger? Because you must add power for activities beyond just heating, air conditioning (maybe not so much on Mars), and lighting. Power is required to make water, oxygen, and food. Without them you die on Mars. You die in the cold, too.

The typical daily power demand variation here on Earth is quite a bit higher during the day when people are doing things, and quite a bit less at night when they are sleeping. Solar only works when the sun is brightly shining. You can use batteries to get through the night, but they are heavy, expensive, and you have to send them there. It would be totally infeasible to send enough batteries to get through a big dust storm's darkness, which lasts weeks to many months.

So, what you do is use nuclear as a base load that gets you through the darkness at night, plus a few percent more. Use the solar during the day when the sun shines to make the higher daytime power required. You can restrict activities during bad dust storms to what the nuke can supply. Use the batteries in your vehicles. Then you don't have to ship so many batteries to Mars.

I'm all for doing something that actually makes sense. Base load nuclear plus daytime solar makes a lot of sense.

GW

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