High Guard 2e - Solar Panels

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baithammer
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Re: High Guard 2e - Solar Panels

Postby baithammer » Mon Aug 20, 2018 2:47 am

Ugh forgot to put "as if thrust 1".
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Re: High Guard 2e - Solar Panels

Postby AnotherDilbert » Mon Aug 20, 2018 2:52 am

DickTurpin wrote: This gives solar panels the power production per ton of exactly ten times that of a fusion plant of the same tech level.
Not quite, the solar panel are based on an imaginary PP-1, but still does not allow manoeuvring.

That kind of performance is theoretically possible, provided the solar "panels" are an extremely thin film.

viewtopic.php?f=89&t=119491&p=908896&hi ... ar#p908881
PsiTraveller
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Re: High Guard 2e - Solar Panels

Postby PsiTraveller » Mon Aug 20, 2018 3:46 am

Well the 1 ton of solar panels is the volume of very thin panels all folded up. Fold things out to catch the sun and assume the panels are 1cm thick. 1m3 of storage space is now 100 m2 of unfolded panels.
1 dTon is 1400 m2 of unfolded panels.

Or make the panels thinner and have a larger surface area. The film may be hectares in size.

Maybe they are inflatable balloins of mylar that inflate to massive size and concentrate the sunlight onto a central point. This is what creates the power. They could be hundreds of meters in diameter. These solar power bubbles prevent the movement of the ship.
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Re: High Guard 2e - Solar Panels

Postby DickTurpin » Mon Aug 20, 2018 8:45 pm

AnotherDilbert wrote:
Mon Aug 20, 2018 2:52 am
DickTurpin wrote: This gives solar panels the power production per ton of exactly ten times that of a fusion plant of the same tech level.
Not quite, the solar panel are based on an imaginary PP-1, but still does not allow manoeuvring.
Good catch. Since the solar panels are 1/10th the size of a fusion plant that would provide 30 power yet they only provide 20 power, the actual power/ton ration is actually 20/3rds (say 7x) in favor of the solar panels. It still seems excessive.
AnotherDilbert wrote:
Mon Aug 20, 2018 2:52 am
That kind of performance is theoretically possible, provided the solar "panels" are an extremely thin film.

viewtopic.php?f=89&t=119491&p=908896&hi ... ar#p908881
We were talking about the power generating capacity of solar sails, not the thrust provided by solar sails. There is no reason the two could not be used together such as a solar sail made of or lined with a power generating film but that is another discussion.
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Re: High Guard 2e - Solar Panels

Postby baithammer » Tue Aug 21, 2018 9:29 am

Solar Sails don't generate power, solar panels do.
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Re: High Guard 2e - Solar Panels

Postby AnotherDilbert » Tue Aug 21, 2018 12:24 pm

DickTurpin wrote: We were talking about the power generating capacity of solar sails, not the thrust provided by solar sails. There is no reason the two could not be used together such as a solar sail made of or lined with a power generating film but that is another discussion.
Solar cells can be a thin layer on a thin film substrate, so that a solar "panel" would look like a solar sail. The solar sail acceleration would be negligible.

Even a small ship would need a square kilometre or so of panel, so a thick, solid panel is quite impractical.

AnotherDilbert wrote:
Sun Sep 04, 2016 8:21 am
wbnc wrote:Hmm now there's an idea combine the solar sail with the solar array as a single unit...pay cost and tonnage for both systems and in the write up of the craft describe them as being one device and that to use one you have to deploy both...
A 800 m × 800 m = 640 000 m2 sail/panel would generate 5 N as a sail and perhaps 640 MW as a panel. 640 MW fed into a M-drive would generate a thrust in the region of 30 000 000 N.

The solar sail effect is negligible.

An experimental sail https://en.wikipedia.org/wiki/IKAROS produced a thrust of 0,00112 N from a sail system massing about 4 kg. That would be enough to accelerate the sail (without any payload) at 0,00003 G. If you add a payload we are talking about 0,000001 G or so. Solar sails are completely obsoleted by anti-grav and M-drives.
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Re: High Guard 2e - Solar Panels

Postby Linwood » Wed Aug 22, 2018 12:02 am

Slightly different topic - there’s been proposals to use high-albedo coatings applied to asteroids to force them (very gradually I assume) into a different and presumably less dangerous orbit. Given the low thrust calculated for solar sails, is that idea even remotely possible?
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Re: High Guard 2e - Solar Panels

Postby Sigtrygg » Wed Aug 22, 2018 10:15 am

Yes, you have to take into account that the thrust is low but it is continuous. Building a solar sail that could achieve solar escape velocity is something we are more than capable of - the physics and the materials exist, what's missing is money and political will.
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Re: High Guard 2e - Solar Panels

Postby AnotherDilbert » Wed Aug 22, 2018 3:13 pm

Linwood wrote: ... there’s been proposals to use high-albedo coatings applied to asteroids to force them (very gradually I assume) into a different and presumably less dangerous orbit. Given the low thrust calculated for solar sails, is that idea even remotely possible?
I would guess that it is not very practical. A painted asteroid would have much lower acceleration than a spacecraft with a solar sail.

At less than a millionth of a g it would gain 0.1 km/s or so per year of acceleration (in Earth orbit, much less in the belt). It would take decades to change the asteroids orbit even a little.
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Re: High Guard 2e - Solar Panels

Postby Sigtrygg » Wed Aug 22, 2018 3:52 pm

Oh its practical - it could be done with current technology in very little turnaround time. The draw back is it takes years to perturb the orbit of the asteroid.

So it is a serious proposition for an Earth crossing asteroid that 'may' impact in 30+ years time. It is of no use whatsoever against something that is going to hit in only a few months or years time.
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Re: High Guard 2e - Solar Panels

Postby Linwood » Thu Aug 23, 2018 12:08 am

So now I’m picturing a company painting an asteroid to do just that - with an enormous replica of the corporate logo to remind everyone just who brought the world the not-Apocalypse..... :)
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Re: High Guard 2e - Solar Panels

Postby Reynard » Thu Aug 23, 2018 11:56 am

My interpretation concerning Traveller solar panels. First, a vessel's power plant also includes a lot of empty space. The displacement is not a solid block. A solar panel array is tightly and efficiently packed until deployed. It includes bracing and armatures to extend a huge yet thin surface area with energy catching cells that are probably more advanced than we have today in order to explain the amount of power they absorb. The size explains one reason they can't be deployed when jumping, it most likely extends beyond the jump bubble. Any velocity above 1g will tear the array apart.

The array is used mostly to supplement a power plant to reduce fuel use. A vessel with no power plant cannot sustain functions much beyond minimal basic power and maneuvering without sacrificing other priority systems (See Running Out of Power, CR. pg. 144). Vessels without power plants are more often satellites and stations equipped with station keeping 0g thrusters at best. The Thrust 1 motive system would allow the craft the extra ability to reposition itself as well as hold a stable position and only for very short distances rather than interplanetary trips. It's minimally maneuvering between 0g and 1g thrust.

By not manuevering (M drive is turned off), you can run a station without fuel. There's enough power for basic needs plus the power points for operating the M-drive can be allocated to other power point using systems. Position corrections would mean shutting down systems (dimming the lights) to operate the M-drive for brief periods. If there is power left over with M-drive shut down, those power points could be added to High Efficiency Batteries which can hold enough charges to fire energy weapons as well as powering the turret a finite number of rounds. Missile and sandcasters won't need power but the turrets will.
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Re: High Guard 2e - Solar Panels

Postby PsiTraveller » Thu Aug 23, 2018 2:59 pm

I want clearer rules for solar panels as power supply for space stations or asteroid facility/processing operations. These facilities would be in orbit in the good solar capture area, not too far from the sun.

I am not worried about Thrust 1, this is a facility that has been placed in orbit, built there or towed, so minimal station keeping is needed.

I am interested in building large solar arrays to power the facility and the processing operations. So I want solar panels to produce more than just minimal power to extend minimum operational levels. I want excess power, if in orbit of a planet let's microwave beam the excess down to the planet for free energy to the grid. In non-orbital facilities I want enough power to give power for a manufacturing facility, ore processing. or any other operation I want to operate in the asteroid.

You can do hand wavey descriptions of massive solar arrays visible as the player's ship approaches the facility. But some hard crunchy numbers just to make a design printable for a description would be good.
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Re: High Guard 2e - Solar Panels

Postby Linwood » Fri Aug 24, 2018 1:19 am

Adding to that - it’s reasonable to assume that even with the most advanced materials there would be some wear and tear over time. So some allowance for that - maybe just that for X dtons of solar sail you need so much of an allowance for repair drones - would be a good idea.
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Re: High Guard 2e - Solar Panels

Postby DickTurpin » Fri Aug 24, 2018 4:14 am

Linwood wrote:
Fri Aug 24, 2018 1:19 am
Adding to that - it’s reasonable to assume that even with the most advanced materials there would be some wear and tear over time. So some allowance for that - maybe just that for X dtons of solar sail you need so much of an allowance for repair drones - would be a good idea.
Since the cost of the solar panels is included in the ship cost, annual maintenance already includes the panels.
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Re: High Guard 2e - Solar Panels

Postby Sigtrygg » Fri Aug 24, 2018 9:15 am

PsiTraveller wrote:
Thu Aug 23, 2018 2:59 pm
I want clearer rules for solar panels as power supply for space stations or asteroid facility/processing operations. These facilities would be in orbit in the good solar capture area, not too far from the sun.

I am not worried about Thrust 1, this is a facility that has been placed in orbit, built there or towed, so minimal station keeping is needed.

I am interested in building large solar arrays to power the facility and the processing operations. So I want solar panels to produce more than just minimal power to extend minimum operational levels. I want excess power, if in orbit of a planet let's microwave beam the excess down to the planet for free energy to the grid. In non-orbital facilities I want enough power to give power for a manufacturing facility, ore processing. or any other operation I want to operate in the asteroid.

You can do hand wavey descriptions of massive solar arrays visible as the player's ship approaches the facility. But some hard crunchy numbers just to make a design printable for a description would be good.
You could look at the real world numbers and convert and extrapolate. A solar cell on a satellite in orbit around the Earth gets 1361 W per square metre incident radiation, the efficiency of the cell will reduce this - current tech is between 20%-40%

Let's go with the best efficiency and say a TL8 solar array can generate 500 W per square meter - 0.5kW per square metre. What is needed is a conversion to MgT EPs.

Since I do know the conversion rate for CT (250MW per EP) if I go with that 500,000 square metres of solar array are needed (the solar arrays on the ISS are each about half as efficient as the best we could make today and have an area of 375 square metres each).
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Re: High Guard 2e - Solar Panels

Postby AnotherDilbert » Fri Aug 24, 2018 9:38 am

Sigtrygg wrote: Since I do know the conversion rate for CT (250MW per EP) if I go with that 500,000 square metres of solar array are needed ...
Plus a safety margin, since solar panels degrade in space¹, that would be something like a million square metres per EP.

¹ https://en.wikipedia.org/wiki/Space-bas ... te_note-39
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Re: High Guard 2e - Solar Panels

Postby Sigtrygg » Fri Aug 24, 2018 10:41 am

AnotherDilbert wrote:
Fri Aug 24, 2018 9:38 am
Sigtrygg wrote: Since I do know the conversion rate for CT (250MW per EP) if I go with that 500,000 square metres of solar array are needed ...
Plus a safety margin, since solar panels degrade in space¹, that would be something like a million square metres per EP.

¹ https://en.wikipedia.org/wiki/Space-bas ... te_note-39
That's with ten year old technology, and I don't think you need to double your array size just to cope with a 0.25% loss per year.

Let's assume a TL8 panel also includes a coating to lessen this degradation, and at TL10+ the materials are intrinsically resistant to this degradation.

Now to advance the TLs:

higher TLs would bring more efficiency and more durable materials, how about 750 W per square metre at TL10 and 1000W per square metre at TL12
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Re: High Guard 2e - Solar Panels

Postby AnotherDilbert » Fri Aug 24, 2018 11:13 am

Sigtrygg wrote:
AnotherDilbert wrote: Plus a safety margin, since solar panels degrade in space¹, that would be something like a million square metres per EP.
¹ https://en.wikipedia.org/wiki/Space-bas ... te_note-39
That's with ten year old technology, and I don't think you need to double your array size just to cope with a 0.25% loss per year.
0.25% is on Earth, much more in space. In the example a panel degraded by 14% in seven years, which would be about 58% in 40 years, hence a safety margin of 200% would leave a life-length of 32 years. We generally assume spacecraft systems have better life-lengths.

Sigtrygg wrote: Let's assume a TL8 panel also includes a coating to lessen this degradation, and at TL10+ the materials are intrinsically resistant to this degradation.
Quite possibly, but I don't think we are quite there yet.
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Re: High Guard 2e - Solar Panels

Postby Sigtrygg » Fri Aug 24, 2018 12:08 pm

AnotherDilbert wrote:
Fri Aug 24, 2018 11:13 am
0.25% is on Earth, much more in space. In the example a panel degraded by 14% in seven years, which would be about 58% in 40 years, hence a safety margin of 200% would leave a life-length of 32 years. We generally assume spacecraft systems have better life-lengths.
Yup, I misread the footnote.
Still what I am proposing as TL8 is the equivalent of the peak of out current technology and as I say a protective coat, perhaps one that requires refurbishment during annual maintainance :)

A TL7 solar panel would be 250 W per square metre and suffer for the 10% degradation per year.
Quite possibly, but I don't think we are quite there yet.
I peg current Earth TL as 7.7 - working fusion power, grav vehicles and man portable laser weapons are still to be declassified :)

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