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Researching maximum life span of the power supply of a small satellite.

For use in a private scientific project I'm researching how long a small earth orbiting satellite will operate. The satellite's electronics needs to generate for over 30 seconds 15 watts of power each day.

I'm not scientific/technical educated so please excuse me for saying stupid things. The project is still in a hypothetical stage so don't be afraid to tell it won't work.

I'm aiming at a life span of 100 years! Is this possible? For engineering reasons I want to minimize the use of solar cells.

A good quality solar cell panel of 25 square centimeters (10 square inches) will generate about 15 watts of energy. Solar cells have a durability of some 40 years. But by light-induced degradation (LID) the effectiveness of the cells will slowly degrade. Can this problem be solved if you use a 3 times as big (75 square centimeters/ 30 square inches) solar panel covered for 2/3 and shift this covering each 40 years to expose a new set of solar cells?

Other options are.

Extreme durable batteries The longest shelf life of batteries are about 20 years.

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This is accomplished by keeping the electrolyte separate of the plates until the battery is activated. Can this shelf life be expanded? By lowering the temperature for example? How long will such a battery give an amount of energy of a daily 15 watts over 30 seconds?

Fuel cells; A fuel cell is also very durable. 40,000 hours for stationary applications (wikipedia.org). 100 years*30 seconds = 305 hours. Or will the electrolyte chemicals just like normal batteries degrade after a few decades? The amounts of fuels like hydrogen and oxygen will be quite a lot I think.

Atomic batteries: Most satellites and space probes make use of nuclear. These batteries are extremely durable. Even the Radioisotopic Thermoelectric Generator of the space probe voyager 1 still makes some 300 watts ( at launch date 1977 it generated 470 watts) after 29 years of use. But nuclear devices are the least desirable choice of power supply for a small satellite orbiting the earth. If the satellite burns up in the atmosphere the nuclear elements will cause a very dangerous pollution. However this is an example of a very small nickel-63 battery wich will give electrical energy for over some 50 years! The power specs (volt, amperes, watts) are not given.

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I would be pleased by any comments!

Marcel

Reply to
alphacentauri
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Possibly but the one used on the aborted Apollo 13 lander didn't burn up and is believed to be intact and sitting at the bottom of the sea.

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Some info..

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but they also rely on radioactive decay so you would need roughly the same amount of radioactive material as used in a conventional Radioisotopic Thermoelectric Generator.

Reply to
CWatters

snipped-for-privacy@doglover.com wrote in news: snipped-for-privacy@m73g2000cwd.googlegroups.com:

Overdesign for capacity to reduce effects of age induced degradation and use a solar cell and capacitor bank. You only need 30 seconds per day and this would be the lightest and cheapest long-term solution. Many applictions are using so-called super capacitors for short duration rechargable power.

Reply to
Smaug Ichorfang

Is there any non-nuclear solution.

15 watts each day for 30 seconds over 100 years is to much for conventional non-nuclear power sources?

Marcel

Reply to
alphacentauri

you'll have a hard time getting an RTG (Radioisotopic Thermoelectric Generator) into orbit, and I can't see chemical batteries lasting that long in space (even with a solar recharge)

a movable cover seems like a good idea, you could keep most of the cells covered for 23.96 hours every day. that'd reduce LID.

that's only commercial batteries.

Hydrogen leaks through steel (and other solid materials) not as bad as helium but it still leaks,

Yeah that would be one way to get a long duration power source, pick an isotope with an apropriate half-life and put an RTG up there. but I think it'd have to orbit higher than geosynchronous to be assured of not re-entering the earths atmosphere.

One problem with RTGs is you can't turn them off to save their energy for later,

Fairly low output I think. that sort of thing was running pacemakers IIRC.

How about a solar thermoelectric generator ? Focus sunlight on one end of a thermopile and darkness on the other, the sun's brighter up there.

Bye. Jasen

Reply to
jasen

I think the idea of a solar thermoelectric generator hold real promise. Don't think there would be any degradation (except to the concentrator). Hell of a lot of thermocouples tho

M Walter

Reply to
Mark

Hmmm... Yes indeed. A solar thermoelectric generator seems promising. But don't you still need some batteries to store the energy?

Marcel

Reply to
alphacentauri

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