Recharge satellite batteries utilizing a ground-based laser?

[Scott Ryals]

Is it feasible to recharge satellite's batteries utilizing a ground-based laser?

 

[anorlunda]

Not a bad question.

Most satellites have PV (solar) panels. You could certainly shine some light on them from a ground based laser. However, almost all of the laser's power would be dissipated as heat in the atmosphere. The real question is how powerful would the laser have to be to match the intensity of natural radiation from the sun shining on the panels?

I don't have a specific calculation for that, but I trust that since NASA does not use ground-based lasers to charge batteries, it is not an attractive option. (Danger to airplanes overhead are among the many secondary problems that contribute to attractiveness.)

Did you know that astronauts left a mirror on the moon? Experimenters can aim a laser at it, and detect the reflected beam coming back. That means a two-way trip through our atmosphere. But transmitting signals, and transmitting significant power are very different.

 

[BPHH85]

From the point of the internal photoelectric effect, yes it might be possible to transmit energy to the satelitte. But why should one? First of all, I think it's rather tricky to strike the satellite with the laser beam if it isn't geostationary. Next laser beam genration is rather inefficient. Besides that you have much attenuation of the laser power through scattering and absorption especially at rainy weather and of course, as anorlunda already wrote, there are many safty concernes. There it is more efficient to charge the satellite battery by harvesting the sun light.

 

[Rive]

Any satellite around Earth has 1000+W/m² radiation source at hand for free. It should be some very special circumstances if somebody want to compete in feasibility with 'free'.

 

[trurle]

Is it feasible to recharge satellite's batteries utilizing a ground-based laser?

Usually a reverse situation is considered (i.e. recharging a difficult-to-access ground equipment via satellite beam). For example, sensing network over dormant volcano kept powered by microwave beam, allowing operations beyond lifespan of batteries with small maintenance (because power satellite can service entire world, in sequence).
The laser-powered satellite is considered usually only if very high power to weight (~20 kW/kg) is required - the only related talk i can remember was about laser-powered upper stages, to slash the cost of launch. Normal solar panels are good enough up to 5 W/kg satellites.

 

[Scott Ryals]

Usually a reverse situation is considered (i.e. recharging a difficult-to-access ground equipment via satellite beam). For example, sensing network over dormant volcano kept powered by microwave beam, allowing operations beyond lifespan of batteries with small maintenance (because power satellite can service entire world, in sequence).
The laser-powered satellite is considered usually only if very high power to weight (~20 kW/kg) is required - the only related talk i can remember was about laser-powered upper stages, to slash the cost of launch. Normal solar panels are good enough up to 5 W/kg satellites.

What are your thoughts regarding the Breakthrough Starshot initiative?

 

[trurle]

What are your thoughts regarding the Breakthrough Starshot initiative?

It would be interesting from engineering and exploration perspective to try and see how it will fail. My estimation of chances of "breakthrough starshot" reaching another star and communicating back to Earth is 0.00%.

I was engaged few years ago in much less ambitious study of lightsail-craft reaching the orbit of Saturn. The material and communication challenges were enormous, and project was shelved waiting for better technology.