In the last few years several projects have been proposed to collect solar power in orbit and then transmit it to Earth. Two of the possible designs are: a) generate power using solar cells in space and transmit the energy to Earth as microwaves, and b) reflect sunlight to boost power generation for Earth-based solar panels.
Several experiments have been run so far to examine the viability of the long-distance power transmission. However, up to my knowledge, direct power transmission from space to ground hasn't been tested yet. This question will resolve positively as soon as it is first demonstrated.
To distinguish power transmission from a radio or laser communication, the receiver has to have efficiency >0, i.e. it should produce more power than it uses for the reception.
Returning charged batteries in the landing modules doesn't count.
I do not bet on my own questions.
Here it is in more detail, including (point 4), the beaming (of power) to earth.
http://arxiv.org/pdf/2401.15267
Unfortunately, answering the question heavily depends on which definitions of "Power Transfer" or "Power Transmission" one uses. Wikipedia also understands "Power Transmission" to include the utilization of received energy for "useful work," which would be something different again... Overall, as you are simply adhering to the usual definitions of the technical terms: Thank you for the clarifications.
@peterjanicki Thank you for the link to the article.
The reason why I thought this was necessary is that otherwise looking at a satellite in a telescope has to also qualify, since the satellite reflects solar radiation and this energy is transferred to you through the telescope.
that should count:
„In a step forward, Ali Hajimiri at the California Institute of Technology and his colleagues launched the Microwave Array Power Transfer LEO Experiment (MAPLE) to space in January 2023. Two months later, they successfully beamed the first power to Earth, after which they ran the experiment for a further eight months.“
@peterjanicki They've transmitted power between the transmitter and receiver in space, and are only claiming that the transmission in the direction of Earth is "detectable". To me it sounds about the same as a radio transmission from space being received by an antenna on Earth.
I think to demonstrate "power transmission" you need to get more power from the receiver than you are putting into it. I'll add the clarification.
@OlegEterevsky Here's a non-paywalled article about their experiment: https://www.caltech.edu/about/news/in-a-first-caltechs-space-solar-power-demonstrator-wirelessly-transmits-power-in-space