The proposal is to use solar bodies, such as large planets, to bounce radio signals off of, as a means of high capacity, high latency data storage.
The digital data is converted in to a radio signal and transmitted from an Earth-based station at another planetary body, e.g. Neptune, which is around four hours away at the speed of light, so round-trip time would be about eight hours. A second receiving station would receive the radio signal, convert it back in to an error corrected digital form, hand the data off to transmitting station which would then send the signal back to an Earth-bound receiver, which would then perform the same steps as the remote receiver, and the entire cycle would repeat, the data endlessly bouncing back and forth between Earth and a remote transceiver.
The amount of data that can be placed in to the storage buffer is orders of magnitude larger than anything that we could hold on Earth. A radio signal can easily pack several megabits in to a single pulse traveling at the speed of light. Before your transmitted signal has reached the receiving station you can begin transmitting again. As the circular data buffer fills up so the pulses become longer until it is a continuous signal.
You wouldn’t need to build and complete the remote receiver at the final destination to make this system work either. You could construct your remote transceiver in near Earth orbit, then tow it out to the desired location, so long as you keep the transceiver powered up and firmly fixed in the path of the signal, it can be operational with data capacity (and latency) increasing the further it moves away from Earth.
Problems with this approach: High latency accessing any one piece of data. Error correction. Planetary bodies being eclipsed by large objects transiting across their orbit. Planetary bodies suddenly exploding with a vast shockwave due to excessive mining with nuclear devices.