[maxov]

I think this situation is a good illustration of latency vs bandwidth. Latency is unavoidable due to the speed of light, but there’s no physical barrier to bitrate aside from power consumption.

Seems like the best bitrate we have from Mars is MRO at ~5 megabits/s which is enough for standard definition video. I’m certain we have the technology to push it higher, but it would be expensive and it seems it’s not really needed for existing projects.

[dredmorbius]

Nit, though I'm going a bit (pun status unspecified) beyond my paygrade here: bandwidth is ultimately limited by the frequency of the trandsmission channel, though multiple channels can be multiplexed. This is the heart of Claude Shannon's work.

For deep-space transmission, other factors apply, though if you're operating in the right frequencies, the background noise level is low (at least as compared to Earth where there are numerous competing signals of terrestrial origin). And whilst signal/noise ratio does impose limits, there's only so much that boosting volume dB will achieve before you hit the channel limits themselves.

To increase bandwith beyond channel limits, you'd have to multiplex channels, which would involve different frequencies, different transmission routes (say, to widely-separated relay systems), or both. For physical media (e.g., fibre) this is relatively easy. For broadcast, given mass and energy budgets of spacecraft, probes, and rovers, the problems are harder.

Encoding, redundancy, error-correction, and retransmit protocols can all increase the ultimate reliability of the signal, though these impose other costs, notably on bitrate or at least time until the transmission is confirmed.