But this wouldn’t be in orbit; it would be in what NASA calls “deep space”, which relies on the Deep Space Network [1]. The DSN is severely bandwidth constrained, due primarily to a lack of ground antennas. Indeed, for instruments that are located outside Earth’s orbit (e.g. SOHO, which is at Sun-Earth L1 [2]), bandwidth is often a limiting constraint in the design.

My understanding is that some newer instruments do both compress and select data to be downloaded (i.e. prioritizing signal over noise), and that there is more and more consideration of on-board processing for future missions, as well as possibly introducing the capability within DSN itself to prioritize which instruments get bandwidth based on scientific value of their data.

Source: A presentation from people at NASA Heliophysics last week, where this very topic came up.

[1]: < https://www.nasa.gov/communicating-with-missions/dsn/> [2]: < https://science.nasa.gov/mission/soho/>