Bigger focal plane means more power, more data processing/storage means more power. More power means more solar arrays/batteries. More solar arrays/batteries means more mass. More mass means larger actuators to move it around. Larger actuators means more power...all of the above means more money.
I can't give a specific reason why, but there are likely cascading effects and system impacts to the mission. Its not like larger space rated focal planes, larger data storage and high powered amplifiers to get more data down don't exist. But at some point you do just have to call it "good enough" or "meets requirements" to avoid the system spiraling out of control.
Salgat
4K cameras are tiny, and you could only turn them on for a brief moment to take a picture.
Bigger focal plane means more power, more data processing/storage means more power. More power means more solar arrays/batteries. More solar arrays/batteries means more mass. More mass means larger actuators to move it around. Larger actuators means more power...all of the above means more money.
I can't give a specific reason why, but there are likely cascading effects and system impacts to the mission. Its not like larger space rated focal planes, larger data storage and high powered amplifiers to get more data down don't exist. But at some point you do just have to call it "good enough" or "meets requirements" to avoid the system spiraling out of control.