[enraged_camel]

As an engineer, you should know that engineering involves designing systems that will get the job done with the minimal amount of resources possible.

What would be the point of a higher quality video in this context? Is it necessary, or simply a nice-to-have?

One of the most popular axioms of engineering is "if it ain't broke, don't fix it." It could be revised for this scenario: "if it gets the job done, don't improve it."

[yew]

As an engineer he should know that the ISS has to be rad-resistant. They'll upgrade soon enough.

[mrb]

Being rad-resistant does not prevent the ISS from having many other communication links which are digital and not analog.

[yew]

Sure, if you want to spend the money to add (more) redundant links. You want to front a few thousand dollars?

Unless you mean that digital links aren't more vulnerable to radiation, in which case I recommend you read up on large-scale analog circuitry and get back to me.

Wait for SpaceX or somebody else to bring the per-kg cost down and we'll have all the digital video anyone could ever want.

[mrb]

You seem to be arguing rad-resistance is the factor that made them decide on analog instead of digital video.

I doubt it.

Like someone said, initially they chose analog because back in the day nobody did digital video streaming. It has worked okay since then. And there just hasn't been enough reasons to justify a change to digital.