Why are poles missing from GIS topographic data?

SRTM (Shuttle Radar Topography Mission) was a shuttle mission, no satellite involved. But essentially the satellites do not cross the poles.

In a sun-synchronous orbit, which most imaging satellites are in, you get a pattern like:

This is great because it means that the orbit can be timed and most parts of the Earth get covered at around noon, getting good lighting and few shadows. But essentially it is revolving around the earth in a way that the poles are never flown over.

Side effect stays, you may have missing information at poles, example with GDEM which covers 83⁰N-83⁰S :

But as we see, polar areas present more artifacts. To avoid such corrupt data, the easy solution seems to cut out poles, and 60⁰N-60⁰S

There is no SRTM data of the pole regions because

• the shuttle flight did not cover that area and
• the nature of the recording makes it difficult to gather data from ice areas (same as some mountain regions)