I can't seem to get geolocation information for the Twitter account @MarsCuriosity . Am I doing something wrong, or does Twitter lack geolocation support for locations outside of Earth?
Geolocation is an optional field, in this instance it appears NASA has opted not to use it.
You are also correct in saying Twitter doesn't currently support it. According to the spec for the Twitter API, the
is formatted as geoJSON (longitude first, then latitude).
geoJSON does allow you to specify a coordinate reference system (CRS) which defines the map projection for the points. It defaults to WGS84, the standard used for GPS on Earth. Given there isn't an option in the Twitter settings to specify what planet you are on, it looks like you are stuck with points on the surface of the Earth.
Even assuming it was an option, the lack of GPS around Mars (MPS?) means that granularity of the rover's location wouldn't be particularly good anyway.