A recent answer on this question mentioned that skyhooks have a low TRL. This is probably due to many factors since they have not been built yet.
What is the current TRL/status of skyhooks and what is the next step needed to get them to a higher TRL?
There's a detailed breakdown of TRLs of various subsystems in Boeing's 2001 HASTOL architecture report. Bottom line is that the overall TRL is 2, though many of the subsystems have much higher TRLs.
The next step needed, a cynical person might suggest, is to secure several billion dollars in funding.
