Long year on International Space Station essentially very hard (8)

I believe the answer is:

intently

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'very hard' is the definition.
(eg to stare intently is to stare hard)

'long year on international space station essentially' is the wordplay.
'long year' becomes 'ent' (I can't explain this - if you can you should believe this answer much more).
'on' means one lot of letters go next to another.
'international' becomes 'int' (abbreviation for international).
'space station' becomes 'Salyut' (Salyut is an example).
'essentially' indicates the central letters.
The centre of 'salyut' is 'ly'.
'ent' after 'int' is 'intent'.
'intent'+'ly'='INTENTLY'

Can you help me to learn more?

(Other definitions for intently that I've seen before include "Closely" , "hard!" , "Diligently" .)

I've seen this clue in The Independent.

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