Wearing this one looks like nothing on earth (9)
I believe the answer is:
spacesuit
'nothing on earth' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'wearing this one looks' is the wordplay.
I cannot quite see how this works, but
'one' could be 'ace' (ace has a value of one in some card games) and 'ace' is present in the answer.
This explanation may well be incorrect...
'like' is the link.
Can you help me to learn more?
(Other definitions for spacesuit that I've seen before include "Astronaut's clothing" , "Astronaut clothing" , "- "heavenly" outfit here?" , "satellite outfit?" , "Sealed garment worn by an astronaut" .)