HR Giger: Mordor XII (1976) (work 296) references illustration from Linda C. Cain and Susan Rosenbaum's "Blast Off" (1973) by Leo and Diane Dillon?

leading from

HR Giger's Mordor XII (1976)

and

Illustrations from Linda C. Cain and Susan Rosenbaum's "Blast Off" (1973) by Leo and Diane Dillon

 

a)  Mordor XII (1976) (work 296) by HR Giger

b.i) Illustration from Linda C. Cain and Susan Rosenbaum's "Blast Off" (1973) by Leo and Diane Dillon

If there's a connection between the two, Giger would have had to displace a lot of the features because the illustration was so long in width and the picture if the same height would only have been less than half of the width of the illustration

b.ii) The whole illustration as seen in the two pages of the book

c) The rim around the space helmet visor becomes near vertical part of the tentacle

d) The tentacle might pass along the circle near the place of the ears.

e) The top of the helmet from the side resembles a simple bird's head and so Giger has transformed it into a beaked mutant, and where the circle is, it looks as if this is where the band is around the creature's neck

f)  The back of the sea becomes the tentacles of the head of a Cthulhu like beast
 

g) The shoulder areas becomes this fleshy bag with tubes connecting into tubes
 

h) Perhaps the stars become the steam.