James Horner (1953–2015) was an American composer, conductor and orchestrator of film scores, writing over 100. He was known for the integration of choral and electronic elements, and for his frequent use of motifs associated with Celtic music.
"Aliens" was a movie made by James Cameron in 1986 with Sigourney Weaver.
The Main title composed by Horner is inspired from Khachaturian's adagio from the the ballet "Gayaneh".
https://www.youtube.com/watch?v=aiHraYuMHGg
http://www.marcolomuscio.com