Who voiced the ship's computer, "Mother", in the 1979 film "Alien"?

Helen Virginia Horton (November 21, 1923 – September 28, 2007) was an American actress. She was born in Chicago and had a brief career in New York. She married Scotsman Hamish Thomson and lived near London. She worked extensively in British television, radio and theatre, and had three children; her granddaughter is the British actress Lily James. Horton voiced the ship's computer, "Mother", in the 1979 film "Alien".

In Ridley Scott’s science fiction thriller, "Alien", there is a pivotal being that affects the course of the film. This being is the MU-TH-UR 600, which is main computer intelligence for the ship. MU-TH-UR 600, also known as "Mother", controls many of the ships functions such as auto-pilot and communicated with the crew. Eventually, Mother is destroyed while trying to save another part of the ship for its function.