Ripley:
This is commercial towing vehicle Nostromo out of the Solomons, registration number 1-8-0-niner-2-4-6-0-niner. Calling Antarctica traffic control. Do you read me? Over.
This quote occurs at 00:09:42-00:09:56 in the video.
After a space merchant vessel perceives an unknown transmission as a distress call, its landing on the source moon finds one of the crew attacked by a mysterious lifeform, and they soon realize that its life cycle has merely begun.