Who is Captain Lindsey Joyce from The Stars My Destination and what is their importance?

Captain Lindsey Joyce is the Captain of the Vorga. It is Joyce who abandons Foyle on the wreckage of the Nomad. Joyce is now a resident of the Skoptsy Colony, where she has had her nervous system severed. Foyle brings the kidnapped telepath Sigurd Magsman to question Joyce, and the telepath is able to extract the name of the person who gave the order to space the refugees and leave Foyle behind. Joyce reveals Olivia Presteign's name to Foyle.