Astall was a 24th century female Starfleet officer. Lieutenant Astall, a Huanni, was assigned to the USS Voyager as Ship's Counselor under the command of Captain Chakotay in 2378. Chakotay believed that Astall was assigned to him as a favor granted by Admiral Kathryn Janeway. Her skin was pale purple, her hair a deeper shade of that color, and ears that resembled a kangaroo's. Like all of her people, one could tell the emotions she was feeling by her ear position. During her posting to the USS Voyager, she assisted Jarem Kaz. In her professional capacity as a counselor she helped him try to workout issues relating to a past host. Specifically, when his previous host Gradak's memories began to stir in relationship to a past trauma she had some success in the use of guided imagery techniques to bring these memories to the surface with the intention of exploring them further. In the events that followed, both she and Jarem was distracted and otherwise occupied and could not help Jarem as she planned. As a result, Jarem's behavior became erratic to the point where Gradak's memories intruded on Jarem while he was awake and impaired his ability to work. Astall became increasingly concerned and wanted to relive Jarem of duty until she could work with him to resolve the issues at hand; an option he refused because he wanted to perform well on his first mission for Chakotay. As an alternative, she suggested working with the Vulcan engineer Vorik and use a simplified version of the mind meld to connect with Gradak. After matters relating to the renegade Changeling and Crell Moset were resolved Astall tried to help Moset who became a broken man after Gradak in possession of Jarem's body broke Moset's Spirit. Also, Astall and Jarem began to develop a close friendship.
Later in 2378, Astall took an extended leave of absence, and was permanently replaced on Voyager by Hugh Cambridge.