Ensign Penelope Halliwell was a 24th century Human woman who served Starfleet, stationed on the USS Excalibur-A. She worked as a transporter officer. She was twin sister to Patience Halliwell. (NF novel: After the Fall)

USS Excalibur personnel
USS Excalibur (2240s)	R. Bannock
USS Excalibur (NCC-1664)	T. Haleakala-LoBrutto • Harris • J.T. Kirk • H. Ogden • Thonen • M. Walsh
USS Excalibur II	Preye
USS Excalibur (NCC-26517)	Argyle • R. Beth • Boyajian • Burgoyne 172 • M. Calhoun • M. Christiano • Howard • M. Gold • Hecht • M. Houle • Janos • Z. Kebron • M. Korsmo • Kothari • K. Kurdziel • G. La Forge • R. Lefler • Lowe • Martins • Maxwell • M. McHenry • Meyer • C. Mitchell • Morgen • W. Morrison • K. Mueller • Ramirez • W.T. Riker • B.G. Robinson • Scannel • Selar • Shastakovich • E.P. Shelby • Soleta • Somak • R. Takahashi • Torelli • T'Shanik • D. Voyskunsky • P. Watson • M. Wilkarah • Yates
USS Excalibur (NCC-26517-A)	Burgoyne 172 • M. Calhoun • Candido • Dreyfuss • Janos • Z. Kebron • R. Lefler • M. McHenry • Selar • E.P. Shelby • Soleta • T. Tobias • Xy