LOS ANGELES, Dec. 2 — Sentencing is scheduled Jan. 24 for Charles Manson cultist Susan Murphy and a woman companion on their guilty pleas to a charge of assaulting a federal officer when they escaped from prison last August.

U.S. District Court Judge Malcolm M. Lucas accepted the pleas of Miss Murphy, 34, and Diane Ellis, 33, on Tuesday.

Court officials said the two admitted beating Terminal Island Prison guard Melinda Eisenhart before allegedly fleeing in the guard’s car. They were arrested by FBI agents in Portland, Ore. on Aug 26.

When she escaped, Miss Murphy was serving a five-year term for conspiring with Sandra Good, another Manson follower, to mail threatening letters to businessmen they claimed were harming the environment.

Miss Ellis had been imprisoned for parole violations following a bank robbery conviction.