Question: Which film, directed by Roger Christian is based upon the first half of L. Ron Hubbard's 1982 novel of the same name? 
Context: Bare-faced Messiah: The True Story of L. Ron Hubbard is a posthumous biography of Scientology founder L. Ron Hubbard by British journalist Russell Miller.  First published in the United Kingdom on 26 October 1987, the book takes a critical perspective, challenging the Church of Scientology's account of Hubbard's life and work.  It quotes extensively from official documents acquired using the Freedom of Information Act and from Hubbard's personal papers, which were obtained via a defector from the Church.  It was also published in Australia, Canada and the United States. L. Ron Hubbard, Messiah or Madman? , is a posthumous biography of Scientology founder L. Ron Hubbard written by Bent Corydon, which makes extensive use of interviews he conducted with Hubbard's son Ronald DeWolf.  Though originally published in 1987 by Lyle Stuart Inc., the book was re-issued in a paperback edition on July 25, 1992 and a hardcover edition in October 1995, both by publisher Barricade Books.  The 1995 edition also featured Brian Ambry as principal researcher.  The first edition of the book listed DeWolf as coauthor. The L. Ron Hubbard House, also known as the Original Founding Church of Scientology, is a writer's house museum and former Scientology church located at 1812 19th Street NW in the Dupont Circle neighborhood of Washington, D.C., United States.  The home served as the residence of Scientology founder L. Ron Hubbard from 1955 until 1959, during which time he incorporated the Founding Church of Scientology and performed the first Scientology wedding.  The building is a contributing property to the Dupont Circle Historic District, a neighborhood listed on the National Register of Historic Places. Roger Christian (born 25 February 1944) is an English set decorator, production designer and feature film director.  He won an Academy Award for his work on the original "Star Wars" and was Oscar-nominated for his work on "Alien".  Christian directed the second unit on both "Return of the Jedi" and "" as well as feature films including "The Sender" and "Nostradamus".  He also directed the 2000 film "Battlefield Earth" which is regarded as one of the worst films ever made. Margaret Louise "Polly" Grubb (September 22, 1907 – November 17, 1963) was the first wife of pulp fiction author and Scientology founder L. Ron Hubbard, to whom she was married between 1933 and 1947.  She was the mother of Hubbard's first son, L. Ron Hubbard, Jr. and his first daughter, Katherine May "Kay" Hubbard. The Church of Scientology is a multinational network and hierarchy of numerous ostensibly independent but interconnected corporate entities and other organizations devoted to the practice, administration and dissemination of Scientology, a new religious movement.  The Church of Scientology International (CSI) is officially the Church of Scientology's parent organization, and is responsible for guiding local Scientology churches.  At a local level, every church is a separate corporate entity set up as a licensed franchise and has its own board of directors and executives.  The first Scientology church was incorporated in December 1953 in Camden, New Jersey by L. Ron Hubbard.  Its international headquarters are located at the Gold Base, in an unincorporated area of Riverside County, California.  The location at Gilman Hotsprings is private property and not accessible by the public.  Scientology Missions International is under CSI and oversees Scientology missions, which are local Scientology organizations smaller than churches.  The Church of Spiritual Technology (CST) is the organization which owns all the copyrights of the estate of L. Ron Hubbard. Revolt in the Stars is a science fiction film screenplay written by Scientology founder L. Ron Hubbard in 1977.  It tells the space opera story of how an evil galactic dictator, named Xenu, massacres many of his subjects by transporting them to Earth and killing them with atomic bombs.  L. Ron Hubbard had already presented this story to his followers, as a true account of events that happened 75 million years ago, in a secret level of Scientology scripture called Operating Thetan, Level III.  The screenplay was promoted around Hollywood circles in 1979, but attempts at fundraising and obtaining financing fell through, and the film was never made.  Unofficial copies circulate on the Internet. Battlefield Earth (also referred to as Battlefield Earth: A Saga of the Year 3000) is a 2000 American science fiction action film based upon the first half of L. Ron Hubbard's 1982 novel of the same name.  Directed by Roger Christian and starring John Travolta, Barry Pepper and Forest Whitaker, the film depicts an Earth that has been under the rule of the alien Psychlos for 1,000 years and tells the story of the rebellion that develops when the Psychlos attempt to use the surviving humans as gold miners. The Church of Spiritual Technology, also known as CST, is a California 501(c)(3) non-profit corporation, incorporated in 1982, which owns all the copyrights of the estate of L. Ron Hubbard and licenses their use.  CST does business as L. Ron Hubbard Library. Brain-Washing: A Synthesis of the Russian Textbook on Psychopolitics, sometimes referred to as The Brainwashing Manual, is a book published by the Church of Scientology in 1955.  It purports to be a condensation of the work of Lavrentiy Beria, the Soviet secret police chief.  The book states Kenneth Goff as author.  Its true authorship is not clear, the three common hypotheses being: Scientology founder L Ron Hubbard, Kenneth Goff (alias Oliver Kenneth Goff), or both L Ron Hubbard and Kenneth Goff based on an acquired US agency report.  The third hypothesis is questionable as there is not proof that the two men ever knew each other.  Claims that L Ron Hubbard was the author are also dubious as the only source of this claim is his estranged son, L Ron Hubbard Jr., who made it his life work trying to intentionally discredit his father in every possible way, and in addition to withdrawing all his accusations before his death, has been discredited in courts of law.
Answer: Battlefield Earth