As a children's genre in the late 1940s and early 1950s, science fiction programming most often followed a serial format. appearing in the afternoon on Saturdays or at the beginning of prime time during the weeknight schedule. At times playing in several installments per week, these early examples of the genre featured the adventures of male protagonists working to maintain law and order in outer space. These early "space westerns" included Buck Rogers (ABC. 1950-51). Captain Video and His Video Rangers (Du­mont. 1949-54). Flash Gordon (syndicated. 1953),

     Space Patrol (ABC, 1951-52), and Tom Corbett, Space Cadet (CBS/ABC/NBC, 1950-52). Each series pitted its dynamic hero against a variety of intergalactic menaces. be they malevolent alien conquerors, evil mad scientists. or mysterious forces of the universe. All these programs were produced on shoestring budgets, but this did not stop each series from equipping its hero with a fantastic array of futuristic gadgetry, including radio helmets, ray guns, and Captain Video's famous "decoder ring." Viewers at home could follow along with their heroes on the quest for justice by ordering plastic replicas of these gadgets through popular premium campaigns. Of these first examples of televised science fiction, Captain Video was particularly popular, airing Monday through Friday in half­ hour (and. later. 15-minute) installments. One of the first "hits" of television, the program served for many years as a financial lynchpin for the struggling Dumont network and left the air only when the network itself collapsed in 1954.

     As was typical of much early programming for children, Captain Video concluded each episode with its hero delivering a lecture on moral values, good citizenship or other uplifting qualities for his young audience to emulate. Such gestures, however, did not spare Captain Video and his space brethren from becoming the focus of the first of many major public controversies over children's television. In a theme that would become familiar over the history of the medium. critics attacked these shows for their "addictive" nature, their perceived excesses of violence, and their ability to "over excite" a childish imagination. In this respect, early science fiction on television became caught up in a larger anxiety over children's culture in the 1950s. a debate that culminated with the 1954 publication of Dr. Fredric Wertham 's Seduction of the Innocent, an attack on the comic book industry that eventually led to a series of congressional hearings on the imagined links between popular culture and juvenile delinquency.

     In early television, science fiction programming aimed at older audiences was rarer. confined almost entirely to dramatic anthology series such as Lights Out (NBC.  1949-52), Out There (CBS,  1951-52), and Tales of Tomorrow (ABC, 1951-53). As with other dramatic anthologies of the era, these programs depended heavily on adaptations of preexisting stories, borrowing from the work of such noted science fiction writers as Jules Verne. H.G. Wells. and Ray Bradbury. Tales of Tomorrow even attempted a half-hour adaptation of Mary Shelly's Frankenstein. When not producing adaptations, these anthologies did provide space for original and at times innovative teleplays. Interestingly, however, as science fiction  became an increasingly important genre in Hollywood during the mid- to late 1950s, especially in capturing the burgeoning teenage market, its presence on American television declined sharply. One exception was Science Fiction Theater (1955-57), a syndicated series that presented speculative stories based on contemporary topics of scientific research.

     Science fiction's eventual return to network air­ waves coincided with the rising domestic tensions and Cold War anxieties associated with the rhetoric of the Kennedy administration's "New Frontier." As a response to the Soviet launch of Sputnik, for example, CBS's Men into Space (1959-60) participated in the larger cultural project of explicitly promoting interest in the emerging "space race" while also celebrating American technology and heroism that had been threatened by the Soviets’ success. Other series were more complex in their response to the social and technological conflicts of the New Frontier era. In particular, The Twilight Zone (CBS, 1959-64) and The Outer Limits (ABC, 1963-65), programs that would become two of the genre's most celebrated series, frequently engaged in critical commentary on the three pillars of New Frontier ideology: space, suburbia, and the super­ powers.

     Hosted and for the most part scripted by Rod Ser­ling, a highly acclaimed writer of live television drama in the 1950s, The Twilight Zone was an anthology series that, while not exclusively based in science fiction, frequently turned to the genre to frame allegorical tales of the human condition and the national character of the United States. Some of the most memorable episodes of the series used science fiction to defamiliarize and question the conformist values of postwar suburbia as well as the rising paranoia of Cold War confrontation. Of these, "The Monsters Are Due on Maple Street" was perhaps the most emblematic of these critiques . In this episode, a "typical" American neighborhood is racked with suspicion and fear when a delusion spreads that the community has been invaded by aliens. Neighbor turns against neighbor to create panic until at the end, in a "twist" ending that would become a trademark of the series, the viewer discovers that invading aliens have actually arrived on Earth. Their plan is to plant such rumors in every American town in order to tear these communities apart, thus laying the groundwork for a full-scale alien conquest.

     More finely grounded in science fiction was The Outer Limits, an hour-long anthology series known primarily for its menagerie of gruesome monsters. Much more sinister in tone than Serling's Twilight Zone, The Outer Limits also engaged in allegories about space, science, and American society. However, in an era marked by the almost uniform celebration of American science and technology, this series stood out for its particularly bleak vision of technocracy and the future, using an anthology format to present a variety of dystopic parables and narratives of annihilation. Of the individual episodes, perhaps most celebrated was Harlan Ellison's award-winning time-travel story "Demon with a Glass Hand," an episode that remains one of the most narratively sophisticated and willfully obtuse hours of television ever produced.

     While The Twilight Zone and The Outer Limits remain the most memorable examples of the genre in this era, science fiction television of the mid- 1960s was dominated, in terms of total programming hours, by the work of producer Irwin Allen. Allen's series, aimed primarily at juvenile audiences on ABC, included Voyage to the Bottom of the Sea (ABC, 1964-68), Lost in Space (CBS, 1965-68), Time Tunnel (ABC, 1966-67), and Land of the Giants (ABC, 1968-70). Each series used a science fiction premise to motivate familiar action-adventure stories. Of these, Lost in Space has been the most enduring in both syndication and national memory. Centering on young Will Robinson and his friend the Robot, the series adapted the Swiss Family Robinson story to outer space, chronicling a wandering family's adventures as they tried to return to Earth.

     Many other television series of the 1960s, while not explicitly science fiction, nevertheless incorporated elements of space and futuristic technology into their story worlds. Following the success of The Flintstones, a prime-time animated series about a prehistoric family, ABC premiered The Jetsons (1962-63), a cartoon about a futuristic family of the next century. The sitcom My Favorite Martian (CBS, 1963-66), meanwhile, paired an Earthling newspaper reporter with a Martian visitor, while / Dream of Jeannie (NBC, 1965-70) matched a NASA astronaut with a beautiful genie. The camp hit Batman (ABC, 1966-68) routinely featured all manner of innovative "bat" technologies that allowed its hero to outwit Gotham City's criminals. Also prominent in this era was a cycle of spy and espionage series inspired by the success of the James Bond films, each incorporating a variety of se­cret advanced technologies. Of this cycle, the British­ produced series The Prisoner (CBS, 1968-69) was the most finely based in science fiction, telling the Orwellian story of a former secret agent stripped of his identity and trapped on an island community run as a futuristic police state.

     By far the best-known  and widely  viewed  science fiction series of the 1960s (and probably in all of television) was Star Trek (NBC, 1966-69), a series described by its creator, Gene Roddenberry, as "Wagon Train in space." Although  set in the 23rd century, the world of Star Trek was firmly grounded in the concerns of 1960s America. Intermixing action-adventure with social commentary, the series addresses such issues as racism, war, sexism, and even the era's flourishing hippie movement. A moderately successful series during its three-year network run, Star Trek would become through syndication perhaps the most actively celebrated program in television history, inspiring a whole subculture of fans (known variously as "trekkies" or "trekkers"), whose devotion to the series led to fan conventions, book series, and eventually a commercial return of the Star Trek universe in the 1980s, 1990s, and 2000s through motion pictures and television spin-offs.

     Like Star Trek, the British Broadcasting Corporation (BBC) serial Doctor Who also attracted a tremendous fan following. In production from 1963 to 1989, Doctor Who stands as the longest-running continuous science fiction series in all of television. A time-travel adventure story aimed primarily at children, the series proved popular enough in the United Kingdom to inspire two motion pictures pitting the Doctor against his most famous nemesis-the Daleks: Doctor Who and the Daleks ( 1965) and Daleks: /Invasion Earth 2I50 AD ( 1966). The series was later imported to the United States. where it aired primarily on Public Broadcasting Service (PBS) affiliates and quickly became an international cult favorite.

     While most television science fiction in the 1950s and I 960s had followed the adventures of  Earthlings in outer space, increasing popular interest in unidentified flying objects (UFOs) led to the production, in the late I 960s and into the 1970s, of a handful of programs based on the premise of secretive and potentially hostile aliens visiting Earth. The Invaders (ABC. 1967-68) chronicled one man's struggle to expose an alien invasion plot. while UFO (syndicated. 1972) told of a secret organization dedicated to repelling an imminent UFO attack. Veteran producer Jack Webb debuted Project UFO (NBC) in 1978, which investigated. in Webb's characteristically terse style, unexplained UFO cases taken from the files of the U.S. Air Force. Such series fed a growing interest in the early 1970s with all manner of paranormal and extraterrestrial phenomena. ranging from Erich von Daniken's incredibly popular speculations on ancient alien contact in Chariots of the Gods to accounts of the mysterious forces in the "Bermuda Triangle." Such topics from the fringes of science were the focus of the syndicated documentary series /In Search Of (syndicated, 1976), hosted by Star Trek's Leonard Nimoy.

     For the most part, however, science fiction once again went into decline during the 1970s as examples of the genre became more sporadic and short lived, many series running only a season or less. Series such as Planet of the Apes (CBS, 1974) and Logan- Run (CBS, 1977-78) attempted to adapt popular motion pictures to prime-time television but with little success. A much more prominent and expensive failure was the British series Space: 1999 (syndicated, 1975). Starring Martin Landau and Barbara Bain, the program followed a group of lunar colonists who are sent hurtling through space when a tremendous explosion drives the moon out of its orbit. The series was promoted in syndication as the most expensive program of its kind ever produced. but despite such publicity, the series went out of production after only 48 episodes.

     Two of the more successful science fiction series of the era were The Six Million Dollar Man (ABC, 1975-78) and its spin-off The Bionic Woman (ABC/NBC, 1976-78). The "six million dollar man" was Lt. Steve Austin, a test pilot who was severely injured in a crash and then reconstructed with cybernetic limbs and powers that made him an almost superhuman "bionic man." Austin's girlfriend, also severely injured (in a separate incident) and rebuilt (by the same doctors), debuted her own show the following season (complete with a "bionic" dog). The moderate success of these two series sparked a cycle of programs targeted at children featuring superheroes with superpowers of one kind or another, including The Invisible Man (NBC. 1975-76), Gemini Man (NBC. 1976), Man from Atlantis (NBC. 1977-78), Wonder Woman (ABC/CBS. 1976-79), and The Incredible Hulk (CBS, 1978-82).

     Also moderately successful in the late 1970s were a pair of series designed to capitalize on the extraordinary popularity of George Lucas's 1977 blockbuster film Star Wars. Both Battlestar Galactica (ABC. 1978-80), starring Bonanza's patriarch Lorne Greene. and Buck Rogers in the 25th Century (NBC. 1979-81) spent large amounts of money on the most complex special effects yet seen on television, all in an attempt to re-create the dazzling hardware, fast-paced space battles, and realistic aliens of Lucas film. Less successful in riding Star Wars' coattails was the parodic sitcom Quark (NBC. 1978). the story of a garbage scow in outer space.

     In England, the 1970s saw the debut of another BBC-produced series that would go on to acquire an international audience. Blake: Seven ( BBC, 1978-81) was created by Terry Nation, the same man who introduced the Daleks to the world of Doctor Who in the early 1960s. Distinguished by a much darker tone than most television science fiction, Blakes Seven followed the adventures of a band of rebels in space struggling to overthrow an oppressive regime.

     Alien invasion was once again the theme on American television in 1983, when NBC programmed a high-profile miniseries that pitted Earth against a race of lizard-like creatures who, though friendly at first, were actually intent on using Earth's population for food. V (NBC, 1984-85) proved popular enough to return in a sequel miniseries the following year, which in turn led to its debut as a weekly series in the 1984-85 season. More provocative was ABC's short-lived Max Headroom (1987), television's only attempt at a subgenre of science fiction prominent in the 1980s known as "cyberpunk." "Max," who through commercials  and a talk show became a pop cult phenomenon in his own right, was the computerized consciousness of TV reporter Edison Carter. Evoking the same "tech noir" landscape and thematic concerns of such cinematic contemporaries as Blade Runner, Robocop, and The Running Man, Max and Edison worked together to expose corporate corruption and injustice in the nation's dark, cybernetic, and oppressively urbanized future.

     Less weighty than Max but certainly more success­ful in their network runs were two series that, while not necessarily true "science fiction," utilized fantastic premises and attracted devoted cult audiences. Beauty and the Beast (CBS, 1987-90) was a romantic fantasy about a woman in love with a lion-like creature who lived in a secret subterranean community beneath New York City, while Quantum Leap (NBC, 1989-93) followed Dr. Sam Beckett as he "leapt" in time from body to body, occupying different consciousnesses in differ­ ent historical periods. The series was less concerned with the "science" of time travel, however, than with the moral lessons to be learned or taught by seeing the world through another person's eyes.

     By far the most pivotal series in rekindling science fiction as a viable television genre was Star Trek: The Next Generation (syndicated, 1987-94), produced by Paramount and supervised by the creator of the original Star Trek, Gene Roddenberry. Already benefiting from the tremendous built-in audience of Star Trek fans eager for a spin-off of the old series, Paramount was able to bypass the networks and take the show directly into first-run syndication, where it quickly became the highest-rated syndicated show ever. In many ways, Next Generation had more in common with other dramatic series of the 1980s and 1990s than it did with the original series. In this new incarnation, Star Trek became an ensemble drama structured much like Hill St. Blues or St. Elsewhere, featuring an expanded cast involved in both episodic and serial adventures. Broadcast in conjunction with a series of cinematic releases featuring the original Star Trek characters, Next Generation helped solidify Star Trek as a major economic and cultural institution in the 1980s and 1990s.

     After a seven-year run, Paramount retired the series in 1994 to convert the Next Generation universe into a cinematic property, but not before the studio debuted a second spin-off, Star Trek: Deep Space Nine (syndicated, 1993-99), which proved to be a more claustrophobic and less popular reading of the Star Trek universe. A third spin-off, Star Trek: Voyager (United Paramount Network [UPN], 1995-200 I), served as the anchor in Paramount's bid to create its own television network in 1995.

     The success of the Star Trek series in first-run syndication reflected the changing marketplace of television in the 1980s and 1990s. As the three major networks continued to lose their audience base to the competition of independents, cable, and new networks such as FOX, The WB, and UPN, the entire industry sought out new niche markets to target in order to maintain their audiences. The Star Trek franchise's ability to deliver quality demographics and dedicated viewership inspired a number of producers to move into science fiction during this period. These series ranged from the literate serial drama Babylon 5 (syndicated, 1994-98) to the bizarre police burlesque of Space Precinct (syndicated, 1994). Also successful in syndication were "fantasy" series such as Highlander (syndicated, 1992-97) and Hercules: The Legendary Journeys (syndicated, 1995-99).

     For the most part, the three major networks (ABC, CBS, and NBC) stayed away from science fiction in the 1990s, the exceptions being NBC's Earth 2 (1994-95) and Seaquest DSV (1993), the latter produced by Steven Spielberg's Amblin Entertainment. By far the most active broadcaster in developing science fiction in the 1990s was the FOX network, which used the genre to target even more precisely its characteristically younger demographics. FOX productions included Alien Nation (1989-91), M.A.N.T.l.S. (1994-95),  Sliders  (1995),  VR.5  (1995),  and Space:

     Above and Beyond (1995-96). FOX's most successful foray into science fiction, however, was The X-Files (1993-2002). A surprise hit for the network, The X-Files combined horror, suspense, and intrigue in stories about two FBI agents assigned to unsolved cases involving seemingly paranormal phenomena. Although the series originally centered on a single "spook" of the week for each episode, it eventually developed a compelling serial narrative line concerning a massive government conspiracy to cover up evidence of extraterrestrial contact. Like so many other science fiction programs, the series quickly developed a large and organized fan community. After the departure in May 200 I of series colead David Duchovny and a failed attempt at a spin-off in The Lone Gunmen (FOX, 200 I), The X-Files faltered into cancellation at the end of the 2001-02 season. FOX. however. remains the only U.S. network to include science fiction as a significant component in its marketing strategy. Working with The Simpsons creator Matt Groening. the network has enjoyed success with the animated sci­-fi comedy Futurama. FOX also tapped the futuristic talents of director James Cameron for the post apocalyptic action series Dark Angel (2000---02). The only other network with a continuing interest in science fiction has been UPN. courting younger viewers with the teen-centered Roswell (which debuted on The WB in 1999 before transferring to UPN for its third and final season, 2001-02) and a revamped version of the Star Trek franchise, Enterprise (2001- ).

At the end of the 20th century. television science fiction had amassed a sizable enough program history and a large enough viewing audience to support a new cable network. A product of the entertainment industry's overall move toward niche marketing. The Sci-Fi channel debuted in 1992. Although the network began with only a library of old movies and television reruns. it soon became a significant source of production for both cable series and made-for-cable movies. Balancing its schedule with original productions, "classics" such as Star Trek and The Twilight Zone, and series in the related genres of horror and the supernatural, the Sci-Fi channel has quite successfully transformed its ratings and demographics to become a major network in basic cable.