"Star Trek" was a science fiction television series created by Gene Roddenberry. For three seasons in the late 1960's, the show detailed the adventures of the starship USS Enterprise as it explored the reaches of outer space. The main characters are the dashing Captain James T. Kirk, the logical alien Science Officer Mr. Spock, and irrascible Chief Medical Officer Dr. Leonard McCoy.
Due to low ratings, the show was originally scheduled to be cancelled during its second season, but an unprecedented fan-generated letter campaign led to Paramount renewing the show for a third season. Somewhat perversely, it was scheduled for a day and time when most of its most fervent fans would not be able to watch it, and the show died after the third season.
All this took place before the concept of "demographics" was available to television executives; all they knew were the raw numbers of who was (and wasn't) watching, rather than specific audience traits (age, sex, level of income, level of education, etc). Had those statistics been known, the show might have lived to fulfill its original five year mission.
The show proved extremely popular in syndication, and plans were put into place to revive the franchise in some fashion. First up was an animated series, starring most of the original cast. While imaginative in spots, and free from the limitations of live-action depiction, it suffered from stiff animation and an overall tendency toward juvenalia common on Saturday morning cartoons.
After the success of Star Wars in 1977, a Star Trek feature was announced. Despite time and budget overruns, the finished film was enough of a success that more films were planned. The first sequel, Star Trek II: The Wrath of Khan, was originally planned as a television movie but was released to theatres first. It proved to be even more of a success than the first film and the revivial of Star Trek was truly underway.
In 1987, "Star Trek: The Next Generation" relaunched the television series with an all-new cast, once again under the aegis of Gene Roddenberry. Popular characters from this new series include the inquisitive, naive android Data, the honor-obsessed Klingon Worf, cheese-eating surrender-monkey Captain Jean-Luc Pickard, and William Riker, who stood around and pined or glowered as the script required while failing to note that his last name was a clever invert of "Kirk."
More films and television series followed, until, sometime in the early twenty-first century, audience fatigue set in and the concept was largely abandoned again.
A new Star Trek film was released in May, 2009. It appears that there is still meat on the Star Trek carcass.