Project Quantum Leap is a fictional, top-secret, government-run science project involving time travel on the sci-fi/drama Quantum Leap, created by Donald Bellisario.
Located in a largely underground complex in the desert mountains of Stallion's Gate, New Mexico, Project Quantum Leap is rooted in the scientific theories of project head Dr. Samuel Beckett, whose string theory of linear time forms the basis of time travel—but only within the period of one's own life. Thus, according to Sam's theory, a time traveller cannot travel further back in time than the moment of one's own birth, and he cannot travel beyond the point he began leaping or 'died'. (However, in 'Play It Again, Seymour,' the leap date is April 14, 1953 - just under 4 months before he was born. Also in the episode 'The Americanization of Machiko,' the leap date is given as August 4, 1953 – 4 days before he was born. So it is possible his 'lifetime' includes time periods after his conception and prior to his birth). Another exception to the rule is when he leaped into his ancestor during the Civil War
"Theorizing that one could time travel within his own lifetime, Doctor Sam Beckett stepped into the Quantum Leap accelerator—and vanished. He awoke to find himself trapped in the past, facing mirror images that were not his own, and driven by an unknown force to change history for the better. His only guide on this journey is Al, an observer from his own time that appears in the form of a hologram that only Sam can see and hear. And so Doctor Beckett finds himself leaping from life to life, striving to put right what once went wrong, and hoping each time that his next leap will be the leap home."
In the beginning, the project was funded on the private level. However, subsequent events; specifically Sam changing history and reuniting his future wife with her estranged father set off a chain of events that caused the project to be funded by the government. The government's rationale for doing this i.e strategic gain have never been discussed. To prove his theory to private sponsors who were about to cut funding for the project, Sam tested the experiment on himself and found himself stuck in the past, with amnesia as an unexpected side-effect of the time travel. Furthermore, he found himself inhabiting other people's "physical aura," meaning he retains the illusion of their physical appearance, form and even voice. Whether this aspect of time travel is expected or (as the show strongly suggests) unexpected is never explicitly revealed. Sam soon discovers that the only way to "leap" from one point in time to the next is to correct mistakes in the lives of the people he inhabits. For the next four years, Sam would continue to travel back and forth through time in a continuing effort to leap home (to his proper time and identity), swapping identities with various people, and putting things right that once went wrong.
The project is run by Sam until his "disappearance" into the Accelerating Chamber. After Sam's disappearance (depicted in the first scene of the pilot episode), the project is ostensibly run by Sam's best friend, Albert 'Al' Calavicci, a former Navy Admiral, who seems to operate with a great deal of autonomy but occasionally must answer to such government authorities as The Pentagon or a United States Senate committee (the latter depicted in the season two premiere, "Honeymoon Express"). Despite government funding, the extent of actual government involvement in the project (at least as depicted in the series) seems more or less limited to security (provided by U.S. Marines) and intelligence (since the project's computer seems to have nearly unlimited access to government records).
The Accelerating Chamber, also known as the Quantum Accelerator, is a nuclear-powered device that acts as the project's time machine. It is able to send someone into the past, but apparently unable to retrieve them again, despite repeated attempts by various members of the project to design a "retrieval program."
The Imaging Chamber is Sam's means of communication with the project during his travels. From Al's perspective, the Imaging Chamber is a large, cavernous room that takes the form of Sam's surroundings. However, this form is just a holographic projection; Al can't physically interact with these surroundings in any way, other than to converse with Sam (and, in rare circumstances, other people; see the entry on Albert Calavicci for the examples of this). Sam, in turn, can hear and see Al as a holographic projection (which remains invisible to everyone else). To Al, Sam looks like the person whose life he is inhabiting.
The Waiting Room is the room where Project Quantum Leap keeps the people Sam leaps into; they are held here (sometimes against their will) until they can only again trade places with Sam and return to their lives in their proper time period. As Sam appears to all, even Al, as the form of the person he leaped into, the person in the waiting room supposedly appears in Sam's form; this causes psychological issues with Al if Sam leaps into the body of an attractive female, as Al has trouble coming to terms with his best friend's goal to leap and being a heterosexual male in truth and Al's naturally high sex drive and Sam's visual appearance. However, in one episode, when Sam leaps into the body of real-life radio psychologist Dr. Ruth, Al confers with Dr. Ruth in the Waiting Room and she nonetheless appears in her actual form, contradicting the show's canon (however, this may match the internal logic of the show: as Sam appears to the viewer with his own form, so people in whom he leap into should appear with his/her own appearance to the show's viewer).
Ziggy is a sentient supercomputer designed by Sam and programmed mostly by Gushie. It controls many of the functions at the Project Quantum Leap complex, has access to countless databases and sources of public records, and seems to specialize in calculating probability based on enormous amounts of data; during Sam's travels through time, Ziggy uses these abilities to postulate the "mission" Sam must complete in order to make his next leap in time.
Some episodes of the final season reveal that security for the project is provided by armed U.S. Marines; other episodes in the series hint that a whole team of scientists work at Project Quantum Leap, but of those scientists, only the ones below are ever mentioned.
Dr. Samuel Beckett is the project manager of Project Quantum Leap. Notably, he is both the designer of Ziggy and the creator of the string theory of linear time that makes time travel possible. A brilliant scientist with multiple doctoral degrees (including Music, Medicine, Physics, Archeology, Ancient Languages, Chemistry and Astronomy), Sam specializes in quantum physics. Sam is played on the show by Scott Bakula.
Albert Calavicci serves as Sam's contact with the project (and also as the acting project manager) while Sam travels through time. Al is a Rear Admiral in the United States Navy and had previously worked with Sam on another top-secret government science project, known only as "the Starbright Project" (the nature of which is never revealed on the show). Al is played by Dean Stockwell.
Donna Eleese is Sam's wife, an astrophysicist who clearly has top security clearance but whose actual involvement with the project is never clarified. Like Al and Gushie, Donna worked with Sam on the Starbright Project. Donna appears only twice on the show; she is played by Teri Hatcher in the season one episode "Star-Crossed" and by Mimi Kuzyk in the season four premiere "The Leap Back." When the show began, Sam was not married to Donna nor was she a part of the project, as she had left him at the altar many years previously due to her own abandonment issues with her father. However, in the second episode of the entire series, "Star-Crossed", Sam uses his leap to help Donna resolve her father's abandonment issues and subsequently changes his own personal history; as a result of this leap, Donna does not leave Sam at the altar and they are happily married when Sam begins leaping, both of them working on the project together.
Dr. Verbeena Beeks is the staff psychiatrist; she is sometimes referred to by Al, but is seen in only two episodes, the season three finale "Shock Theater" and the season four premiere "The Leap Back."
Gooshie, often referred to as "a little guy with bad breath," serves as both a general technician and Ziggy's head programmer. Portrayed by stand-up comedian Dennis Wolfberg, Gushie appeared in five episodes—more than any other recurring character (besides Sam and Al, of course).
Tina Martinez, despite possessing the appearance, mannerisms, and voice of a stereotypical air-head, is a brilliant computer programmer, introduced into the project by her sometime boyfriend, Al Calavicci. Despite many references in the show, she appears in only one episode, "The Leap Back."