Area 51, also known as US Air Force Flight Test Center, was a top secret military installation operated by the government of the United States of America. It was located on a remote tract of land on the dry salt flat called Groom Lake, in southwestern Nevada. The entire installation was operated under top secret conditions. It was believed to be used for the testing and operation of enemy and alien technology, and also to develop new technologies. Area 51 was the subject of a large number of conspiracy theories because of the secrecy surrounding the installation.
One of the projects undertaken at Area 51 was an attempt led by Jeffrey Carlson to decipher the technology found on Quark's spaceship which had crashed near Roswell, New Mexico in 1947 after accidentally traveling back in time. (DS9 episode: "Little Green Men", TOS novel: The Rise and Fall of Khan Noonien Singh, Volume 1}
In 1984, Shannon O'Donnel joined the project when she began working at Area 51. Two years later, Project F (as Carlson's operation was known) had a burst of activity after Naval Intelligence gave them several devices recovered from Pavel Chekov (who had traveled back in time from the year 2286) after he was captured aboard the aircraft carrier USS Enterprise while it was docked at Alameda Naval Base. However, before the Area 51 staff could conduct a detailed examination of the devices, Roberta Lincoln was able to penetrate Area 51 and retrieve the devices. In the process Lincoln encountered and tranquilized O'Donnel. (TOS novel: The Rise and Fall of Khan Noonien Singh, Volume 1}
By the 1990s, one of the projects being worked on at Area 51 was the development of the top secret DY-100 sleeper ship. In addition to O'Donnel, others working on the project included Doctor Marcus Walter Nichols and pilot Shaun Geoffrey Christopher. Roberta Lincoln also provided technical assistance, giving O'Donnel access to technological specifications to help complete the ship. Once the unnamed ship was completed, Lincoln and O'Donnel launched the ship. As instructed, O'Donnell later claimed that she was under Ferengi mind control at the time when questioned about the incident. While no charges were brought up against her, O'Donnel did lose her position at Area 51. (TOS novel: The Rise and Fall of Khan Noonien Singh, Volume 2)