From 2008 to 2011, the US government spent £16.4million ($22million) in the program that was funded by former Senate majority leader Harry Reid and was lead by military intelligence official Luis Elizondo.
The Defence Department acknowledged the existence of the program following a recent investigation – they claim the initiative was shut down in 2012.
Mr Reid recently expressed his pride in the creation of the program that was used to investigate reports of UFOs.
He said: “I’m not embarrassed or ashamed or sorry I got this thing going.”
“I think it’s one of the good things I did in my congressional service. I’ve done something that no one has done before.”