| Started in 1949 This project was originally called project Sign, but was nicknamed Grudge. This project investigated UFO reports using Air Force officer witnesses rather than civilian experts on contract to the military. All sightings reported to this project were explained away as natural phenomenon. When the data was reviewed at the end of the project, 23 percent of the reports were were explained as psychological problems of the observers. However, no medical evidence was provided to support these claims. Project Grudge came to a close late in 1949, but was reactivated in 1951 and became Project Blue Book in 1952. |