Project Grudge was a U.S. Air Force investigation that succeeded Project Sign in February 1949 and was subsequently succeeded by Project Blue Book in March 1952.

Authors

• Person: Not available Organization: Wikipedia
  Unidentified flying object - Wikipedia

Sources

• Unidentified flying object - Wikipedia en.wikipedia.org Wikipedia via serper

Referenced by nodes (5)

• Project Blue Book event
• Air Force entity
• Project Blue Book concept
• Project Sign concept
• Project Sign event