 James LurieNarrator (voice) | Narrator (voice) |
 Seth ShostakSelf - SETI Institute | Self - SETI Institute |
 Nick PopeSelf - U.K. Ministry of Defense | Self - U.K. Ministry of Defense |
| BBrian De ToySelf - Director of Defense Studies, West Point | Self - Director of Defense Studies, West Point |
 Stephen HawkingSelf - Theoretical Physicist (archive footage) | Self - Theoretical Physicist (archive footage) |
| PPaul SpringerSelf - USAF Air Command and Staff College | Self - USAF Air Command and Staff College |
| TTravis TaylorSelf - Physicist & Author | Self - Physicist & Author |
| BBob BoanSelf - Co-Author, Alien Invasion: How to Defend Earth | Self - Co-Author, Alien Invasion: How to Defend Earth |
| MMichael MichaudSelf - Author, Contact with Alien Civilizations | Self - Author, Contact with Alien Civilizations |
| PPaul ParsonsSelf | Self |
| JJohn RingoSelf - Author, Live Free or Die | Self - Author, Live Free or Die |
| MMark MoffettSelf - Author: Adventures Among Ants | Self - Author: Adventures Among Ants |
| DDirk Schulze-MakuchSelf - Washington State University | Self - Washington State University |
 Neil StraussSelf - Author, Emergency | Self - Author, Emergency |
| KKevin ReeveSelf - onPoint Tactical | Self - onPoint Tactical |
| QQuay TerrySelf - Gunnery Sergeant, USMC | Self - Gunnery Sergeant, USMC |
| BBill BrownSelf - High Altitude Research Corp. | Self - High Altitude Research Corp. |
| EElise CantuSurvivor | Survivor |
 Carin CheaLaboratory Scientist | Laboratory Scientist |
| ZZee CruiseSurvivor | Survivor |
 Leandro DiMonrivaScientist | Scientist |
| KKenneth FavellSurvivor | Survivor |
 Philip HershNews Correspondent | News Correspondent |
| SSydney JaySurvivor | Survivor |
| CChristopher Clay JonesResistance Leader | Resistance Leader |
 Matt LaskySurvival Expert | Survival Expert |
 Eric Raymond LimResistance Fighter | Resistance Fighter |
| DDesiree MartinSurvivor | Survivor |
| TTiffany MartinezSurvivor | Survivor |
 Richard MiraanAstronomer | Astronomer |
