Operation Argus was a real life series of high altitude nuclear missile tests by the US military in 1958. In relation to the movie plot these tests are really for Operation Belttrap which was made up for the movie. This operation is under the guise of Argus. Belttrap's goal is by detonating nuclear weapons at high altitudes they hope to bring down the alien craft that is orbiting earth and to have it crash on earth. If this happens the operation calls for the craft to be picked up and brought to area 51. This alien craft is made up of the white cubes found in the movie and the craft contains the alien himself.