earth vs flying saucer

Newly wed, Dr. Russell and Carol Marvin are the research scientist and his assistant overseeing Operation Sky Hook, a project investigating activity in the upper atmosphere of the Earth via twelve satellites placed into orbit. While they have not yet received any information back from the first ten satellites with rocket number eleven ready to launch, they learn from her father, Brigadier General John Hanley, of evidence that they have probably been destroyed, the reason for not receiving any information. That belief becomes stronger when first Russ and Carol witness what they are certain is a flying saucer, and second that or another flying saucer attacks the project's rocket launch site. Russ and Carol learn directly from the aliens in that first saucer that that first sighting was meant to be communication to Russ regarding their intention - that message which literally got lost in translation - he chosen for his scientific expertise, and when he did not respond, they decided to attack the installation and destroy the satellites in their unknown purpose. The aliens, superior in intellect and who come from a destroyed solar system, disclose that their intent is to conquer Earth in needing a new place to live, but to do it in cooperation with Earth's political leaders in not wanting to achieve their goal via violence, unless necessary, they giving Russ two lunar cycles, or fifty-six days, to convene those leaders in Washington, DC for an alien/human summit. With the US military behind them, Russ and Carol have to figure out how to use their scientific know how to save Earth from this imminent invasion.