An article about Hansen, NASA

Could anybody help me with better understanding of this English sentence?

"The United States had become a space-faring nation and the allure of the unknown called many planetary physicists' attention to worlds beyond Earth's atmosphere."

The allure of the unknown.....means people's much interest(towards the physicists)?

Beyond Earth's atmosphere      It represents their ongoing research?(phsycists researching about inner space?) 

Call attention it's idiom, (so many people's interests are looking eagerly at the physicists' work).?

I would be grateful for your help!