E. Everett Evans & E.E. ‘Doc’ Smith 
Masters of Space [EPUB ebook] 

Jarvis Hilton is in charge of a handpicked team of scientists — and a navy warship on a deep space mission, dubbed Project Theta Orionis. On the outbound journey, automatic sensors drop their ship — the Perseus — into normal space for an encounter with a mysterious skeletal object. The encounter leaves them baffled, and leads them to a view an epic space battle. But strange as that is, it’s nowhere near as mysterious as finding a planet covered in radioactive fuel ore — and populated with humanoid robots who have been expecting their arrival and greet them as returning masters. . . !