Saturn is the ruling planet of the Capricorn sign, and Ketu shares a friendly relationship with Saturn. Due to Ketu in Capricorn in your Birth Chart, you may have a strong sense of social service. There are lots of things about these planetary combinations, which can be known through the website of Dr. Vinay Bajrangi. He is a Vedic Astrologer and knows many things about Vedic Astrology. You can get a lot of information from his website.