Here are two translations from a passage of an open letter from Kepler to Galileo published in the Conversation with the Star Messenger on April 19, 1610. We are still creating the maps of the universe for the future space explorers after four hundred years.
"There will certainly be no lack of human pioneers when we have mastered the art of flight. Who would have thought that navigation across the vast ocean is less dangerous and quieter than in the narrow, threatening gulfs of the Adriatic, or the Baltic, or the British straits? Let us create vessels and sails adjusted to the heavenly ether, and there will be plenty of people unafraid of the empty wastes. In the meantime, we shall prepare, for the brave sky-travellers, maps of the celestial bodies – I shall do it for the moon, you Galileo, for Jupiter." (1)
(1) Koestler, A., & Butterfield, H. (1959). The Sleepwalkers: A History of Man's Changing Vision of the Universe. Arthur Koestler. Introduction by Herbert Butterfield, Hutchinson.
(2) Kepler, J., & Rosen, E. (1965). Kepler's Conversation with Galileo's Sidereal messenger. 1st complete translation, with an introd. and notes. New York, Johnson Reprint Corp., 1965., 1.