Two Planets by Kurd Lasswitz (1897)
en.wikipedia.org
en.wikipedia.org
Unabridged German editions are rare and expensive, e.g. https://www.lwcurrey.com/pages/books/133185/kurd-lasswitz/au....
1971 abridged English translation quoted a leader of German and later American rocket and space programs, https://www.amazon.com/Two-Planets-Kurd-Lasswitz/dp/08093050...
Wernher von Braun: "I shall never forget how I devoured this novel with curiosity and excitement as a young man."
Lasswitz's Martians differ little from man physically, but ethically, intellectually, scientifically, and socially they are the prototype of the ideal human being. They seek to educate man, asking in return only air and energy to supplement the diminished supplies in their own, older world.
The story revolves around a group of German scientists who, when seeking the North Pole, come upon a Martian settlement there. The Martians have built an artificial island, adapted to their physical needs, above which-6356 kilometers above-hovers their space station, a giant ring such as twentieth-century astronautical scientists have seriously speculated upon.
... More important than the fantastic technological developments in the story is the author's belief in the humanizing potential of science and technology and his vision of a utopian world based on the ideals and ideas which the Martians seek to transmit to the men of Earth.
Kurd Lasswitz wrote his novel when scientific and industrial developments were sweeping the Western world. The balloon was a product of the late eighteenth century, but the dirigible had just entered the skies-Count Zeppelin began building his ships in 1898-and although the forerunner of today's airplane was already on the drawing board the first actual tests were almost a decade away. Yet Lasswitz's prophetic vision went far beyond the technological achievements of his day.