As a student, he came in contact with Hermann Oberth's book Die Rakete zu den Planetenräumen ("By Rocket into Planetary Space"), which inspired him to change from studying civil engineering to aeronautics.

He also joined Germany's amateur rocket movement, the Verein für Raumschiffahrt (VfR – "Society for Space Travel") which was centered on Oberth.

These attracted the attention of the Reichsluftfahrtministerium (RLM, or "Reich Aviation Ministry") which saw Sänger's ideas as a potential way to accomplish the goal of building a bomber that could strike the United States from Germany (the Amerikabomber project).

The RLM gave him a research institute near Braunschweig and also built a liquid oxygen plant and a test stand for a 100 tonne thrust engine.

He gradually conceived a rocket-powered sled that would launch a bomber with its own rocket engines that would climb to the fringe of space and then skip along the upper atmosphere – not actually entering orbit, but able to cover vast distances in a series of sub-orbital hops.

Joseph Stalin had become intrigued by reports of the Silbervogel design and sent his son, Vasily, and scientist Grigori Tokaty to convince him to come to the Soviet Union, but they failed to do so.

Honorary member of numerous societies for Space Research in Germany, Great Britain, Austria, the United States of America, Norway, Sweden, Switzerland, Argentina, Italy.