Question: Konstantin Tsiolkovsky and what American credited with creating and building the world's first liquid-fueled rocket, made  theoretical and practical breakthroughs for spaceflight?
Sentence (from "History of spaceflight"): Spaceflight became part of human achievement in the 20th century following theoretical and practical breakthroughs by Konstantin Tsiolkovsky and Robert H. Goddard.
Relevant evidence: Yes