I want to know the answer to the following question:
What professor began working on solid-fuel rockets since 1914?
All the background I'm provided with is that "Von Braun, himself inspired by Goddard's work, was bemused by this when debriefed by his American handlers, asking them, "Why didn't you just ask Dr. Goddard?"[citation needed]". Is that enough to answer the question?
Answer: no