Possibly Big Butterfries.
Why do you think he'd leave Germany for the US? They weren't even funding Goddard. Also why would the Germans allow him to leave? The US isn't going to be allying with anyone without WW2 and Germany will probably run its own power bloc in Europe.
One scenario:
1936, Hitler dies in car crash.
1938, Nazi dictatorship under (Der Grossherman?) collapses in food riots due to incompetent Nazi handling of economy.
1940, France takes Rhineland, in deal with Soviets who take Poland (the deal, no war over Poland.)
1944, Fearing a Soviet take-over, von Braun and the VfR flee to England. The Brits, seeing the "mene, mene" on the wall, decide to fund rocket research for self-defense.

1945, the US, finally seeing the Red Menace come to life when Germany is absorbed into the GSU, begins to fund Goddard's Children in order to "stop the Reds at the Atlantic." The US and Brits share much info, not yet realizing how deep the Soviet moles have burrowed under the Transatlantic Union. But having notes on research is not the same as practical experience, as Soviet rocketeers discover.
1947, a von Braun multistage bomb-thrower topped with a plutonium head is operational. The Soviets begin to reconsider their rocket program.
1948, Hoover's FBI exposes Soviet spies in the US, with leads to the Brit's network also. James Bond has a field day with his authorization.
1953, von Braun orbits a grapefruit-sized transponder from a rocket base near Woomera. Stalin dies of heart failure.
1959, the first US-British space station becomes operational, complete with space-spy gear, and atomic bombs marked with names like "Moscow", "Stalingrad", and "Baikonur". Admiral Heinlein, on loan from the USN, commands the station.
1964, first Moon landing, followed in two years by Moonbase One.
1989, the GSU collapses in economic chaos, Germany, Poland, and parts of the former Soviet Union become Republics ( thug-run kleptocracies, but who's counting?)
