Conversation so far:
what was snake river canyon for Evel Knievel?
Knievel hired subcontractor and aeronautical engineer Doug Malewicki to build him a rocket-powered cycle to jump across the Snake River, and called it the Skycycle X-1.
What was the Evel Knievel's snake river canyon jump a launch of?
The decision was then made to have Truax build the Skycycle X-2 and have it take off and fly more like a rocket than a motorcycle.

Question: when was the launch?
Self-contained rewrite: when was the evel knievel snake river canyon jump launch?