Good Hyperloop news: G-forces won't crush you
Jaffe writes, however, that he "can't say that it will or it won't work," and he believes the idea was "well thought-out" and "clearly worth investigating further." That statement doesn't appear to support the "Why 'Hyperloop' won't work" headline USA Today is running.
(Read more: Cramer: "Why I'm betting on Musk")
In his proposal, Musk addresses other concerns, writing that the "design of Hyperloop has been considered from the start with safety in mind."
Musk said the tube would be built with the "necessary flexibility" to handle California's earthquakes, and the capsules would use mechanical emergency braking systems for a "severe" quake.
"Unlike other modes of transport, Hyperloop is a single system that incorporates the vehicle, propulsion system, energy management, timing, and route," he said. "Capsules travel in a carefully controlled and maintained tube environment. The system is immune to wind, ice, fog, and rain. The propulsion system is integrated into the tube and can only accelerate the capsule to speeds that are safe in each section. With human control error and unpredictable weather removed from the system, very few safety concerns remain."
In any case, he said, the system would be "intrinsically" safer than the alternatives, including cars, trains and planes.
Musk called Hyperloop an "open-source transportation concept" that needs additional work. He encouraged contributions to bring it from "an idea to a reality."