Why doesn't Elon Musk use Project Orion type technology to colonize Mars?

https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion) Project Orion was perhaps the most ambitious and exciting scientific/engineering project undertaken, in human history. A geniune effort to build a starship, that actually predated the first Star Trek series! For a variety of reasons, it came to nothing. And this despite the fact that it employed relatively conventional technologies, and almost certainly would have been successful, if adequately funded. The idea was simply to use small H-bombs in deep space, as a form of propulsion. Perfectly feasible. Bear in mind, A-bombs -- which form the core of an H-bomb -- can have yields as low as ten tons of TNT, or less. So, in terms of the energy levels involved in large rocket propulsion systems in space, perfectly practical, and feasible. Now, some sixty years later, we're still muddling with exotic alternatives, and, despite innumerable optimistic predictions, not really getting anywhere with practical controlled nuclear fusion technologies, at all. Isn't it time to go back to Project Orion? And, if we got somewhere with deep space fusion technologies, who knows? Maybe there might be some generalization to practical controlled nuclear fusion technologies for energy production right here on earth. Stranger things have happened, haven't there, in the history of science and technology? Using this type of technology, trips to Mars could be made in mere days, from Earth. So, resupplying Martian colonies would be no problem, at all. No need for terraforming or the development of new, unknown technologies for "living off the land", on Mars. Also, it would probably be much cheaper than methalox rockets, once the technology was fully developed. So, what's stopping our friend Elon, here? Isn't Project Orion the answer to all his hopes and dreams?