I guess that Orion was just ahead of its time.
The risks of fast tracking that system back in the 1960’s would have been quite high. The bugs had not yet been worked out for living in space. The design was a hugely inefficient brute force approach - the great bulk of the energy was dissipated, with only a tiny fraction providing thrust. And it was pretty dirty - a thousand plutonium bombs to liftoff, with no solution for the fallout. Also, if there was a single Challenger-like malfunction (which were more common back then), it would burn in with thousands of warheads aboard - goodbye to the careers of all decision makers involved. Also, if we developed it, it would be subject to proliferation through espionage - just like our nuclear weapons programs were.
I would guess that after two terms of Clinton, and two terms of Obama, that the Chinese have the full files on this project, as well as the rest of our programs (e.g. Wen Ho Lee), so maybe they will build one for military use.
It is still probably a leading solution for the planetary defense mission of diverting an asteroid impact. if that would ever be funded. I imagine that by now there would be significant refinement of a lot of components, so that a freshly designed system could use and adjust the thrust much more efficiently. George Dyson alluded to that in the video you linked.
An updated Orion-like propulsion system might even be used for heavy lift operations around the solar system, like the mining envisioned in the article of this thread.
There is no doubt in my mind though, that we you want to accomplish big things in space, we need to use nuclear power.
Nuclear power - other than battery supplied - is pretty much a dead issue. There are numerous power plants being developed, sure, but they will never be permitted off the ground - thanks to our local envirowackos’ work in the courts. There is even a very strong lobby to block any further exploration of the moon because it will disturb the ‘pristine’ environment, etc. Nuclear power use in space by the US will never happen unless there is a sea-change in the public’s perception of nuclear use and power, which will only come about if the US returns to classical education, and if the public at large has something other than self- indulgence on its collective mind.
Back in those days bugs were worked out on the spot. People had real classical educations and knew how to fix things, without waiting for some study to be completed. Called self-reliance - a novel concept today.
Now we have committees to study each individual problem, publish papers no one reads, and that’s that until the need or funds get large enough to pursue. It is easier to study the problem than to actually do it. (Which is why it took so long to pioneer west of the Alleghenies - all those committees took decades to figure out if a wooden wagon wheel would be up to the task, and what if one broke? Oh my!)
Yep, accidents happen, and that is why no man should leave the safety of his home and bed. Oh and dread someone steal the tech! Like the Soviet union, perhaps? We would have been so far ahead by that time we could have easily shut them down.
China will make use of those designs for military use (there is no other use for them), but the whole trick - as I mentioned - is in the design of very small reliable efficient small nukes - an extremely difficult task when you cannot actually test one. (Although the Chinese may have tested something on that order timed to coincide with the mysterious huge explosion which happened in NK in 2004). All of this is part of China’s ongoing Project 863 - the search for the next super-weapon.