Mea culpa redux

The reason why you can't use NTRs is that if there's an engine failure you going to have a hot reactor coming down on the ground somewhere, and it can be very inconvenient. Secondly, the numbers for thrust given in the nuclear rocket book looks insufficient to achieve orbit. That one got by me. It still may be possible to get to orbit using a lighter payload than the 17 K mentioned in that same configuration that I've been using as an example. Another possibility is to use the x33 to get to a higher delta V before switching over to the NTR. The newly configured system may not be able to work at all if the thrust to weight ratio isn't good enough. It may have to be as high as thirty to one. The project timber wind boys claim to get that, but there's some doubts about that. Even if all of that could be made to work, you still would have no guarantee that it could get to orbit. But you have increased your odds of success. You have also increased your control over your launch system which may allow this to be launched after all.