>>11575403If you consider an expendable launch vehicle, sure. In reality the most valuable feature of Orion is its high thrust and high specific impulse, greater than 50,000 seconds. For reference that's ten times more efficient than a mid level ion drive at several billion times the thrust for only a few tens of thousands of times the mass. Using Orion drive as a launch vehicle only makes sense for worlds with much higher delta V requirements than Earth. For example if you found yourself hovering in Jupiter's upper cloud layers, an Orion drive vehicle would not only let you launch yourself back into orbit, you'd have enough juice to probably get to any other planet in the solar system and insert into orbit.
The thing about any Orion drive is that it differs from chemical vehicles significantly in an economic sense; Orion costs a lot to fuel, but not so much to build. Nukes are expensive, even if you can mass produce them with no red tape. Meanwhile, expendable chemical rockets are expensive to build, but cheap to fuel. Without reusable chemical launch vehicles, an Orion drive makes economic sense for launch because it costs way less per kilogram than a similarly sized expendable chemical vehicle would, plus it can go farther. However, once reusable TSTO becomes a thing, you suddenly have an expensive vehicle that is cheap to fly over and over again because fuel is cheap, whereas Orion remains expensive, and obviously can never come back to Earth for reuse as a launch vehicle.
Big Orion drive type vehicles only really make sense for truly massive spacecraft heading off on relatively slow trajectories to other Stars. We can get similar performance and useful thrust to weight ratio out of a scaled down version that uses magnets to crush fuel pellets, though it probably couldn't be used to launch to orbit from Earth, rather it'd be used for quick scoots out to the outer planets and back, or for high mass capacity tug vehicles. The efficiency is what we need anyway.
