Orion v Starship

Last October I touted Starship as, implicitly, better than pulsed tactical-nuke launch, of Orion-Project (in)fame. Yesterday we looked at whether pulsed tactical-nuke launch was legal. At the same time I was typing, Zimmerman was dismissing ol' Boom Boom as politically impossible. But never mind all that. Tonight, we discuss whether this be practical, as compared with the competition, since the competition is likely to get to space first.

First: the point of Orion. This was to get lots of cargo into space for cheap, at once.

Nuclear-pulse, from a planet, is a one way trip: the process cannot decelerate this thing for a soft landing for itself with safety for everyone else. The Orion chassis stays in orbit, or just disintegrates. If in orbit, dead-Orion's orbit is polar. Orion should only launch above, what, 75°. This because in temperate-tropical lattitudes even small nuclear blasts mess with the Earth's magnetic field and, of course, they EMP all those densely-populated LEO sats and maybe even Nairobi and Rio de Janeiro. What's the delta-V to salvage a polar sat for reuse as, I dunno, a cargo habitat? By the way, Boom Boom's backend is probably radioactive - although, in space, all hulls get a bit glowy, so, maybe that's okay.

Starship, when we allow it to, stands to ship cargo not all at once. The model is a rotating fleet of reusable craft, fueled by chemical reactions burning white-hot through the Raptor Two. Chemical reactions also stand to be cheaper than fissile metal.

Overall, Orion looks like an emergency situation for Earth, or something for other planets lacking a magnetic field (meaning: before they build a ring) and don't care about the rads. The best use is to push asteroid ores around orbit-intersecting trajectories, probably Hohmann.

tl;dr Zimmerman is right.

I do still wonder about metastable metal as something that can heat propellant in a cheap and ecliptic-friendly latitude. But now we're not really talking Orion anymore.