>Why do you limit it to current R&D? Because if all their current R&D is 100% worthless towards their future business (if any) then they aren't actually buildi

>Why do you limit it to current R&D? Because if all their current R&D is 100% worthless towards their future business (if any) then they aren't actually building any engineering fundamentals right now and might as well be starting from scratch when they need to pivot. It takes many, many years to build up to orbital flight, and everyone starts building that experience and capability at a smaller level. So it's very important if that "smaller level" actually is building towards the next step. Blue Origin for example has been doing a lot of suborbital work with New Shepard, but that is clearly directly building towards full orbital+reusable, they've been building their capabilities wrt vertical landing, scalable engine work, etc. But if VG's hybrid engine and entire carry/plane concept is simply a fundamental dead end (because it will never have an acceptable mass fraction or hit orbital delta-v reqs or be able to handle orbital reentry say) then most/all of their current R&D is effectively being flushed down the drain. It's not building towards anything new. And that's ignoring whether it could possibly be competitive against what the others are doing. >Build profitable “space” business. But what business? Sounding rockets don't match this at all, point-to-point transport doesn't look like a real case for it either, and it also can't do space tourism, just joyrides. But it doesn't look like it'll even be able to do joyrides very well compared to competitors, nor more cheaply. >scale it up Some things don't scale up, particularly in rocketry. There is no escaping the rocket equation. >trips into orbit, around moon The problem is that from the looks of it not only is nothing they're doing capable of that, it will never be capable of that. I've done some more reading since my post and the hybrid engine concept really just looks like a dud. Their whole plane thing represents a huge amount of wasted mass and extra complexity too. And again: there is competition here now. If this was all in the 80s/90s yeah it'd be more interesting, even if everyone concluded they'd need to start over from scratch to make a real orbital rocket perhaps there really would be a decade of joyride potential or odd niche uses or something to experiment with. But not against the likes of SpaceX or Blue Origin.