

Honest answer? Nukes.
Or rods from god.
But the system doesn’t chill in orbit- it launches on Sub-O trajectories to get the cargo or payload in place quickly.
The problem is it’s only slightly more subtle than a nuke in the face, costs ridiculous per launch, has extremely limited capacity, and is only a few hours faster than say, Mach 6 (aka hypersonic.)
We already have a best in class logistical system that makes either of the hypersonic or sub-o systems… extremely niche.
they’re talking about sub-o cargo things, yes. But the only thing you need that kind of global delivery window, and don’t want to keep, you know, mostly discrete… all make really big explosions.
the launch vehicle could just as easily be used as a ballistic missile of any sort as a cargo thingy.
But again, we have Best-in-Class military logistics; and we have bases all over the world staged with teams ready to go. any conceivable thing that would need a 90-minute response is so niche, it’d probably never actually get used. the cost of just a single launch vehicle is probably a fairly large chunk of the operating costs for those bases; and those methods of deployment don’t come with the added issue of being really freaking obvious.