They've not shown up where I read. ...Until now.
Orbital Kinetic Bombardment gets close to nuclear on damage and cost
https://www.nextbigfuture.com/2018/11/orbital-kinetic-bombardment-gets-close-to-nuclear-on-damage-and-cost.html
These were featured in a science fiction story I read long ago.
IIRC, variations of this have been part of US Government plans on and off since Reagan's Star Wars/SDI in the early 80s.
Seems do-able with SpaceX frequent flyer miles.
I hope we never have these things sitting up on satellites in space, waiting to malfunction or be hacked.
I think the big danger is not that they are hackable, but that they are thinkable.
The thing that has stopped nuclear war all these years is not the explosive power of the devices, but the long-term contamination. Nuclear war is "unthinkable" because the consequences are grave and global. The world has twice been saved by Soviet officers who elected not to follow orders and elected not to launch despite a clear indication of incoming US warheads (in one case) or the sub with weapons being directly fired upon by a US ship. If nuclear war were not unthinkable, those two officers would certainly have followed orders.
So what scares me about this option is that they are saying it has nuclear-level destructive power, but it's completely thinkable, usable, reasonable, tactical. Which means it will get used as soon as it's convenient, not just when the unthinkable option becomes the only option left.
>it will get used as soon as it's convenient
Exactly my thought.
QuoteMr. President, I'm not saying we wouldn't get our hair mussed. But I do say... no more than ten to twenty million killed, tops. Uh... depending on the breaks.
<added>
Secretive X-37B Military Space Plane Wings Past 200 Days in Orbit
https://www.space.com/40227-x-37b-space-plane-200-days-in-orbit-otv5.html
Yes, that is a terrifying thought. It is pretty good incentive for less capable nations to develop nuclear weapons.