US has an even greater supply of SM-3 IIAs with the same terminal capability.
IIA is at the early stage of ICBM coverage, like the S-500. But S-550 takes it to the next level.
I'm also leaning on the PAK DP theory. And I could be wrong on both counts.
So new theory. Probably something like a loitering drone type satellite that stays up in space and then chases and kills other satellites.
Russia rejects space weapon claim as ‘propaganda’
Moscow responds after the US Space Command accused Russia of test-firing an anti-satellite weapon in space.
www.aljazeera.com
So this has been going on for quite a few years.