New USSA Hypersonic Engine perhaps?

[Scarmoge]

https://news.northropgrumman.com/srm/us-navy-selects-northrop-grumman-for-second-stage-solid-rocket-motor-program

[Divergent]

Northrop Grumman … and solid fuel rockets…?
Is this a joke,junk kind of joke?USSA have need hypersonic rocket" projectile" engines?
Since when?