[Mariner]

"Who is the only US manufacturer of rocket engines? Currently, that is SpaceX. I am sure Musk will sell to Lockeed. "

No, look up Rocketdyne.

It's just that we don't build the big stuff here anymore...heavy lift5.

Musk got past this by clustering smaller engines...many of decades old design...into various stages of the rocket.

Of course Rocketdyne used to build the ultimate Heavy Lift...the Saturn rockets. They could do it again.

[null and void]

All we lack is the resolve.