ars technica article on the F1B engine the derivative of the Saturn 5 main engines competing for the strap on for the Senatorial Launch System… I don’t love the SLS but the F1B is exciting and worthy, I just wish it were part of a more commercially driven program.

2nd page has a great explanation of the difference between kerosene and liquid hydrogen as a fuel for first stage engines, fun for the rocket scientist in all of us…or at least me.