Better not to do a spacex and blow it up. A ULA perfect record is preferred.
The question is what will future iterations look like? The desired design philosophy, in my view, is that of the original Shuttle which the boosters and engines come from, which is a Saturn V class launch vehicle that expends one tank on the altar of the rocket equation and reuses everything else. The Shuttle accomplished this in the most inefficient, expensive, and risky way possible- in the interest of going cheap. We see the SLS as what the Shuttle might have been, except now they have thrown the baby out with the bathwater and made it all expendable, as well as even more expensive. Why did this happen? Not, as the spacex fanboys scream, due to satan-as-cost-plus. It was due to political uncertainty and lack of funding. Without a long-range commitment, a plan, and funding, the cost over-runs were a certainty. What is the solution?
NOT the shiny. That thing is intended to make a certain entrepreneur the owner of cyberspace, not “expand the light of consciousness into the universe.” They are not Moon people.
In my view liquid landback boosters to replace the SRB’s (two New Glenn first stages would seem to be what is needed) and recoverable pod for the RS-25’s (studied long ago) are the correct path. Reusing the escape tower and capsule, the boosters and core engines, and expending the core tank, leaves what is between the core and the capsule to be decided.
Increasing launch cadence to four to six launches a year would enable a permanent human presence in cislunar space and bring costs down. The how and where of that presence also yet to be decided. My recommendation would be to first bring water up from the lunar poles robotically for cosmic ray shielding in “Fat Workshops” and then send people.
Hydrogen is tricky stuff. von Braun really did not like it but was finally convinced it was how to get to the Moon. The only reason it happened was a top secret failed reconnaissance aircraft called “Suntan.” The hydrogen was available in quantity because they had already built the plants to supply the airplane that was finally cancelled as impractical. Air refueling became a requirement and….you can’t air refuel liquid hydrogen.
Handling and especially the turbopumps are expensive, which is why rocket jesus would not use it, but if we are going to be launching hundreds of times a year then hydrogen is what you want, instead of kerosene or methane byproducts in the upper atmosphere.
They were working on an integrated power head demonstrator for a full-flow hydrogen engine some years ago but ran out of money. It was too small anyway. What is needed is an engine in the 2 million pound thrust range like the Aerojet M-1, except full flow. Never big enough though and something with double that amount of thrust would make the most sense. A first stage with 4 such 4 million pound thrust engines and a central variable thrust engine, sized to land the first stage back, would be the way to go.
It might even be possible to use a turbo pump system to supply two of the thrust chambers, like the RD-180, and this would make for fewer components and in a sense be akin to a modern jetliner with two engines and third smaller one as the landing gear.
Ice on the Moon 