@Henry Wertz 1
"I wonder if these X-37Bs are more modern"
Well the Space Transportation System design does date from roughly the mid 70s. There have been a few improvements since then.
"(cheaper and easier to prep for relaunch mainly) compared to the shuttle?"
Easier to prep almost certainly (A too stage liquid fueled rocket is essentially 4 *very* large empty tanks. Fragile, but *nowhere* near the hazard of the 2 SRBs)
Note what it *can't* do.
Not crew rated.
LV *not* crew rated (Load safety factors of 1.25, rather than 1.4 of crew rated)
Payload bay size of a pickup truck, not a Greyhound bus (c14'x65' with a capacity of c55Klbs)
Replaces *highly* toxic hypergolics of Shuttle as Peroxide/kerosene engines (dating form mid 50s) were not included.
Recover *any* of its launch vehicle.
A launch *should* be more straightforward but the price may not be as cheap as you think (and given the *massive* reduction in payload as little as people would *expect*)
It is an interesting vehicle.