Earmarks and pork are nothing other than corruption. The SLS is the clearest example.
US taxpayers have invested close to $20B in a launch system that was outdated the day it was designed and will literally cost 100 times more per pound than commercially available launch systems.
The first reason it's so costly is that the US congress required it to use solid rocket boosters, which increase launch risks, and substantially increase launch costs.
The second reason the SLS is so costly is that congress required it to use RS-25 engines, which were some of the most expensive rocket engines ever designed, originally costing $45M a pop. They were so expensive because they were used on the Shuttle and had to be refurbished between launches instead of expended (destroyed) every launch.
But not only will the RS-25s used on the SLS be expended every launch, Aeroject is getting $100M(!) each to build new ones. And it forced the SLS to use one of the worst possible first stage fuels, Hydrogen, which requires carrying a massively heavy cryogenic tank, construction of has held up launches for years,
By contrast, each SpaceX Merlin which has roughly half the thrust of an RS-25 costs around $500,000 to build, 200 TIMES LESS! And uses a far more compact and effective first stage fuel.
