NASA's Space Launch System (SLS) project will cost about $40 billion from now to 2030 and will produce a chemical rocket about 1000 times more expensive to launch than a SpaceX BFR. SLS will start inferior to the SpaceX Falcon Heavy and then will be years later than a superior SpaceX BFR. SLS funds would be better spent on making a vastly superior Turbo rocket.
There is a 104 page presentation on the Turbo rocket.
John Bucknell created the pre-conceptual design for the SpaceX Raptor engine which will be used for the SpaceX BFR. John Bucknell says the nuclear turbo rocket technology and his designs are ready for development. The air-breathing nuclear thermal rocket will enable 7 times more payload fraction to be delivered to low-earth orbit and it will have 6 times the ISP (rocket fuel efficiency) as chemical rockets. The rocket will have two to three times the speed and performance of chemical rockets for missions outside of the atmosphere.