It could finally be the beginning of the end for the Space Launch System/Orion. The Office of Management and Budget March 11 propose to defer work on the Block 1B version of the SLS. Block 1B would increase the rocket’s performance by replacing its existing Interim Cryogenic Propulsion Stage with the more powerful Exploration Upper Stage.
In 2020, the combined Space Launch System/Orion budget could drop to $3 billion instead of $3.5 billion.
There is also a proposal to launch the Europa Clipper mission on a commercial launcher for $600 million. This would save $700 million instead of launching on a future Space Launch System.
Europa Clipper could probably be launched by the SpaceX Falcon Heavy.
SOURCES – Office of Management and Budget, Space News