In the current era, White House budget requests often don’t matter much in the outcome of NASA’s budget, but they do speak volumes about the administration’s intentions.
There are a bunch of things in this request that will be tossed out quickly by Congress—the cuts to Earth science mission, WFIRST, and NASA Education, to name a few. More funding for Mars sample return, the Lunar Gateway, and walking back the “Sink ISS in 2025” statements will almost certainly be welcomed.
The request also shifts Europa Clipper and Lunar Gateway elements from SLS to commercial launch vehicles, and delays (read: cancels) SLS Block 1B for just about 10 years. This is the most full-throated rebuke of SLS since the 2011 budget request in which the Obama administration canceled Constellation.
But don’t forget that Congress promptly reinstated SLS and Orion.