Posted: Sun, Mar 17, 2019, 7:58 AM ET (1158 GMT)

The administration's $21 billion budget proposal for NASA deemphasizes the development of the Space Launch System. The fiscal year 2020 budget requests calls for deferring work on the Block 1B version of the SLS, with its larger Exploration Upper Stage, for an indefinite period, and would instead use commercially procured rockets to launch elements of the lunar Gateway. It also would transfer the Europa Clipper mission from the SLS to a commercial vehicle. NASA officials said they are working on a new, "realistic" launch readiness date for the first SLS mission, now expected to slip from 2020. The proposal emphasizes commercial aspects of exploration, including development of larger commercial lunar landers and commercial communications services. The proposal, nearly $500 million below what NASA received in 2019, makes another attempt to cancel the WFIRST astrophysics mission and two Earth science missions, as well as close the agency's education office.