Assertion: spacecraft's engine | /r/HasProperty | a block 1a variant
Facets:
Source sentences:
text: During the early development of the SLS a number of configurations were considered, including a Block 0 variant with three main engines, a Block 1A variant with upgraded boosters instead of the improved second stage, and a Block 2 with five main engines and the Earth Departure Stage, with up to three J-2X engines.