In article ,
says...

Jeff Findley wrote on Sat, 29 Jun 2019
08:27:43 -0400:

That would certainly be possible, but it wouldn't be as high fidelity as
a Block 5. According to NexxusWolf on Reddit, it will be a Block 5
booster. Yes, I know, not the most reliable spot for info, but it is
what it is.

https://www.reddit.com/r/spacex/comm...at_i_got_from_
my_tour/


Well, they're already removing grid fins and landing legs, so does not
having Block 5 upgrades really make that much additional difference?

I tend to agree that it shouldn't matter, but since the customer is
NASA...

Of course, Orion's abort test won't happen on an SLS, but NASA has more
"insight" into that design. Same as flying crew on the 2nd flight of
SLS but SpaceX had to have something like 7 launches of the Block 5 with
the upgraded COPVs to prove that design for Dragon 2 crew.

So, yes, there is a pattern of NASA making SpaceX jump through hoops
that it doesn't make Boeing and the other big contractors jump through.

Jeff
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