Originally Posted by georgegassaway

What do you call this?

And what do you think this is, being put into place on a static test stand at Stennis?

It's the real thing. SLS first stage core.

As for dimensions, there are "enough" to be found, with drawings that can be measured to fill in what's missing to build a good scale model. Note I'm not saying data for NAR "precision" scale, because there have been plenty of Scale model kits for which there was not NAR contest-detailed-level dimensions available at that time (people so spoiled by Peter Alway's work, and lack of internet google searching in the 1960's, 70's, and 80's).

Heck, the Centuri 1/45 Little Joe-II turned out to have some glaring inaccuracies but nobody would think of that as "semi-scale". And even the Estes upgrade of that kit, still has some of those inaccuracies (No Boost Protective Cover details that the A-004 and A-005 missions had, and that kit is representative of only those two missions without massive fin modification). Not a complaint, and the upgraded kit is fantastic, but pointing out even the best can leave out some significant scale parts. Would never call that kit semi-scale for not having the BPC detail.

To me, "semi-scale" has been when the kit-maker intentionally took a lot of liberties with accuracy for the sake of making a kit simpler and/or cheaper (Or using a pre-existing nose cone with not quite the right shape). Best example being the old Estes Semi-Scale Saturn-V, the worst model rocket Saturn-V ever (OK, Micro-Maxx a close 2nd), but also the most affordable. Also, the Estes profile Vostok with V-folded cardboard in place of the four outer boosters.

The EASIEST to get dimensions for on SLS are the 5-segment SRB's. Because those are pretty much the same as the Shuttle SRB's externally but with a 5th segment added (each segment 320" long). Shuttle SRB dimensions are out there, look 'em up. Might be surprised where one of the most useful dimensioned drawings is. Or not surprised.

And the SLS core uses the same diameter as the shuttle ET, and the same attachment fittings as the shuttle SRB's to the ET.