Guys, these are both really old artist concepts.
The first is in pretty good form, but I've seen several different versions of it going
way back. Also, there are similar designs in old SAE and AIAA papers from
other aerospace companies going back to the 50's and 60's.
And the second, that someone wants to assert is what motivated certain authors
to give us "Aurora", was offered for sale on eBay not that long ago.
I will give you some photos of some of the murals/logos that used to be at
(maybe still are) Marqardt that show similar concepts. Unfortunately they are small.
Also Marquardt had a company magazine that featured these concepts from time to time, back in the 1950's,1960's, ... ? as well. As I recall, it was called "REMARQ",
or some such.
I have a very nice blow up of a Marquardt scramjet concept that I had blown up
and framed that was different from all of these. Let me see if I can find the
small version of it to post here.