"Advanced Earth-to-Orbit Vehicles Jet-Powered and Nuclear Rocket-Powered" via Mike Acs Flickr Page

Convair (Astronautics) - General Dynamics photo, no. 09600-A)

"Advanced Earth-to-Orbit Vehicles Jet-Powered and Nuclear Rocket-Powered"

 

So, does that mean both (jet-powered & nuclear-powered) are depicted here? It would appear so; with the forward section/stage being nuclear-powered and the aft (it also being delta-winged) section/stage being jet-powered. At least that's what I think I'm seeing.

 

So, that makes the below linked image quite plausible as being that of the same vehicle, after its release/launch from the carrier aircraft.

 

Finally, based on the block letters he used for his "signature", I think this is an early work by John Sentovic. Regardless, my date range is a total SWAG.

 

Lastly & most inconsequentially, note the bubble canopy of the carrier aircraft, not unlike that of Convair's B-36 "Peacemaker" bomber.