Jan 282017
Below is a piece of Convair art from the SDASM Flickr account showing an early (1959) concept for a space booster with a glideback manned first stage. It’s a little unclear what’s going on with the second stage… the cutaway *seems* to show a space station-like payload where you’d expect to find the second stage engine.
See the SDASM Flickr page for a higher rez version.
Remember that Kraft Ehricke was involved in Convair. https://s-media-cache-ak0.pinimg.com/originals/50/7f/72/507f72712ee9b3a22ecd48375411e285.jpg
So the winged flyback was the booster, next in the stack is the crew cabin, and on top of that is the nuclear rocket. On staging, the crew cabin drops back on cables and the nuclear engine fires up.
Agreed, looks suspiciously like it inspired the Helios flyback booster. No proof though.
See images here:
http://www.projectrho.com/public_html/rocket/realdesigns.php#heliogallery