Author:
Space Shuttle: The Virtus System, 1973/74 [Artist, Douglas Ettridge]:
Note: The Virtus System would seem to have been a proposed Transport System for the Space Shuttle which did not get beyond the drawing board. I have yet to find a connection between Douglas Ettridge and the Virtus System.At the time [early 1974] NASA Langley had a study ongoing on a large aircraft design called VIRTUS that would have carried the Orbiter under the center wing flanked by twin fuselages and a twin boom tail with power coming from four Pratt & Whitney JT9D turbofans.