The illustrious Steve Burg had already done a lot of work on the Prometheus (originally Magellan) spacecraft when I took it over, and I worked extensively with his geometry and also the look of some of his illustrations as I continued the design process. Steve's work (and a lot of new images, from what I can tell) are here: http://steveburg.blogspot.com/2012/06/prometheus-concept-art-ii.html  Mechanically my main contributions were to solve the engine repositioning problem, integrate the landing feet into the engine look instead of covering them in flight, and shortening the ship and giving it a neck per a UK study. A dorsal hump, some reproportioning, and other small details brought the composition together.