The study of educational serious games as a medium to motivate player learning through teaching astronomy in video games is examined through the iterative development of the video game Starfarer. It contributes to the better understanding of the development of educational serious games. The theoretical frameworks used are Game Based Learning (GBL) theory and Narrative Learning (NL) theory. Research through Design (RtD) was conducted to evaluate the use of these frameworks in cultivating motivation to learn in-game. The most important aspects of each that are identified through the development of Starfarer are; in GBL, attractive learning objectives, iterative problem-solving with positive feedback, and relevant simulations; and in NL, narrative context, pacing, and empathy for characters. From this, an additional missing design element of emotion is identified. In evaluating GBL and NL, it is found that they are in many ways balanced, and in others opposed. Furthermore, it was discovered that many players have an affinity towards either GBL or NL, thus a design process utilising both must balance such preferences. Suggestions for further study expanding on these findings are in developing and testing combining GBL, NL, and an emotional component into a new framework to better motivate player learning in-game.