Nanosatellites, traditionally, have found application in the fields of Earth observation, communication, science, remote-sensing and technology demonstration. However, it is a general belief that the era of Nanosatellites has just begun. With dedicated research and the inherent versatility of Nanosatellites, today the Nanosatellite market is booming with big satellite constellations and thrilling inter-planetary missions. The recognition of the capabilities of Nanosatellites has resulted in more complex missions and payload integrations and as a result a higher sophistication in the design. This translates directly into an ever-growing demand for power in Nanosatellites. One challenge the power density imposes on the Nanosatellite thermal control system is the challenge to radiate the dissipated power. With the surge in power density, improved thermal control solutions are imperative for the successful operation of Nanosatellites. This thesis aims to offer a solution to overcomethis challenge. One way of controlling the temperatures of a spacecraft passively is by coating the external surfaces of the spacecraft with wavelength dependent coatings. As the exterior surfaces form a radiative coupling between the spacecraft and the space environment, these coatings can regulate the amount of heat entering and leaving the spacecraft. Traditional thermal design involves selection of the surface coatings manually by a thermal engineer using experience and/or sensitivity analysis. The selected coatings may emerge non-optimal which might prove unfavorable to the power dissipating components and likewise to the Nanosatellite. This thesis aims at exploring the possibility to optimize the surface properties (Solar Absorptivity and Infrared (IR) Emissivity) of the exterior surfaces and to automate the selection of surface coatings to overcome the challenge of increased power density and its dissipation in a Nanosatellite. GOMX-4A Nanosatellite serves as a case-study to test the thermal analysis and optimization stratergy. The primary objective of optimization problem is to maintain the component temperatures within operating limits. Further, the optimization scheme also attempts to reduce temperature cycling of the components. The optimization scheme is developed on a simplified thermal model of GOMX-4A. Accordingly, first a thermal model of GOMX-4A is developed and is validated within-orbit temperatures obtained from telemetry to correlate the trend of componenttemperatures of the Nanosatellite. Next, an optimization process is formulated andis then implemented on the GOMX-4A thermal model using the optimization tool, CORTIME. The outcome of the optimization scheme is the optimal thermo-optical properties of the exterior surfaces of GOMX-4A that regulate the component temperatures.The optimal solution which resulted from the optimization scheme is a coating on radiation backplate on -Y face of GOMX-4A, which has an absorptivity of 0.8 and an emissivity of 0.01. Further, a favourable solution range of thermo-optical properties is discussed which guides a thermal engineer to select a coating whichis feasible from the point of view of Nanosatellite production.