Cube Satellites are miniaturized satellites used for space research with a mass of not more than 1.33 kg per unit. They are widely used in space applications because of its low cost of manufacturing and flexibility of applications. Since, they use commercial off-the-shelf components, thermal consideration of internal components of 1-unit cube satellites becomes a necessity. In this paper, transient thermal analysis of a 1-unit cube satellite is conducted to analyze its behavior during the first 29 seconds of orbit insertion from the launch vehicle. Transient thermal analysis yielded a temperature range that exceeded the optimum limit. As a result, to reduce heat dissipation, two main types of thermal management systems for satellites: active control and passive control systems are included. To maintain critical components at their operating temperature, a passive thermal control is implemented. Thermal strap and multi-layer insulation are used to analyze internal components of 1-unit cube satellite. Using graphite fiber thermal strap and aerogel multi-layer insulation for internal components, the 1-unit modular cube satellite is found to be more suitable under low earth orbit conditions.