## 1 Introduction
Energy is also drawn by the experimentation payload and on-board electronics such as the altitude controller and telecommunications [9]. An isolated propulsion system can be used to direct the craft. Many technologies are currently available, ranging from tradition cold gas/chemical thrusters to Pulse Plasma thrusters [3]. These and several other systems will be evaluated throughout the course of this paper. The propulsion system is designated as a key component. It is responsible for maintaining altitude, stabilizing the craft after deployment from the OD and conducting maneuvers [4]. Conventional thrusters typically have a finite fuel supply and are actuated and controlled by the Power System. It is vital during orbit that this power system can constantly feed all electrically powered components, even during an eclipse period [10]. As the CubeSat orbits Earth it will be exposed to direct solar radiation as well as many other heating factors and be subjected to extremely low temperatures in shade as background space temperatures are typically 3 K [10]. It is vital that all CubeSat components can maintain operation throughout orbit and do not fail due to the harsh environmental conditions; this will form the base of the thermal analysis. The development and integration of propulsion systems into CubeSats is slow and limited because standards for launch designs stipulated low-and reduced-cost launches with no harm to primary payload [11; 12]. In current CubeSat specifications there is no mention of propulsion systems; however, the requirements of the design impose limitations such as pyrotechnics are not allowed on board to prevent any leakage that might compromise the primary payload launch mission [12; 13]. This means chemical solid rocket propulsion systems and ignition systems are discounted and require a waiver, which will increase the time and cost of payload readiness to be launched. Limits on the chemical stored energy to 100 W-hr which is equivalent to 360 kJ significantly decrease the amount of chemical propellant on board CubeSats [12; 13]. With regards to maximum allowable pressure stored, this is limited by the pressure of the storage tank, systems pressure cannot exceed 100 psig which is designated as hazardous flight hardware [12; 14]. Therefore, due to the above limitation, inert gas is preferred which favored cold gas propulsion and chemical storage system limitation restricted propulsion systems applications to attitude control and reaction wheel desaturation. As of the 8 February 2017, very few CubeSats have been flown featuring propulsion systems [12]; these were mainly designated for technology demonstration. The IMPACT mission featured several electrospray thrusters from MIT, launched by the Aerospace Corporation and BricSAT-P featured four micro-Cathodes arc thrusters launched form United States Naval Academy in collaboration with George Washington University. The other CubeSats missions, less than ten [12], featured cold gas propulsion systems for attitude control and reaction wheel desaturation. More flight missions are required to validate complex propulsion systems currently under development; however, electromagnetic interferences [15] from power system units and thermal management from EP will require a solution before attempting any future flights [12; 15]. Pulsed Plasma Thrusters (PPTCUP) are being developed as standalone modules that can be bolted onto CubeSat structures; this approach is becoming popular since the production of a subsystem is decoupled from the main CubeSat [16]. However, this development is mainly focused on providing translational and orbit control for CubeSat platforms. Recent studies also have addressed the limitation of onboard power by designing modular deployable solar panels [17] and solar sails [18]. To simulate dynamical situations in orbit, a testbed was developed for the solar panel deployment system and the overall performance of the system was discussed in addition to mechanical stresses acting on solar panels during deployment acceleration [17].