Development, Qualification and First Flight Data of the Iodine Based Cold Gas Thruster for CubeSats

In this work we describe the development process and present the first flight results obtained for the I2T5, the first ever iodine-based propulsion system launched to space in November 2019. The system uses the sublimation of

solid iodine to build up a gas pressure in the storage tank, which is then guided to the nozzle. The main challenge of using iodine as a propellant in a cold gas

propulsion system is the corrosive nature of the iodine, which is a halogen with moderate chemical activity towards most of the metals including stainless steel, as well as other common substances found in spacecrafts. The acceleration

of flows in such system is also a complex task, since the maximum vapor pressure of the propellant is defined by the maximum allowed temperature of operation, chosen to avoid solid-to-liquid phase transition which would result in the need to use precise micro-nozzles. The other challenges,

such as the possibility of fragmentation of the propellant with consequent loss of the thermal contact and “bouncing” in microgravity conditions, have also been studied and resolved. Here we present the main approaches to our development process and describe the key solutions which resulted in having a space-ready operational device.