I just thought about "SUBLIMATION METHOD" for deep space propulsion.As per sketch if camphor solid heated then the vapor will be ejected and a thrust will be created to propell the craft.The camphor vapor will be again deposited on a surface to reuse again and again.The deposited camphor can be reused several time and it is technically possible.Now my question is that should this method will work to propel the spacecraft without spring??Second if it doesn't work without a spring and if i use a spring then should it work as the deposited camphor will work to stretch the spring after each 3 second(the vapor will be ejected after each 3 seconds) and the spring will again compressed, pushing the craft.