Spacecraft images are an invaluable source of information in Planetary Science. However, they must be processed and the initial stage is to navigate them, i.e., determine the longitude and latitude coordinates of each pixel on the image plane. The main goal of the present work is to develop an open-source tool to do so. It will be independent of proprietary software and implemented in a widely used language (Java, Python). It will be able to analyse planetary images taken by different spacecraft, such as New Horizons, Cassini or Voyager, with minimal user intervention. Here we present the first steps of the process illustrating the techniques to navigate an image of an ellipsoidal body, obtained from mission kernels using NASA Jet Propulsion Laboratory SPICE library, considering that the attitude and position of the spacecraft are available; correct the camera attitude information; determine the image resolution for each pixel; and combine different images of a body to generate mosaics with high resolution