Extended COSMOS, COSMOS X, is a major upgrade of the air shower simulation tool COSMOS, which has been developed since 1970’s. To be compatible with the environment of the modern personal computers, COSMOS X can be compiled with gfortran and intel fortran helped by cmake. In addition to the earth’s atmosphere, particle tracking in the arbitrary spherical media with a common center is available with COSMOS X. This allows seamless simulations in air, water, ice, soil, concrete and also simulations in the atmosphere of stars and planets. For the design of new experiments and calculations of cosmic-ray interactions in the non-earth environments, COSMOS X opens wide possibilities. Basic functions and some interesting applications of COSMOS X are presented in the conference.