The idea of a Digital-Twin has received a lot of attention in the field of space travel. A Digital-Twin, which enables real-time monitoring, analysis, and predictive modeling, is a virtual replica or simulation of a real system, such a spacecraft. This article aims to describe a new concept, the Digital-Twin, and show how it can be used for space missions. Using Free Open Source Software, the main purpose is to simulate the spacecraft going to Mars with a solar sail and create a digital copy of the mission by getting realistic results. Diagrams of open source programs used to solve problems that may be encountered in this process are included.