With an increasing satellite population, the accurate prediction of spacecraft trajectories becomes crucial for space situational awareness. It becomes necessary to estimate aerodynamic coefficients in the free-molecular flow and transitional flow regimes, to get a precise orbital trajectory by predicting the drag force perturbation. For LEO orbit satellites, the drag force perturbation comes second in magnitude after the gravitational disturbance due to Earth's topography. Traditionally, Direct Simulation Monte Carlo (DSMC) simulations are performed to quantify free-molecular aerodynamics but those can be time-intensive and cumbersome to perform. Hence, a quick tool to estimate these coefficients is developed, which intakes the external geometry of the spacecraft in Standard Triangle Language (STL) format, the orientation information of the spacecraft and the external environment conditions. The estimation of these free-molecular aerodynamic coefficients is also affected by the Solar flux cycles and Earth's Geomagnetic activity. The Spacecrafts that are meant to de-orbit within one solar cycle show significant variation in de-orbit times, with respect to the date of de-orbit initiation within the solar cycle; being fastest near the solar maxima. These coefficients can be further used to estimate the life of a spacecraft, design its decay trajectory and also to quantify perturbations in orbit. Through analysis, it is inferred that the drag coefficient (CD) varies substantially with spacecraft attitude. Validation of the tool is performed with literature data and DSMC results.