Effect of Orbit Parameters on Manned Spacecraft Impact Risk Against Orbital Debris

The Meteoroid and Orbital Debris Risk Assessment and Shielding System (MODRASS) is used to simulate and assess the impact risk of manned spacecraft against orbital debris. The influencing factors of the impact risk of manned spacecraft include orbit inclination angle, orbital altitude and spacecraft attitude. It is shown that different inclination angles affect the impact risk of manned spacecraft against orbital debris in the orbit in the manner that in the orbit with 170° inclination angle, the manned spacecraft may encounter the most frequent collisions; in the orbit with inclination angle between 20° and 60° and also near 110°, the impact risk would decrease greatly. The collision risk at different orbital altitudes could have a difference of above 10 times. At the orbital altitude of 1400km, the manned spacecraft would encounter most frequent collisions; however, at the orbital altitude of 200km, the number of collisions is reduced to 410881, a difference of two orders of magnitude.. In addition, the operating attitude of the manned spacecraft also affects the impact risk against the orbital debris and the collision area. So adjusting the operating attitude of the manned spacecraft can reduce the threat of orbital debris.