Satellite & Space Missions

Biography

Biography: Zhang Rong Zhi

Abstract

More than 23,000 space objects around the earth orbits in total are regularly tracked by the space surveillance network and maintained in the catalogue, which cover objects whose size are larger than approximately 5 to 10 cm in low earth orbit (LEO). Most of these space objects, especially the size of only several centimeters, are called space debris which are very dangers for in-orbit operational spacecraft because of potential collision. Space debris collision avoidance has almost been a routine activity for incapable space powers for the purpose to ensure the security of their spacecraft operation. In view of the current engineering and technological basics, the confidence level of collision warning is still to be further improved. In engineering, both the ability of tracking space objects of surveillance network and the integrality of measuring data limit the accuracy of orbit determination of space objects. But according to current technologies, the prediction accuracy of orbit dynamics model, especially low orbit atmospheric model, seriously decreases the accuracy of precise orbit prediction with time prolongs. On one hand, the shorter the time duration between the prediction and potential and potential collision is, the higher confidence level of the collision avoidance warning will be. On the other hand, the preparation procedure of spacecraft maneuver and the power consumption budget require collision avoidance to be made earlier. This paper focuses on the selection of the optimum time for spacecraft collision avoidance operation.