Active Space Debris Removal Based On Laser Technology

With theory and technology of space grow mature gradually, human activities of space exploration become more frequently. Since the first artificial earth satellite has been launched, human space launch activities have got rapid development and great success. At the same time, a large number of space debris have been produced in earth orbit. The normal human space activities have been affected by the increasing space debris. In addition to the growing space debris will cause severe harm to the space station and other orbiting spacecraft. So, how to slow down or active remove space debris is the critical issues. This paper is mainly focused on method of space debris removal using ground-based laser, and the theoretical analysis and simulation is preformed.In this paper, firstly, the composition of ground-based laser and the work flow of remove space debris are introduced. The laser removal space debris uses high energy laser to ablate the surfaces of space debris, and get the blow-off impulse, thus reduce orbit speed and perigee altitude of space debris. When the space debris migrate to line of the center of the earth and ground-based laser, we call it pass. Because the energy and power density of laser space debris are removed will not succeed, which space debris after one laser irradiation or one pass. Space debris need more laser irradiation or multiple passes. Before a laser irradiation, until the perigee altitude of space debris reach the critical value of burn in the atmosphere. At this moment, the space debris are considered to burn up in the atmosphere. And the space debris are removed successfully.Then, according to basic principles, the model of laser removal space debris is build.And the two scenarios are considered, which the initial orbit of space debris is circular orbit and elliptical orbit. Because the laser in the atmosphere will affect by a series influence of atmosphere, such as atmospheric absorption, scattering, turbulence and atmospheric nonlinear effects, comprehensive analysis these influencing factors. Then,according to the simulation results, calculate the laser pulse number of laser removal a piece of space debris, and compute the pass number of space debris. Finally, the two scenarios are researched, which the same laser remove the different space debris and the different lasers remove the same space debris, and analyses and compares the removal effect of them.The results show that removal Na/K coolant debris with a orbit altitude of 870 kmused a 30 kw average power, 15 kJ pulse energy, 2Hz repetition rate, 10 ns pulse duration laser, the space debris need five passes, the number of laser pulse is 174 and the time of laser pulse is 87.5 seconds. The simulation results show that the laser pulse number decreased with the rise in velocity increment, impulse coupling of space debris and average power, pulse duration of laser. The laser pulse number increased with increasing orbit altitude of space debris and repetition rate of laser. The pass number increased with decreasing orbit altitude of space debris and pulse duration of laser. Therefore, the ground-based laser parameters selection have been provided by these study results.