Articulated linkage arms based reliable capture device for janitor satellites

Abstract

As the number of operational satellites in orbit has dramatically increased, orbiting space debris has become a serious problem. To solve this problem, de-orbiter studies have been conducted to eliminate space debris and inactive satellites. Other studies have proposed the use of janitor satellites which capture and deorbit inactive satellites. This study further develops the janitor satellite idea and proposes a specific capture device design to retrieve space debris and obsolete orbiting devices. In order to capture a wide range of target objects with various sizes and shapes securely, the proposed design features articulated arms consisting of a series of jointed segments. Each segment in the arm structure is a different length, which allows the device to capture targets of different sizes. The device linkages are driven by two motors pulling on a Kevlar cord, and a latching mechanism is employed as a redundant component in the event the Kevlar cord loses tension, ensuring continuous operation. A static analysis is performed to determine the motor power for capture device and force requirements for latching mechanism. Based on the results of theoretical analysis, the capture device is fabricated, and functional tests are carried out. In addition, the reliability of the capture device is investigated based on reliability analysis using one-shot device evaluation method. As a result, device reliability rate was calculated as 0.999841. Conclusively, more than 20 times deployment and capturing experiments are successfully performed.