LAUSR

Asteroids are scientific windows for understanding the universe while having enormous economic value. Instead of merely bringing back a small sample, capturing an asteroid into earth's orbit is one of the most promising ways to explore and subsequently exploit space. In this article, the authors study the process of capturing an asteroid using a flexible net spacecraft (FNS). The net capture dynamics, comprising the net and nonlinear contact dynamics models, are constructed for the asteroid mission. The sliding mode control is applied for designing the controllers of the FNS. Numerical simulations show that the asteroid 101955 Bennu can be fully enveloped using a spider-shaped FNS around a kilometer diameter. During the capture mission, the opening area of the FNS gradually decreases, which is much smaller than the projected area of the asteroid at the end of the capture; the elongation rate of each net thread in the FNS is far less than its material's endurable value; and the actuators in the FNS have not collided with each other, thus selfdestruction does not happen. All of these results suggest the feasibility of the FNS for the asteroid capture mission.