Capture of small near-Earth asteroids to Earth orbit using aerobraking

This paper investigates the concept of capturing near-Earth asteroids into bound orbits around the Earth by using aerobraking. To guarantee that the candidate asteroids cannot present an impact risk during aerobraldng, an initial aerobraking hazard analysis is undertaken and accordingly only asteroids with a diameter less than 30 m are considered as candidates in this paper. Then, two asteroid capture strategies utilizing aerobraking are defined. These are termed single-impulse capture and bi-impulse capture, corresponding to two approaches to raising the perigee height of the captured asteroid's orbit after the aerobraking manoeuvre. A Lambert arc in the Sun-asteroid two-body problem is used as an initial estimate for the transfer trajectory to the Earth and then a global optimisation is undertaken, using the total transfer energy cost and the retrieved asteroid mass ratio (due to ablation) as objective functions. It is shown that the aerobraking can in principle enable candidate asteroids to be captured around the Earth with, in some cases, extremely low energy requirements.