Abstract This paper investigates the dynamics of an orbital siphon anchored to a rotating ellipsoidal asteroid. The siphon is a chain of tether-connected payload masses arranged vertically from the asteroid surface, envisaged for propellantless delivery of payloads (e.g., mined material) from the asteroid surface to a collecting spacecraft. If the structure is long enough, the centrifugal-induced force can overcome the gravitational force on the payloads, eventually allowing resource payloads to escape. By connecting new payloads at the bottom of this chain while removing upper payloads a net orbital siphon effect is established, which provides a net continuous flow of resources from the asteroid surface to a collecting spacecraft, attached at the top of the siphon. The dynamics of the siphon is investigated in detail by varying a set of relevant parameters, in particular, chain length, anchor location and asteroid shape. It is shown that the system exhibits oscillatory behaviour in the equatorial plane, with decreasing oscillation amplitude over time and that the longest equatorial end is the best anchor location to guarantee proper siphon operation while minimizing the chain length. Eventually, a method is proposed to exploit the equatorial Coriolis-induced oscillations of the siphon to transfer payload masses from the collecting spacecraft to the stable equilibrium points associated with the effective potential of the ellipsoidal asteroid, where a catcher would collect the material.

Highlights • Dynamics of orbital siphon anchored at ellipsoidal asteroid is studied. • Anchoring at longest equatorial end minimizes siphon length. • Siphon exhibits damped oscillatory behaviour. • Stable equilibrium points can be used as gravitational depots.