A chain of tether-connected payload masses assembled from the surface material of a spherical rotating asteroid is envisaged as a means of delivering a fraction of the asteroid mass into orbit, without the need of external work to be done. Under conditions to be discussed, a net radial force is established on the chain which can be exploited to initialize an orbital siphon effect: new payloads are connected to the chain while top payloads are removed and released into orbit. Adopting simplifying assumptions, the underlying dynamics of the problem is entirely analytical and is investigated in detail. The amount of mass extractable from the asteroid is then discussed, according to a range of strategies. It is proposed that the scheme could in future provide an efficient means of extracting material resources from rotating Near Earth Asteroids.

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.

The orbital siphon is a novel concept for propellantless payload transfer from the surface of a rotating body to orbit. In the context of asteroid mining, the orbital siphon represents an e cient solution to deliver mined material from the asteroid surface to an orbiting station for later processing or storage. The key idea is that the centrifugal-induced force exerted on a tether-connected chain of payload masses assembled from the surface of a rotating body can be large enough to pull the lower masses, to initialize an orbital siphon e ect: new payloads are connected to the chain while upper payloads are removed. In this paper, the dynamics of an orbital siphon anchored to two irregularly shaped near-Earth asteroids is investigated. The siphon is modelled as a closed chain of tether-connected buckets, kept taut by two pulleys,

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A novel concept for the deflection of rotating asteroids is presented, based on the conversion of the asteroid rotational kinetic energy into translational kinetic energy. Such conversion is achieved using an orbital siphon, a tether-connected chain of masses, arranged vertically from the asteroid surface, which exploits the rotation of the asteroid for the delivery of mass from the asteroid to escape. Under the conditions to be discussed, the siphon can be initiated to ensure self-sustained flow of mass from the asteroid to escape. This mechanism is proposed to use a fraction of the asteroid as reaction mass, with the asteroid rotational kinetic energy leveraged to deliver the mass to escape and hence impart a reaction on the asteroid itself. Key parameters, such as velocity change, deflection duration, tension requirements and siphon length, are discussed. Deflection e ectiveness is assessed for di erent release strategies. It is shown that typical velocity changes on the order of 1 cm s 1 can be achieved within a time window of a decade.