Dynamic analysis and motion control of spinning tether system during its Earth to Mars flight

The dynamic analysis and motion control of a spinning tether system for an interplanetary mission to Mars is considered. The space system consists of two spacecraft connected by a tether with thrusts to control its movement. The movements of the tether system in the sphere of action of the Earth, on the interplanetary trajectory and in the sphere of action of Mars are consistently analyzed. In near-Earth orbit, the transfer of the system into rotation with the help of jet engines installed on the end spacecrafts is considered. The spin of the system is used to create artificial gravity during the interplanetary flight. The tether system spins in the plane perpendicular to the plane of the orbital motion of the center of mass of the system. To describe spatial motion of the system, a mathematical model is used, in which the tether is represented as a set of material points with viscoelastic unilateral mechanical connections. When calculating the movement of the system, an approach based on the method of spheres of action is used. Spacecrafts are considered as material points. The level of gravity and spin of tether system is controlled by thrusters. The structure of the controller for controlling the angular speed of rotation of the tether system is proposed. The simulation results are presented to confirm the effectiveness of the proposed control algorithm, which provides a given level of artificial gravity for th e interplanetary mission under consideration.

The Comet Interceptor Mission

<div>Comet Interceptor was selected in 2019 as the European Space Agency's next planetary mission, to which the Japanese space agency, JAXA, will make a major contribution. The mission is ESA's first Fast (F) project, and its primary science goal is to characterise, for the first time, a long period comet, preferably dynamically-new, or an interstellar object. An encounter with one of these objects for the first time will provide valuable data to complement that from all previous comet missions, which have by necessity studied short-period comets that have evolved during their time orbiting near the Sun from their original condition. Planned measurements of the target include its surface composition, shape, and structure, its dust environment, and the composition of the gas coma. A unique, multi-point ‘snapshot’ measurement of the comet- solar wind interaction region is to be obtained, complementing single spacecraft observations made at other comets. The spacecraft will be delivered to Sun-Earth Lagrange Point L2 with the ESA Ariel mission in 2029, a relatively stable location suitable for later injection onto an interplanetary trajectory to intersect the path of its target. A suitable new comet would be searched for from Earth prior to launch, and after launch if necessary, with short period comets serving as a backup destinations. With the advent of powerful facilities such as the Vera Rubin Observatory, the prospects of finding a suitable comet nearing the Sun are very promising. The possibility may exist for the spacecraft to encounter an interstellar object if one is found on a suitable trajectory. When approaching the target, two sub-spacecraft – one provided by ESA, the other by JAXA, would be released from the primary craft. The main spacecraft, which would act as the primary communication point for the whole constellation, would be targeted to pass outside the hazardous inner coma, making remote and in situ observations on the sunward side of the comet. The two sub-spacecraft will be targeted closer to the nucleus and inner coma region. We shall describe the science drivers, planned observations, and the mission’s instrument complement, to be provided by consortia of institutions in Europe and Japan.</div>

A Unified Framework for Aerocapture Systems Analysis

A unified framework for aerocapture systems analysis studies is presented, taking into account the interconnected nature of interplanetary trajectory design and vehicle design. One of the limitations of previous aerocapture systems studies is their focus on a single interplanetary trajectory for detailed subsystem level analysis. The proposed framework and aerocapture feasibility charts enable a mission designer to perform rapid trajectory and vehicle design trade-offs, and is illustrated with its application to a Neptune mission. The approach can be applied to other atmosphere-bearing Solar System destinations. The framework can be be implemented in an aerocapture software suite to enable rapid mission design studies.