Roger Förstner

Mission concept selection for an asteroid mining mission

Purpose The paper aims to introduce a trade-off method for selecting a mission concept for an asteroid mining mission. In particular, the method is applied to the KaNaRiA mission concept selection. After introducing the KaNaRiA project, the KaNaRiA mission concept selection and reference scenario are described in detail. Design/methodology/approach The paper introduces past relevant asteroid missions in general and the previous studies on asteroid mining in particular. Based on the review of past mission concepts to minor planets, the paper discusses the operational phases of a potential industrial and commercial space mining mission. The methodology for selecting a mission reference scenario is explained and the selected KaNaRiA mission scenario is described. Findings The key technology driver for a space mining mission is the autonomous on-board capability related to navigation, guidance and handling of hardware/software anomalies or unexpected events. With the methodology presented here, it is possible to derive a mission concept which provides an adequate test-bed for the validation and verification of algorithms for enhanced spacecraft autonomy. This is the primary scientific and engineering goal of the KaNaRiA project. Practical implications The mission concept selection method presented here can be used as a generalized approach for mining missions targeting asteroids in the solar system. Originality/value The availability and usage of space resources is seen as a possible solution for the imminent problem of diminishing terrestrial materials in the foreseen future. This paper explains a methodology to select mission concepts for asteroid mining missions.

The far-infrared space interferometer study IRASSI: motivation, principle design, and technical aspects

The far-infrared (FIR) regime is one of the few wavelength ranges where no astronomical data with sub-arcsecond spatial resolution exist yet. Also medium-term satellite projects like SPICA, Millimetron or OST will not resolve this malady. For many research areas, however, information at high spatial and spectral resolution in the FIR, taken from atomic fine-structure lines, from highly excited CO and especially from water lines would open the door for transformative science. These demands call for interferometric concepts. We present here first results of our feasibility study IRASSI (Infrared Astronomy Satellite Swarm Interferometry) for an FIR space interferometer. Extending on the principal concept of the previous study ESPRIT, it features heterodyne interferometry within a swarm of 5 satellite elements. The satellites can drift in and out within a range of several hundred meters, thereby achieving spatial resolutions of <0.1 arcsec over the whole wavelength range of 1–6 THz. Precise knowledge on the baselines will be ensured by metrology employing laser frequency combs, for which first ground-based tests have been designed by members of our study team. In this contribution, we first give a motivation how the science requirements translated into operational and design parameters for IRASSI. Our consortium has put much emphasis on the navigational aspects of such a free-flying swarm of satellites operating in relatively close vicinity. We hence present work on the formation geometry, the relative dynamics of the swarm, and aspects of our investigation towards attitude estimation. Furthermore, we discuss issues regarding the real-time capability of the autonomous relative positioning system, which is an important aspect for IRASSI where, due to the large raw data rates expected, the interferometric correlation has to be done onboard, quasi in real-time. We also address questions regarding the spacecraft architecture and how a first thermomechanical model is used to study the effect of thermal perturbations on the spacecraft. This will have implications for the necessary internal calibration of the local tie between the laser metrology and the phase centres of the science signals.

Simulation Environment for the Rendezvous Path and Abort Trajectory of ADReS-A

The threat of space debris to operational satellites is a growing concern for satellite op- erators. Large objects with high collision probability, e.g. rocket bodies and non-functional satellites on highly frequented orbits, form hereby the largest source for the debris’ increase in number. Various ideas on how to remove those objects have been proposed, always point- ing out, that the handling of an uncooperative target comes with many difficulties. Being in close vicinity, the spacecraft relies on its on-board sensors to calculate relative position and velocity. A flawless connection to ground control cannot be ensured and is, moreover, time consuming, which creates the need for high-level autonomy and on-board processing of the spacecraft. The idea of implementing autonomy in spacecraft in general has been followed for some time, however, requirements for a specific implementation need to be de- rived from a designated mission architecture. Therefore, this paper introduces the concept of ADReS-A, short for Autonomous Debris Removal Satellite #A, its mission architecture and a first approach of how to visualize the rendezvous path of the satellite and the abort in case of a failure. The simulation shall serve as a testbed for the coming autonomy and is based on the sensor data of ADReS-A, derived from the spacecraft preliminary design, also presented briefly within this work.

Mission Architecture for active Space Debris Removal using the Example of SL-8 Rocket Bodies

Space debris has become a serious problem for the safe operations of spacecraft in low Earth orbit. Attempts such as improving trajectory predictions of non-functional objects in space, guidelines for safer launches nowadays, and an implementation of post-mission disposal however will not stop the growth in debris numbers. One solution for mitigation is therefore the realization of removal missions.Due to space debris being an issue for all space faring nations, this paper introduces an exemplary removal mission for 5 Russian SL-8 rocket bodies at an inclination of 83∘ orbiting at an altitude of 970 km - an area crowded with space debris and thus involving a high collision risk.The mission draft presented is based on a main satellite (Autonomous Debris Removal Satellite - ADReS-A) and - according to the number of targets - 5 de-orbit kits. The idea presented includes a parking orbit close to the targets positions, into which the set-up is launched. While the kits are equipped with a de-orbit thruster, the task of ADReS-A is, to approach the uncooperative target, berth it, stabilize the compound system and attach the de-orbit kit onto the target. The main satellite will take each de-orbit kit separately to the individual targets, shuttling between the parking orbit and the target orbits.A prospect addressing the highly critical situations resulting from the interaction with an uncooperative target is given towards the end of the paper with a preliminary design for a decision process for autonomy.