Orbital Transfer System Research Articles

Robust optimization of the design of monopropellant propulsion control systems using an advanced teaching-learning-based optimization method

This research proposes a novel approach for the robust optimization of the design of hydrogen peroxide propulsion control systems using the efficient and advanced Teaching-Learning-Based Optimization (TLBO) method. This study adopts a robust design optimization (RDO) formulation that considers both epistemic and aleatory uncertainties, including sparse points and interval data, and uses the Johnson distribution family for uncertainty representation. The maximum likelihood estimation method is applied to determine the distribution parameters, also considering interval data with a nested optimization technique. A novel advanced TLBO method with high accuracy and convergence rate is employed to optimization of this robust design approach. The method’s originality and advancement come from two categories of modifications to the original framework: the structure of the teaching and learning phases and the initialization and search approach. The efficacy and applicability of the proposed Ad-TLBO, respectively, were evaluated using benchmark problems from the CEC2020 competition and three real-world engineering problems, with a comparison to some recently published and the CEC competition’s top-ranked algorithms. The results and statistical analyses of the Quade test, Wilcoxon signed-rank test, and Friedman test show that the proposed Ad-TLBO method outperforms the other algorithms. The proposed optimization method is eventually applied to design a monopropellant propulsion system as the control actuator of a satellite orbital transfer system. It is found that the proposed advanced TLBO is effective in handling uncertainty in real design problems and improves both the convergence rate and accuracy of the optimization process.

Performance and Applicability of Orbital Transfer with Bare Electrodynamic Tether

Electrodynamic tether technology is a novel way to perform spacecraft orbital transfers. This paper focuses on a bare electrodynamic tether (BEDT) system and evaluates its orbital transfer performance and mission applicability. A nonsingular dynamic model of the BEDT orbital transfer system is developed. In particular, the ambient perturbation forces, including the atmospheric drag and Earth oblateness effect, are taken into account. Numerical simulations are then performed to investigate the orbital transfer performance under various mission parameters involving the initial orbital altitude, initial orbital inclination, tether length, tether diameter, spacecraft mass, and power voltage. An orbital transfer scheme is designed to raise and regulate the orbit. Furthermore, to verify its practicability, the mission applicability of the BEDT system is analyzed for Ariane-4’s H10 upper stage by comparison with the conventional chemical propulsion method. Finally, the conclusions and some discussions are presented to support conducting BEDT-based orbital transfer mission planning in practice.

Space debris removal system using a small satellite

Since the number of satellites in Earth orbit is steadily increasing, space debris will eventually pose a serious problem to near-Earth space activities if left unchecked, and so effective measures to mitigate it are becoming urgent. Equipping new satellites with an end-of-life de-orbit or orbital lifetime reduction capability could be an effective means of reducing the amount of debris by reducing the probability of the collisions between objects. On the other hand, the active removal of space debris and the retrieval of failed satellites by spacecraft are other possible measures. The Institute of Aerospace Technology, Japan Aerospace Exploration Agency (JAXA), is studying a micro-satellite system for active space debris removal, and is examining the applicability of electro-dynamic tether (EDT) technology as its high efficiency orbital transfer system. A small EDT package provides a possible means for lowering the orbits of objects without the need for propellant. Capture is indispensable for the retrieval of large space debris objects, and we propose a flexible robot arm for this purpose. This paper discusses a space debris removal satellite system and describes the development status of prototypes of the EDT package and a new robot arm for capturing non-cooperative targets.

Deployment of an Electrodynamic Tether from a Small Satellite

As an effective countermeasure for suppressing space debris growth, the Aerospace Research and Development Directorate, Japan Aerospace Exploration Agency (JAXA) has been investigating an active space debris removal system that employs highly-efficient electrodynamic tether (EDT) technology as its orbital transfer system. A test flight experiment using a small satellite is planned for establishing and demonstrating the EDT technology. Precise tether dynamics during deployment phase is investigated in this study by numerical simulations in which the coiling of the tether is taken into consideration. The results of the simulation showed that the tether length becomes shorter than the full tether length when the coiling of the tether is severe. The in-plane libration angle of the tether grows larger when the spring constant of the coiling of the tether is specific value. The attitude motion of a mother satellite is less stable when the spring constant of the coiling of the tether is small because of the large tether tension.

Analytical Evaluation of Orbit Transfer Performance of Hybrid Tether System from LEO to GEO

This study presents an analysis that seeks to optimize the performance of a LEO-GEO Orbit Transfer System using tethers. We propose a new rotational tether transfer system with an electrodynamic tether (EDT) for orbit transfer from LEO to GEO. The EDT is used for orbit restoration to the initial orbit after release of the payload. The EDT can be propelled without propellant, so the total system mass is expected to be much lower than that of a conventional system with ion thrusters for orbit restoration. In addition, a balance tether is also used as a rotational tether so that the EDT can be attached to the platform, and the center of mass of a balance-tether system is on the platform when the payload is not attached. For transfer from GTO to GEO, we compared three types of transfer system: chemical propulsion; ion thrusters; and a rotational tether. The results of the mission analysis show that the EDT-balance tether hybrid system can reduce total system mass by almost 30% compared to an ion thruster-balance tether combination for the same mission. The results also show that there is an optimum mission interval for each transfer method from GTO to GEO.

Precise numerical simulations of electrodynamic tethers for an active debris removal system

As a countermeasure for suppressing space debris growth, the Institute of Space Technology and Aeronautics, Japan Aerospace Exploration Agency (JAXA), is investigating an active space debris removal system that employs highly efficient electrodynamic tether (EDT) technology as its orbital transfer system. A small, expendable EDT package is under development that consists of a bare conductive tether and field emitter cathodes (FECs) that utilize carbon nanotubes. First, the status of the trial manufacture of the bare tether, reel mechanism, and the FECs are described. Some tests for example for measuring tensile strength and thermal expansion have been conducted on the tether. Next, precise numerical simulations are performed for some aspects of mission analysis, such as available electric currents, orbital changes, tether stability, and deployment dynamics. A tether is modeled as a lumped mass to take into account tether flexibility, and environment models (changes in the plasma density and geomagnetic field, and so on) are also considered. Measured parameters of the manufactured tether described above are reflected in the numerical simulations. Differences between the precise and simple models are compared and discussed.

エレクトロダイナミックテザーとモーメンタムテザーを使った混成軌道間輸送システムに関する研究

An orbit transfer system that transports a payload from LEO to GEO using spinning-momentum-tether is introduced in this paper. This system is analyzed in consideration of the change of the angular velocity before and after the catch or the release of the payload for the various parameters of the tether system. The time and the propellant mass required for reboosting the stage are also calculated in detail. As the new thruster for reboosting, the electrodynamic tether (ED tether) system is considered in this study and this system is compared with the conventional ion-thruster system. In addition, the total system mass is optimized for the mission interval that the next transportation of a payload is possible. The results also show that ED tether system can reduce the total system mass compared with ion-thruster system for the same orbit transfer mission.

Study on electrodynamic tether system for space debris removal

As a countermeasure for suppressing space debris growth (P. Eighler, A. Bade, Chain Reaction of Debris Generation by Collisions in Space—A Final Threat to Spaceflight? in: 40th Congress of the International Astronautical Federation, IAA-89-628, October 1989), the National Aerospace Laboratory of Japan is investigating a satellite capture, repair and removal system for non-cooperative satellites, part of which involves assessing the viability of electrodynamic tether (EDT) technology as an orbital transfer system. In this paper, some results concerning the time required to remove existing satellites, the behavior of flexible tethers during the debris separation phase, and orbital transfer strategies of EDT systems during space debris removal operations are described. From numerical simulations, it is found that EDT systems can transfer satellites from LEO to orbits with a short lifetime within a realistic timeframe. It is also found that the stability of EDT systems is compromised when debris separation occurs both while a tether current is running and when the ratio of the end mass to that of the service satellite is high. To ensure stability, the end mass should be selected from the target debris group with due regard for the maximum possible mass that can be maneuvered safely. Moreover, it is also found that orbital elements (a, e, i) can be changed independently with an adequate current control strategy.

Performance Optimization of a Multi-Stage Spinning-Balance Tether Orbit Transfer System

An orbit transfer system that transports a payload from LEO to GEO using multi-stage spinning tethers is studied in this paper. We propose a tether configuration called “Balance Tether.” The variations in the total mass and mission duration of the system are analyzed for different numbers of stages and different lengths of tethers. In addition, the possibility of debris impact damaging each of several tether system configurations is also analyzed. As a result, we obtain the guidelines for a system design that minimizes total system mass while also taking into account the system lifetime as limited by debris impact. In addition, it is shown that the Balance Tether can reduce the total system mass compared to a single-tether system. The results also show the effectiveness of the spinning-tether system as compared to a conventional chemical propulsion system for the same orbit transfer mission.

Analytical Study of the Performance of Electrodynamic Tether Orbit Transfer System with Consideration of Lifetime by the Impact of Space Debris.

The performance of an elecrodynamic tether orbit transfer system was analyzed in consideration of the tether lifetime in relation to the possible impact of debris to examine the possibility of its application to round-trip transportation missions between near-earth orbits. The mass, the electric power, and the mission duration of a tether orbit transfer system were determined by using the operating principles of an electrodynamic tether, with the mission analysis based on a simplified orbit transfer analysis model of a low-thrust thruster for representative parameters. The results were compared with those of an ion thruster orbit transfer system. A tether lifetime was determined by using a “ORDEM96” space debris model produced by NASA and the relation of impact cross-section between tether wire and debris. The results showed the existence of a lower limit of mission duration for each altitude of arrival orbit and a higher limit of arrival orbit altitude for each mission duration, and the increase of tether length or the number of tethers was not necessarily effective in regard to tether lifetime and the possibility of debris impact. The results also showed that the tether orbit transfer system had a mass advantage when compared to the ion thruster orbit transfer system for the same missions up to an altitude of 6,000 km.

Performance Analysis of Electrodynamic Tether Orbit Transfer System for Round Trip Mission

Performance Analysis of Electrodynamic Tether Orbit Transfer System for Round Trip Mission

太陽発電衛星開発における電気推進輸送システム エネルギー投資の観点からの評価

The electric propulsion orbit transfer system for using the development of Solar Power Satellite (SPS) is evaluated from the point of view of energy investment. First, the energy cost of total SPS system is analyzed for the cases that the electric propulsion or the chemical propulsion is used as an orbit transfer system of SPS. Then, the minimum energy investment ratio in SPS to the total energy consumption on the earth in which the high levels of population and capital on the earth can be maintained is estimated by the evaluation model of SPS using World Dynamics. The simulation results show that about 12-18% reduction of energy investment ratio is possible in the case that the electric propulsion is used compared with in the case that the chemical propulsion is used as an orbit transfer system of SPS.

Orbital transfer systems for lunar missions

For future Lunar mission operations basically two types of transfer systems can be conceived (a) the conventional direct-injection expendable vehicle approach, and (b) the re-usable orbit-to-orbit (LEO-LLO-LEO round-trip system. The second solution has been studied in Europe in the SPACE TUG Phase A Study in 1971/72 for NASA as a fully reusable system and this is compared to a more recent NASA-MSFC transfer vehicle concept with expendable propellant tanks and aerobraking. The results of an analysis on mission opportunities for LEO-LLO transfers is presented. A European option is also shown for mode (a), using the ARIANE 5 for lunar missions with an optimized cryogenic transfer vehicle, derived from the H.10 Stage (ARIANE 4) plus a lunar vehicle derived from the MMII-CRAF propulsion module using the 27.5 kN engine from the ARIANE L.9 Stage which could land a 3.4 ton vehicle on the lunar surface. Finally a completely new option (c) is discussed: the use of a ballistic SSTO vehicle for lunar landing missions after refuelling in LEO. This seems to be a highly effective single transportation element approach compared to the seven elements SATURN V-APOLLO-LM system of the 60ies.

Space-based orbital transfer vehicle

The objectives of the Orbital Transfer Vehicle (OTV) Concept Definition and Systems Analysis study, conducted by General Dynamics Space Systems Division under company funds with data provided to NASA-MSFC, were to define the requirements, concepts, and evolutionary approaches for development of an OTV for reusable operations to GEO and beyond, including manned access; assess the requirements of space basing; and define the interaction between the OTV and Space Station. The study focused primarily on answering fundamental OTV questions: whether the OTV should be reusable or expendable; ground-based or space-based; cryogenic or storable; delivered in the STS cargo bay or the ACC; single-stage, two-stage, or with modular tanks; aeroassisted or all-propulsive; and whether it should use a new advanced engine or an RL-10 derivative. Major effort centered on concept generation, evaluation, and selection; operations and Space Station accommodations; system analysis and evaluation; and program definition. Study findings show that mission requirements and substantial economic benefits justify a reusable, cryogenic H 2 O 2 ), space-based OTV. The success of the Space Shuttle has demonstrated the effectiveness of reusable launch vehicles to Low Earth Orbit. With reusability extended to OTVs and with the coming of the Space Station, a new era in orbital transfer operations will offer lower cost for payload users and open the way for manned exploration of the solar system.

Concepts for, and Utility of, Future Space Central-Power Stations

T rate of industrial development in space is largely dependent on the cost of transportation to, through, and from space and the cost of electrical power in space. The technological and economical impact of a large central-power station in Earth orbit on the cost and performance of future spacecraft and their orbital-transfer systems has been examined. Analysis of the cost effectiveness of meeting Earth-orbiting spacecraft electrical power demands from a central-power station indicates that this application cannot justify the investment required for the central station. However, laser-thermal and laser-electric propulsion systems powered from a central-power station promise major cost savings when compared to orbital-transfer vehicles using advanced, conventional, chemical, and solar-electric propulsion—at least within the bounds of the assumptions made.

Space escalator, semi-perpetual motion in space

A novel orbital transfer system using the mutual action-reaction of two spacecraft as the main propulsive force is proposed. A set of space platforms which are deployed on circular orbits of various altitude and have mobility to transfer to other orbits by themselves can work on a very little propellant.