Docking Mission Research Articles

Design and implementation of China’s manned rendezvous and docking technology

In the first step of the second phase of Chinas manned space program, China independently developed Tiangong-1, Shenzhou-8, Shenzhou-9 and Shenzhou-10 spacecrafts. Through three in-orbit spaceflight missions, China successfully completed eight rendezvous and six docking missions covering various autonomous and manual modes of rendezvous and docking (RVD), and eventually made a breakthrough and mastered the RVD technology. From the aspects of RVD system, rendezvous orbit, rendezvous measurement and control, information transmission, docking and separation, flight plan and experimental verifications, this paper introduces the technology characteristics, innovation technology methods, and technical problems solved in Chinas RVD. Based on the flight tests, this paper also analyzes the achievements made by the mission and compares them with international levels. Finally the design and development conditions of Chinas RVD technology are summarized.

Survey of orbital dynamics and control of space rendezvous

Rendezvous orbital dynamics and control (RODC) is a key technology for operating space rendezvous and docking missions. This paper surveys the studies on RODC. Firstly, the basic relative dynamics equation set is introduced and its improved versions are evaluated. Secondly, studies on rendezvous trajectory optimization are commented from three aspects: the linear rendezvous, the nonlinear two-body rendezvous, and the perturbed and constrained rendezvous. Thirdly, studies on relative navigation are briefly reviewed, and then close-range control methods including automated control, manual control, and telecontrol are analyzed. Fourthly, advances in rendezvous trajectory safety and robust analysis are surveyed, and their applications in trajectory optimization are discussed. Finally, conclusions are drawn and prospects of studies on RODC are presented.

Study on Trajectory Planning for Space Simulator Based on Minimum Acceleration Limitation

Trajectory planning and simulation of docking tests on the ground for space simulator is one of key technologies to complete space docking mission. A new time-optimal trajectory planning algorithm is proposed based on minimum acceleration limitation. It is realized by searching maximum acceleration to obtain the best time according to PSO (particle swarm optimization). Through calling matlab script by LabView and capturing control set points, 3D CAD model is driven to verify the rationality of the trajectory planning algorithm and model design. The simulation results show that the simulator using the proposed algorithm can move smoothly and reliably meeting the experiment requirements.

Space shuttle testing of the TriDAR 3D rendezvous and docking sensor

AbstractThis paper presents results from the first two Space Shuttle test flights of the TriDAR vision system. TriDAR was developed as a proximity operations sensor for autonomous rendezvous and docking (AR&D) missions to noncooperative targets in space. The system does not require the use of cooperative markers, such as retro‐reflectors, on the target spacecraft. TriDAR includes a hybrid three‐dimensional (3D) sensor along with embedded model based tracking algorithms to provide six‐degree‐of‐freedom (6 DOF) relative pose information in real time. A thermal imager is also included to provide range and bearing information for far‐range rendezvous operations. In partnership with the Canadian Space Agency (CSA) and NASA, Neptec has space‐qualified the TriDAR vision system and integrated it on board Space Shuttle Discovery to fly as a detailed test objective (DTO) on the STS‐128 and STS‐131 missions to the International Space Station (ISS). The objective of the TriDAR DTO missions was to demonstrate the system's ability to perform acquisition and tracking of a known target in space autonomously and provide real‐time relative navigation cues. Knowledge (reference 3D model) about the target can be obtained on the ground or in orbit. Autonomous operations involved automatic acquisition of the ISS and real‐time tracking, as well as detection and recovery from system malfunctions and/or loss of tracking. © 2012 Wiley Periodicals, Inc.

Comparison of filter techniques for relative state estimation of in-orbit servicing missions

Future in-orbit servicing missions will require autonomous in-orbit approach and coupling with a non-cooperative client. In contrast to existing docking missions no support by the client is given, neither active via a communication link nor passive via target pattern. Therefore the servicer satellite has to fully rely on its own sensors to estimate the relative state. Classically state estimation is implemented by a linear or extended Kalman Filter, depending on the motion model. Recent developments show good results when applying other variants of navigation filters. This paper presents a comparison of classical and advanced filter types for non-cooperative relative navigation in low earth orbits and shows application to the DEOS in-orbit servicing technology demonstration mission. Apart from navigation solution accuracy the computational requirements are an important factor as satellite on-board hardware capabilities are usually very limited.

Orbital rendezvous mission planning using mixed integer nonlinear programming

The rendezvous and docking mission is usually divided into several phases, and the mission planning is performed phase by phase. A new planning method using mixed integer nonlinear programming, which investigates single phase parameters and phase connecting parameters simultaneously, is proposed to improve the rendezvous mission’s overall performance. The design variables are composed of integers and continuous-valued numbers. The integer part consists of the parameters for station-keeping and sensor-switching, the number of maneuvers in each rendezvous phase and the number of repeating periods to start the rendezvous mission. The continuous part consists of the orbital transfer time and the station-keeping duration. The objective function is a combination of the propellant consumed, the sun angle which represents the power available, and the terminal precision of each rendezvous phase. The operational requirements for the spacecraft–ground communication, sun illumination and the sensor transition are considered. The simple genetic algorithm, which is a combination of the integer-coded and real-coded genetic algorithm, is chosen to obtain the optimal solution. A practical rendezvous mission planning problem is solved by the proposed method. The results show that the method proposed can solve the integral rendezvous mission planning problem effectively, and the solution obtained can satisfy the operational constraints and has a good overall performance.

Navigating the Road to Autonomous Orbital Rendezvous

The fundamental techniques and approaches to orbital rendezvous have predominantly been defined by the United States and Russian space programs. Although both programs were initially pursuing the same goal, they chose two very distinct paths. Themanualmethod pursued by theUnited States has given it the capability to handle a variety of complex rendezvous and docking missions, whereas the Russians’ automated approach has come to symbolize efficiency and reliability. What is the reason that these two storied programs chose such different paths? How have these pioneering decisions affected the course of orbital rendezvous?Where is orbital rendezvous heading in the future? This paper provides a comprehensive overview of the programs,missions, and techniques that have set the standards for orbital rendezvous. In particular, it reveals the rationale and events behind the early engineering decisions regarding orbital rendezvous navigation systems, how they have come to influence ensuing programs, and why these traditional methods are beginning to be replaced by new autonomous approaches for current and future missions.

Relative position and attitude estimation and control schemes for the final phase of an autonomous docking mission of spacecraft

This paper describe schemes for onboard relative position and attitude estimation and control for the final translational phase of an autonomous space rendezvous and docking system. Different estimators for attitude and position parameters based on a vision system outputs are given. Relative position control based on phase–plane control technique and relative attitude control based on relative quaternion feedback scheme are described. Based on the study, it turns out that fixed gain observers are sufficient for the estimation of position and attitude. Sensitivity of different parameters on these estimators and controllers are also described. A detailed computer simulation provides the expected range of parameters for which a successful maneuver towards the target can be achieved.

One year old and growing: a status report of the internationalspace station and its partners

The International Space Station (ISS), as the largest international science and engineering program in history, features unprecedented technical, cost, scheduling, managerial, and international complexity. A number of major milestones have been accomplished to date, including the construction of major elements of flight hardware, the development of operations and sustaining engineering centers, astronaut training, and eight Space Shuttle/Mir docking missions. International partner contributions and levels of participation have been baselined, and negotiations and discussions are nearing completion regarding bartering arrangements for services and new hardware. As ISS is successfully executed, it can pave the way for more inspiring cooperative achievements in the future.

Estimating pose of known target satellite

A method of estimating the relative position and orientation of a known target satellite is presented, using only passive imagery. Such a method is intended as a prelude to systems required in future autonomous satellite docking missions.

Study of Relative Position and Attitude Estimation and Control Scheme for the Final Phase of an Autonomous Docking Mission

This paper describes a schemes for onboard relative position and attitude estimation and control for the final translational phase of an autonomous space rendezvous and docking system. Different estimators for attitude and position parameters based on a vision system outputs are given. Relative position control based on phase-plane control technique and relative attitude control based on relative quaternion feedb~k scheme are described. Sensitivity of different parameters on these estimators and controllers are also described. A detailed computer simulation provides the expected range of parameters for which a successful maneuver towards the target can be achieved. Finally fixed gain matrix estimators are also suggested as suitable options for such amission.

A quaternion solution to the pose determination problem for rendezvous and docking simulations

This paper presents the mathematical framework for the attitude and position estimation of an object from its image using three point correspondence information. A closed-form solution for the pose determination problem is derived by representing the relative attitude parameters using quaternions. The quaternion elements can be used to model the outputs of a vision sensor in attitude control simulations for the final approach phase of a rendezvous and docking mission. The algorithm has been validated with real images of a scaled model of the target features in a vision system test facility. Simulation results showing the comparison between the actual and estimated pose parameters are included.

A Lighting and Visibility Evaluation of the Shuttle/Mir Docking Target

As a prelude to the assembly of the International Space Station Alpha, the Space Shuttle will dock with the current Russian Mir Space Station several times. In order to align the docking interfaces, the Shuttle commander will use a camera view of a target mounted inside the Mir docking hatch to determine and to correct misalignment. An evaluation took place at NASA's Johnson Space Center to determine if modifications to the target design resolved previous visibility issues and to quantify the effect of orbital shadows on the commander's ability to perceive target cues. Both the commander and pilot of the first two docking missions participated as subjects. Results of this evaluation showed that target visibility issues were resolved. Critical information was also provided to operations engineers regarding how to deal with orbital shadows during rendezvous. These results assisted ground operations controllers in instructing the STS-63 crew on what image data was required to verify expected on-orbit conditions for upcoming Shuttle/Mir missions.

Orbital Rendezvous Systems

The sybstem requirements for orbital rendezvous systems vary greatly depending on the mission in question. A few of the mission parameters which significantly affect subsystem requirements are: 1. Launch Window. The permitted launch window may be very short in an emergency rescue mission or could be relaxed on a supply mission. The size of the launch window, in turn, affects the variation in terminal geometry, and the ascent and terminal phase performance requirements. 2. Ground Tracking and Control On-board Tracking and Control. For many earth-orbiting missions the ground track will be well covered by tracking stations which can determine a precise ephemeris for the target and/or the chaser, which, in turn, permits ground control of orbital maneuvers up to some point in the terminal phase. This procedure would not be possible, of course, for lunar orbital rendezvous. A related question is then the point in the terminal phase at which relative position and velocity data are adequate for terminal guidance. 3. Cooperative: vs. Non-cooperative Target. Rendezvous with a non-cooperative target usually requires a high powered skin tracking radar capability of acquisition at fairly extended ranges whereas a cooperative target permits use of a transponder, greatly reducing power requirements, and also pernuts cooperative attitude reorientation and corrective maneuvers of the target. 4. Manned vs. Unmanned. It, has been demonstrated by ground simulation that a pilot can visually monitor and control portions of the terminal phase of a rendezvous and docking mission, whereby the tracking and computation requirements for such missions can be greatly altered. Even within the framework of a given mission there are a number of major system parameters to be determined. For example, the question of whether tracking sensors can be fixed to the body or require isolation from vehicle motions in the acquisition and terminal phases, in turn depends on the nature and accuracy of the vehicle stabilization and control systein, and the number and location of corrective rockets which will affect the reorientation requirements to achieve velocity corrections. Furthermore, the number and size of these corrections, which depend on tracking accuracy, will affect whether or not tracking is required during such corrections. The factors which lead to a choice among radar, optical or infrared targeting during the various phases will he discussed. Finally, the discussion and comparison of various guidance laws for controlling the closing rate and lateral corrections will be discussed, including the effects on propulsion requirements and tracking accuracy requirements. In particular, proportional navigation, bang-bang correction, and orbital maneuver laws will be compared.