Basic aspects in Designing Space Grasper Missions
- Paper number
IAC-07-D1.1.07
- Author
Mrs. Chiara Toglia, University of Rome "La Sapienza", Italy
- Coauthor
Dr. Giovanni B. Palmerini, University of Rome "La Sapienza", Italy
- Coauthor
Prof. Paolo Gasbarri, University of Rome "La Sapienza", Italy
- Year
2007
- Abstract
Automation of in-orbit activities represents a goal of great interest for the aerospace research, due to high risk and cost related to tasks performed by astroauts. Following this approach manned mission could be replaced by servicing orbiters, conceived as graspers with arm-like appendages, whose job is to "capture" the to-be-repaired spacecraft and therefore perform the required fixes. These topics match with current interest for manipulators operating in the space environment, with a clear trend towards systems smaller than the big arms developed in the past for the Shuttle.
The proposed paper presents the preliminary results for the grasper mission concept. Several aspects are important and therefoer investigated:
- Trajectory optimization from the parking to the servicing orbit for the space grasper. The resulting transfer orbit will be constrained by the flight time that depends on the relative position of the grasper and the to-be-repaired spacecraft. Impulsive manoeuvres will be considered, in order to minimize the velocity fuel consumption throughout the total velocity impulse (see Tsiolkovsky’s equation).
- Rendez-vous phase navigation and guidance, in order to smoothly dock the end of the grasper link to the satellite. A manoeuvre time history, optimal for the duration and/or the applied driving torque, will be found in a class of allowable solutions. The navigation aspect, which is instrumental to correctly execute the rendez-vous, will be performed by using GNSS signals. In particular, in order to match the accuracy requested, we will refer to the phase observable instead of the pseudo random code, looking therefore to a real-time kinematics.
- Flexibility effects typical of space manipulators will be considered. During the guided manoeuvre the elastic oscillations with respect to the rigid body behavior will be controlled, imposing a constraint on the driving torque in order to be acceptably bounded.
The carried out simulations will take into account previous facts and aim to provide a sort of guideline for further studies. Moreover the first findings of a research program recently started at the University of Rome "La Sapienza" will be used while implementing the model.
The analysis presented here can be readily extended to other classes of orbital missions involving the use of flexible links.
- Abstract document
- Manuscript document
IAC-07-D1.1.07.pdf (🔒 authorized access only).
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