Nomenclature β,γ(∈ S) = The gimbal and wheel angles. (rad) Rβ(∈ SO(3)) = Transformation from gimbal frame G to the spacecraft body frame B. Is = Spacecraft inertia without the CMG gimbal and wheel inertia. (kg.m) Ig, Ir = Gimbal frame inertia, wheel inertia about own centre of mass represented in gimbal frame. (kg.m) (Igr)β = Combined inertia of gimbal frame and wheel in the spacecraft frame. R...

The focus of this paper is the spacecraft formation flying problem where the formation switches successively among multiple shapes, the number and the composition of spacecraft in the group may change among these shapes, and some spacecraft may be faulty. The whole flying process is modeled as a state-varying switched system. The formation stability and fault tolerability are analyzed by using ...

Mission design engineers identify a spacecraft design and mission plan that best achieves the mission objectives while staying within cost, mass, and operability constraints. It is often easiest to evaluate a spacecraft design in the context of a detailed mission plan. Generating plans by hand is labor-intensive. We present an AI planning system that automatically generates and evaluates missio...

INTRODUCTION The Attitude and Orbit Control System (AOCS) plays an essential role in the flight control of a spacecraft. This system usually contains a minimum of three reaction wheels (often 4-5 wheels are used for optimization and redundancy [1]). By accelerating the appropriate wheels, the system can produce a zero-mean reaction torque about any axis to the spacecraft, which enables the spac...

Built on the combined strength of decentralized control and the recently introduced virtual structure approach, a decentralized formation scheme for spacecraft formation flying is presented in this paper. Following a decentralized coordination architecture via the virtual structure approach, decentralized formation control strategies are introduced, which are appropriate when a large number of ...

abstract. — Spacecraft are complex systems that involve different subsystems with multiple relationships among them. For these reasons, the design of a spacecraft is a time-evolving process that starts from requirements and evolves over time across different design phases. During this process, a lot of changes can happen. They can affect mass and power at the component level, at the subsystem l...

This paper will present recent advances in algorithms developed to achieve accurate on-line ID. These algorithms use and reference the MCRLS ID algorithm [1]. Initial mass-property ID algorithms as developed for the X-38 v.201 spacecraft and Mini-AERCam [2] are updated and extended here. Experimental results validating a subset of these algorithms on the MIT SPHERES spacecraft in zero-g aircraf...

The ground-based spacecraft simulator is a useful tool to develop and verify new control laws required by modern spacecraft applications. In order to simulate the space environment with the ground-based spacecraft simulator, the effects of gravity should be minimized. In this paper, a three-axis rotational rigid spacecraft simulator on a spherical air-bearing system is considered. The method of...

This paper describes technology to support a new paradigm of space science campaigns. These campaigns enable opportunistic science observations to be autonomously coordinated between multiple spacecraft. Coordinated spacecraft can consist of multiple orbiters, landers, rovers, or other in-situ vehicles (such as an aerobot). In this paradigm, opportunistic science detections can be cued by any o...

A Hierarchical Model-Based Reasoning Approach for Fault Diagnosis in MultiPlatform Space Systems Amitabh Barua, Ph.D. Concordia University, 2010 Health monitoring and fault diagnosis in traditional single spacecraft missions are mostly accomplished by human operators on ground through around-the-clock monitoring and trend analysis on huge amount of telemetry data. Future multiplatform space mis...