This paper presents the development of a control system design to keep the spacecraft attitude at a prescribed sun vector. A bounded controller is proposed which utilizes the measured sun vector and spacecraft spin rates, and the control gains are model independent and can be tuned for individual axis. An adaptive control scheme is developed for control parameters to ensure closed-loop performa...

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 ...

This paper summarizes basic concepts and the current state of the art in spacecraft fault detection, isolation and recovery. A gap analysis focuses on drawbacks of classical fault diagnosis methods in deep space applications. Studies that propose innovative techniques are summarized and evaluated briefly with respect to enhanced spacecraft on-board fault diagnosis on system level. Research chal...

Servicing satellites on-orbit requires ability to rendezvous and dock by an unmanned spacecraft with no or minimum human input. Novel imaging sensors and computer vision technologies are required to detect a target spacecraft at a distance of several kilometers and to guide the approaching spacecraft to contact. Current optical systems operate at much shorter distances, provide only bearing and...

This paper compares and contrasts several coordination schemes for a system that continuously plans to control collections of rovers or spacecraft using collective mission goals instead of goals or command sequences for each spacecraft. A collection of self-commanding robotic systems would autonomously coordinate itself to satisfy high level science and engineering goals in a changing partially...

The investigation of fundamental scientific problems is a core mission of the university. Professors and researchers have had a long, successful history as principal investigators for such projects. Now, because technological advances have made small spacecraft less expensive and more capable, universities can offer their services in the area of spacecraft design and development as well. This i...

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...