A, B, C = state-space matrices a = acceleration due to linear-quadratic-regulatorand artificial-potential-field-determined control effort aAPF = acceleration due to artificial-potential-fielddetermined control effort aLQR = acceleration due to linear-quadratic-regulatordetermined control effort am = maximum acceleration aobs = acceleration of chaser spacecraft toward an obstacle ax;y;z = accele...

This paper describes a prototype of software system of neural network control of telemetry data for malfunction diagnosis of spacecraft subsystems. The prototype is used for testing of intelligent technologies for processing information about a spacecraft subsystems state, prediction and detection of irregularities of the spacecraft subsystem modes. The Information obtained from on-board data s...

Nonlinear pulse width modulation (PWM) controlled system is considered to achieve control performance of thrustercontrolled spacecraft. The actual PWM controlled motions occur, very closely, around the average model trajectory. Furthermore nonlinear PWM controller design can be directly applied to thruster controlled spacecraft to determine thruster on-time. Sliding mode control for attitude tr...

The joint ESA/NASA LISA mission consists in three spacecraft on heliocentric orbits, flying in a triangular formation of 5 Mkm each side, linked by infrared optical beams. The aim of the mission is to detect gravitational waves in a low frequency band. For properly processing the scientific data, the propagation delays between spacecraft must be accurately known. We thus analyse the propagation...

The time delay effect for planets and spacecraft is obtained from a fully relativistic modified gravity theory including a fifth force skew symmetric field by fitting to the Pioneer 10/11 anomalous acceleration data. A possible detection of the predicted time delay corrections to general relativity for the outer planets and future spacecraft missions is considered. The time delay correction to ...

Material collected from an asteroid’s surface can be used to increase gravitational attraction between the asteroid and a Gravity Tractor (GT); the spacecraft therefore operates more effectively and is referred to as an Enhanced Gravity Tractor (EGT). The use of tethers and solar sails to further improve effectiveness and simplify operations is investigated. By employing a tether, the asteroida...

This paper describes the New Millennium Remote Agent (NMRA) architecture for autonomous spacecraft control systems. This architecture integrates traditional real-time monitoring and control with constraintbased planning and scheduling, robust multi-threaded execution, and model-based diagnosis and recon guration. We implemented a prototype autonomous spacecraft agent within the architecture and...

As Electric Propulsion (EP) increases in recognition as a means of spacecraft primary propulsion and orbit maintenance, more complex spacecraft using EP will be produced. With the proven adage, test what we fly and fly what we test, the ground and on-orbit verification programs for those spacecraft utilizing EP for primary propulsion also increases in complexity. While EP systems have been test...