On the simulation of fluid spacecraft interactive dynamics

The present report contains a study on the simulation of interactive fluid spacecraft dynamics. The equations of motion of the two dimensional full tank case as well as the corresponding finite different discretized equations are presented. The numerical solution of this system is studied. Results are presented for a number of cases. Based on...

Some aerospace applications of estimation theory

In this report, the application of estimation theory to three problems from aerospace research is described. The applications considered deal with spacecraft attitude estimation, software reliability modelling and estimation, and with a satellite-based navigation algorithm. Maximum likelihood estimation is used in the software reliability case...

Two-dimensional modelling of capillary liquid flow in a thin annulus

One of the experiments performed on board Spacelab, involves a partially filled annular cylinder which is subjected to prescribed motions (Ref. 1). The interest in this configuration arises from its practical use; for instance, the coolant in IRAS was stored in an annulus-like tank. In this report, a mathematical model for the transient liquid...

Testing of spacecraft attitude and orbit control systems

The testing of Spacecraft Attitude and Orbit Control Subsystems is described from the early design up to in-flight, inclusive. Main topics dealt with are: description of three generic AOCS test classes, model philosophy, standardization, subsystem static test methods, subsystem dynamic test methods, generic test equipment and test facilities....

In-flight attitude estimations and control experiments with Iras based on modern control theory

One of the research activities of the Space Division of the National Aerospace Laboratory NLR is the application of modern estimation and control theory to spacecraft attitude control problems. Algorithms for spacecraft state estimation and attitude control, as well as for inertial-optical attitude determination have been developed previously...

Towards digital computer simulation of the dynamics of flexible spacecraft

Software design for digital computer simulation of the dynamics of flexible spacecraft equipped with actuators and sensors, should take into account two properties of the overall system: (i) s.ampled-data control of the spacecraft leads to discontinuous inputs (forcing functions) in the differential equations of motion, thereby requiring...

Application of model following control and estimation techniques to attitude control of manoeuvring spacecraft Part II: Simulation software description

This document describes two computer programs developed during a study of the application of modern control techniques in the area of spacecraft attitude control. Theory and simulation results are described in part I of this report. In part II a general overview of the tasks of the simulation program is presented, and program design aspects are...

Multiple attitude maneuvers for a spinning spacecraft disturbed by solar radiation

The attitude motion of interplanetary, spinning spacecraft under the influence of solar radiation and optimal thrusting, is investigated. A general model is formulated to describe the forces and torques exerted on the spacecraft due to solar radiation. The model is compared with model! available in the large body of literature on the subject. It...

IRAS on-board software

The infra Red Astronomical Satellite IRAS will be laimched in February I98I for a mission of one year duration. The purpose of the mission is to produce a full sky catalogue in the infrared waveband. The IRAS satellite will be equipped with an on-board computer system to control the satellite and to execute the measurements necessary to fulfil...

In-orbit experiment with an attitude control algorithm for ANS based on modern control principles

The existing fine attitude system of the Astronomical Netherlands Satellite was designed on the basis of conventional digital control techniques. The possibility of a more advanced approach is presented in this report. As an example, an alternative control algorithm for the scan mode has been developed with the use of state estimation and state...

Stability of double gimballed momentum wheels

Due to the finite stiffness of rotor- and gimbal-suspensions, a double gimballed momentum wheel will oscillate with high natural frequencies. The stability of these oscillations is studied, in order to obtain requirements for the stiffness of the suspensions and/or the gimbal inertia properties. From energy considerations, it is concluded that...