Showing papers by "European Space Operations Centre published in 1981"
TL;DR: In this article, the authors show that all geostationary satellites should be removed from the ring at the end of their operational lifetime in order that the collisional risk remains within acceptable bounds in the future.
Abstract: Geostationary satellites not removed from the geosynchronous altitude at the end of their useful life will expose future spacecraft orbiting in this unique region to a continual collision hazard. The probability of a collision occurring before the end of this century is less than 2 x 10 ~ , unless large space structures such as solarpower satellites become operational, in which case collisions would likely occur every few years. Fundamental data on the collision probabilities are derived from deterministic orbit propagation for a representative sample of uncontrolled objects using an intersection process in which the active satellites are described by a probability distribution within the geostationary ring. The study clearly points out that all geostationary satellites should be removed from the ring at the end of their operational lifetime in order that the collisional risk remains within acceptable bounds in the future. The cost of this remedy amounts to no more than that of one month of active station-keeping for present-day satellites.
29 citations
TL;DR: The need for a close coupling between mission control and payload quality control is emphasized and the observed quality of the imagery from the first flight model of Meteosat is discussed.
Abstract: The various aspects of Meteosat image quality control are considered User requirements on the quality of end-products (mainly meteorological products) and on the image quality are presented, showing how image errors contribute to the total error budget Methods of evaluating the various measures of image quality are briefly outlined and the implementation of these methods within the Meteosat Ground Computer System is critically reviewed The need for a close coupling between mission control and payload quality control is emphasized The observed quality of the imagery from the first flight model (F1) of Meteosat is also discussed
7 citations
TL;DR: In this article, a simple formula is given for the perturbation of the anomalistic period of a highly eccentric orbit due to the zonal harmonics, which depends essentially only on the semi-major axisa, the eccentricitye (or pericentre radius rπ =a(1-e)) and the latitude β of the percentre.
Abstract: In this note a simple formula is given for the perturbation of the anomalistic period of a highly eccentric orbit due to the zonal harmonics. This perturbation depends essentially only on the semi-major axisa, the eccentricitye (or pericentre radius rπ =a(1-e)) and the latitude β of the pericentre.
2 citations
TL;DR: In this article, two techniques for increasing the accuracy of the numerical integration of eccentric orbits in Cartesian coordinates are discussed, one involves the use of an independent variable different from time, and the other uses a time element, which reduces the in-track error.
2 citations
TL;DR: In this paper, a general introduction to Flight Control of Satellites is presented. But the authors mainly concentrate on the systems and operational aspects. And they point out that automatic closed loop control from ground is, for certain control functions, in particular for geostationary application satellites, a recommendable and cost effective alternative to onboard autonomous control.
1 citations
TL;DR: The data processing system used at the European Space Operations Centre, for the remote control of GEOS, a multi-experiment scientific research spacecraft, and the trends in this field towards distribution of control in the instruments of spacecraft are dealt with.
1 citations
01 Jan 1981
TL;DR: In this article, the authors address the preparation of the ground facilities necessary for the control of the satellite on the one hand and payload acquisition, processing, archiving and distribution of the payload data on the other.
Abstract: At the present time the European Space Agency is making preparations for a European Remote Sensing Satellite Programme. Within this programme, the first satellite to be launched will be ERS-1, an ocean monitoring satellite carrying as payload a multi-spectral scanner and a number of active microwave instruments, namely a Synthetic Aperture Radar (SAR), a scatterometer, an altimeter, and very likely a scientific payload still to be determined. This paper addresses that portion of the programme concerned with the preparation of the ground facilities necessary for the control of the satellite on the one hand and payload acquisition, processing, archiving and distribution of the payload data on the other.
TL;DR: The Meteosat system is described, together with a description of its performance during the operational year of the FGGE, including both the spacecraft and ground system.