European Space Operations Centre

About: European Space Operations Centre is a government organization based out in Darmstadt, Germany. It is known for research contribution in the topics: Orbit determination & Satellite. The organization has 309 authors who have published 331 publications receiving 10399 citations. The organization is also known as: ESOC.

The Use of Ellipsoidal Harmonics for the Representation of the Geopotential

Abstract: The potential of the Earth is developed in ellipsoidal harmonics, and the mathematical tools required, which are the generation of Lame’s functions and the relationship between rectangular and ellipsoidal coordinates, are compiled. Brief reference is made to a procedure utilized for the determination of the gravity coefficients in the expansion ot the geopotential in ellipsoidal harmonics when precise satellite tracking data is available.

Are Microtektites the Result of Cometary Impacts with the Earth

Abstract: Durrani and Khan1 suggest that microtektites obtained from ocean sediments near Australia and the Ivory Coast may be the result of impacts of comets with the Earth. They measured the ages of the microtektites obtained from the two regions and determined the ages at 0.71 ± 0.1 and 0.88 ± 0.13 m.y., respectively, for Australasian and Ivory Coast tektites. These ages agree closely with the dates of two of the reversals of the geomagnetic field, and this close agreement is interpreted by them as suggesting that the microtektites and magnetic reversals have resulted from impacts of comets with the Earth.

Ulysses operations at Jupiter - Planning for the unknown

Abstract: The operational preparations for the Ulysses encounter with Jupiter are described with particular attention given to requirements for survival in the Jovian environment, ground-segment planning, a deep-space network, and encounter activities. It is concluded that the successful operation of the Ulysses spacecraft at Jupiter was the culmination of many years of activity, from spacecraft design and mission planning to the coordination of the encounter activities and production of the detailed timeline.

Challenges in testing and validating operational spacecraft simulators

Abstract: Flight Control Teams (FCT) at the European Space Operations Centre (ESOC) of the European Space Agency (ESA), start flight operations training and preparation on a specific Spacecraft (S/C), about 3 years prior to launch through, mainly, the preparation of flight operations procedures. The training ends just before launch and has its peak starting 6 months before it, through a critical specific training called Simulations Campaign. The FCT starts its preparation while the spacecraft itself is being built and is therefore unavailable for testing. In order to surpass the lack of a real spacecraft with which to test procedures and train, the FCT uses an Operational Spacecraft Simulator that closely models the spacecraft (with its systems and subsystems modelled to the detail).The procurement and management of the development, testing and validation of the Mission Data Systems, such as the Spacecraft Operational Simulator and the Mission Control System, for each specific ESA spacecraft is the responsibility of the Mission Data Systems Division of the Ground Segment Department (OPS-GD) at ESOC.A new operational Simulator is developed per spacecraft based on common reusable infrastructure software. The challenges in the development, testing and validation of complex Operational Spacecraft Simulators are manifold. The first and major challenge resides in the fact that the majority of the requirements on which the development is based, must be generic enough to cope with the lack of detailed Spacecraft specifications, since the Spacecraft itself is also under development. Also, if there are any changes in the Spacecraft systems or subsystems specification consequent changes in the models developed for the Simulator are expected.Generic requirements, however, make it difficult to specify and execute relevant test cases. In addition, the continuously evolving Spacecraft specifications imply constant changes in the test and verification process.This paper intends to illustrate the complex process of testing and verification of Operational Spacecraft Simulators, coping with the parallel development of the spacecraft being modelled and the consequences that this brings.