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Re-entry prediction of spent rocket bodies in GTO
No full textSpent upper stages are bodies consisting of components likely to survive re-entry, for example propellant tanks. Therefore, the re-entry of upper stages might be associated with high on-ground casualty risk. This paper presents a tool for re-entry prediction of spent rocket bodies in GTO based exclusively on Two Line Element set (TLE) data. TLE analysis and filtering, spacecraft parameters estimation, and combined state and parameters estimation are the main building blocks of the tool. The performance of the tool is assessed by computing the accuracy of the re-entry prediction of 92 GTO objects, which re-entered in the past 50 years
Optical observations of Briz-M fragments in GEO
No full textOn January 21, 2016 the Joint Space Operations Center (JSpOC) of the US Strategic Command was informing about a possible breakup of a Briz-M upper stage in the geostationary ring. This upper stage with the International Designator 2015-075B is associated with the launch of the Russian Cosmos 2513 which took place only 6 weeks earlier on December 13, 2015. The same day, ESA together with the Astronomical Institute of the University of Bern (AIUB) prepared for a survey campaign using the 1-meter Space Debris Telesc
ope (ESASDT) at ESA’s Optical Ground Station on Tenerife and AIUB’s sensors at the Zimmerwald Observatory. The selection of the survey strategy to search for fragments of this event was based on a synthetic debris cloud, assuming a hypothetical fragmentation epoch (the real fragmentation
epoch was not known at this time). Observations with the ESASDT were performed on January 23 and 24, and in additional two nights in February. The uncorrelated objects found during this campaign were followed-up with the Zimmerwald sensors. We will present the observation results and the challenges related to the association of the candidate fragment tracklets with each other, the initial orbit determination, and the determination of the breakup epoch
Automated Operations for the Maintenance of a Space Object Database
No full textTo cope with the increasing number of objects in space around Earth, the processing of observations of these objects shall be automated as much as possible. In this work, the automation of three parts of the maintenance of a space object orbit database, commonly called catalogue, is analysed. The first one is the association of new measurements with stored orbits in the database based on a comparison in a common coordinate frame using the Mahalanobis distance under the assumption of normally distributed errors. It is shown for radar observations, that making this comparison in either the observation or orbit coordinates is only feasible if the error in the transformed system is small enough to remain normal after the transformation. Additional work is dedicated to derive a quality measure from the orbit state and covariance to give feedback, which also considers new measurements, on the current status or quality of an object in the database. Different concepts from information theory, namely the entropy and the surprisal, are tested and found to be useful quantities for these tasks. Future work will need to extend these parameters to consider further information and test their robustness with large data sets
Impact of End-of-Life manoeuvres on the collision risk in protected regions
Full text linkThe Inter-Agency Space Debris Coordination Committee (IADC) Space Debris Mitigation Guidelines, issued in 2002 and revised in 2007, address the post mission disposal of objects in orbit. After their mission, objects crossing the Low Earth Orbit (LEO) should have a remaining lifetime in orbit not exceeding 25 years. Objects near the Geostationary Orbit (GEO) region should be placed in an orbit that remains outside of the GEO protected region. In this paper, the impact of satellites and rocket bodies performing End-of-Life (EOL) orbital manoeuvres on the collision risk in the LEO and GEO protected regions is investigated. The cases of full or partial compliance with the IADC post mission disposal guideline are studied. ESA's Meteoroid and Space Debris Terrestrial Environment Reference (MASTER) model is used to compare the space debris flux rate of the object during the remaining lifetime estimated for the pre-EOL-manoeuvre and for the post-EOL-manoeuvre orbit. The study shows that, on average, the probability of collision can be significantly decreased by performing an EOL-manoeuver
Proposed Strategies for Optical Observations in a Future European Space Surveillance Network
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Challenges Related to Discovery, Follow-Up, and Study of Small High Area-to-Mass Ratio Objects at GEO
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