ANALYSIS OF OBSERVED AND SIMULATED LIGHT CURVES OF SPACE DEBRIS

2017

Space debris population increased drastically during the last years. One of the contributing factors is the incidental collisions involving massive objects which are predicted to be more pronounced in the future. The removal of large, massive space debris is considered necessary to stabilize the population. In this respect, not only precise orbits, but also more detailed information about their attitude states such as spin period and spin axis orientation is required. Non-resolving optical observations of the magnitude variations, so-called light curves, are a promising technique to determine the tumbling rates and the orientations of the actual objects' rotational axis, as well as their temporal changes. For this purpose, we use the 1-meter telescope ZIMLAT at the Astronomical Institute of the University of Bern (AIUB) to collect light curves of selected LEO, MEO and GEO objects on a regular basis. We have acquired more than 3,000 light curves from 512 objects in various types ...

2015

The population of space debris increased drastically during the last years. Collisions involving massive objects may produce large number of fragments leading to significantly growth of the space debris population. An effective remediation measure in order to stabilize the population in LEO, is therefore the removal of large, massive space debris. To remove these objects, not only precise orbits, but also more detailed information about their attitude states will be required. One important property of an object targeted for removal is its spin period and spin axis orientation. If we observe a rotating object, the observer sees different surface areas of the object which leads to changes in the measured intensity. Rotating objects will produce periodic brightness vari ations with frequencies which are related to the spin periods. Photometric monitoring is the real tool for remote diagnostics of the satellite rotation around its center of mass. This information is also useful, for exa...

The ESA debris surveys at high altitudes revealed a significant population of small-size debris in GEO and GEO-like orbits. For a sub-set of the discovered objects high area-to-mass ratios were determined. The nature and the origin of most of this debris are currently unknown. There are several ways to identify possible progenitors or parent objects. Studies of the dynamical properties of the objects are one way; another possibility is to acquire more information on the sizes, shapes and possibly the material of the debris pieces. Non-resolving observation techniques like color photometry, light curves, and spectrometry are the only ground-based optical methods applicable for objects at the given distances. Objects are searched for and discovered by performing dedicated survey campaigns with the ESA 1-meter telescope (ESASDT) in Tenerife, Canary Islands. Observations are then shared in a network of observing sites, which acquire further observations allowing to determine and maintain orbits and to provide ephemerides to other observation techniques and partners, especially in the context of the Inter-Agency Space Debris coordination Committee (IADC). Currently these ephemerides are in particular used to acquire light curves and color photometry observations with AIUB's 1-meter ZIMLAT telescope in Zimmerwald, Switzerland. Color observations may help inferring the material type of the debris and thus may provide information on the potential parent objects of the debris. Light curves are used to estimate rotation or tumbling rates. Finally empirical characteristics of light curves may help to identify object classes or even individual objects and thus may provide crucial information when trying to correlate new observations with the existing catalogue of objects. Multi-color observations of small-size space debris including high area-to-mass ratio debris were obtained with ZIM-LAT. We will discuss the techniques used to obtain colors for objects with considerable brightness variations over short time intervals. Light curves of a variety of space debris were obtained over different time spans. Some debris objects show distinct signatures and periods in their light curves. These features seem to be stable over long time intervals and may thus be used to identify the objects. Other objects show highly variable light curves with strongly changing amplitudes and periods, indicating complex shapes and scattering properties.

amostech.com

Optical observations of rotating space debris near GEO contain important information on size, shape, composition, and rotational states, but these aspects are difficult to extract due to data limitations and the high number of degrees of freedom in the ...

2018

The Astronomical Institute of the University of Bern (AIUB) maintains a light curve database of debris objects in various orbital regions. Currently the database contains more than 3,000 light curves from more than 500 objects. All the light curves were obtained using the 1-meter telescope ZIMLAT which is located at Zimmerwald Observatory in Switzerland through non-resolving optical observations. The database also contains apparent rotation periods and phase diagrams for most of the objects. In this paper we discuss our analysis of the temporal evolution of the rotation rates and of the signatures in the light curves for different types of objects and orbital regions in the database. The information resulted from the analysis could be useful for the future active debris removal missions and to understand the intricate relationship between natural forces and satellites attitude in space.

2008

The ESA debris surveys at high altitudes revealed a significant population of small-size debris in GEO and GEO-like orbits. For a sub-set of the discovered objects high area-to-mass ratios were determined. The nature and the origin of most of this debris are currently unknown. There are several ways to identify possible progenitors or parent objects. Studies of the dynamical properties of the objects are one way; another possibility is to acquire more information on the sizes, shapes and possibly the material of the debris pieces. Non-resolving observation techniques like color photometry, light curves, and spectrometry are the only ground-based optical methods applicable for objects at the given distances. Objects are searched for and discovered by performing dedicated survey campaigns with the ESA 1-meter telescope (ESASDT) in Tenerife, Canary Islands. Observations are then shared in a network of observing sites, which acquire further observations allowing to determine and maintai...

2017

The population of space debris increased drastically during the last years. Collisions involving massive objects may produce large number of fragments leading to significantly growth of the space debris population. An effective remediation measure in order to stabilize the population in LEO is therefore the removal of large, massive space debris. To remove these objects, not only precise orbits, but also more detailed information about their attitude states will be required. One important property of an object targeted for removal is its spin period and spin axis orientation. Non-resolving optical observations of the magnitude variations, so-called light curves, are a promising technique to determine rotation or tumbling rates and the orientations of the actual rotation axis of objects, as well as their temporal changes. Acquiring such observations as well extracting attitude states from these measurements is challenging and requires sophisticated observations and processing techniq...

Астрономический журнал, 2016

Variations of light curves for space objects are investigated. Optical observations and photometric measurements for small space debris on highly elliptical orbits (HEO) and geostationary orbits (GEO) are used to determine their orbital parameters. Light curves of small space debris with various area-to-mass ratios and orbital characteristics are discussed. Tracking of some objects shows very rapid brightness variations related to perturbations of the orbital parameters. Changes in brightness and equatorial coordinates of the studied objects are found in observational data. Our results allow improving the accuracy of space debris orbital elements.

Proceedings of the …, 2007

For 14 nights in March 2007, we used two telescopes at the Cerro Tololo Inter-American Observatory (CTIO) in Chile to study the nature of space debris at Geosynchronous Earth Orbit (GEO).