Updating SIMPLE model parameters for the Present LEO debris Environment
- Paper number
IAC-08.A6.5.9
- Author
Mr. Sudheer Reddy D, Indian Space Research Organization (ISRO), India
- Coauthor
Dr. Anilkumar A K, Indian Space Research Organization (ISRO), VSSC, India
- Year
2008
- Abstract
A model to describe the space debris scenario in Low Earth Orbit, named Stochastic IMPressionistic Low Earth (SIMPLE) model, was proposed by Ananthasayanam et.al. (Ref. 1, 2). SIMPLE model gives a closer picture of low Earth environment (upto 2000 km) by classifying the physical process into two models viz., gross model and local model. The number density ‘n’ in all the gross models can be represented in terms of a mixture of Laplace distributions. The distribution of ‘e’ and ‘B’ in each and every gross and local model can be represented by suitable lognormal distributions. The model described the number density of the LEO catalogued objects with respect to different altitude bins and inclination bands. The model parameters were derived based on the catalogued data from 1996 to 2002. It is assumed that the model parameters would not vary much if the decay or launch rate does not overshoot significantly. As is reported in Orbital Debris Quarterly News, the breakups occurred during the recent period has created numerous debris objects of size more than 10 cm in LEO whose lifetimes vary from decades to centuries. In 2007, more than 2000 fragments were catalogued. This has completely redefined the distribution pattern of the LEO catalogued objects and magnified the collision probability in LEO. As a result these fragmentation events have changed the whole scenario regarding the SIMPLE parameters. It is imperative to work out afresh the model parameters in SIMPLE. The variation in the parameters, location and scale parameters, will give insight into the effect of these fragmentations. This paper deals with the updating of the SIMPLE model parameters utilizing the catalogued objects in LEO, based on TLE sets in the present LEO environment. The comparison between the earlier parameters and the present model parameters are also made. References (1) Anilkumar. A.K., “New Perspectives for Analyzing The Breakup Environment, Evolution, Collision Risk and Reentry of Space Debris Objects,” Ph.D. thesis, Department of Aerospace Engineering, Indian Institute of Science, Bangalore, India, 2004. (2) Ananthasayanam. M.R., Anilkumar. A.K., Subba Rao. P.V., “A new stochastic impressionistic low Earth model of the space debris scenario,” Acta Astronautica, Vol.59, 2006, pp.547-559. (3) Orbital Debris Quarterly News, Volume 12, Issue 1, January 2008.
- Abstract document
- Manuscript document
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