1. Dept. of Astronmy Optical surveys for space debris Byeon Jae Gyu

2. Dept. of Astronmy What is space debris? Space debris Non-functional, man-made objects in space Several meters in size like defunct satellites Centimeter and milimeter-sized debris created by explosion and collisions Very small particals like flakes, and solid rocket motor slag or dust Low Earth orbit (LEO) Region up to 2,000km altitude / about 20cm Geostationary Earth orbit (GEO) Around 36,000km altitude / about 0.1 ~ 1m Geostationary transfer orbits (GTOs) 2,000 ~ 36,000km altitude / larger than about 1m

3. Dept. of Astronmy What is space debris?

4. Dept. of Astronmy What is space debris?

5. Dept. of Astronmy What is space debris? Simulated explosion in LEO

6. Dept. of Astronmy Why is space debris a problem?

7. Dept. of Astronmy Why is space debris a problem?

8. Dept. of Astronmy The USSTRATCOM catalogue The US Strategic Command (USSTRATCOM), a military entity of the USA, maintains a catalog of about 9,000 known ‘large’ objects Russia maintains a similar catalog USSTRATCOM catalog, although generated for a different purpose and known to be incomplete, is extensively used in space debris research.

9. Dept. of Astronmy Radar observations Radar is mostly used to survey the LEO region Detection and tracking all objects larger than about 10-20cm High altitudes is using optical telescopes of 1m aperture Can dectct in GEO, have size of the order of 1m in diameter NASA : the 36-m Haystack dish antenna in MA ESA : German 34-m dish radar facility

10. Dept. of Astronmy Optical observations LEO measurements form the NASA Liquid Mirror Telescope (LMT) GEO survey result from the NASA CCD Debris Telescope (CDT) The NASA funded Michigan Orbital Debris Survey Telescope (MODEST) The TAROT telescope supported by the French space agency CNES GEO and GTO observations from the ESA 1-m telescope

11. Dept. of Astronmy Optical observations

12. Dept. of Astronmy Optical observations

13. Dept. of Astronmy Optical observations

14. Dept. of Astronmy Optical observations

15. Dept. of Astronmy Models

16. Models

17. Protecting the space environment We realize that space cannot be cleaned from debris with any technical means in near future De-orbit larger objects Ground-based high power lasers to perturb the orbits of small fragment forcing the fragments to reenter the atmosphere United Nations Committee on the Peaceful Uses of Outer Space (UNCOPUOS)