Fifth European Conference on Space Debris
30 March - 2 April 2009
ESA/ESOC
Darmstadt, Germany
Ten Years of Observations at the ESA Space Debris Telescope –
Discoveries, Highlights and Lessons Learned
T. Schildknecht, R. Musci
Astronomical Institute, University of Bern, Switzerland
R. Jehn
ESA/ESOC, Darmstadt, Germany
J. Kuusela
Aboa Space Research Oy (ASRO), Tenerife, Spain
5th European Conference of Space Debris,
March 30 - April 2 2009
The ESA Surveys
ESA 1-m Telescope (OGS), Tenerife
Used for:
Surveys, faint objects follow-up
OGS (Optical Ground Station)
- 1 m aperture
- f = 4.4 m
- 4k x 4k CCD
- FOV 0.7°
ESA SDT
OGS Observation Statistics
- August 1999:
First 13 nights after long years of preparation!
- Continuous program, ~80 nights per year
- Observation Nights 2007/2008
- Number of Detections/Objects
Early discoveries
August 1999: First Detections!
- First test observations
- 13 nights
ESA 2008 GEO/GTO Survey
Continuous program, ~80 nights per year
August 1999: Clouds!?
- First test observations
- 13 nights
ESA 2008 Survey - i vs Ω
Evolution: i vs Ω 2001
Evolution: i vs Ω 2002
Evolution: i vs Ω 2003
Evolution: i vs Ω 2004
Evolution: i vs Ω 2005
Numerical Propagation of a Cluster
GTO Surveys & the Discovery of the High Area-to-Mass Ratio (AMR) Population
2002 GTO Surveys – Unusual Objects
- January 2002 onwards:
Real-time follow-up observations to derive 6-parameter orbits
- June 2002 onwards:
Optimized GTO surveys
- July 2002:
First indication of debris in “unusual” orbits
- March 2003:
Debris objects in GTO and highly eccentric orbits but with GEO semimajor axis
- September 2003:
First clear picture
July 2002: Debris in “Unusual” Orbits
| Semimajor axis [km] | Eccentricity | Inclination [deg] | Magnitude [mag] |
|---|
| 39074 | 0.31 | 7.7 | 19.5 |
| 43211 | 0.13 | 12.9 | 18.6 |
| 44012 | 0.14 | 13.6 | 16.7 |
| 23259 | 0.71 | 8.88 | 16.7 |
| 37541 | 0.49 | 10.6 | 17.3 |
| 22853 | 0.697 | 7.20 | 18.8 |
| 23820 | 0.715 | 6.69 | 17.2 |
GTO
Unusual GEO
March 2003: Objects in Elliptical Orbits
| Semimajor axis [km] | Eccentricity | Inclination [deg] | Magnitude [mag] |
|---|
| 43631.9 | 0.1476 | 13.59 | 16.7 |
| 37403.6 | 0.1862 | 8.73 | 19.2 |
| 41755.3 | 0.2224 | 6.89 | 17.3 |
| 46529.9 | 0.2455 | 3.69 | 17.4 |
| 33283.4 | 0.3352 | 5.87 | 18.2 |
| 33262.2 | 0.3368 | 6.20 | 17.5 |
| 40179.6 | 0.3412 | 9.16 | 19.1 |
| 39622.5 | 0.3708 | 3.98 | 17.2 |
| 31046.2 | 0.3751 | 5.40 | 18.2 |
| 51005.4 | 0.3901 | 10.51 | 19.0 |
| 37244.1 | 0.4073 | 7.49 | 18.0 |
| 33380.3 | 0.4180 | 7.06 | 19.0 |
| 37250.6 | 0.4968 | 10.67 | 17.3 |
| 41844.9 | 0.5050 | 4.67 | 18.9 |
| 19880.3 | 0.6565 | 3.45 | 17.0 |
| 22072.8 | 0.6826 | 6.27 | 18.1 |
| 22116.5 | 0.6829 | 7.04 | 16.1 |
| 22695.0 | 0.7012 | 7.17 | 18.8 |
| 25959.7 | 0.7019 | 1.40 | 17.6 |
| 23256.9 | 0.7115 | 7.88 | 16.7 |
| 23599.3 | 0.7141 | 7.06 | 18.1 |
| 23819.4 | 0.7146 | 6.70 | 17.2 |
GTO
Unusual GEO
For all objects there are several follow-up observations
September 2003: Clear Picture?
Picture in June 2008
Questions
- What might be the source of the objects seen at n~1 and 0 < e < 0.5?
- May this population be explained by natural perturbations of objects which were originally in GEO?
- Mechanism to increase e from 0 to 0.6?
Yes, solar radiation pressure if area-to-mass ratio (A/m) large (suggested by J.C Liou, private comm. March 2004)
July 2004: First Area-to-Mass Ratios!
Area-to-Mass Ratios 2008
Properties of the High AMR Population
Evolution in e-n diagram (2 y)
Zimmerwald 1 m Telescope
Used for:
Faint objects, light curves, color photometry
1 m ZIMLAT Switzerland
ZIMLAT
(Zimmerwald Laser and Astromtry Telescope)
- 1 m aperture
- 4 focal stations:
- 2k x 2k CCD
- 3k x 3k CCD
- FOV 10' – 23'
- Johnson BVRI filters
- Fast mount:
Light Curves of Object E06321D
- 5.5s sampling
- ~100s beat period
- ~15.75 mag avg.
- 4.5s sampling
- ~40s beat period
Color Indices from Light Curves
EGEO45:
- V-R ~ 0.5 mag
- From averages:
V-R = 0.73 ± 0.3 mag
Spectra from the OGS
Object S92005
- GTO debris
- Magnitude 14
- AMR 0.02
- two nights
AMR may Vary Considerably!
Lessons Learned
Networking Required!
We need orbits, statistical observations would have never revealed the high AMR population!
- Discover new objects: Obs. From Tenerife (OGS)
- Secure orbits: obs. from OGS, Zimmerwald (AIUB)
- Maintain orbits: obs. from OGS, Zimmerwald, ISON, ...
- Orbit maintenance at AIUB and Keldysh Institute of Applied Mathematics of the Russian Academy of Sciences (KIAM)
- Provide predictions:
- → to investigate physical properties of objects
- Use Zimmerwald facilities to collect:
- Photometric light curves
- Multi-color photometry/light curves
Conclusions
The 10 years of Observations at the OGS were highly successful:
- Continuous monitoring of GEO environment
- → clusters of debris in orbital element space discovered
- → evolution of clusters
- Validation data for MASTER 2005 and 2009 model
- Continuous monitoring of GTO environment
- Discovery of "new" population of high area-to-mass (AMR) ratio objects
- Investigation of physical properties of debris objects
- light curves
- color photometry
- spectroscopy
- Significant contributions to IADC campaigns
- Unique knowledge base for future European Space Situational Awareness System
Acknowledgments
- Great thanks to our observers Julia de Leon and Lilian de Fatima Dominguez Palmero!
- Support in the form observations to maintain the orbits was provided by the Keldysh Institute of Applied Mathematics (KIAM) in the framework of the ISON collaboration (AIUB-KIAM collaboration).
Размещено 13 апреля 2009
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