Tailoring the Observation Scenarios and Data Processing Techniques for Supporting Conjunction Event Assessments

Transcription

1 Tailoring the Observation Scenarios and Data Processing Techniques for Supporting Conjunction Event Assessments T. Flohrer *, B. Bastida Virgili *, H. Krag *, H. Klinkrad *, K. Merz *, T. Schildknecht +, S. Lemmens * ( * ) ESA/ESOC Space Debris Office (HSO-GR), Darmstadt, Germany; tim.flohrer@esa.int ( + ) Astronomical Institute, University of Bern, Bern, Switzerland 9 th US/Russian Space Surveillance Workshop Listvyanka, Irkutsk region, Russia, August 2012 ESA UNCLASSIFIED For Official Use

2 ESA s Space Debris Office (HSO-GR) 1. Entity within the Ground Segment Engineering Department, Directorate of Human Spaceflight and Operations 2. Responsibilities: development and maintenance of an infrastructure in support of ESA s commitment on space debris mitigation and risk reduction a. development & maintenance of debris environment and risk analysis tools b. acquisition & processing of measurement data (e.g. OGS, TIRA, EISCAT) c. operational & contingency support to ESA and 3 rd party missions (mainly LEOP, collision avoidance & re-entry) d. coordination of ESA space debris research e. contribution to ESA, ECSS/ISO standards f. promotion of ESA-internal & public awareness on space debris issues 3. Expertise: flight dynamics (orbital & re-entry), orbit determination, radar & optical tracking, sensor performance modeling, debris environment models, re-entry & collision risk assessments 4. Cooperation: ESA-internal, IADC, others: UNCOPUOS STSC; USSTRATCOM/JSpOC; TIRA, EISCAT, ISON; COSPAR, IAA, IAF 5. Internationally recognized as a centre of expertise in space debris matters ESA SDO Obs Scen COLA T. Flohrer 9th US/Russian Space Surveillance Workshop 27/Aug/2012 HSO Slide 2

3 ESA s Space Debris Office (HSO-GR) Operational Support Collision Avoidance Re-entry Predictions Various Support Task Engineering Support Impact risk analysis On-ground risk analysis Space Surveillance User Products Space Debris Office Standardisation Research Measurements Environment Modelling Environment Predictions Sensor Performance ESA SDO Obs Scen COLA T. Flohrer 9th US/Russian Space Surveillance Workshop 27/Aug/2012 HSO Slide 3

4 Introduction ESA s Space Debris Office Service provides service to support operational collision avoidance activities Conjunction event detection, collision risk assessment, orbit determination and orbit and covariance propagation, and avoidance manoeuvre planning Use of external sensors to acquire additional tracking data Since 2006 the service allows to present some statistical analysis Two characteristic examples are described How to optimise the acquisition of tracking data? Tool chain to examine different sensor architectures and data acquisition strategies Variation of sensor and observation strategy parameters Improvement of the determined orbit vs reference is used as a metric ESA SDO Obs Scen COLA T. Flohrer 9th US/Russian Space Surveillance Workshop 27/Aug/2012 HSO Slide 4

5 Operational collision avoidance process at ESA/ESOC Operator Coordination of tracking opportunities Orbit tracks Flight Dynamics Target orbits Daily, automated runs Warnings to FCT depending on risk threshold Space-track Chaser TLEs ODIN Chaser orbits and covariance data CRASS DISCOS Target properties Manoeuvre planning Verification of absence of secondary conjunctions Operators Flight Dynamics ESA SDO Obs Scen COLA T. Flohrer 9th US/Russian Space Surveillance Workshop 27/Aug/2012 HSO Slide 5 Solar & geomag. activity data (+forecasts)

6 Extended operational collision avoidance process at ESA/ESOC with CSMs JSpOC CSMs, s Flight Dynamics Operator Target orbits Orbit tracks ODIN Chaser orbits and covariance data CRASS DISCOS Target properties Operators Flight Dynamics Solar & geomag. activity data ESA SDO Obs Scen COLA T. Flohrer 9th US/Russian Space Surveillance Workshop 27/Aug/2012 HSO Slide 6

7 Operational collision avoidance at ESA/ESOC statistics (as of mid 2012) Number JSPOC warning bulletins (since end 2009) Tracking campaigns (operational since end of 2006) CRASS JSPOC bulletins Tracking campaigns Avoidance Maneuvers (p) ESA SDO Obs Scen COLA T. Flohrer 9th US/Russian Space Surveillance Workshop 27/Aug/2012 HSO Slide 7

8 Operational collision avoidance at ESA/ESOC - statistics 2500 Envisat - Class of chasers involved in conjunction events S/C-D S/C R/B-D R/B MRO IRI33 C2251 FengYun1C /I 2009/I 2010/I 2011/I 2012/I Year/Quarter Screening volume now: (u,v,w)=(10,25,25)km ESA SDO Obs Scen COLA T. Flohrer 9th US/Russian Space Surveillance Workshop 27/Aug/2012 HSO Slide 8

9 CRASS statistics for 2012 Jan-Jun, chaser origin for Envisat and Cryosat-2 ENV CRY-2 S/C-D 6% R/B 5% MRO 3% R/B-D 10% S/C 7% IRI33 23% FengYu n1c 13% C % R/B 2% R/B-D 14% S/C 7% MRO 8% S/C-D 8% IRI33 17% C % FengYu n1c 18% Screening volume now: (u,v,w)=(10,25,25)km ESA SDO Obs Scen COLA T. Flohrer 9th US/Russian Space Surveillance Workshop 27/Aug/2012 HSO Slide 9

10 Sample events LEO and GEO Jan 21, 2010 Envisat (02009A) vs CZ-2C second stage (09061A) of 3.8t Total miss of 64 m (JSpOC) 5 TIRA of Jan: 48m total, 15m radial, collision probability of 1/77 avoidance manoeuvre: +4cm/s and -4cm/s in along-track direction Feb 11, 2011: close conjunction between two GEO objects: 9.3 km total (-8.98/+2.40/+0.172)km Favourable observation conditions for optical sensors in Europe, operator data, observation campaign OGS+Zimmerwald Regular orbit maintenance cleared situation ESA SDO Obs Scen COLA T. Flohrer 9th US/Russian Space Surveillance Workshop 27/Aug/2012 HSO Slide 10

11 Toolchain based on ODIN ESA SDO Obs Scen COLA T. Flohrer 9th US/Russian Space Surveillance Workshop 27/Aug/2012 HSO Slide 11

12 Selected simulation results - LEO Observation of ENV (simulation of CZ-2C yields similar results) Square radial, dot along-track, diamond cross-track Noise cases: TIRA-like plus conventional radar sensor (30 m/30 mdeg) Number of considered (subsequent) tracks and elevation mask varied Sampling varied too, no effect ESA SDO Obs Scen COLA T. Flohrer 9th US/Russian Space Surveillance Workshop 27/Aug/2012 HSO Slide 12

13 Selected simulation results - LEO Variation of track length From beginning // around peak ESA SDO Obs Scen COLA T. Flohrer 9th US/Russian Space Surveillance Workshop 27/Aug/2012 HSO Slide 13

14 Selected simulation results - LEO Effect of second hypothetic tracking site: Kiruna, Kourou, New Zealand TIRA+Kiruna TIRA+Kourou TIRA+New Zealand ESA SDO Obs Scen COLA T. Flohrer 9th US/Russian Space Surveillance Workshop 27/Aug/2012 HSO Slide 14

15 Selected simulation results - LEO Effect of hypotetical global coverage: TIRA + Kiruna + Kourou, and TIRA + Kiruna + Kourou + New Zealand TIRA+Kiruna+ Kourou TIRA+Kiruna+ Kourou+New Zealand ESA SDO Obs Scen COLA T. Flohrer 9th US/Russian Space Surveillance Workshop 27/Aug/2012 HSO Slide 15

16 Selected simulation results - GEO Effect of instrument noise vs. shortening tracks vs. data from subsequent nights coverage of identical fraction of orbit! not shown: no effect of OGS noise level visible (0.7 in right ascension and declination) Effect of instrument noise vs. sampling vs. data from subsequent nights (assumed data distribution over full nautical night), combination of two sites, OGS and Zimmerwald ESA SDO Obs Scen COLA T. Flohrer 9th US/Russian Space Surveillance Workshop 27/Aug/2012 HSO Slide 16

17 Summary Collision avoidance as routine service by ESA s Space Debris Office, with handling of CSMs included, and on demand execution of dedicated tracking campaigns Increased frequency of close conjunctions in LEO due to recent severe fragmentation events Simulation tool chain based on the ODIN software to study data acquisition scenarios for efficient use of external tracking means applied to two example cases For single site with radar tracking data: 4-5 subsequent tracks Low elevation cut-offs (10 deg) problematic Flexibility in selecting sampling rate the length of the observed arc matters, focus on orbit part around the local peak elevation For conflicting tracking requests keep the high elevation part, as unbalanced shortening may degrade the results Multiple site tracking for faster acquisition of data(!), always improvements Consider optimal coverage of representative full orbits Strive for geographical separation Optical tracking of high altitudes Data acquisition during two full nights (with two displaced sensors) Flexibility in selecting sampling rate the length of the observed arc matters ESA SDO Obs Scen COLA T. Flohrer 9th US/Russian Space Surveillance Workshop 27/Aug/2012 HSO Slide 17