Orbital Debris and Di Carlo T. BRIEFING Collisional Cascading

Mar 08Mar 08Collisional Cascading - T. Di Carlo2 The Problem Random collisions between man-made objects in earth orbit may some day initiate cascading collisions that will exponentially pollute these high-value orbits, rendering them exceedingly hazardous for space ventures. As suggested by.: Collisional Cascading - The Limits of Population Growth in Low Earth Orbit, Kessler, Donald J., NASA Doc ID , Adv. Space Res. Vol. 11, No. 12, pp. (12)63-(12)66, 1991

Mar 08Mar 08Collisional Cascading - T. Di Carlo3 Sampling of Prior Art EVOLVE - one-dimensional, LEO-only, deterministic and stochastic environment evolution model with Monte Carlo processing (NASA) LEGEND – Leo-to-Geo Environment Debris model, 3-dimensional (altitude, latitude, longitude) evolutionary model (NASA) CHAINEE – PIB model for long-term LEO predictions based on traffic assumptions and mitigation measures (ESA) SDM/STAT – like CHAINEE, based on modulation of background population (ESA) PIB – particle in a box (1) (1) for a description of PIB see: Analytic Model for orbital Debris Environmental Management, David L. Talent, Journal of Spacecraft and Rockets, Vol. 29, No. 4, pp , 1992

Mar 08Mar 08Collisional Cascading - T. Di Carlo4 NASA Orbital Debris Program Architecture ORDEM Engineering Model Source: NASA 26 July 2006 Orbital Debris Environment Presentation to ISS Independent Safety Task Force

Mar 08Mar 08Collisional Cascading - T. Di Carlo5 Sources / Sinks Satellites ~120 launches per year worldwide (but, emerging China, Japan and India space programs could inflate this figure; double it?) (1) (2) Rocket Body Parts ~ 2-3 per launch (1) Spontaneous Explosions, Fragmentations – 3% (6), 124 since 1961 (2) Anti-Satellite Tests (ASAT) Soviet Union, at least 4 between 1968 and 1982 (3) (5) USA, at least 1 in 1985 (Solwind) (4) China, 1 in 2007 Space Warfare – none, yet Random Collisions – 1 to date (Cerise, 1996, without explosion) (5) Natural Decay – due to drag, also function of solar activity DeOrbits and Retrievals – policy options (1) Analytic Model for orbital Debris Environmental Management, David L. Talent, Journal of Spacecraft and Rockets, Vol. 29, No. 4, pp , 1992 (2) Office of Science and Technology, Nov 1995 Interagency Report on Orbital Debris (3) (4) (5) Survey of past on-orbit fragmentation events, Carmen Pardini, Acta Astronautica 56 (2005) (6) Future Planned Space Traffic: and Beyond, Phillip D. Anz-Meador, AIAA/NASA/DOD Orbital Debris Conf., April 16-19, 1990, Baltimore MD

Mar 08Mar 08Collisional Cascading - T. Di Carlo6 Solar Flux The System DEBRIS SOURCES SPONTANEOUS EXPLOSIONS COLLISIONS Nations Vying for Space Superiority Nation’s Technological Development Nations Wanting Access to Space New Space Programs SATELLITE LAUNCHES DECAY DEORBIT, RETRIEVAL DEBRIS SINKS ANTI- SATELLITE TEST ORBITAL SPACE DEBRIS POPULATION

Mar 08Mar 08Collisional Cascading - T. Di Carlo Objects in LEO! [1cm or larger] CNES/ill.D.DUCROS, Inter-Agency Space Debris Coordination Committee, 43 rd Session by 2050 (1998 U.N. Committee on Peaceful Uses of Outer-Space prediction)

Mar 08Mar 08Collisional Cascading - T. Di Carlo8 Conceptual Model 1m10 cm1cm1mm Decay Block Collision Block c1c2 c3c4 w1 g1g2 g3g4 s1s2s3s4 Breakup Block Holding Tanks s1s2s3s4Exit ASAT Input New Satellites Input Solar Flux SSN Catalog est. of untrackable objects initialization

Mar 08Mar 08Collisional Cascading - T. Di Carlo9 Reference Behavior (measurement) Number of Catalogued Space Objects (typically 4 in. or larger) / yr

Mar 08Mar 08Collisional Cascading - T. Di Carlo10 Reference Behavior (simulation) NASA EVOLVE PROJECTIONS SOURCE:

Mar 08Mar 08Collisional Cascading - T. Di Carlo11 Preliminary Extend Model USER INTERFACE EXCEL INTERFACE LEVELS PIB EQUATION COEFFICIENTS COUNTERS, PLOTTERS, AND CONSTANTS

Mar 08Mar 08Collisional Cascading - T. Di Carlo12 Particle In a Box Equation debris sweep rate- a policy measure temporary place-holder, suggesting dependence on altitude crude attempt to model modulating effect of solar activity orbit decay; crude and semi- empirical new objects; mostly policy- driven

Mar 08Mar 08Collisional Cascading - T. Di Carlo13 Notional User Interface

Mar 08Mar 08Collisional Cascading - T. Di Carlo14 Extend Deposition Sub-Model Number of significant fragments generated per explosion (could be stochastic)

Mar 08Mar 08Collisional Cascading - T. Di Carlo15 Extend Removal Sub-Model Extend – Excel INTERFACE

Mar 08Mar 08Collisional Cascading - T. Di Carlo16 Extend Collisions Sub-Model Number of significant fragments generated per collision (could be stochastic)

Mar 08Mar 08Collisional Cascading - T. Di Carlo17 Extend ◄► Excel Extend Global Array Managers

Mar 08Mar 08Collisional Cascading - T. Di Carlo18 1-Tier, 1-Species Altitude Range: 350 – 1800 km

Mar 08Mar 08Collisional Cascading - T. Di Carlo19 4-Tier, 1-Species (to be implemented) km km km km

Mar 08Mar 08Collisional Cascading - T. Di Carlo20 Critical Simplifying Assumptions De-Orbit Algorithm – crude, based on average debris diameter, which is turn estimated a function of on-orbit mass, number of orbiting objects, and the simplifying assumption that objects are spherical and of uniform density. Solar Flux Prediction – I assume a repeating 21 cycle; may be critical for longer-term predictions Number of Pieces per explosion – 120, could be stochastic Number of Fragments per collision – 200, could be stochastic

Mar 08Mar 08Collisional Cascading - T. Di Carlo21 Preliminary Extend Results ( ) Solar Activity (F10) and Orbital Decay (N_out) Solar Activity (Jansky) Decay (number/year) Simulation Year

Mar 08Mar 08Collisional Cascading - T. Di Carlo22 Preliminary Extend Results ( ) Significant Objects in Low Earth Orbit (N) Simulation Year Significant Objects in LEO

Mar 08Mar 08Collisional Cascading - T. Di Carlo23 Preliminary Extend Results ( ) Satellite Kill Rate (rough estimate) Simulation Year Collision Coefficient (C) SAT Kill Rate (#/yr)

Mar 08Mar 08Collisional Cascading - T. Di Carlo24 Preliminary Insights Will Collisional Cascading Occur? - maybe, but I’m not seeing it yet (N tends to level out) Policy and Design – they DO make a difference, for example - post-mission disposal of upper stages reduces N 20% - Doubling SAT density (packaging) reduces N 20%

Mar 08Mar 08Collisional Cascading - T. Di Carlo25 Forward Work Validation – match reference behaviors; get/implement Kessler’s input Sensitivity Analysis – screen for critical parameters and fine tune them 4-Tier, 1-Species Implementation – if time allows (for granularity) Historical Satellite Database – link to database Implement as a Discrete Event n-Tier, n-Species Simulation Simplify user Interface – using Extend Notebook [NEAR-TERM] [LONG-TERM]

Mar 08Mar 08Collisional Cascading - T. Di Carlo26 Summary Simulation of orbital accumulation: Inspired by 1991 paper describing idea of Collisional Cascading – AKA The Kessler Syndrome Resources, Reference Behaviors: Extend6 Simulation Development Environment SSN Catalog; published historical trends; loads of studies and published papers; Don Kessler Implementation: Particle-in-a-Box Continuous Simulation Model Extend◄►Excel; User “Policy” Interface Potential Benefits, and Lessons to be Learned: Dynamics of orbital crowding Conditions for Collisional Cascading Space as a Sustainable Resource

Mar 08Mar 08Collisional Cascading - T. Di Carlo27 Publications and Resources (1) Collisional cascading - The Limits of Population Growth in Low Earth Orbit, Kessler, Donald J., NASA Doc ID (2) Littered Skies, NYTimes.com, 6 Feb 2007, f=slogin f=slogin (3) Overview of Orbital Space Debris, IPS Radio and Space Services, (4) Space Simulation and Modeling - Roles and Applications Throughout the System Life Cycle, Larry B. Rainey editor, The Aerospace Press, El Segundo CA, 2002 (5) Simulation Model of Space Station Operations in the Space Debris Environment, Mark M. Mekaru and Brian M. Waechter, Proceedings of the 1985 Winter Simulation Conference (6) Collisions of Artificial Earth Orbiting Bodies, L. Sehnal and L. Pospisilova, Publishing House of the Czechoslovak Academy of Sciences, 18 Nov 1980 (7) Orbital Debris Environment Resulting from Future Activities in Space, Shin-Yi Su, Center for Space and Remote Sensing Research and the Department of Atmospheric Physics, National Central University, Chung-Li, P.R.C., Taiwan, 23 Oct 2002 (8) The New NASA Orbital Debris Engineering Model, NASA/TP— , May 2002 ORDEM2000www.orbitaldebris.jsc.nasa.gov/library/ORDEM/ORDEM2K.pdf