ASEN Aerospace Environments -- Orbital Debris 1 IMPACT CHARACTERIZATION posigrade impulse original orbit final orbit Semi-major axis & period increase final orbit retrograde impulse Semi-major axis & period decrease At perigee: posigrade/retrograde will raise/lower apogee At apogee: posigrade/retrograde will raise/lower perigee Radial impulse apogee, perigee change semi- major axis & period unchanged Out-of-plane (  ) impulse little change Brief review of orbital perturbations Gabbard Diagrams original orbit

ASEN Aerospace Environments -- Orbital Debris 2 Gabbard Diagrams  + circular orbit  + elliptical orbit Single-satellite Gabbard diagrams Depict apogee, perigee, and period of orbiting objects Used to infer information about fragmentation events

ASEN Aerospace Environments -- Orbital Debris B Gabbard diagram for debris from breakup of satellite B same apogees different perigees These fragments received a net retrograde impulse from the breakup These fragments received a net posigrade impulse from the breakup different apogees same perigees  + initially circular orbit Note: retrograde pieces have apogee altitudes similar to the perigees of the posigrade pieces. This follows from the impulse maneuver analogies: An impulse at perigee (apogee) does not affect perigee (apogee) height, but only changes the apogee (perigee) height. For a circular orbit, apogees and perigees are defined once the impulse occurs.

ASEN Aerospace Environments -- Orbital Debris A  + Gabbard diagram for breakup of a satellite in elliptical orbit mostly retrograde impulse Same perigee height; therefore, fragmentation occurred near perigee Range of apogees depends on magnitude of impulse fragmentation height = 587 km

ASEN Aerospace Environments -- Orbital Debris A  + mostly retrograde impulse Nearly same apogee height; therefore, fragmentation occurred near apogee Another example of satellite fragmentation in elliptical orbit Fragmentation height = 2088 km

ASEN Aerospace Environments -- Orbital Debris B  + fragmentation height = 1450 km Fragmentation at a height other than apogee or perigee will exhibit some combination of the previous characteristics

ASEN Aerospace Environments -- Orbital Debris B  + nearly circular; breakup at 750 km A pure radial impulse alters both apogee and perigee while maintaining the same orbital period. A particular explosive event will produce points above and below the “arms” of the Gabbard diagram. Since they appear to surround the parent satellite, they are sometimes called “halo” debris

ASEN Aerospace Environments -- Orbital Debris C For low-altitude breakups, the left arm of the Gabbard diagram can collapse due to orbital decay

ASEN Aerospace Environments -- Orbital Debris 9 Gabbard Diagram for 2007 Chinese ASAT Test Apogee Perigee Period ISS Altitude

ASEN Aerospace Environments -- Orbital Debris 10 “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.” 1 1 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, pages This document contains Gabbard diagrams and other historical information on satellite fragmentations

ASEN Aerospace Environments -- Orbital Debris 11 NASA Orbital Debris Program Architecture ORDEM Engineering Model Source: NASA 26 July 2006 Orbital Debris Environment Presentation to ISS Independent Safety Task Force

ASEN Aerospace Environments -- Orbital Debris 12 Orbital Debris Impacts on Spacecraft Window pit from orbital debris on STS-007. An important source of information about the debris environment is the study of impact pits on surfaces that have been exposed to space in Earth orbit, and that result from hypervelocity impacts. Studies are performed (1)At the Hypervelocity Impact Technology Facility (HIT-F) at NASA JSC in Houston, and the HVI facility at NASA/JSC White Sands Test Facility (WSTF) (2)On samples returned from space Long Duration Exposure Facility (LDEF) Spacecraft Light-Gas gun at the Hypervelocity Impact Technology Facility launches projectiles at velocities high enough to simulate orbital debris impacts. Debris cloud formation captured by high speed camera.

ASEN Aerospace Environments -- Orbital Debris 13 Hypervelocity Impact Technology Facility Side view of an impacted multi-shock shield with Nextel bumpers and a Kevlar rearwall Hypervelocity impact tests Shield development Simulation Threat assessment HITF seeks to develop advanced shielding concepts to protect spacecraft on orbit., particularly ISS, which is covered with meteoroid and orbital debris shields. The goal is always to develop a shield that is effective, while being lightweight. Numerical simulations are used to evaluate impacts at speeds not obtainable in the laboratory (i.e., > 10 km/sec). This is an EXOS hydrocode simulation which models the impact of a cylindrical aluminum impactor into an aluminum flat plate. The geometry of the impactor and the plate are represented by 46,878 uniform particles.

ASEN Aerospace Environments -- Orbital Debris 14 Space Environments and Technology Archive System (SETAS) NASA Langley Research Center, Hampton, Virginia SETAS has been established to preserve and provide easy access to the diverse collection of space environments and technology (SET) resources in terms of both technical disciplines and data sources. The technical disciplines encompass ionizing radiation, meteoroids and debris, neutral external contamination, plasmas and fields, thermal and solar, electromagnetic effects, materials and processes, and systems. The data sources refer to space missions and experiments, including the Long Duration Exposure Facility (LDEF), Hubble Space Telescope (HST), the European Retrievable Carrier (EuReCa), and Clementine / Deep Space Probe Science Experiment (DSPSE). This list is continually being expanded to include all available data sources.

ASEN Aerospace Environments -- Orbital Debris 15 NASA's Long Duration Exposure Facility (LDEF) was designed to provide long- term data on the space environment and its effects on space systems and operations. LDEF had a nearly cylindrical structure 57 experiments were mounted in 86 trays about its periphery and on the two ends. The spacecraft measured 30 feet by 14 feet and weighed ~21,500 pounds with mounted experiments LDEF remains one of the largest Shuttle-deployed payloads LDEF was deployed in orbit on April 7, 1984 by the Shuttle Challenger. LDEF was retrieved on January 11, 1990 by the Shuttle Columbia.

ASEN Aerospace Environments -- Orbital Debris 16

ASEN Aerospace Environments -- Orbital Debris 17 Blanket penetration Typical Aluminum Impact Typical Aluminum penetration Metal Silica Oxide (MOS) detector Beta cloth penetration

ASEN Aerospace Environments -- Orbital Debris 18 Largest impact - side view Crater & Ejecta Thermal Blanket Penetration On-Orbit Thermal Blanket

ASEN Aerospace Environments -- Orbital Debris 19 LDEF was deployed at an altitude of 479 km (259 nautical mi.) in a circular 28.5 degree inclination orbit. At this orbital altitude and inclination, two sources of energetic particles dominate most of the penetrating charge particle radiation encountered--high energy galactic cosmic rays and the geomagnetically-trapped Van Allen protons (E ~ Mev). Where near-surface shielding is less than 1.0 g/cm squared, geomagnetically trapped electrons make a significant contribution.

ASEN Aerospace Environments -- Orbital Debris 20 The LDEF observations revealed data on crater numbers (and fluxes) as a function of crater size, surface orientations relative to the spacecraft orbiting velocity vector, and surface materials, including metals, polymers, composites, ceramics and glasses, some with coatings and paints applied.

ASEN Aerospace Environments -- Orbital Debris 21 Inorganic thermal-control paints, anodized aluminum and silverized Teflon thermal-control blankets maintained their optical properties, and thus, their thermal control function. Organic materials such as Mylar, Kapton, paint binders, and bare composites showed the expected severe erosion and degradation under atomic oxygen exposure. Coated composite materials survived and generally maintained their mechanical properties. Some effects originated from preflight & postflight exposures, and Shuttle sources, as well as on-orbit material degradation. Some thin polymeric films and blanket materials were virtually destroyed and created on-orbit debris that were distributed over adjacent surfaces. A low-density particulate debris cloud in LDEF's wake was observed as the Shuttle approached for retrieval.

ASEN Aerospace Environments -- Orbital Debris 22 Typical List of LDEF Experiments (Systems) * Interstellar Gas Experiment / AO038 * Holographic Data Storage Crystals for LDEF / AO044 * Space Plasma High Voltage Drainage / AO054 * Exposure to Space Radiation of High-Performance Infrared Multilayer Filters and Materials Technology Experiments / AO056 * Cascade Variable Conductance Heat Pipe / AO076 * Effect of Space Environment on Space Based Radar Phased Array Antenna / AO133 * Effect of Space Exposure of Pyroelectric Infrared Detectors / AO135 * Ruled and Holographic Gratings Experiment / AO138-5 * Optical Fibers and Components Experiment / AO138-7 * Passive Exposure of Earth Radiation Budget Experiment Components / AO147 * Study of Factors Determining the Radiation Sensitivity of Quartz Crystal Oscillators / AO189 * Advanced Photovoltaic Experiment / S0014 * Investigation of the Effects of Long Duration Exposure of Active Optical Systems Components / S0050/S * Fiber Optic Data Transmission Experiment / S0109 * Low Temperature Heat Pipe / S1001 * Transverse Flat Plate Heat Pipe Experiment / S1005 * Space Environment Effects on Fiber Optics Systems * Space Environment Effects / M0006 * LDEF Thermal Measurements System / P0003 * Space Aging of Solid Rocket Materials / P0005 LDEF exposed a number of dedicated experiments designed to study the effects of long- term exposure on active and passive systems to the LEO environment.

ASEN Aerospace Environments -- Orbital Debris 23 Summary of LDEF Contributions on Materials Knowledge gained from LDEF research on materials and coatings has led to the following conclusions applicable to spacecraft design: LEO is hostile to spacecraft materials and coatings. Synergistic effects of all aspects of the low-Earth orbit environment must be considered; this includes both the natural environments and the spacecraft induced environments. Contamination must be a significant consideration in spacecraft design. The pre-LDEF knowledge of space environmental effects on materials had major flaws. LDEF knowledge forced revision of environment-related test and qualification procedures. Some examples of the influence of LDEF data on spacecraft designs include: ISS radiator design changed from using second-surface silvered Teflon® to the use of Z-93 ceramic paint because silvered Teflon on LDEF showed substantial deteoriation due to [O], and Z-93 paint samples on LDEF were observed to be very stable in the same environment. Kapton is no longer used as a substrate for flexible solar arrays when high atomic oxygen fluence is expected due to erosion observed on LDEF Dacron thread no longer used to sew spacecraft multi-layer insulation (MLI) together, since [O] was noted to destroy dacron threads of LDEF MLI.

ASEN Aerospace Environments -- Orbital Debris 24 MATERIAL INTERNATIONAL SPACE STATION EXPERIMENT (MISSE) 454 materials flown on MISSE- 1 (also MISSE-2, -3, -4 and -5) solar cell materials thermal control coatings mirrors optical coatings composite materials optical materials Inflatable materials environmental monitors thin film polymers Identifier Category Material -1-B1-1 specialty application materials "new" Beta Cloth with Kapton underneath -1-B1-2 specialty application materials "new" Beta Cloth (with Al light blocker) with Kapton underneath -1-B1-3 proprietary materials TOR Fabric -1-B1-4 proprietary materials TOR Fabric sewn with TOR Thread 4” x 4”

ASEN Aerospace Environments -- Orbital Debris 25 The NASA Orbital Debris Engineering Model ORDEM2000 (in process of being updated to ORDEM2008) LEO km Supercedes ORDEM96 Based on “finite element” concept, rather than curve-fitting Two modes: 1. Orbiting spacecraft 2. Ground-based detection Provides statistical debris environment as a function of altitude, inclination, & size distributions 10 µm to 10 m Similar ESA model -- MASTER’99 For satellite breakup risk assessment --- use NASA SBRAM For more realistic long-term debris evolution --- use NASA EVOLVE ProvidesUsers 1. Debris flux onto spacecraft designers Spacecraft surfacesand operators 2. Debris detection rateDebris observers

ASEN Aerospace Environments -- Orbital Debris 26 Data Sources Primary: SSN catalogto build the 1-m and 10-cm populations Haystack radar datato build the 1-cm population LDEF msmsts.to build the 10-  m and 100-  m populations Other sources used to verify and validate model predictions

ASEN Aerospace Environments -- Orbital Debris 27 Used theoretical & experimental equations and empirical fitting to relate crater depth and material density to particle density and impact speed. Extrapolated to non- LDEF altitudes

ASEN Aerospace Environments -- Orbital Debris 28 Analysis of some LDEF surfaces allowed estimates of the relative fluxes of artificial debris and micrometeoroids Fitted meteoroid crater distribution Craters due to meteoroids + unknowns Craters due to debris Cumulative number Fitted crater debris distribution Crater size (microns) CME gold surface

ASEN Aerospace Environments -- Orbital Debris 29 Sample ORDEM2000 Output: Debris Flux on ISS in 2005 No/m2/year Diameter (cm)

ASEN Aerospace Environments -- Orbital Debris 30 ORDEM2000 Comparisons with Observations

ASEN Aerospace Environments -- Orbital Debris 31 ORDEM2000 Comparisons with Observations

ASEN Aerospace Environments -- Orbital Debris 32 ORDEM2000 Comparisons with Observations Cumulative Number ORDEM 2000 STS

ASEN Aerospace Environments -- Orbital Debris 33 EVOLVE is a 1-D model used to extrapolate the current orbital debris environment into the future Places launched objects and explosion or collision breakup fragments into orbit and calculates how these orbits will change in time. Calculates from these orbits debris environment characteristics such as orbital debris spatial density as a function of time, altitude, and debris size. Places breakup fragments in the environment according to the size and velocity distribution of these fragments in the NASA breakup models. Debris mitigation measures are modeled in EVOLVE through a scenario definition file. Scenarios have been run controlling future launch rates, accidental explosions, and post-mission orbit lifetime for payloads and upper stages. Launched objects are placed in orbit in accordance with historical data or for environment projections with mission model data that specifies the launch date, orbit, payload, and upper stage data for future launches. SOURCE:

ASEN Aerospace Environments -- Orbital Debris 34 NASA Orbital Debris Program Architecture ORDEM Engineering Model Source: NASA 26 July 2006 Orbital Debris Environment Presentation to ISS Independent Safety Task Force

ASEN Aerospace Environments -- Orbital Debris 35 Mitigation is the Best Strategy for Diminishing Future Orbital Debris Impacts!