National Aeronautics and Space Administration

Risk from Orbital Debris

J.-C. Liou, PhD Chief Scientist for Orbital Debris NASA Orbital Debris Program Office

RAS Specialist Discussion Meeting on Space Dust and Debris in the Vicinity of the Earth London, UK, 9 November 2018 National Aeronautics and Space Administration Outline

• Overview of the orbital debris (OD) problem • NASA Orbital Debris Program Office (ODPO) • Characterization of the OD risk to space missions

Orbital debris = human-made debris in Earth orbit = micrometeoroids and orbital debris (MMOD)

2/25 JCL National Aeronautics and Space Administration

Overview of the Orbital Debris Problem

3/25 JCL National Aeronautics and Space Administration What Is Orbital Debris?

• Orbital debris is any human-made object in orbit about the Earth that no longer serves any useful function

Objects in the Near-Earth Environment

R/Bs, S/C

Breakup Fragments

Mission-related Debris

NaK

Orbital Debris Orbital Al2O3 Al2O3 (slag)

Degradation Debris MLI Pieces

Meteoroids

10 µm 100 µm 1 mm 1 cm 10 cm 1 m 10 m Size (diameter) (Boundaries are notional) 4/25 JCL National Aeronautics and Space Administration Historical Orbital Debris Environment

• Only objects in the U.S. Space Surveillance Network (SSN) catalog are shown • Sizes of the dots are not to scale

5/25 JCL National Aeronautics and Space Administration How Much Junk Is Currently Up There?

Softball size or larger (≥10 cm): ~23,000 (tracked by U.S. Combined Space Operations Center, CSpOC)

Marble size or larger (≥1 cm): ~500,000

Dot or larger (≥1 mm): >100,000,000 (a grain of salt)

• Due to high impact speed in space (~10 km/sec in LEO), even sub-millimeter debris pose a realistic threat to human spaceflight and robotic missions  10 km/sec = 22,000 miles per hour (the speed of a bullet ~1,500 miles per hour) • Mission-ending threat is dominated by small (mm-to-cm sized) debris impacts

• Total mass: >7600 tons LEO-to-GEO (~30006/25 tons in LEO) JCL National Aeronautics and Space Administration Growth of the Cataloged Populations

• The CSpOC is tracking ~23,000 large objects and maintains most of their orbits in the U.S. Satellite Catalog

20000

18000 Total Objects Collision of Cosmos 2251 and Iridium 33 16000 Fragmentation Debris

14000 Spacecraft Destruction of Fengyun-1C 12000 Rocket Bodies

10000 Mission-related Debris

8000 ~1700 are operational 6000 Number of Objects 4000

2000

0 1956 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 2016 2018 Year 7/25 JCL National Aeronautics and Space Administration Mass in Orbit Continues to Increase

• The material mass in Earth orbit continues to increase and has exceeded 7600 metric tons 8000

7000 Total Objects

6000 Spacecraft Rocket Bodies 5000 Fragmentation Debris No sign of slowing down! 4000 Mission-related Debris

3000

2000

MassOrbit in (metric tons) 1000

0 1956 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 2016 2018 Year 8/25 JCL National Aeronautics and Space Administration Distribution of the Cataloged Objects, LEO-to-GEO

• The (LEO, the region below 2000 km altitude) has the highest concentration of the cataloged objects, followed by GEO. LEO to GEO (1 Januar 2018) 1.E-07

1.E-08 Global Navigation Satellite Systems

) (GPS, GLONASS, Beidou, Galileo) 3 1.E-09

1.E-10

1.E-11 LEO

1.E-12

Spatial Density Density Spatial (no/km Geosynchronous Earth Orbit (GEO) 1.E-13 0 10000 20000 30000 40000 Altitude (km)

9/25 JCL National Aeronautics and Space Administration Distribution of the Cataloged Objects in LEO

LEO (1 Jan 2018 Catalog) 6.E-08

Iridium 5.E-08 ) 3

4.E-08 A-Train

3.E-08 Orbcomm

2.E-08 Globalstar Spatial Density Density Spatial (no/km 1.E-08 ISS

HST

0.E+00 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 Altitude (km)

10/25 JCL National Aeronautics and Space Administration Threat from Orbital Debris - Examples

• The gravity-gradient boom of an operational French satellite (CERISE) was cut in half by a tracked debris fragment in 1996 • The fully operational Iridium 33 was destroyed by the retired Russian Cosmos 2251 in 2009 • Near the end of the Space Shuttle Program, the Loss of Crew and Vehicle risks from MMOD impact damage were in the range of 1 in 250 to 1 in 300 per mission (OD to MM ~2:1 at ISS altitude) • Impacts by small, untracked debris could be responsible for many satellite anomalies – A 17-cm Russian retro reflector, BLITS, Impact damage on was damaged and shed a piece of trackable Sentinel-1 solar panel debris in January 2013 – The ’s Sentinel-1 was hit by a small debris, leading to some power loss and 6 trackable debris in August 2016

Image Credit: ESA BLITS 11/25 JCL National Aeronautics and Space Administration Orbital Debris Success Story (1/2)

• Based on debris modeling and impact testing efforts to better protect the Space Shuttle, key modifications were approved in 1997 to “harden” the Orbiter from the increased OD impact risk – An extra layer of 0.5-mm thick aluminum (aluminum doubler) bonded to the radiator face sheet directly over the cooling tubes – Automatic isolation valves added to each coolant loop to isolate a leak in a radiator panel from the rest of the Freon system

STS-128 (Discovery), 2009

12/25 JCL National Aeronautics and Space Administration Orbital Debris Success Story (2/2)

• An impact on the aluminum doubler directly above the Freon tube was identified during the 2009 STS-128 (Discovery) postmission inspection – Simulations show that had the doubler not been in place, the Freon tube would have been breached – Without the second modification isolating the leak to the radiator panels, all of the Freon (which is under pressure) would have leaked from the system, requiring the Shuttle to terminate its mission and land within 24 hours, and with reduced avionics (due to depletion of coolant) simulated impact aluminum doubler (0.18-mm steel debris)

1 cm

13/25 JCL National Aeronautics and Space Administration Orbital Debris Size Distribution

Notional CumulativeSize Distribution of LEO-Crossing Objects 10,000,000

5 mm 1,000,000

1 cm

100,000

5 cm

10,000 10 cm 50 cm Cumulative NumberCumulative 1 m

1,000 0.1 1.0 10.0 100.0 Size (cm)

Mission-ending threat is dominated by small debris impacts

14/25 JCL National Aeronautics and Space Administration Top Risk for NASA Missions in LEO (1/2)

• NASA currently operates more than 20 missions in LEO – Thirteen missions at 600-1000 km altitude: Aqua, Aura, CALIPSO, CloudSat, OCO-2, QuikSCAT, Terra, SORCE, TIMED, NuSTAR, IRIS, O/OREOS, SMAP – Seven missions for NOAA and USGS at 600-1000 km altitude: NOAA-15, -18, -19, Suomi NPP, JPSS-1, Landsat 7, Landsat 8 – Seven missions below 600 km alt: ISS, HST, GPM, Fermi, AIM, Swift, CYGNSS (8 spacecraft)

• Millimeter-sized orbital debris represents the highest penetration risk to most operational (robotic) spacecraft in LEO

15/25 JCL National Aeronautics and Space Administration Top Risk for NASA Missions in LEO (2/2)

• The 2015 NESC JPSS MMOD assessment report includes the following findings and recommendation F10. In spite of the identified uncertainties, ORDEM 3.0 possesses several advantages over ORDEM2000, MASTER-2009 and the current version of ADEPT. F-4. The models disagree significantly for particles <3 mm, which is also the size that poses the highest penetration risk to most spacecraft. F-2. For the flux for particles < 3 mm, orbital debris model validation for altitudes above 600 km is most effective using in situ data. R-19. Increase efforts to directly characterize the debris environment, especially at altitudes above 600 km for which there is currently no in situ data.

NESC = NASA Engineering and Safety Center JPSS = Joint Polar Satellite System

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The NASA Orbital Debris Program Office

17/25 JCL National Aeronautics and Space Administration NASA Orbital Debris Program Office (ODPO)

• The ODPO is the only organization in the U.S. Government conducting a full range of research on orbital debris – This unique NASA capability was established at JSC in 1979 (D. Kessler, J. Loftus, B. Cour-Palais, etc.) – ODPO’s roles and responsibilities are defined in NPR 8715.6B – ODPO is currently funded through HQ/OSMA • ODPO provides technical and policy level support to NASA Centers, NASA HQ, OSTP, other U.S. Government agencies and the commercial sector • ODPO represents the U.S. Government in international fora, including the Inter-Agency Space Debris Coordination Committee (IADC) and the United Nations • ODPO is recognized as the world leader in environment definition and modeling, and in mitigation policy development

18/25 JCL National Aeronautics and Space Administration End-to-End Orbital Debris Activities at ODPO

12000 Total Intacts + mission related debris 10000 Explosion fragments Collision fragments Mission Risk Assessments 8000

6000 NASA space assets

4000 (ISS, Orion, robotic missions, etc.)

2000 Effective Number of Objects (>10cm, LEO) Objects Effective Number of Reentry

0 1950 1970 1990 2010 2030 2050 2070 2090 2110 2130 2150 2170 2190 2210 Year

Measurements Modeling Environment Management Radar Breakup Mitigation Optical Engineering Remediation In-situ Evolutionary Policy Laboratory Reentry Mission Requirements

Coordination U.S. Government IADC, ISO United Nations

19/25 JCL National Aeronautics and Space Administration Current NASA Orbital Debris Database

36,000 MODEST telescope (04-14) Data Gap

10,000 Goldstone radars (>32.2º) HUSIR (Haystack radar) (>30º)

2000 Data Gap 1000

HST-WFPC2 (580x610 km, 93-09) U.S. Space Surveillance Network

STS (300x400 km, 95-11)

Haystack Auxiliary (HAX) radar (>42.6º) 100

10 µm 100 µm 1 mm 1 cm 10 cm 1 m 10 m (Boundaries are notional) Particle Diameter

20/25 JCL National Aeronautics and Space Administration Radar Measurements

• Data processing • Object detection/correlation • Debris size estimation • Orbit assessment • Environment definition

HUSIR = Haystack Ultra-wideband Goldstone Satellite Imaging Radar HUSIR and HAX (MIT/LL) (NASA/JPL) HAX = Haystack Auxiliary Radar

21/25 JCL National Aeronautics and Space Administration Eugene Stansbery Meter Class Autonomous Telescope (ES-MCAT) • A NASA, U.S. Air Force, and Air Force Research Laboratory joint project • The facility is located on Ascension Island (7° 58ʹ S, 14° 24ʹ W) • The two instruments are a 1.3-m telescope (MCAT) and a 0.4-m Mini-CAT telescope – MCAT: a double horse-shoe DFM telescope Orion nebula (MCAT) with a field-of-view of 41ʹ × 41ʹ – Mini-CAT: an Officina Stellare telescope with a field-of-view of 44ʹ × 44ʹ • Objectives for operations – Conduct GEO and LEO statistical surveys – Detect debris as small as ~20 cm in GEO – Characterize low inclination objects in LEO – Provide rapid break-up response – Support space situational awareness coverage

Ascension Island 22/25 JCL National Aeronautics and Space Administration In-Situ Measurements of Small Debris

• NASA, the Naval Academy, the Naval Research Lab, Virginia Tech, and the University of Kent (Canterbury, UK) have developed new technologies for in-situ measurements of small debris from space – The Space Debris Sensor (SDS) / Debris Resistive/Acoustic Grid Orbital NASA-Navy Sensor (DRAGONS) combines several particle impact detection principles to measure time, location, speed, direction, energy, and the size of each impacting particle • SDS was launched as a technology demonstration mission and installed on the ISS on 1 January 2018 • The sensor collected good test and calibration data for more than 3 weeks, but also experienced two serious computer-related anomalies and ceased to function on Jan 26th – The DRAGONS team continues to pursue new mission opportunities

SpaceX-13 launch

SDS Columbus SDS

ISS MAGIK SpaceX Dragon trunk Animation 23/25 JCL National Aeronautics and Space Administration Laboratory-Based Satellite Impact Experiments

• To better understand the outcome of an on-orbit collision, NASA, the Air Force Space and Missile Systems Center, the Aerospace Corporation, and the University of Florida are collaborating on a project called DebriSat – Conduct laboratory-based hypervelocity impact experiments on a representative, modern LEO satellite and an upper stage mockup – Collect, process, and measure fragments down to a few millimeters in size – Use the data to improve satellite breakup models for better protection of the operational spacecraft and to improve space situational awareness of the orbital debris environment

570 g projectile @ 6.8 km/sec

24/25 JCL National Aeronautics and Space Administration Forward Challenges

• Conduct space-based in-situ measurements on millimeter-sized OD populations in LEO to address the top risk for missions in low Earth orbit

• Improve mission compliance with the existing OD mitigation requirements

• Develop near- and long-term cost-effective OD mitigation and remediation strategies to preserve the near Earth space environment for future generations

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