NASANASA--Marshall Space Flight Center’s Advanced Marshall Space Flight Center’s Advanced Concepts Office (MSFCConcepts Office (MSFC--ED04)ED04)

Bruce M. WiegmannBruce M. WiegmannggDecember 10, 2009December 10, 2009

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https://ntrs.nasa.gov/search.jsp?R=20100002197 2020-05-01T17:45:56+00:00Z

Outline

• The Orbital Debris Environment

N t N d t Mi i i K l S d• Near-term Needs to Minimize Kessler Syndrome

• Survey of Active Orbital Debris Mitigation StrategiesSurvey of Active Orbital Debris Mitigation Strategies

• Best Paths to Actively Remove Orbital Debris

• Technologies Required for Active Debris Mitigation

• Conclusions

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Orbital Debris Environment (June 2008)

36000 km

GEO

GEO DebrisGEO Debris

2000 kmLEO

•• 19,000 objects tracked by the US Space Surveillance Network**19,000 objects tracked by the US Space Surveillance Network**•• There are approximately 900 operational spacecraft currently in orbit. There are approximately 900 operational spacecraft currently in orbit.

Of those, approximately 800 are maneuverable. *Of those, approximately 800 are maneuverable. *•• 12,000 objects > 10 cm in diameter***12,000 objects > 10 cm in diameter***

bj i i *bj i i *

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•• 18,000 objects > 5 cm or greater in size.*18,000 objects > 5 cm or greater in size.*•• 300,000 objects > 1 cm in size or greater. *300,000 objects > 1 cm in size or greater. ** From US Congressional Hearing  Charter April 28, 2009**From prepared testimony of NASA’s N.L. Johnson at April 28, 2009 Congressional Hearing*** from ESA Space Debris web site

Projected Growth of LEO Populations(no new launches beyond 1/1/2006)

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Active debris removal needs to be fielded within the Active debris removal needs to be fielded within the next 20 years to minimize Kessler Syndrome effectsnext 20 years to minimize Kessler Syndrome effects

Active Removal of LEO Debris Minimizes the Kessler Syndrome

Analysis shows that the Kessler Syndrome can be minimizedAnalysis shows that the Kessler Syndrome can be minimized

5* Chart from N. Johnson’s “Debris Removal: An Opportunity for Cooperative Research?”presentation at INMARSAT Headquarters, London (25-26 October 2007) “

Analysis shows that the Kessler Syndrome can be minimized Analysis shows that the Kessler Syndrome can be minimized by removing from 5 to 20 LEO objects per yearby removing from 5 to 20 LEO objects per year

Survey of Solutions forActive Orbital Debris Removal

LEO GEO

Debris Size < 1 cm 1 to 10 cm Large (derelict spacecraft or expended rocket bodies)

Large (derelict spacecraft or expended rocket bodies)

Number ofNumber of Objects

Millions ~ 150,000 objects in LEO approximately 20,000 (>10 cm) Hundreds

Potential

Space-based Magnetic Field Generator Space Based Laser Magnetic Sail Solar Sail

Sweeping/Retarding Surface (balloon film

Airborne Based Laser Momentum Tethers Momentum Tethers

OptionsSurface (balloon, film,

foam ball, etc.) Ground Based Laser(Orion) Drag Augmentation Device Capture/Orbital Transfer Vehicle

Electrodynamic Tethers Attachable Propulsive ModuleAttachable Prop Module or OTV

Ground based lasers as Either a Electrodynamic Tether or GEO space junk needs to be put

Systems with Most

PotentialNo practical solutions

Ground based lasers as studied by MSFC in the 1990s show promise. Advances in

pico pulsed lasers may bring desirable effects. All 1-10 cm

debris (>150,000 objects) under 1500 km in altitude could

a large drag device must be attached to the large spacecraft via

AR&D or other methods. The drawback to tethers is the re-entry point is not controllable whereas a propulsive de-orbit module allows

into a disposal or graveyard orbit at least 300 km greater in

altitude than GEO. A space based vehicle stationed at GEO seems to offer the best solution.

AR&D or Capture is needed. under 1500 km in altitude could be removed in approx 3-5

years with one facility located near the equator.

precision guidance upon disposal. Decay times with tethers go from 325 yrs at an 800 km orbit to 200

days.

Propulsion options between storable or ion systems do not seem to be the system driving

design factor.

1) Alexander Karl, “Active Removal of Space Debris – Discussing Technical & Economical Issues”, IAC-06-B6.4.04

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There is no immediately available, single optimum technical There is no immediately available, single optimum technical solution for all aspects of orbital debris removalsolution for all aspects of orbital debris removal

2) USSTRATCOM Global Innovation and Strategy Center, “Eliminating Space Debris: Applied Technology and Policy Prescriptions”, Jan 2008

Satellite Decay Times with an EDT versus Natural Decay Time

10000

Natural DecayNatural Decay Inclination

10

100

1000

Time (yr) 75 deg

50 deg

25 deg

Natural DecayNatural Decay Inclination

0.1

1

Decay 

0 deg

Tether AssistedTether Assisted

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0.01

200 400 600 800 1000 1200 1400 1600

Initial Altitude (km)Time to de-orbit a 1500 kg spacecraft to 250 km with a 7.5 km Terminator Tether TM with a mass of 1% of the spacecraft (1)

Chronology of Tethers in Space

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Tether Technology has matured and is ideally suited Tether Technology has matured and is ideally suited for Active Debris Removalfor Active Debris Removal

Active Orbital Debris Removal Methodsfor GEO Debris

• Non-operating satellites or operational satellites in GEO must be moved to disposal or graveyard orbits which are 300 km above GEOabove GEO.– Less energy required to place dead satellite in disposal orbit versus energy

required to de-orbit satellite.

Active spacecraft designed to accomplish GEO disposal missions could be– Active spacecraft designed to accomplish GEO disposal missions could be designed for numerous disposal missions as the mass impacts for the total delta V necessary are minimal when compared to overall system mass.

– Spacecraft design trades would look at differences in propulsion techniques: Spacec a t des g t ades ou d oo at d e e ces p opu s o tec quesStorable propellants

Ion propulsion

A GEO based space tug with Autonomous A GEO based space tug with Autonomous Rendezvous & Docking or grappling capabilityRendezvous & Docking or grappling capability

b th b t l ti f thi blb th b t l ti f thi bl

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may be the best solution for this problemmay be the best solution for this problem

Technologies Required for Active Debris Removal

• Autonomous Rendezvous &

Technologies required to develop and demonstrate Active Orbital Debris Technologies required to develop and demonstrate Active Orbital Debris Removal exist and are at mature TRLs nowRemoval exist and are at mature TRLs now

Docking –DOD & NASA• The DARPA Front End Robotic Enabling Near-Term

Demonstrations (FREND) project will help improve the robotic arms necessary to remove large objects

• Autonomous Space transfer and Robotic OrbiterAutonomous Space transfer and Robotic Orbiter (ASTRO)

• Demonstration of Autonomous Rendezvous Technology (DART),

• Airborne or Ground Based Lasers –• Airborne or Ground Based Lasers –DOD

• Tethers - USA (NASA & DOD), ESA ( ),& JAXA

• Ion Propulsion - NASA

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A system of systems could be fielded within a few years given A system of systems could be fielded within a few years given appropriate levels of fundingappropriate levels of funding

Conclusions

Technology System Technology System Demonstrators needDemonstrators needto be funded soon.to be funded soon.

Active Orbital Debris removal system demonstrators Active Orbital Debris removal system demonstrators can integrate the technologies available today and can integrate the technologies available today and

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g g yg g ybe assessed for overall effectiveness.be assessed for overall effectiveness.

References

• Slide 4 - Projected Growth of LEO Populations • Slide 5 - Active Removal of LEO Debris Minimizes the Kessler SyndromeJohnson, N., “Debris Removal: An Opportunity for Cooperative Research?”, Improving our Vision II: Building pp y p p g gTransparency and Cooperation, INMARSAT Headquarters, London, UK, 25-26 October 2007

• Slide 6 - Survey of Solutions for Active Orbital Debris RemovalSlide 6 Survey of Solutions for Active Orbital Debris Removal1) Alexander Karl, “Active Removal of Space Debris – Discussing Technical & Economical Issues”, IAC-06-B6.4.042) USSTRATCOM Global Innovation and Strategy Center, “Eliminating Space Debris: Applied Technology and Policy Prescriptions”, Jan 2008

• Slide 7 - Satellite Decay Times with an EDT versus Natural Decay Time•(1) Pardini, C., T. Hanada and P.H. Krisko, Benefits and Risks of Using Electrodynamic Tethers to De-Orbit Spacecraft; Document No IAC-06-B6.2.10

• Slide 8 - Chronology of Tethers in Space

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S de 8 C o o ogy o et e s SpaceWatanabe, T., Fujii, H., Mazawa, T., Sukekawa, M., Kojima, H., Sahara, H., “Experiments of Electro Dynamic Tether System Using Bare Tape Tether and Development of the Tape Tether Deplorer”, 2009-c-31

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BACKUP

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Recent Conclusions from NASA & ESA Experts Regarding Need for Active Debris Removal

• The 5th European Conference on Space Debris (April 2009)Main Conference Finding:However, it is common understanding that mitigation alone cannot maintainHowever, it is common understanding that mitigation alone cannot maintain a safe and stable debris environment in the long-term future. Active space Active space debris remediation measures will need to be devised and debris remediation measures will need to be devised and implemented. implemented.

• Recent Congressional Testimony Concerning Orbital Debris (April 28, 2009)

Written testimony of Mr. N. Johnson, Chief Scientist for Orbital Debris – NASAWritten testimony of Mr. N. Johnson, Chief Scientist for Orbital Debris NASA at “Keeping the Space Environment Safe For Civil and Commercial Users”

“The recent collision of two intact satellites underscores a NASA 1970s-era finding, ….that the amount of debris already in Earth orbit is sufficient to lead to more accidentalthat the amount of debris already in Earth orbit is sufficient to lead to more accidental collisions, which in turn will lead to an unintended increase in space debris and increased risk to operational space systems. …. The most effective means of limiting satellite collisions is to remove non-functional spacecraft and launch vehicle orbital stages from orbit However the remediation of the near Earth space

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vehicle orbital stages from orbit. However, the remediation of the near-Earth space environment presents substantial technical and economic challenges.”

Benefits of Active Debris Removal(Source: NASA/JSC/L.-C. Liou; N.L. Johnson , July 16, 2009)

LEGEND‐simulated LEO debris populations (objects 10cm and larger) between 1957 and 2006 (historical), and between 2007 and 2206 (future projection). 

Each curve represented the average of 100 Monte Carlo runs. Spatial density distribution of objects 10cm and larger in LEO. The bottom curve 

represents the LEO environment at the end of 2006

Altitude distributions of objects removed from the three ADR scenarios.Each distribution is the average of 100 Monte Carlo runs

Inclination distributions of objects removed from the three ADR scenarios. Each distribution is the average of 100 Monte Carlo runs.

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Each distribution is the average of 100 Monte Carlo runs. Each distribution is the average of 100 Monte Carlo runs.   

Positive results of Active Debris Removal by the removal of Positive results of Active Debris Removal by the removal of 5, 10, or 20 objects removed per year. 5, 10, or 20 objects removed per year.

Impacts to LEO Debris Density from PRC ASAT Test and Iridium/Cosmos Collision

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The growth of the cataloged satellite population during the past 15 yearsThe growth of the cataloged satellite population during the past 15 yearshas been primarily influenced by China’s ASAT test in January 2007.has been primarily influenced by China’s ASAT test in January 2007.