© The Aerospace Corporation 2010

IAC-10.A6.2.10

Effects of Space Debris on the Cost of Space Operations

William Ailor, The Aerospace CorporationJames Womack, The Aerospace CorporationGlenn Peterson, The Aerospace CorporationNorman Lao, The Aerospace Corporation

61st International Astronautical CongressPrague, Czech Republic

September 28, 2010

Overview

• Background

• Study Approach

• Satellite Model

• Constellations

• Debris Model

• Debris Effects on Satellite Lifetime

• Debris Effects on Cost to Maintain Constellations

2

Today

• Have about 1000 operating satellites• More than 20,000 tracked objects• Up to 600,000 pieces of debris large

enough to cause loss of a satellite• Millions of smaller particles that can

degrade performance

3

Possible Futures• No mitigation (no post-mission

maneuvers to dispose of hardware)

• 200 to 2000 km altitude orbits

• 1997-2004 launch cycle

• Predicts ~24 collisions in next 100 years

• NASA study* shows removal of 5 large debris objects/year will stabilize population of orbiting objects in LEO

• Discussions beginning on debris removal technique

LEO Environment Projection (averages of 100 LEGEND MC runs)

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

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

Year

Eff

ecti

ve N

um

ber

of

Ob

ject

s (>

10 c

m)

PMD

PMD + ADR02

PMD + ADR05

• PMD—Post-Mission Disposal actions• ADR—Active Debris Removal• Select objects with the highest [ mass Pc ], where Pc is

the instantaneous collision probability at the beginning of the year

*J.-C. Liou and N.L. Johnson, “Active Debris Removal - The Next Step in LEO Debris Mitigation,” 26th IADC Meeting, 14-17 April 2008, Moscow, Russia.

4

0

5000

10000

15000

20000

25000

1955 1965 1975 1985 1995 2005 2015 2025 2035 2045 2055 2065 2075 2085 2095 2105

Year

Eff

ecti

ve N

um

ber

of

Ob

ject

s (>

10cm

, L

EO

)

Total

Intacts + mission related debris

Exp fragments

Col fragments

J.-C. Liou, “A statistical analysis of the future debris environment,” Acta Astronautica 62 (2008) 264 – 271.

Effects on Satellites and Satellite Operations

• Higher costs of constellation maintenance – Replace degraded and destroyed satellites– Increased costs of satellites (robustness)

• More collision avoidance maneuver actions (if service available)

– Depends on quality of data

• Increased threat during launch– Possible launch holds

What will be the effect on cost?

5

Analysis Approach

• Project populations of orbiting objects for 50 years• Define three generic satellites• Define critical areas for each satellite type and size of

impacting object– 1 mm to 1 cm (untracked)—degrade solar panel performance– 1 cm to 10 cm (untracked)—degrade solar panel or kill satellite if

strikes critical area– >10 cm (tracked objects)—strike anywhere kills satellite

• Place satellites in “constellations” at worst-case altitude (850 km)• Assume constellations fully constituted in 2010, 2020, 2030• Estimate changes in satellite lifetime due to debris environment• Estimate increased cost to maintain constellation at full

strength for 20 years

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Three Satellite Types & Sizes

• Government satellite– Multiple missions– High reliability– High cost

• Commercial #1– Medium cost

• Commercial #2– Single mission– Low cost “factory built”

X direction

Z direction

Y direction

X direction

Z direction

Y direction

Generic Government Satellite

Generic Commercial Satellite

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•Impacts on bus and payload

1 cm0 10 cm

{not fatal} {fatal only in critical areas}

{fatal anywhere on bus and payload}

Size of debris

•Impacts on solar arrays

No Damage

50% chance of no damage40% chance knocks out 1 string5% chance knocks out 2 strings5% chance of fatal impact*

50% chance knocks out 2 strings35% chance knocks out 3 strings10% chance knocks out 4 strings5% chance of fatal impact*

1 mm0 1 cm 10 cm

*This accounts for impact to harness, root connector, or yoke which would remove 25-100% of the array power and causes loss of mission

critical areas

solar arrays

Debris Damage Assumptions

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Constellations

ConstellationNo. of Satellites in

ConstellationSatellite Design

Life (Years)Satellite Unit Cost

($M)Launch

Cost ($M)Notes

Government 5 6 750 250 Heavy lift ELV

Commercial #1 20 9 250 80 Medium lift ELV

Commercial #2 70 12 50 80Medium lift ELV, 5 satellites co-manifested per launch

Government Commercial #1 Commercial #2

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Location of Constellations

• Satellites placed in region where flux of objects (and probability of collision) is highest

• Sun-synchronous orbits at 850 km

Location of constellations

10

Debris Size Ranges & Flux• Debris flux estimated using

Aerospace model (>10 cm objects) and modified version of ESA’s MASTER05 (1 cm & 1 mm particles)

– Includes man-made debris, micrometeoroids, operating satellites

– Historical population up to 2005– Model for 2010 and beyond adjusted

for 2007 Chinese ASAT and 2009 Iridium/Cosmos debris

– Added 2 to 3 debris producing events each decade

– Collisions create debris clouds similar to Iridium-Cosmos collision

• All satellites in highly inclined, sun synchronous orbits at ~850 km

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Satellite Reliability Results

Satellite Type

Mean Lifetime

(No Debris)

Mean Lifetime &Percent Reduction

(With Fatal Impacts Only)

Mean Lifetime &Percent Reduction

(All Impacts)

Launch Year 2010 2040 2010 2040

Government5.67 years

5.55 years2.1%

5.54 years2.3%

5.48 years3.4%

5.42 years4.4%

Commercial #18.97 years

8.56 years4.6%

8.52 years5.0%

8.29 years7.6

8.17 years8.9%

Commercial #212.26 years

11.63 years5.1%

11.56 years5.7%

11.24 years8.3%

10.65years13.1%

2-6% decrease 3-13% decrease

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Constellation Replenishment Results

ConstellationYear

Constellation Constituted

Number of Replenishment

Launches(No Debris)

Number of Replenishment

Launches(With Fatal Impacts

Only)

Number of Replenishment

Launches(All Impacts)

Government201020202030

20.120.120.1

20.4 (2% Increase)20.5 (2% Increase)20.5 (2% Increase)

20.8 (4% Increase)20.8 (4% Increase)20.9 (4% Increase)

Commercial #1201020202030

51.451.451.4

53.7 (5% Increase)53.8 (5% Increase)54.1 (5% Increase)

55.9 (9% Increase)55.9 (9% Increase)56.2 (9% Increase)

Commercial #2(5 sats/launch)

201020202030

24.124.124.1

25.9 (7% Increase)25.9 (7% Increase)26.0 (8% Increase)

27.5 (14% Increase)28.0 (16% Increase)28.5 (18% Increase)

2-8% increase 4-18% increase

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Replenishment Costs due to Debris

ConstellationSatellite Unit

Cost ($M)Launch Cost

($M)Notes

Government 750 250 Heavy lift ELV

Commercial #1 250 80 Medium lift ELV

Commercial #2 50 80Medium lift ELV, 5 satellites co-

manifested per launch

ConstellationYear Constellation

Constituted

Replenishment Cost ($B)

No debris Fatal only All impacts

Government201020202030

20.120.120.1

20.4 (1% increase)20.5 (2% increase)20.5 (2% increase)

20.8 (3% increase)20.8 (3% increase)20.9 (3% increase)

Commercial #1201020202030

17.017.017.0

17.7 (5% increase)17.8 (5% increase)17.9 (5% increase)

18.4 (9% increase)18.4 (9% increase)18.5 (9% increase)

Commercial #2201020202030

7.97.97.9

8.5 (8% increase)8.5 (8% increase)8.6 (9% increase)

9.1 (14% increase)9.2 (16% increase)9.4 (18% increase)

1-9% increase 3-18% increase

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Summary

• Results indicate slow cost increase due to debris environment at worst-case altitude

• Small cost increase to operate in debris environment for next 30 to 50 years

• Higher increase for commercial satellites due to lower solar panel margins; Increasing solar panel robustness reduces cost increase by ~50%

• Collision avoidance service reduces cost increase by ~10%

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