Space Debris: Future Challenges

Dr Hugh Lewis

2

Outline 1. Space debris past and present: 1957-2012

2. Space debris futures: 2012-2212

– Space debris mitigation

– Space debris removal

3. Challenges

3

Annual number of launches

20

40

60

80

100

120

140

Mis

sion

s to

Ear

th o

rbit

and

beyo

nd

1960 1970 1980 1990 2000 2010 Year

4

Annual number of explosions

1

2

3

4

5

6

7

Num

ber o

f fra

gmen

tatio

n ev

ents

per

yea

r

1960 1970 1980 1990 2000 Year

8

9

5

Top “10” worst fragmentations

Space debris population • Catalogue data 1957-2012:

Courtesy NASA

Future predictions • University of Southampton’s DAMAGE model:

8

Active satellites (Aug 2012)

Union of Concerned Scientists Satellite Database seen in DAMAGE 999 active satellites

9

10 cm population (May 2009)

ESA MASTER 2009 population seen in DAMAGE 29,370 objects ≥ 10 cm (1 catastrophic collision)

10

10 cm population (May 2209)

ESA MASTER 2009 population evolved to 2209 using DAMAGE 120,000+ objects ≥ 10 cm (~100 catastrophic collisions)

11

Low Earth Orbit

Effective number of objects in LEO

488 active satellites

Active satellites 10 cm population (2009) 10 cm population (2209)

16,000 objects 50,000+ objects

12

LEO future projection: 10 cm

Note: averages only (100 Monte Carlo runs)

Total

Collision fragments

Explosion fragments

Intact objects

• Non-mitigation case, 2009-2209

0

10000

20000

30000

40000

50000

60000

70000

80000

2010 2030 2050 2070 2090 2110 2130 2150 2170 2190 2210Year

Mea

n Ef

fect

ive

Num

ber o

f Obj

ects

>10

cm in

LEO PMD BASELINE

13

LEO post-mission disposal • Compliance with the “25-year rule” has significant benefits

Non-mitigation

Post-mission disposal

14

Remediation

• Even with good compliance with the commonly adopted mitigation guidelines, the space debris population is likely to grow:

– Active Debris Removal

DEOS (DLR) “Clean Space One” concept (Swiss Space Center)

15

Which objects to remove?

4

1

2

3 5

16

How many objects to remove?

4 2 5

• About 50 removals are needed to prevent one collision

• DAMAGE studies suggest 3 to 10 removals per year:

– In 50 years: 150 to 500 removals

– $45 – 150 billion ($1 – 3 billion per year)

– 25 – 50% chance the LEO population still increases

– Adaptive Removal Strategy:

17

How many objects to remove?

3.1 removals per year 84% confidence

29 removals to prevent one collision

5 removals per year 74% confidence

44 removals to prevent one collision

Note: averages only (100 Monte Carlo runs)

18

Future challenges

• Five challenges (C’s) of space debris clean-up:

• Compliance with debris mitigation guidelines.

• Consensus on active debris removal.

• Cooperation: removal targets may belong to a different country.

• Collaboration: it is highly unlikely that any single organization or country can accomplish the goal by itself.

• Contributions: cost-sharing will be important for engaging in active debris removal.

2-5, courtesy J.-C. Liou, NASA

Acknowledgements: J.-C. Liou (NASA), Holger Krag, Heiner Klinkrad & Tim Flohrer (ESA), EU Framework 7 ACCORD Project (No. 262824), Richard Crowther (UK Space Agency), Adam White & the Project SHARP Team (University of Southampton), Hedley Stokes (PHS Space Ltd)