Post on 08-Jul-2020
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)