Transcript Now there is Earth Orbiting Debris

An Introduction to the
Kessler Syndrome:
Collisional Cascade of Orbital Debris
National Climatic Data Center
May 23, 2012
by Don Kessler
Retired NASA Senior Scientist for
Orbital Debris Research
Asheville NC
Common Program Issues:
Climate Change and Orbital debris
• Require international agreements
• Program elements include modeling,
measurements, mitigation
• Models predict a “tipping point”
• Thermosphere
• Shield spacecraft to ensure planned life
Major Planets of the Solar System:
Circular Orbits confined to a plane
A stable system
Meteoroids come from
Comets and Asteroids
(contribute to a slightly unstable system)
Orbital Debris (larger than a softball):
Mostly circular orbits with high inclinations
A very unstable system
Iridium 33/Cosmos 2251 Collision
Iridium Constellation of 66 communication satellites
Iridium/Cosmos Collision
One year after the Iridium/Cosmos collision,
about 2000 fragments cataloged, as
longitudes of nodes randomize
Altitude (kilometers)
1800
1600
Apogee
1400
Perigee
1200
Cosmos 2251 Debris
1000
800
600
400
200
0
85
90
95
100
Orbital Period (minutes)
105
110
115
Iridium 33 Debris
Number of Cataloged Objects in Earth Orbit
Anti-satellite Test plus the
Iridium/Cosmos Collision
doubled fragment count
Iridium/Cosmos
China Anti-satellite
Year
1981: Upper stage
explosion mitigation
1996: Began 25-yr Rule
Predicted Collisions in LEO
Compared to observed collisions
Historical
Business as Usual
Post-Mission Disposal
No Future Launches
Data (excludes Cerise)
Iridium 33 & Cosmos 2251
Thor-Burner upper stage
Cosmos 1934
Damage to 8” x 8” x 4” Aluminum Block hit
at orbital speeds with ¾ inch plastic cylinder
Single collision between
satellites produces:
• 10,000 fragments size of
¾” cylinder in this test
• 100,000 smaller fragments
but large enough to
significantly damage most
spacecraft
Every returned spacecraft surface
has craters from orbital debris impacts
STS-118 Radiator panel Puncture
2 mm titanium-rich debris
Entry hole 7 mm
Exit hole 14 mm
Orbital debris impacts on returned spacecraft surfaces exceed the number
of meteoroid impacts. Materials melted into the craters include aluminum,
titanium, paint, copper, silicone, circuit board, sodium-potassium
Intact Rocket Bodies and Payloads:
Regions of Instability in 1999
10-7
Spatial
Density,
Number/km3
Runaway
10-8 1999 Catalogue
of intact objects
Runaway
Unstable
10-9
0
10-10
0
500
1000
500 Altitude,1000
Km
Altitude, Km
1500
1500
2000
2000
Geosynchronous Orbit:
Less of an immediate problem
Beginning of a long-term problem
Program Elements
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Modeling: Debris sources and sinks
Measurements: Ground and in-situ
Spacecraft shielding: Design and testing
Mitigation1: Minimize creation of debris
Collision avoidance: Against tracked objects
Reentry ground hazard: Largest tracked objects
Remediation2: Remove debris from orbit
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2
Supported in 1988 National Space Policy
Added in 2010 National Space Policy
Summary
•Collisions in orbit between spacecraft are the
visible symptom of deeper problems
•Runaway increase in hazardous fragments
•Increasing cost of space related activities
•Loss of critical satellites
•Mitigation has proven insufficient
•Remediation required
•Interdisciplinary fields of study
•Scientist and Engineers
•Operations
•Legal
•Political
•Coordination required between fields of study
End
No plan to use remaining slides
Pre-Space Age Knowledge of Meteoroids
Potential Hazard to Spacecraft
•Earth-based observations
-Comets
-Asteroids
-Meteors
-Meteorites
-Zodiacal Light
•Potential hazard for spacecraft
-Measured Flux
-Uncertainty in size
-Flight experiments required
-Hazard proved to be manageable
1966 Leonid meteor shower
Major Accomplishments over the last 30 years
• Measured the environment very small sizes
• Established international organization (IADC)
• UN acceptance of Debris Mitigation Guidelines
– Minimize possibility of explosions in orbit
– Require reentry within 25 years after operations
• Concluded current debris environment has
exceeded a “critical density”
• Current National Space Policy expands debris
activities
Necessary Remedial Action to Stabilize LEO
• The only way to reduce or eliminate the instability is to
reduce the number of intact objects
– NASA study concludes removing between 5 and 10 massive
objects per year is sufficient
– Could be accomplished with fewer than 5 to 10 additional launches
per year over the current average of 75.
• 2010 President’s Space Policy:
Pursue research and development of technologies and techniques
…. to mitigate and remove on-orbit debris…
Techniques to Remove Debris
• Debris Sweeper: Debris comes to Remover
-Eliminates debris that happens to pass within 20 km
-40 km diameter natural Earth moon
-Very large “catcher” that can quickly maneuver 20 km
-Space or Ground based laser
• Debris Grabber: Remover goes to debris
-Small spacecraft retrieves one intact object per launch
-Large spacecraft retrieves several intact objects with
similar inclinations per launch
-Tethers