SPACE DEBRIS Past, Present, Future - PowerPoint Presentation

Slide1

SPACE DEBRISPast, Present, Future

Society of Physics Students

Guest Science Speaker

Embry-Riddle Aeronautical University

Prescott, Arizona

Professor Robert D. Culp

University of Colorado

October, 2016Slide2
Slide3

The history, causes, and growth of space debris

Current state of space debris hazards

Future prospects for debris growth and mitigation

Sketch of CU Space Debris Group’s researchSlide4

Ronald A. Madler, Ph.D. thesis

“Evolution of the Near-Earth Man-Made Orbital Debris Environment” 1994, University of Colorado

One of the pioneers and key researchers in the investigation of the cascade effect

Madler’s

work contributed significantly to the current acceptance of the inevitable growth of the space debris hazardSlide5

The Current Problem

More than 17,000 cataloged pieces

The NORAD catalog contains all pieces bigger than 50 cm., most pieces bigger than 5 cm.

Estimated 500,000 pieces greater than 1 cm.

Nearly all pieces between 1 cm and 5 cm are untrackable, uncataloged, yet pose catastrophic consequences to Resident Space Objects (RSO).

All pose critical risk to resident space objects

Typical relative impact speed is 10-20 km/s.Slide6

Summary of all objects in Earth orbit officially cataloged

by the U.S. Space Surveillance NetworkSlide7

Only 1381 Operational Satellitesas of December 31, 2015

T

hese 1381 active satellites are divided into the following categories:

37% Commercial

14% Communications (Civil and Military)

14% Earth Observers

12% Research and Development8% Military Surveillance

7% Navigation

5% Scientific

5% MeteorologySlide8

Debris Distribution

B

ands at altitudes of 800 km, 1500 km, and GEO (35786 km)

Both cataloged (large) and untrackable (small) have these altitude distributions.

Small debris is distributed evenly longitudinally.

Large debris objects, including working satellites, have inclination concentrations.Slide9

Large Debris Inclination Concentrations

6000 tons mass in orbit, 99% in large masses

At 1000 km, 82 degree inclination, 290 large masses

At 800 km, 99 degree inclination, 140 large masses

At 850 km, 71 degree inclination, 40 large masses

At GEO (35,800 km altitude) 1200 tons, 520 large massesSlide10

Fragmentation: the source of small debris

Explosions: rocket bodies, batteries, intentional

Collisions, including antisatellite experiments

Normal operations

Deterioration of satellites and other large bodiesSlide11

Over 200 Fragmentation Events to Date

More than half of cataloged pieces are from fragmentations.

Worst: Chinese Fengyun-1C, (2007)

An antisatellite test, intentional collision

Second worst: Russian Cosmos 2251 collision with Iridium 33

Accidental collision between two intact catalog objects

The only accidental collision between two intact satellites thus far.Slide12

Early Fragmentation Events

Earliest fragmentations raised the space debris alarm

Very first: Transit 4A Rocket Body, June 29, 1961

R

esidual fuel explosion

Early worst: Ariane Spot 1 Rocket Body, November 13, 1986

Residual fuel explosion. Still the 6

th

worst of all time.

Notable: 7 Delta Rocket 2

nd

Stage Explosions, (1973-1981)

Residual fuel explosions, led to corrective venting of surplus fuel

Also, 30 USSR deliberate end-of-life explosions, (paranoia)Slide13

Untrackable Debris from Normal OperationsFar Less Serious than from explosions or collisions

Solid Rocket Effluent (primarily aluminum oxide)

Staging and Reentry Events that are Explosive

Planned Experiments

Waste and Refuse from ISS and Shuttles

Deterioration of Large Masses (paint flecks, insulation, atomic oxygen corrosion, small particle abrasion)

Slide14

Untrackable Debris

1 cm – 5 cm: estimated 500,000 pieces (potentially catastrophic)

1 mm – 1 cm: millions of pieces (damaging or mission degrading)

Untrackable debris can only be defended against by shielding, satellite design, or orbit selectionSlide15
Slide16

Debris Cloud Evolution

An explosion or collision creates a cloud of fragments.

The cloud becomes an ellipsoid following the original orbit for a few revolutions.

The ellipsoid elongates along the orbital path until (days) a torus is formed. Cause: differing periods of particles

The torus spreads and gradually (months) becomes a belt with the same ground coverage of the original orbit. Cause: differing plane precession of particlesSlide17
Slide18

Long-term Debris Cloud Evolution

The debris becomes (years) evenly distributed background particles around the same region covered by the belt.

For LEO breakups, the debris slowly rains down through lower elevations, beginning at once, continuing for decades.

Cause: atmospheric drag, small but still present up through a thousand kilometers.Slide19

The Cascade Effect

1978 Paper by Don Kessler and Burton

Cour-Palais

“Collision Frequency of Artificial Satellites: The Creation of a Debris Belt”

Collisions between orbiting objects create large numbers of equally dangerous smaller debris.

This greatly increases the threat to other orbiting objects including large satellites.

This increasing threat of collisions leads to a chain effect, or cascade effect.Slide20

Conclusions from Kessler’s 1978 Paper

Collisions between cataloged objects will begin around the year 2000.

The hazard to spacecraft from small debris will quickly exceed the hazard from natural meteoroids in low Earth orbit (LEO).

Debris flux will increase exponentially from breakup and deterioration of large masses.Slide21

Current Results

Predictions from 1978, and later confirmations by other researchers (including

Madler

) have become increasingly accurate.

From now on, debris

f

rom random collisions between orbiting objects, both cataloged and smaller, will be the dominant source of small debris.

This cascade effect, or chain reaction, was called “The Kessler Syndrome” by John

Gabbard

.

Kessler himself is lukewarm to this name!Slide22

Predicted Collision Rate between Catalogued Objects

Assuming various growth rates in the catalogue

From 1978 Kessler/Cour-Palais JGR publicationSlide23

1978 JGR Predicted Collision Rate

Compared to1991 to 2009 Observed Collision Rate

Observed catalogued collisions: Important to short-term environment only

(Cosmos 1934, Cerise, Thor-Burner, Iridium)

Observed catastrophic collisions: Important to short and long-term environment

(Iridium)Slide24

The Only Feasible Solution

First:

Compliance with mitigation guidelines by all space-faring nations.

Second:

Active retrieval of large orbiting masses at end of usefulness.

Otherwise, and perhaps even so, small debris will continue to increase exponentially (the cascade effect).

Collision data over the next decade will confirm this prediction.Slide25

The Future

The world will continue to use space.

The cascade effect says the 6000 tons mass currently in space will eventually become a threatening background of untrackable small debris.

The FAA expects a five-fold increase in cataloged objects in the next 2-5 years.

Today’s catalog of 15-20,000 pieces will grow to 100,000.Slide26

Solutions

Some solutions are obvious. Some are yet to be imagined.

Solutions will be developed--have faith in our technology.

The solutions will differ for tracked and cataloged debris, for small, untrackable debris, and for debris at GEO altitudes.Slide27

Large, Trackable Debris

Catalog, track, avoid! Space Situational Awareness (SSA)

Expand the catalog to track most debris down to 3 cm in size.

Expand ability to discover and track debris.

Avoid collisions by choosing orbits, and improving conjunction detection.

Avoid placing satellites in high debris density regions, provide valuable satellites with maneuvering capability.

Remove large masses at end of life. Large masses--the source of small debris

Operate responsibly.Slide28

Untrackable, Small Debris

Improve shielding to protect against debris 1 cm and smaller.

Design satellites to be robust against small debris, and to survive for long lifetimes of encountering the abrasive effects of

untrackable

debris.

Choose orbits to avoid predicted high density regions of

untrackable debris.

Again, remove large masses before they deteriorate.Slide29

A Special Problem: the GEO Region

In GEO, the problem is worse.

There are 1200 tons of mass, 520 satellites in GEO +/- 100 km.

Including debris, there are 1400 cataloged objects in this region.

Detecting is much more difficult for GEO objects, hence the catalog is less complete than at LEO.

There are only about 400 controlled (active) satellites. The rest are drifting.

Disposal orbits are only 300 km above GEO.Slide30

GEO Difficulties

Roger McNamara showed (and Kim

Luu

confirmed) that the official disposal orbits (GEO + 300 km) are unsafe in the long term due to perturbations and collisions.

Removal of large, dead masses in GEO (true removal, not just lifting to disposal orbit) is the most urgent of debris problems.Slide31

Obstacles

FIRST: Technology—must improve detection, tracking, cataloging, and conjunction analysis (collision prediction).

Removal of large masses.

All within reach, but expensive.

SECOND: Economics—the biggest problem.

All of the solutions are expensive. Who will Pay?

THIRD: Political realities—newer space-faring nations refuse to take responsibility.

They resist deorbiting, ending ASAT and other debris generating experiments, and minimizing operational debris.Slide32

A Few Ideas for Large Mass Removal

LEO: Drag additive (balloons, sails)

Orbit modification using attached rockets or lasers from a distance.

All methods have problems: attachment requiring rendezvous and grappling, aim of lasers, hazard of approaching an uncontrolled, spinning large mass…

GEO: Only energy change will work:

Attach rockets, space-based laser propulsion,

tow via nets, bolos, or harpoons.

Relative speeds are lower, so rendezvous is simpler, yet still difficult.

Unusual example: CU Hans-Peter Schaub and four companies: Touchless

reorbiting

using an electrostatic tractor force to tow mass to higher orbit.Slide33
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CU Research in Space Debris

In the ‘70’s, I was working on debris cloud evolution at the time Kessler raised the alarm.

By the early ’80’s, I had established the first University Program to study in depth the space debris problem.

For two decades, it was the only graduate program in space debris anywhere.Slide35

Areas of Research in Space Debris, 1980-2015

Breakup models—collisions and explosions

Environment models—the background debris

Debris Cloud Evolution—from breakup to background debris

Advanced Computer Visualization—interesting, but was soon discarded

Ground-based Hypervelocity Impact Tests—simulating collisionsSlide36

CU research Areas, continued

Advanced Shielding Design—modified Whipple designs and tests

SMART Catalog—the seeds of the expanded catalog

Size and Radar Cross Section Studies—important for modeling

Radar, Ballistic Coefficient, Optical Signature Studies

Lethality and Space-based Defense—SDI and ASAT inspired

GEO Debris Hazards—perhaps the biggest problemSlide37
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The Early Leaders of Space Debris Research

During the ‘80’s, space debris research was led by four key players:

Donald J. Kessler, Project Scientist for Space Debris,

NASA Johnson Space Center

Vladimir A.

Chobotov

, Manager, Space Hazards Section

The Aerospace Corporation

Nicholas L. Johnson, Advisory Scientist

Teledyne Brown Engineering

Robert D. Culp, Professor of Aerospace Engineering Sciences

The University of ColoradoSlide39

The First years of the CU Space Debris Group

In 1980 I collaborated with Kessler through NASA research contracts.

Darren McKnight was assigned to do a PhD under me by the USAF Palace Knight Program. He was at Kirtland AFB for a year awaiting deployment to CU for his graduate work.

I sent him material on space debris and asked him to look into it for a thesis topic.

He, an energetic self-starter, arrived with ideas about the origin of debris clouds from collisions and explosions.Slide40

Darren McKnight—the First Space Debris PhD

In 1985, McKnight’s thesis detailed an empirical means of distinguishing explosion-caused from collision-caused debris clouds.

He put together the SOCIT tests—persuaded the USAF to give us an unused OSCAR satellite. We took the satellite to Tullahoma, TN, to the AEDC test facility, and subjected it to tests in the hypervelocity test range.Slide41

The SOCIT Tests at Tullahoma

The OSCAR satellite

w

as dismantled and subjected to separate tests on the solar panels, on the bus structure, and on the instruments.

Small (0.5 cm) aluminum pellets were shot at these parts at speeds of 6-7 Km/s.

The data from these SOCIT tests remain today as the best source of information about space debris impact on satellites.Slide42

Other Ground Tests of Debris Clouds

CU directed and participated in many space debris impact tests at Tullahoma, at NASA JSC, and at other Hypervelocity Test facilities.

This included tests of new shield designs at NASA JSC.

As our representative, Roger McNamara participated in a productive explosion test in California, and brought back the definitive data on large-scale explosions in space.Slide43

The CU Space Debris Graduates

After McKnight, the golden years of our research featured a dozen PhD graduates and as many outstanding MS graduates.

These graduates went on to dominate the space debris discipline for the next twenty years.

Many of them continued to work with our research group even after they had other responsible positions in the industry. Slide44

Success of Our Graduate Students

These graduate students, along with a cadre of MS students, gained a world-wide reputation.

Madler

and

Maclay

were welcomed on international and national committees as equals to old, established researchers.

All gave papers at international conferences.

The following, unreadable slide, lists these PhD students and their theses:Slide45

Darren S. McKnight, "Simulation of On-Orbit Satellite Fragmentations,"1986Timothy D.

Maclay

, “Untrackable Orbital Debris Hazard Assessment and Shield Design

for

Satellites Operating in Low Earth Orbit”, 1993

Ronald A. Madler

, "Evolution of the Near-Earth Man-Made Orbital Debris Environment," 1994Roger P. McNamara, "The Investigation of Space Debris Generation and Associated Long-Term

Effects in the Geosynchronous Region," 1995

Ian J.

Gravseth

, “Determination of the Physical Properties of Artificial Debris Via

Remote

Observations,” 1996

Christopher A. Sabol, “A Role for Improved Angular Observations in Geosynchronous

Orbit

Determination”, 1998

Khanh

Kim

Luu

, “Effects of Perturbations on Space Debris in

Supersynchronous

Storage

Orbits”, 1998

Kira Michelle (Jorgensen)

Abercromby

, “Using Reflectance Spectroscopy to Determine

Material

Type of Orbital Debris”, 2000

Brian J.

Poller

, “The Photometric Detection of Known Sun Occluding Orbital Debris”,

2009Slide46

Other Major Achievements by the CU Group

Maclay

developed and tested innovative shield designs.

Madler

developed his debris cloud model and published the definitive affirmation of Kessler’s cascade theory.

Madler

and Maclay led the discipline in estimating and modeling the background debris and the evolution of debris clouds.Slide47

More Research Results

Dickey and

Gravseth

completed important work on determining size and composition of space debris via remote sensing—radar cross section, ballistic coefficient (from drag), and optical characteristics.

This led to the ODERACS Projects:

Orbital Debris and Radar Cross Section ExperimentSlide48

ODERACS

We proposed to NASA that we drop calibrated spheres and dipoles from the Space Shuttle, and take data on RCS, optical albedo, and ballistic coefficient.

This was successfully accomplished on two Space Shuttle flights.

CU did all the laboratory calibration of RCS and optical signatures of the objects.

We received two NASA Commendations for these projects.Slide49

Spheres Launched from the CanisterSlide50
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Determining the Mass/Diameter Relation of Space Debris

Madler

,

Maclay

,

Gravseth

, McNamara, and Dickey published definitive methods of determining this relation using remote sensing.The definitive relation, called MAD-CHIMPS in our research papers, is used to this day.Slide52

Long-term Hazard from Space Debris

During this time, our team (primarily

Madler

,

Maclay

, and McNamara) published definitive analyses of the long-term hazard to Resident Space Objects (RSO) from space debris.

Madler published the exposition of the long-term evolution of space debris, establishing the cascade phenomena once and for all.Slide53

Debris Hazard in GEO

McNamara published an historic warning about the space debris hazard in GEO, especially attacking the idea of a super GEO disposal plan.

Kim

Luu

and Chris Sabol, three years later, joined in the GEO analysis and warning regarding the disposal orbits.

McNamara showed that collisions of dead satellites in the disposal area, combined with ever-present perturbations, would threaten active GEO satellites over the coming decades.Slide54

The EXCALIBIR Experiment

A lethality experiment that never happened.

Proposed by Mike Dickey: a plan to intercept the discarded external tank from a shuttle launch.

The tank reentered above the

P

acific ocean, passing

over Kwajalein. A missile from Kwajalein would intercept it, and fire a shotgun-like cloud of pellets at the tank. Instrumentation on the tank would telemeter back the effects of the pellet impacts. A cheap experiment to obtain lethality data. Never funded, never happened.Slide55

Spectroscopy and Space Debris

This is the most recent research by our space debris group.

Spectroscopy applied to the detection and identification of space objects including debris.

Ian

Gravseth

and Kira Jorgensen (now

Abercromby) were the prime participants.

Madler

,

Maclay

, and David Spencer also contributed from their post-graduate positions. Slide56

Spectroscopy Results

Kira Jorgensen (now Kira

Abercromby

) arranged a collaboration with the Federal Research Center near Denver.

In the Federal Laboratory, she established full spectroscopic optical signatures for hundreds of space materials.

This data was used successfully to identify a curious object orbiting the Sun—it was a rocket body from a lunar probe upper stage, long lost.

This data base is still the best source of material spectrographic signatures, and is used to help identify unknown objects in space, and space debris.Slide57

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