Earth-orbiting objects, large enough to be tracked, were surveyed for possible systematic debris removal. Based upon the statistical collision studies of others, it was determined that objects in orbits approximately 1000 km above the Earth's surface are at greatest collisional risk. Russian C-1B boosters were identified as the most important target of opportunity for debris removal. Currently, more than 100 in tact boosters are orbiting the Earth with apogees between 950 km and 1050 km. Using data provided by Energia USA, specific information on the C-1B booster, in terms of rendezvous and capture strategies, was discussed

Ash, R. L.

Chambers, E. J.

Odonoghue, P. J.

Raney, J. P.

English

NASA Technical Reports Server

8EP u z REC'I]
I WORLD III iSPACE •
CONGRESS • ,,_ I,
(_ASA-CP,-19205_) A METHO.r)OLOGY FLIR N93-18154g_LECTIVL ,R,Et4oVAL _3F ORBITAL OE_RIS
(cll,i r)or,_inion Univ.) 14 p
Uncl .Is
B.8-M.2.18X
G3/18 0141629
A Methodology for Selective Removal of Orbital
Debris
)
R. L. Ash, P. J. O'Donoghue and E. J. Chambers
Old Dominion University
Norfolk, VA
J. P. Raney
West Virginia Institute of Technology
Montgomery, WV
World Space Congress
August 28 - September 5, 1992/Washington, D.C.
https://ntrs.nasa.gov/search.jsp?R=19930008965 2020-03-17T07:46:17+00:00Z
B.8-M.2.18X
A METHODOLOGY FOR SELECTIVE REMOVAL OF ORBITAL DEBRIS
by
R. L. Ash*, P. J. O'Donoghue*,
E. J. Chambers* and J. P. Raney**
Abstract
Earth-orbiting objects, large enough to be tracked, have been surveyed for possible systematic
debris removal. Based upon the statistical collision studies of others, it was determined that
objects in orbits approximately 1000 km above the Earth's surface are at greatest collisional risk.
This study has identified Russian C-1B boosters as the most important target of opportunity for
debris removal. Currently, more than 100 in tact boosters are orbiting the Earth with apogees
between 950 km and 1050 km. Using data provided by Energia USA, specific information on
the C-1B booster, in terms of rendezvous and capture strategies, has been discussed.
Introduction
Space Station Freedom is expected to occupy a low Earth orbit for several decades. In
order for it to operate safely for that length of time, it must avoid collisions with spaceborne
objects -- primarily man-made debris. Because of its large size, micrometeoroid impacts will
occur on space structural elements regularly. However, collisions with larger objects must be
avoided and the removal of significant quantities of debris source material will be desirable to
insure safe operation. The goal of this paper is to describe a methodology for identifying and
removing strategic debris elements.
" Mechanical Engineering and Mechanics Department, Old Dominion University, Norfolk, VA 23529--0247
*" Mechanical Engineering Department, West Virginia Institute of Technology, Montgomery, WV 25136
2A recent Space Station Freedom study/1/has indicated that for objects larger than 2 mm,
collision probabilities are higher for man-made debris than for naturally occurring material.
That study estimated that approximately 200 kg of natural debris were present typically within
2000 km of the Earth's surface at any particular time. That mass compares with approximately
3,000,000 kg of man-made material existing currently in Earth orbit. The study estimated that
the most probable collision velocity between space station (target) and man-made debris was
13 krn/s -- nearly a head-on collision. At that collision speed, Ramohalli /2/ has pointed out
that a 1.8 cm diameter aluminum pellet carries the same impact kinetic energy as a mid-size
automobile travelling at 100 krn/hr.
NASA's Long Duration Exposure Facility experienced more than 34,000 micrometeoroid
impacts during its 5.78 yr orbital life, but the largest impacting object had an estimated size of 1
mm (and produced a 5 mm diameter crater,/3/). Butner and Gartrell /3/ have reported that most
of the impacting debris was believed to be man-made (paint flecks, propulsion system residue,
etc.). Furthermore, laboratory tests which simulated collisions between small objects (150 g)
travelling at speeds up to 6 km/s with a small (54 kg) navigation satellite produced millions
of small particles/4/. Since it is not feasible to collect space debris in such quantities after a
collision, it is essential to collect and remove the larger objects before they collide. Ramohalli
/2/has discussed the consequences of the November 1986, breakup of an Ariane upper stage.
That material ultimately becomes distributed over a large orbital volume, leading potentially to
more collisions.
Kessler/5, 6/has been characterizing the orbital debris hazard for a considerable period
of time. Those studies have shown that the possibility of a catastrophic collisional cascade is
increasing and that the population of man-made objects with orbital altitudes between 900 km
and 1000 km is already sufficient to be considered unstable. Ramohalli and co-workers/2, 7, 8/
3haveadvocatedan aggressivedebrisremovalprogram,consideringmethodsfor collecting and
retrieving thematerial. Alternateapproacheshavebeenconsideredby GrummanCorp./9/.
The current study has takena somewhatdifferent approach. Rather than attemptingto
designa general-purposedebris removal system, the project team electedto investigatethe
known populationof orbiting objects to determinewhethera singleclassof debris could be
identified for removal by a single-purposesystem. Orbital debris was definedas all orbiting
objects which were no longer performinga useful function in orbit (dead satellites, rocket
stagesand fragments).The methodologywhich wasemployedto identify a primary targetof
opportunity is reportedherein.
Satellite Population Classification and Selection
NASA GoddardSpaceFlight Centercompilessatellitesituationreportsat regularintervals.
In September1990, their NASA SatelliteSituationReport listed 6,681 items that were being
tracked. Actually, that list understatesthe true populationof large objects. For example,an
item listed as Cosmos1220,which was launchedby the Soviet Union in 1980anddestroyed
intentionally, producedat least80 piecesof debris/10/of which 59 were still being tracked.
It was listed as two items (1980 089A -- Cosmos1220satellite-- and 1980089B-089CG
which representedthe remaining58 pieces). However,sinceretrieval of large objectsfrom a
swarmof smallerobjectswould be too hazardousfor a debrisremovalsystem,this studywas
not concernedaboutthe truetotal satellitecount. Rather,thegoalwas to defineorbiting subsets
which were truly near-termdebrisremoval targetsof opportunity.
BaseduponKessler'scollisionalcascadepredictions/6/, this studyfocusedon largeobjects
with initial orbital altitudes,at perigee,in the 700 km to 1500km altitude range. The upper
altitude limit was selectedsincemany of the higher altitude objects had degradedto lower
altitudes(on the orderof 1000km) after launch.ThenusingtheRAE satellitetables/11/, along
4with the Goddardsatellitesituationreports,objectscould be categorizedin termsof their type
andsize.Theorbitingobjectsin the 1000km altitudeintervalcategorywereSoviet,mostlywith
orbital inclinationsnear83° (between70° and 85°). Using the datacompiled by Johnson/12,
13/as representativeandthereforefocusingon 1987and 1988dataasbeing themostcomplete,
162separateorbiting objectswerecategorized.Thosedataaresummarizedin TableI. Sincethe
listed Soviet satelliteswerelikely to becomplicatedshapes,andin manycasesareoperational,
they were eliminatedas possibletargets.
From thetable,it canbeseenthatrocketbodiesconstitutedapproximately75 percentof the
identifiedmassorbiting near1000km altitude (launchedin 1987and 1988)and thatthe Soviet
C-1B secondstage(U.S.D.o.D. designationis SL-8) representedapproximately75 percentof
therocket body population. Consequently,the datasearchwasexpandedto include all Soviet
CosmoslaunchesthroughJune 1990. A total of 245 rocket bodieswere identified as being in
orbit. Of that number,204 were identified as C-1B boosters.
Sincerocket bodiessurroundedby orbiting debriswere likely to be damaged- making
retrieval more difficult and dangerous-- those rocket bodies were eliminated as potential
targets.Thenumberof "undamaged"rocketbody targetswastherebyreducedfrom 245 to 193.
Unfortunately, the particular type of rocket body in orbit hasnot beenidentified consistently
in the data sets.
Faranetta/14/ has reported that NPO Energia, in Russia, made preliminary studies of
removing debris from geostationary orbits using an orbital maneuvering vehicle and an Energia
Heavy-lift launch vehicle. In addition, through the cooperation of Energia USA, this study
has been able to acquire additional details on the orbiting rocket bodies in lower Earth orbits.
Dr. Boris I. Gubanov was a primary designer of both Cosmos and Cyclone (DoD designated
5SL-14) boosters,aswell as the Energiabooster,and hasassistedEnergiaUSA in cooperating
with us.
The Cosmossecondstage(C-1B) is listed asbeing7.5 m in lengthand 2.4 m in diameter.
Theoriginaldesignutilized asinglenozzle,RD-119,motor. Thenozzlediameterwas1.02m and
extended0.6 m behindthe secondstagetanks.Apparently,the secondstagecould bemodified
to accommodatea twin nozzle,RD-219,engine(which was usedon the Cycloneboosterand
generated900 kN thrust), but it is not clear which, if any, recentrocketbodiesweremodified.
For thepurposesof the presentstudy,all rocketbodieswhich wereeither designatedasSL-8's
or which were listed ashavinganorbiting massof 2200kg with lengthsand diametersof 7.5
m and 2.4 m, respectivelywereclassifiedasC-1B's. Therewere 158,out of 193in tact rocket
bodies, that were designatedas C-1B's.
Ramohalli et al./7/have discussedhow orbital inclinationscan be varied for an orbiting
debris removal systemvia nodal regression. They also investigatedoptimal trajectoriesfor
multiple debrisremovaloperation/7, 8/. Here,it wasdecidedthat rocket body removalcould
beaccomplishedmost efficiently by seekingclustersof rocketbodiesthat were locatedwithin
a narrow bandof inclinationsand altitudes.
It wasdeterminedthat 100C-1Brocketbodieswerelocated at orbital inclination of between
82.9 ° and 83.0 °, with apogees between 950 and 1050 kin. In fact, referring to Figure 1, 56
of the rocket bodies were orbiting in an apogee band of 20 km. The high density of orbiting
rocket bodies has been produced by the requirements for the Cosmos navigation system. Those
navigation satellites are placed in orbit at an approximate rate of one every 13.5 mo. for the
military system and one every 30 mo. for the civilian system. While the Cosmos navigation
system was scheduled for phase out by the year 2000, the population of rocket bodies, produced
by their launch, is already large and is likely to increase.
6Debris Removal Methodology
This study has shown that a debris removal system which was designed to acquire and
remove Soviet C-1B rocket bodies at an orbital inclination of 83 °, with apogee altitudes near 1000
km, could remove more than 200,000 kg of debris and reduce the possibility of a catastrophic
collisional cascade in the 1000 km orbital altitude range significantly. Since these C-1B rocket
bodies are mostly aluminum and of limited value, the most straightforward method for removal
would be to rendezvous with the (tumbling) body, despin it and orient it for reentry. Then,
taking advantage of the fact that the existing rocket motor is already aligned with the center of
gravity of the booster, a small solid-propellant rocket could be designed which could be inserted
into the existing nozzle and fired to reenter the rocket body back into the atmosphere and scatter
any surviving reentry material over the ocean.
Energia USA (Ref. 16) has indicated that the C-1B external tank geometry has features
that can be used as attachment points for a debris capture operation. Referring to Figure 2,
a fuel transfer pipe and two vents are located on one side of the Cosmos second stage. The
electrical conduits, which are located on either side of the fuel transfer pipe in that figure are
approximately 3.5 m long, 36 cm deep and 22 cm wide. In addition, the fuel tank vents are
capable of transferring structural loads.
The Cosmos C-1B second stage udlized unsymmetrical dimethylhydrazine and nitrogen
tetroxide bipropellant. Its propellant was vented as part of the payload]rocket body separation
maneuver, but the venting step did not always occur properly. The propellant tanks utilized 12
mm thick aluminum skin with 19 mm thick stringers. Pending final results from the NASA
Long Duration Exposure Facility experiments, it should be possible to estimate the likelihood
that unrented propellant remains in the tanks, based on micrometeroid penetration predictions.
7Based upon past theoretical studies of the motion of tumbling satellites /15/, it can be
expected that the C-1B boosters will be tumbling about their principle rotational axes. That
is, over time, any rotational energy possessed by an uncontrolled, orbiting object is transferred
gradually to the rotational axis with the largest moment of inertia and hence the C-1B's are likely
to be tumbling about an axis which is between the rocket motor and the payload mating collar.
Consequently, retrieval will require that the debris collector match orbits with the rocket body,
then orient itself so that it can be rotated on an axis which is common with the booster's rotational
axis (Figure 3a and b). Then, the debris collector must achieve rotational synchronization with
the tumbling booster before it can be captured. After the two vehicles have been phase-locked
with respect to rotation, a pair of robotic arms are envisioned that could grab the C-1B conduits
(Figure 3c). A teleoperated system, using a video system that rotated with the platform, would
be the most direct approach.
After the arms have captured the booster, the debris collector would be activated to despin
the system and then maintain the orientation of the booster while a solid rocket and small strap-
on control thrusters were positioned and secured in the throat of the RD-119 motor and on the
body of the C-1 B, respectively (Figure 3d). Subsequently, the booster-solid rocket unit would
be oriented for deorbit firing and the debris collector would loiter long enough to make sure that
the system was stabilized. At that point, the orbital debris collector would depart for its next
target and the C-1B would be launched back into the atmosphere (Figure 3e).
Finally, since ownership of orbiting C-1Bs and possible liability for damages resulting
from uncontrolled collisions with other satellites are problematic, international cooperation is
an essential element. A joint program to remove such a large population of debris will be
necessary to effect a solution within a time frame which will avoid chain-reaction collisions.
Conclusions
8
This studyhasdeterminedthatorbitingCosmosC-1Bbootersarebothnumerousandin orbits
at greatestrisk for multiple, chain-reactioncollisions. By deorbiting the 100 in tact boosters
with apogeesbetween950 and 1050km, more than200,000kg of materialcan be removed,
avoiding a major potential debris source.
While the massof materialis largeenoughto warrantstudiesof how the boosterscouldbe
reprocessedin spacefor otherapplications,this studyhasrecommendedthat for the nearterm
theseboostersshouldbe deorbited.
Acknowledgement
This research was sponsored by the University Space Research Association as part of its
NASA/USRA Advanced Space System Design Program, managed by Dr. Vicki S. Johnson.
Table 1
Categorizationof Soviet Objects in Orbit,
Launchedin 1987-88 and with altitudesnear 1000km
9
Item
Large Fragments
Ferret Satellites
Rocket Bodies
C-1B
Navigation Satellites
Miscellaneous Satellites
Oceanographic
Satellites
Largest
Population Mass Dimension
66 Variable Variable
44 40 kg 1 m
29 variable variable
(22) 2200 kg 7.5 m
12 700 kg 1.9 m
7 Unknown Unknown
4 750 kg 2m
Comments
Debris associated with
satellites
Active satellites
Spent Rocket Boosters
Largest single
population of debris
objects
Active satellites
Not identified
Active satellites
10
References
1. Anonymous, "Space Station Program Natural Environment Definition for Design," SSP
30425, Revision A, NASA Space Station Freedom Program Office, Washington, D.C. (June
1991)
2. K. N. R. Ramohalli, "A Robot for Retrieval of Orbital Debris: Hardware Experience," in
Proceedings of the Sclera Symposium: Selected Topics in Sciences and Technology and
25th Anniversary Celebration, in press (1992).
3. C. Butner and C. Gartrell, "GRC Orbital Debris Mitigation Systems" Innovative Ap-
proaches to Solving Future Problems," AIAA Space Programs and Technologies Conference,
Huntsville, AL. AIAA Paper Number 92-1287 (March 1992).
4. L. David, "Satellite Debris Experiment Produces Surprising Results" Space News
(Feb. 24-March 1, 1992).
5. D. J. Kessler and B. G. Cour-Palais, "Collision Frequency of Artificial Satellites: The
Creation of a Debris Belt" J. ofGeophys. Res., 83, #A6, 2637-2646 (1978).
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Advances in Space Research, 11, pp. 63-66, 1991.
7. K. N. R. Ramohalli, et al., "Autonomous Space Processor for Orbital Debris,"
NASA/University Space Research Association, Summer Design Conference, Huntsville, Al-
abama; June 1989 (Also U.S. Patent Number 5,120,008, June 9, 1992).
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Astronautica, 26, 55-60 (1992).
9. Anonymous, "Concept Evaluation/Test for the Tumbling Satellite Retrieval Kit, Grumman
Corporation, Space Systems Division, Bethpage, NY, NASA Contract NAS 8-36641 (Oc-
tober 1988).
10. Anonymous, "Report on Orbital Debris," Interagency Group (Space) for the National Security
Council, Washington, D.C. (February 1989)
11. D. G. King-Hele, et al., The R.A.E. Table of Earth Satellites 1957-1986, Stockton Press,
New York, N.Y. (1987).
12. N. L. Johnson, The Soviet Year in Space 1987, Teledyne Brown Engineering, Colorado
Springs, Colorado (1988).
13. N. L. Johnson, The Soviet Year in Space 1988, Teledyne Brown Engineering, Colorado
Springs, Colorado (1989).
14. C. J. Faranetta, Energia USA, 2214 Rock Hill Rd., Suite 500, Herndon, Virginia 22070,
Private Communication (1992).
15. J. E. Cochran, Jr. and B. S. Lahr, Satellite Attitude Motion Models for Capture and Retrieval
Investigations, NASA Contractor Report No. NAS8-36470, Marshall Space Flight Center,
Alabama (October 1986).
1050
TARGETLOCATION
C-1B ROCKETBODIES
1
0
1040-
1030-
020-
010-
000-
990- _
980-
970-
0
960-
950
0
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I I I I I I I
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1000
Figure 1 Distribution of orbiting C-1B boosters near 1000 km, at inclinations of 82.90 (o) and
83.0 ° (*)
FUEL TRANSFER
PIPE.
CONDUITS
_- 240
J
VENTS
J
v
35O
RD-119
L
I
,-_----102 -----_1
60
DIMENSIONS IN CENTIMETERS
Figure 2 Schematic diagram of C-IB booster geometry
a. Rendezvous
b. Rotational Matching
c. Capture d. Despin and Rocket Insertion
._ \",_._1
e. Deorbit
Figure 3 Representation of rendezvous and deorbit sequence


A methodology for selective removal of orbital debris

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