The presentation includes information about growth of the satellite population, the U.S. Space Surveillance Network, tracking and catalog maintenance, Haystack and HAX radar observation, Goldstone radar, the Michigan Orbital Debris Survey Telescope (MODEST), spacecraft surface examinations and sample of space shuttle impacts. GEO/LEO observations from Kwajalein Atoll, NASA s Orbital Debris Engineering Model (ORDEM2008), a LEO-to-GEO Environment Debris Model (LEGEND), Debris Assessment Software (DAS) 2.0, the NASA/JSC BUMPER-II meteoroid/debris threat assessment code, satellite reentry risk assessment, optical size and shape determination, work on more complicated fragments, and spectral studies

Stansbery, Gene

NASA Technical Reports Server

National Aeronautics and Space Administration
Orbital Debris Research in the United States
Gene Stansbery                                                          
Program Manager
NASA Orbital Debris Program Office
Lyndon B. Johnson Space Center
June 2009
https://ntrs.nasa.gov/search.jsp?R=20090022146 2019-08-30T07:03:33+00:00Z
National Aeronautics and Space Administration
2
Growth of the Satellite Population
1960 1965 1970
1975 1980 1985
1990 1995 2000
94% of Tracked Object 
Population are Debris
2005
January 2009
National Aeronautics and Space Administration
3
DIEGO
GARCIA
AFSSS
CAPE COD
LSSC
BEALE
FYLINGDALES
CLEAR
THULE
CAVALIER
AMOS
Kwajalein
SOCORRO
ASCENSION
EGLIN
LSSC = Lincoln Space Surveillance Center
(Millstone, Haystack, HAX)
AMOS = AFRL Maui Optical & Super-computing Site               
AFSSS = Air Force Space Surveillance System
MOSS = Moron Optical Space Surveillance
MSX/SBV = Mid-Course Space Experiment/Space Based Visible 
MOSS
US Space Surveillance Network
Radar
Optical Telescope
MSX / SBV
COBRA DANE
GLOBUS II
National Aeronautics and Space Administration
4
Tracking and Catalog Maintenance
• The US Department of Defense maintains a worldwide network of sensors which 
catalogs and tracks man-made orbital debris
– Although some cataloged debris is as small as 5 cm diameter, the nominal size of debris in the 
catalog is 10 cm in low earth orbit and 1 m at geosynchronous altitudes
– Catalog currently has approximately 14,000 objects in orbit
0
5000
10000
15000
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56
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96
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00
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04
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08
N
um
be
r o
f O
bj
ec
ts
Year
Total Objects
Fragmentation Debris
Spacecraft
Mission-related Debris
Rocket Bodies
Iridium-Cosmos Collision
Fengyun 1C Collision
National Aeronautics and Space Administration
5
Haystack and HAX Radars
• Orbital Debris Radar Observations – Objective
– Haystack and HAX are the prime sources of data for orbital debris 
smaller than 10cm.  Haystack and HAX collect debris data in the critical 
size region between 1cm and 10cm.
– Both radars annually collect between 500 hours to 700 hours of debris 
observation data which provides enough statistics for developing orbital 
debris models.
• Radar Description
– Collocated in Tygsboro, Massachusetts at a latitude of 42.6 .
– The main reflector of the Haystack and HAX radars are 36.6m and 
12.2m  diameter, respectively.
– A pulsed continuous wave (CW) single frequency waveform is used for 
debris detection.  Haystack transmits X-band and HAX transmits K-
band.
– Both radars observe a range window of ~ 300 to 1900 km.
– Haystack can observe debris down to 5 mm and  HAX can observe 
down to 2cm for LEO observations.
• Data Collection and Processing
– NASA conducted the Orbital DEbris RAdar Calibration Spheres 
(ODERACS) experiments on two space shuttle missions in 1994 and 
1995 to validate data processing at NASA JSC.
– The experiments showed that the Haystack radar is calibrated within 
nominal limits, with measured RCS values accurate to ±1.5dB.
400
800
1200
1600
2000
40 60 80 100 120 140
FY2003 Haystack 75o East
Altitude vs Doppler Inclination
A
lti
tu
de
 (k
m
)
Doppler Inclination (degrees)
Haystack
HAX
10-8
10-7
10-6
10-5
10-4
200 400 600 800 1000 1200 1400 1600 1800
FY2003 Haystack 75o East
Altitude Distribution, 100 km bins, Diameter > 0.01 m
Fl
ux
 (c
ou
nt
s/
m
2 / 
ye
ar
)
Altitude (km)
National Aeronautics and Space Administration
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10-8
10-7
10-6
10-5
10-4
10-3
0.001 0.01 0.1 1 10
Goldstone, Haystack, HAX, and 10cm Catalogued Flux
FY2001, 600-800km Altitude
Goldstone, flux, 2001, 600-800km
Haystack, FY2001, 600-800km, SSEM
flux - 1 sd
flux + 1 sd
HAX, FY2001, 600-800km, SSEM
flux - 1 sd
flux + 1 sd
10 cm catalogued flux, FY2001, 600-800km
C
um
ul
at
iv
e 
Fl
ux
 (c
ou
nt
s/
m
2 /y
ea
r)
Diameter (m)
Goldstone Radar
• Goldstone Radar Overview
– The NASA Jet Propulsion Laboratory Goldstone radar is used on a 
limited basis to supplement orbital debris observations made by Haystack 
and HAX.
– Collects nearly 100 hours of data annually 
– Goldstone provides a measurement of the debris environment between 2 
mm and 1 cm.
• Radar Description
– Collocated in southern California’s Mojave desert at a latitude of 35.2 .
– Pairs of up chirp and down chirp X-band pulses are used for debris 
detection.
– Observable range window of ~ 350 to 3300km.
– Observable range rates of 0.85km/s.
• This dictates a staring observation mode near the zenith which makes Doppler 
inclination measurements unreliable.
• Upgrades to the data acquisition system are currently being tested to increase 
the observable range rates.  This would allow pointing away from the zenith and 
hence a reliable Doppler inclination measurement.
– The radar cross section measurements have greater uncertainties than 
that of Haystack or HAX since the Goldstone radar:
• does not calibrate using a calibration satellite
• does not have a monopulse system to determine the position of the debris within 
the radar beam.  
• Data Collection and Processing
– The data collected at the radar is processed at JSC using software 
supplied by JPL.
– The processed data is thoroughly inspected at JSC for quality control 
before subsequent extensive analysis.
National Aeronautics and Space Administration
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Michigan Orbital Debris Survey Telescope 
(MODEST)
• GEO debris survey telescope (0.6/0.9 Schmidt 
Telescope)
• Located near La Serena, Chile at the Cerro Tololo 
Inter-American Observatory (CTIO)
• Collecting data since 2002
• Data used in modeling of the future environment 
(sample data shown middle right)
• Limiting Magnitude ~ 19 Mv in R (corresponding to a 
size of 30 cm if you assume 0.13 albedo)
• Figure (bottom right) shows a probability map of 
where we have looked and the detections seen 
– Red shows the orbit planes that were the most visible, while 
blue shows the orbit planes that were the least visible
– Solid diamonds are correlated targets and the open circles are 
uncorrelated targets
• Status of Survey Project
– Collecting survey data every observing run
– Collecting light curve data in specific photometric bands on 
uncorrelated targets
– Use of two telescopes to refine orbits and the orbit 
determination process
• Special Projects – High Area-to-Mass (A/m)
– Joint project through IADC for objects of high A/m
– Following IADC high A/m objects at sites around the world for a 
more complete orbit
– Efforts being made to determine source and material of these 
objects
National Aeronautics and Space Administration
8
Spacecraft Surface Examinations
HST
Mir
ISS 
MPLM
National Aeronautics and Space Administration
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Sample Space Shuttle Impacts
STS-92 Window Impact
~0.1 mm Aluminum Debris
2 mm diameter crater
STS-90 Radiator Penetration
~0.3 mm Paint Particle
1 mm diameter hole
National Aeronautics and Space Administration
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STS-115 Radiator Impact
Outer Face Sheet Damage
Inner Face Sheet Damage
National Aeronautics and Space Administration
11
GEO/LEO Observations from Kwajalein Atoll
• GEO
- Comprehensive assessment of debris 
environment
• High A/m debris
• Determination of orbital parameters as inputs to 
NASA’s environment model
• Current capability
• Broadband color photometry of targets to 16th
magnitude (~50 cm diameter) via an autonomous 
0.35 m telescope (an element of the AFRL High 
Accuracy Network Determination System –
HANDS).
• Planned capability 
• Designing a 1.3 m, 0.96 deg FOV autonomous 
survey telescope (Meter Class Autonomous 
Telescope - MCAT to be installed 3Q 2010) for 
detection and multi-spectral (Optical/NIR) 
photometry of targets to 20th magnitude (10 cm 
diameter)
• LEO 
• MCAT will detect new LEO debris and enable a 
statistical assessment of the low-inclination (0-20 deg) 
debris environment in the 1-10 cm diameter size regime
National Aeronautics and Space Administration
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NASA Orbital Debris Engineering Model: ORDEM2008
• The ORDEM series of models is in the 
process of an upgrade to ORDEM2008
– Time range – 1995 to 2035
– Altitude range – 200 km to 38000 km
– Size range – 10 µm to 1 m
• Main Datasets and complementary 
Models
– SSN, Haystack, STS window impacts, 
MODEST
– LEGEND, NaKModule,  SRMSlag, 
Degradation/Ejecta
• Statistical estimation of ORDEM2007 
OD populations
– The Bayesian algorithm developed in the 
statistical size estimation model (SSEM) is 
used throughout
• Particularly suitable for data in the form 
of counts 
• Allows propagation of uncertainties
– Based on reference populations such as 
LEGEND, NaK Module, SRM slag model …
– Populations estimated for each year from 
1995 to 2035
Haystack 
Detections:
Fragments 
size ≥ 1 cm
FY2003
Estimated 
Population:
(orbital
distribution)
Fragments 
size ≥ 1 cm
FY2003
National Aeronautics and Space Administration
13
LEGEND
(A LEO-to-GEO Environment Debris Model)
• A state-of-the-art orbital debris 
evolutionary model
– Can mimic the historical 
environment, and project it into the 
future (based on user-selected 
scenarios)
– Has a fast pair-wise comparison 
algorithm to estimate Pcol among 
orbiting objects
– Includes two reliable orbit 
propagators for GEO and LEO/GTO 
objects
– Uses the NASA Standard Breakup 
Model to create simulated breakup 
fragments
– Is the tool for the study published in 
Science, and the latest active 
debris removal analysis
National Aeronautics and Space Administration
14
Debris Assessment Software (DAS) 2.0
• NASA’s DAS 2.0 is designed to assist 
NASA programs in performing orbital 
debris assessments.
– Assessment requirements are described 
in NASA-STD 8719.14 “Process for 
Limiting Orbital Debris”
– DAS 2.0 addresses most requirements 
point-by-point
• Recent upgrades to DAS for the 2.0 
version include:
– Improvements to the orbit propagators and 
debris environment model
– Improvements to the reentry survivability 
model and casualty estimation method
– Improvements to the user interface and 
documentation
– Recommendations from users of the 
current DAS (1.5.3)
– Changes in the debris mitigation 
guidelines
National Aeronautics and Space Administration
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National Aeronautics and Space Administration
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Satellite Reentry Risk Assessment
− This code is used to generate 
trajectory, atmosphere, 
aerodynamics, aeroheating, thermal, 
and ablation response of objects 
during a simulated Earth reentry
• Predict demise altitude of objects which 
burn-up during reentry
• Computes footprint and debris casualty 
area of items which do not burn up
− ORSAT Debris Assessments of note
• Hubble Space Telescope
• Atlas V and Delta IV Rocket Bodies
• Tropical Rainfall Measuring Mission 
(TRMM)
• National Polar-orbiting Operational 
Environment Satellite System (NPOESS)
• Compton Gamma Ray Observatory 
(CGRO)
• Early Ammonia Servicer (EAS) (ISS 
Jettison)
Object Reentry Survivability Analysis Tool (ORSAT)
EAS Demise Altitude vs. Downrange
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Downrange (km)
D
em
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 (k
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National Aeronautics and Space Administration
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Optical Size and Shape Determination
• Goal
– To develop a optical size estimation model comparable 
to the existing radar size estimation model .
– To look for difference sin the optical probability 
distributions  of different classes of objects.
• Current work
– Complex 3-D shapes cannot be easily desribed
mathematically although they can be grouped into broad 
catagories such as nuggets, flakes, etc.
– Scanner can take many realistic shapes which can be 
grouped into these shape classes.  
– Characteristic length of each sample is measured, where 
X,Y, Z are the three orthogonal projections of a object as 
seen in top figure.
• Lc= 1/3( X+Y+Z)
• Future work
– Shapes can be manipulated in software to produce 
photometric response as a function of viewing geometry 
for all orientations of the object.
– Calibration of the photometric response and the 
specular, diffuse ratio can be calibrated in the laboratory.
National Aeronautics and Space Administration
18
Work on More Complicated Fragments
National Aeronautics and Space Administration
19
Spectral Studies
• Use reflectance spectroscopy in the visible and near-
infrared to determine the surface material of space 
objects
– Knowledge of material yields better size estimation data
• Each material has specific absorption features that 
make it unique
– Using those features, as well as slope, creates a model for 
materials that best fits the spectrum taken of the object in space
• Results
– Placed objects into categories based on spectral response
• See example on top right, where the object was thought to be either an 
asteroid or a human-made object
• Determined to be human-made due to spectral signature of white paint
– Measured pristine spacecraft prior to launch and looked at space 
weathering of materials
• See example at the bottom right, where the model is based on 
pre-flight measurements showing great agreement in slope and absorption 
features
– Received first data on debris objects (all large pieces)
• Status of the project – Work in Progress
• Continued material modeling
• Determine cause of the unexpected increase in slope for remote 
measurements as compared to laboratory measurements
• Taking ground truth data on spacecraft prior to launch to get better idea of 
changes in material spectra
• Obtain more remote measurements of cataloged objects and debris
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1 1.2 1.4 1.6 1.8 2 2.2 2.4
Wavelength, microns
Sc
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 R
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IRTF
Model #1


Orbital Debris Research in the United States

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