Bryan, Tom

Gagliano, Larry

MacLeod, Todd

NASA Technical Reports Server

SMALL ORBITAL STEREO 
TRACKING CAMERA 
TECHNOLOGY DEVELOPMENT
Tom Bryan, Todd MacLeod, Larry Gagliano
NASA Marshall Space Flight Center
https://ntrs.nasa.gov/search.jsp?R=20160008870 2019-08-31T02:06:40+00:00Z
SMALL ORBITAL STEREO TRACKING CAMERA TECHNOLOGY DEVELOPMENT
Background
0.E+00
1.E-08
2.E-08
3.E-08
4.E-08
5.E-08
6.E-08
100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000
S
p
a
ti
a
l D
e
n
s
it
y
 (#
/k
m
3
)
Altitude (km)
ISS
Iridium comsats
DoD and NOAA weather sats
NASA Earth 
Observation
Hubble Space 
Telescope
Globalstar comsats
Chinese ASAT test altitude
Iridium-Cosmos altitude
Current Estimated Density of debris at various orbital 
attitudes with notation of recent collisions and resulting 
spikes (Figure curtsey of Orbital Debris Program Office: J. C. Lui)
Orbital Debris Tracking and Characterization 
• Is a technical gap in the current National Space 
Situational Awareness necessary to safeguard 
orbital assets and crews due to the risk of Orbital 
Debris damage to ISS & Exploration vehicles.
• Added to NASA Office of Chief Technologist’s 
Technology Development Roadmap in 
Technology Area 5 (TA5) [Communications & 
Tracking]
• Any exploration vehicle assembled in LEO must 
pass through this debris cloud and survive with 
heavy MMOD shields or alternative orbital 
trajectories. 
• Large cross section, low thrust vehicles (such as 
SEP) will spend more time spiraling out through 
the cloud and will suffer more impacts.
The Problem: Traditional orbital trackers looking for small, dim orbital derelicts and debris typically will stare 
at the stars and let any reflected light off the debris integrate in the imager for seconds, thus creating a 
streak across the image. 
A Solution: Small, sensitive “smart” camera trackers staring along the orbital velocity, picking out non-
celestial objects with proven on-board real-time processing and reporting their vectors. Pairs of these 
cameras as secondary payloads provide stereo range/speed via concise data.  
SMALL ORBITAL STEREO TRACKING CAMERA TECHNOLOGY DEVELOPMENT
“Small Tracker”
Small Tracker: 
• Will see Stars and other celestial objects 
“rise” through its Field of View (FOV) at the 
rotational rate of its orbit
• The glint off of orbital objects will move 
through the FOV at different rates and 
directions. Debris on a head-on collision 
course (or close) will stay in the FOV at ~14 
Km per second.
11
*Flux contribution at 800km, i=83°:
•  Front:  ~599 out of 600 objects
•  Back:       ~1 out of 600 objects
Star-
field:
Encountering Debris @ <1000 km
hcirc=800 km
P = 100 min
R_circ = 7178 km
(not to scale)
Vrel = 15,000 m/s
Top View
@10-25km, ±30° =
10 to 25 km area
1000 km 
Z: @ 1000 km, ~2-5°
= 40 to 100 km area
~60 sec prep time
Y: @ 500 km = 30 to 80 km area
(subtended angle=~4-10° )
~30 sec prep time
Star-field: 
~3.6°/min. 
1° x 1° or 2° x 2°
Front View
Debris that is “encounterable” will be moving 
radially towards the center of the viewing area  
-- the slower its “radial” velocity, the better.
X
Z Y X: 10-25 km 
1
0
-2
5
 k
m
 
S/C 
Vs/c=7.45 
km/s
Larry Kos
4-1522
Conceptual images from the Small Tracker using Amplified Real-time Imaging 
(STARING)
The Small Tracker tracking at 60 frames/sec allows 30 fixes 
before a near-miss pass. Stereo pair of Small Trackers can 
provide range data within 5-7 kilometers for better orbital 
measurements. 
Ground Processing: Knowing the orbit of the host vehicle from 
on-orbit GNSS data, the few dozen snapshots of approaching 
orbital debris can be correlated with the reference star locations 
to calculate the trajectory of observed orbital object.
An EBAPS Camera sensor 
amplifies their light with an 
intensified video imager (as found 
in Apache helicopters). For our 
purposes, we will focus our image 
to a narrow field of view with a 
telephoto camera lens that has 
been ruggedized for launch and 
outer-space use. 
Data Processing:
• Uses a FPGA to convert all lit pixels 
to spots and identifies the spots 
NOT moving with the Stars in real-
time. 
• Tracking data only includes only 
bearing, size, and brightness of 
those non-celestial objects and 
reference star data down for ground 
processing
TECHNOLOGY DEVELOPMENT
Small Tracker Amplified Real-time Imagining (STARING) 
Sensor Proof of Concept Testing
SMALL ORBITAL STEREO TRACKING CAMERA TECHNOLOGY DEVELOPMENT
CPU
Memory
ISS or S/C HOST
Memory
FPGA 
Inline 
Processing
Acquisition 
Logic
Image Acquisition Device
FPGA
Integral 
Intensified 
Camera
Ruggedized 
Telescopic 
Camera Lens
1600x1200 pixels @ 60 frames/sec 
= >115 Mpixels/sec
Dynamic 
Star Field 
Simulator
(Texas A&M)
Proof of Concept tests 
• Dynamic Star Field Simulator - generate a high resolution image of the background stars in 
motion and one to three small orbital objects to verify the control and performance of the 
amplified imager, pixel-to-spot FPGA processing, the orbital object discrimination algorithms and 
tracker pitch angle for optimal debris detection & tracking. 
• Other tests - will mount the Small Tracker to MSFC’s Lunar Impact Telescope Observatory to 
verify real-time star-field processing (similar to current Cubesat Star Tracker testing) and stereo 
tracker misalignments will be tested with ground processing to minimize system constrainsts.
Proto-flight Design & Testing 
• Additional proton testing of the intensified imager chip and FPGA controller with pixel & spot 
processing will be required before designing, building, and testing the small tracker for Low Earth 
Orbit testing and missions using knowledge from Shuttle, DART, Orbital Express, and ISS 
experimental sensors. 
Small Tracker Amplified Real-time Imagining (STARING)
On-Orbital Testing and Integration 
SMALL ORBITAL STEREO TRACKING CAMERA TECHNOLOGY DEVELOPMENT
Initial On-Orbit Testing – ISS
• A stationary mount with simple power and a low rate data interface with data processing 
on the ground
• Staring into the velocity vector is the most advantageous vantage point, however, other 
directions may yield good operational experience and some other tracking data. 
• Single small trackers can gather valuable data as well if a stereo pair cannot be flown or 
one unit fails 
• Visiting Vehicles coming into Station for docking and berthing can also be tracked during 
approach and departure operations.  Data generated will enhance the MMOD 
environmental data for ISS orbit.
Host Vehicle Integration 
• Mount a pair of units roughly parallel, provide power and a simple low speed data link for 
ground commands and data downlink of the orbital object spot data and reference stars 
• Would provide dozens of tracking snapshots per day 
• Orbital Tracking data from Low Earth Orbit vehicles will be incorporated into the NASA 
Debris Density Models and can be correlated with ground based observations. 
• This approach is analogous to the NASA-MSFC Ground based Meteor Tracking 
Camera Network composed of many trio of simple cameras collecting data every 
night and processed once a day to collect time, direction, and speed of meteorites or 
orbital debris observed entering our atmosphere.


Small Orbital Stereo Tracking Camera Technology Development

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