The First Orbital Flight of An ELROI Satellite License Plate - David Palmer SmallSat 2019-08-08 Rebecca M. Holmes, Charles T. Weaver ...
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The First Orbital Flight of An
ELROI Satellite License Plate
David Palmer
Rebecca M. Holmes, Charles T. Weaver
SmallSat 2019-08-08
Managed by Triad National Security, LLC for the U.S. Department of Energy’s NNSA
LA-UR-19-27684
Why we need satellite license plates
Once you’ve lost track,
Before
it’s justyou bring itlight
another down,
in the sky
you haveontoyour
or blip nowradar
who owns it
You just launched 101 Cubesats. It’s stopped talking to you.
Great! Which one’s yours? What happened?
If the object has an optical beacon, we
can read its identification from a
ground station.
Black box?
We can read that too!
Land, air and sea objects
Satellites get smaller and have identifiers,
push tracking capability limits.
why not space?
Can we make them ‘brighter’?
Los Alamos National Laboratory 2019-08-08
TLE lottery
• Now, if you don’t keep track of yourself, you can get lost in the crowd
59 Constellation Sats 8 Lemur, 47 Flock
GPS & Radio 2 NORSAT, 2 Corvus
Proton launch 73 Objects
July 2017 in space-track Incl. Primary Payload
9 Other identified objects
9 Unidentified Objects* Many just didn’t check in.
(Thruster impingment)
(arrows not to scale)
3 Flock, 3 Hawk,
46 Identified 2 SkySat, 3 SpaceBee,…
SSO-A Falcon 65 Objects and some other
Dec 2018 in space-track well-resourced payloads
19 Unidentified Objects
Even if it’s conventional – 1 payload, 1 rocket body – you might still end up trying
to talk to the rocket body.
*All numbers as of May 2019
Los Alamos National Laboratory 2019-08-08
A cheap and simple blinking light can do it
(if it’s the right light blinking in the right way)
Every satellite or piece of These beacons produce narrow-
intentional debris is band laser light in all directions.
tagged with optical The laser is pulsed with a coded
beacons
pattern. Each beacon has a
different code: A Serial Number
(and sometimes more information)
Telescope points at satellites
Filter blocks everything
110011010…
but the laser wavelength Add on…
(serial number for SciCube93)
Photon-counting
010110010…
(serial number for GoogCube)
sensor records
x, y, & time
1001001.. (serial number for LookSea5) of each
ALERT: Impact detected 3 hours ago, photon
no payload activity sensed,
Computer processes x,y to
spin rate increased to 1.8 RPM… and sends it to
get image of satellites. computer
For each sat, processes
times
to read the code.
…or build in
Los Alamos National Laboratory 2019-08-08
How ELROI works
Squeezing a small amount of energy into a tight multi-parameter space—
direction, wavelength, time, frequency, and coding
— pushes it up above the background.
1 mW (average) from LEO can be identified in a single pass.
Δλ~1nm
notional values
1 μs pulse width 1 ms clock 1 Watt instantaneous power
period
… 1 0 1 0 1 0 0 0 1 1 …
127-bit Error correcting code for serial number
-150 dBm = +5 dBγ (3 photons/second detected)
Los Alamos National Laboratory 2019-08-08
for 3 minutes is all you need for confident ID
How to observe ELROI
35-cm Celestron on Paramount ME tracking mount
LANL-developed single-photon camera
Photonis camera is
a COTS equivalent
Or use a conventional camera for guiding
and tracking, with a pick-off mirror for a
single-pixel single-photon detector.
Can you do this? We’ll help you.
Los Alamos National Laboratory 2019-08-08
ELROI on NMTSat
3U CubeSat built by students at
New Mexico Institute of Mining and
ELROI-PC104 Technology (NMT).
Hysteresis-damped magnet for
passive stabilization.
2 red diodes point North and down over
North temperate regions.
1 red, 1 blue point South and down over
South temperate regions
2 red (638 nm)
laser diodes on Launched 8 months ago
North face, ELaNa XIX (NASA )
1 red, 1 blue 10 Educational CubeSats
(450 nm) on +3 commercial
South face. Rocket Lab Electron
Los Alamos National Laboratory 2019-08-08
TLE Lottery
Includes R/B and
8 tracks identified
7 CubeSats
ELaNa launch 15 objects Known but not
1
Dec 2018 in space-track reported
6 Unidentified tracks
Includes NMTSat
• Some of the missing satellites were contacted then lost.
• One unidentified track was tentatively identified with two different satellites.
• One unidentified track was said to be claimed, but denied by sat operator.
• Upper stage identity known (priv. comm.) but not identified in public catalog.
• NMTSat has not been contacted by radio.
ELROI can blink, even if its host satellite doesn’t fully work. So we looked for it.
Los Alamos National Laboratory 2019-08-08
ELROI Observation attempts
• We have observed each of the unidentified tracks, with greater or
lesser intensity.
– We initially ignored 2 tracks falsely thought to be identified
– One was much brighter than the others, so we eventually contacted Rocket
Lab who identified it as the kick stage.
• For first 3 months, satellites in shadow.
– Could only point based on TLE predictions.
– Some of the predictions were not very good
– Terminator passes would be available in Southern Hemisphere
• We do not have perfect observations of all unidentified objects
• We have not yet detected the ELROI signal.
Los Alamos National Laboratory 2019-08-08
Good satellite observation
By tracking the TLE prediction
with the telescope, the satellite
Object C
should be ~fixed in field of trail
Object C
view. When sat seen,
tracking can be adjusted
Predicted
Object C to remove offsets.
Predicted
location
Object C
trail
The same data can be
broken up into very
Star trail
short exposures and Star
shifted and stacked to
put into the sky frame.
Star catalog
This lets pointing locations
knowledge be adjusted
based on known star
locations.
Camera FOV (0.5 deg.)
Los Alamos National Laboratory 2019-08-08Missed satellite observation (Obj. E, T+4 months)
Sometimes the available orbital predictions
are too inaccurate to put satellite in FOV.
Error tends to be mostly along-track, so
Predicted
Object E
one strategy is to search forward and
Predictions (latest TLE as of backward to try to detect satellite.
based on observation time.)
prev. and next
TLE This requires sunlight and a good aspect
(or real-time ELROI detection) to make
satellite detectable.
Object E Published orbits do not include
Not detected
in this observation Uncertainty Quantification, so size and
shape of best search area is unknown.
For blind passes, you may never know
Los Alamos National Laboratory 2019-08-08Summary by object
Object Notes
Object C Much brighter than other objects.
Rocket Lab confirmed that this is Upper Kick stage.
Object E Blinking with 10 second period in early May.
Often not seen in observations.
Object F Often not seen in observations.
Object H Blinking at 3s or 6s period in April.
Previously claimed to be ISX, so few observations.
Object K Blinking at 3s or 6s period in May
Object L Not obviously blinking.
Object P Tentatively claimed as two CubeSats, so few observations.
Los Alamos National Laboratory 2019-08-08Fault Tree
Maybe it’s not working,
or maybe we haven’t observed it right.
Keep looking!
Los Alamos National Laboratory 2019-08-08How to make it easier
• Improved tracking
– closed loop tracking, with orbital refinement, for sunlit (terminator) objects
• Real time analysis
– detect ELROI and close tracking loop without sunlight
• Better communication: identifications should be reported
• Better TLEs (wish list)
– uncertainty quantification in TLEs; (Twenty Line Elements)
– observations software to sweep out uncertainty region
• More ground stations
– North-South diversity improves availability of terminator conditions
• ELROI on known object (if NMTSat can be identified)
• ELROI on pointed object (2020 launch) ensures pointing at ground
• ELROI on everything
Los Alamos National Laboratory 2019-08-08ELROI Evolution
Delivered (x2)
August 2018
for 2020
launch
Engineer it to tile size
Launched December 2018
Or design it in
Available
for YOUR
satellite More
(see me). ground
stations
Los Alamos National Laboratory 2019-08-08ELROI team David Palmer and Rebecca Holmes (ISR-2) Electrical: Charley Weaver (ISR-4) Mechanical: David Hemsing (ISR-5) Software: Joellen Lansford (ISR-4) Environmental testing: Ryan Hemphill and Jim Lake (ISR-5) NMTSat: Anders Jorgensen, Sawyer Gill, Zach Harris, Riley Myers, and Aaron Zucherman
BACKUP Los Alamos National Laboratory 2019-08-08
What Next?
• More observations to find ELROI/NMTSat
• Launch of 2 ELROI units late 2020
– On well-resourced satellites, with GPS and pointing control
– Launcher, other details not yet identified
• Your satellite needs an ELROI. Let us help!
• Looking for
– Flight opportunities
– Observers
• Ground segment opportunity
– Industrial partners for manufacturing
• ELROI-1, ELROI-1X, ELROI-GEO, ELROI-Embedded, …
palmer@LANL.gov
• Standardization, Normalization, and Ubiquity.
Los Alamos National Laboratory 2019-08-08Los Alamos National Laboratory 2019-08-08
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