Distributed Space Systems
Overview Briefing of GSFC and
NASA Code R Program to AR&C
Working Group
Dr. Jesse Leitner
GSFC DSS Lead Engineer
Jesse.Leitner@gsfc.nasa.gov
301-286-2630
May 23, 2002
Distributed Space Systems- Revolutionizing Earth &
Space Science
Goddard Space Flight Center
Interferometry
Co-observation
Coincidental Observations
Multi-point observation
Tethered Interferometry
A new era of space exploration will be enabled
by cooperating spacecraft
J. Leitner
2
Sunday, May 29, 2016
Distributed Spacecraft Missions
Goddard Space Flight Center
Projected
Launch Y ear
Mission N ame
00
01
03
03
03
03
New Mille nnium Program (NMP) Earth Observing-1 (2)
Gravity Recovery and Clima te Recovery (GRACE) (2)
University Nanosats (AFRL/GSFC) ORION nanosat mission (2)
University Nanosats (AFRL) 3 Corner Sat misson (3)
University Nanosats (AFRL/GSFC) ION-F m ission (3)
Synchronized Position Hold Engage & Reorient Experimental Satellites
03
NMP ST-5 Nanosat Constellation Trailblazer (3)
04
Techsat-21/AFRL (3)
Technology Demo
04
Auroral Multiscale Mission (AMM)/APL
Space Science/SEC
04
ESSP-3-Cena (w/ Aqua) (2 )
05
Starlight (ST-3) (2)** (ground-based only at the moment)
Space Science/ASO
05
Magnetospheric Multiscale (MMS) (4)
Space Science/SEC
06
MAGnetic Imaging Constellation (MAGIC) (7, string of pearls)
Space Science
06
COACH (2-3)
Earth Science
07
Global Precipitation Mission (EOS-9)
07
Geospace Elec trodynamic Connections (GEC)
Space Science/SEC
08
Constellation-X (4)
Space Science/SEU
08
Magnetospheric Constellation (DRACO) (50-100)
Space Science/SEC
08
Laser Interferometer Space Antenna (LISA) (3)
Space Science/SEU
09
DARWIN S pace Infrared Interferometer/European Space Agency
10
Leonardo (GSFC) (4-8)
15
Stellar Im ager (SI) (10-30)
Astronomical Low Frequency Array (ALFA)/Explorers
J. Leitner
Mission Type
Earth Science
Earth Science
Technology Demonstrator
Technology Demonstrator
Technology Demonstrator
Technology Demonstrator
Space Science
Earth Science
Earth Science
Space Science
Earth Science
Space Science/ASO
Space Science
12
MAXIM Pathfinder (2-3)
05+
Living with a Star (LWS) (many)
Space Science/SEU
Space Science
05+
Soil Moisture and Ocean Salinity Observing Mission (EX-4)
Earth Science
05+
Time -Dependent Gravity Field Mapping Mission (EX-5)
Earth Science
05+
Vegetation Recovery Mission (EX-6)
Earth Science
05+
Cold Land Processes Research Mission (EX-7)
05+
Hercules
05+
Orion Constellation Mission
Space Science/SEC
15
Submillimeter Probe of the Evolution of Cosmic Structure (SPECS) (3)
Space Science/SEU
20+
Planet Imager (PI)
Space Science/ASO
20
MAXIM X-ray Interferometry Mission (34)
Space Science/SEU
15+
15+
Solar Flotilla, IHC, OHRM, OHRI, ITM, IMC, DSB Con
NASA Goddard Space Flight Center Earth Sciences Vision
Space Science/SEC
Earth Science
15+
NASA Institute of Advanced Concepts/Very Lar ge Optics for the Study
of Extrasolar Terrestrial Planets
3
Earth Science
Space Science/SEC
Space Science
Sunday, May 29, 2016
The Large Aperture Sensing Spectrum
Goddard Space Flight Center
What’s best, connected or freeflying?
Extremely Challenging Dynamics!
Hubble
Monolithic
NGST
UltraLITE
SPECS
Deployable
Filled
Deployable
Sparse
Tethered
Formations
Rigidity
Large and heavy
Absolute Resolution Constraint
Near perfect large-scale manufacturing required
J. Leitner
4
LISA
Hybrid
Formations
Stellar Imager
Freeflyer
Formations
Controllability
Sensing extremely challenging
“Unconstrained Resolution”
Manufacturing requirements on
Sunday, May 29, 2016
smaller optics
DSS Example Missions and
Demonstrations
NMP EO-1 Enhanced Formation Flying (EFF)
Experiment
Goddard Space Flight Center
Level - I:
Demonstrate the Capability to Fly Over the Same Ground
Track As LandSat-7 Within 3 Km at a Nodal Separation
Interval of Nominally One Minute During Which Time an
Image Is Collected.
Level-II:
FF Start
Radial Separation (m)
Formation Flying Spacecraft
Reference S/C
Velocity
Nadir
Direction
In-Track Separation (Km)
Ideal FF Location
FF Maneuver
I-minute separation
in observations
Observation Overlaps
J. Leitner
EFF- Shall Provide the Autonomous Capability of Flying
Over the Same Groundtrack of Another S/C at Fixed
Separation Times.
Autonomy - Shall Provide On-Board Autonomous Relative
Navigation and Formation Flying Control for EO-1 and
LandSat-7.
AutoCon Flight Control System - Shall Provide Autonomous
Formation Flying Control Via AutoCon (to provide future
reusability).
Ground Track - EO-1 Shall Fly the Same Ground Track As
LandSat-7.
Separation - EO-1 Shall Remain Within a 1-Minute In-Track
Separation from LandSat-7.
6
Sunday, May 29, 2016
Goddard Space Flight Center
Magnetospheric Multi-scale
How do small-scale processes control largescale phenomenology, such as magnetotail
dynamics, plasma entry into the magnetosphere,
and substorm initiation?
•4 identical spacecraft in a variably spaced tetrahedron
( 1 km to several earth radii )
•4 orbit phases, orbit adjust
•2 year in-orbit (minimum) mission life
•Interspacecraft ranging and communication
•Advanced instrumentation, integrated payload
•Attitude knowledge < 0.1°, spin rate 20 rpm
Phases 1-3, Equatorial - Phase 4, Polar - Determination of Spatial Gradients
J. Leitner
7
Sunday, May 29, 2016
DRACO - Magnetospheric Constellation
Goddard Space Flight Center
Fundamental measurements: magnetic field, plasma flow field, and energetic particle acceleration
•50-100 nanosatellites - “weather observatories”
•Orbits have 3Re perigee with varying apogees from 12Re to 42Re.
•Nanosats communicate with ground during perigee region.
J. Leitner
8
Sunday, May 29, 2016
Future Distributed
Architecture
Goddard Space Flight Center
Information
Synthesis
And
Access to
Knowledge
Advanced
Sensors
Sensor Webs
Information
Data Archive
User
Community
Goddard Space Flight Center
Precision Formation Flying Missions and
Mission Concepts
J. Leitner
10
Sunday, May 29, 2016
Laser Interferometer Space Antenna (LISA)
Goddard Space Flight Center
Mission:
3 spacecraft separated by 5,000,000 km form a threearm ‘Michelson Interferometer’ to observe
gravitational waves in a 10-4 to 10-1 Hz bandwidth
Approach:
Each spacecraft payload includes two freely falling
proof masses which serve as arm “end mirror”
optical references
Test masses must be free of non-gravitational forces
(geodesically pure)
Gravitational waves cause change in optical path in
one arm of interferometer relative to other arm
Distance changes measured with picometer precision
to detect gravitational wave strains down to 10-23
Disturbance Reduction System (DRS) uses proof mass
displacement sensor outputs to drive low-noise
micro-Newton thrusters for ‘drag-free’ system
operation
J. Leitner
11
Sunday, May 29, 2016
Goddard Space Flight Center
Requirements in the small-scale LISA
formation
The spacecraft and
each proof mass are
in different orbits
Proof mass cannot
move more than ~1
nm/Hz^0.5 relative
to chamber
LOS of each proof
mass must hit
wavefront on distant
proof mass
Proof mass cannot hit
vacuum chamber
No control can be
applied in
measurement axis
within the MBW.
J. Leitner
Proof mass cannot
accelerate more than 2
femto-m/s^2/Hz^0.5
12
Sunday, May 29, 2016
Goddard Space Flight Center
MAXIM Pathfinder
•Demonstrate the feasibility in
space of X-ray interferometry for
astronomical applications.
•Provide an imaging of celestial Xray sources with resolution of 100
micro-arcseconds, 5000 times
better than the Chandra
observatory.
J. Leitner
13
Sunday, May 29, 2016
MAXIM-PF Formation Initialization
(Mode 2, 20000 km Baseline)
Goddard Space Flight Center

Possible Configuration




Optics Hub has Minimal or no Propulsion
Detector SC moves to a distance of 20,000 km from Optics Hub
FreeFlyer SC Separates from Optics hub to a maximum separation of 500 m
New Baseline May Require New Class of Continuous Thrusters for Detector SC
Optics Hub S/C
20,000 km
200 km
500 m
Detector S/C
(Mode 1)
Detector S/C
(Mode 2)
FreeFlyer S/C
J. Leitner
14
Sunday, May 29, 2016
Goddard Space Flight Center
The Black Hole Imager:
Micro Arcsecond X-ray Imaging Mission
(MAXIM) Observatory Concept
Optics
32 optics (300  10 cm) held in
phase with 600 m baseline to
give
0.3 micro arc-sec
1 km
10 km
34 Formation Flying Spacecraft
Black hole image!
500 km
System is
adjustable on orbit
to achieve larger
baselines
J. Leitner
Combiner
Spacecraft
Detector
Spacecraft
15
Sunday, May 29, 2016
Goddard Space Flight Center
J. Leitner
16
Sunday, May 29, 2016
DSS Technology
(Overview and selected examples)
Goddard Space Flight Center













DSS Technology Challenges
Centimeter to nanometer control over S/C separations ranging from meters to 1000s of
kilometers
Precise and coordinated spacecraft pointing to sub-arc seconds
Coordinated (simultaneous) Orbit/Attitude control of multiple spacecraft
Tethered formation control
Autonomous fleet reconfiguration, replenishment, upgrade, and repair
Initialization of multi-spacecraft fleets: collision avoidance
Autonomous ground operations for formations and constellations; extreme challenge is
a mission consisting of 100’s to 1000’s of satellites
Multiple spacecraft deployment systems : deployerships and release mechanisms
Data management: Mb-Gb/sec of data in space-to-space communications networks
Inter-spacecraft communications for fleet control
Cross-calibration, data management/processing of distributed instruments
Mass production and I&T of low-cost Microsat and Nanosat vehicles
Modeling, simulation and testbed infrastructure
J. Leitner
18
Sunday, May 29, 2016
Dominant Technology Drivers for NASA
DSS Missions
Goddard Space Flight Center
• Cost!
•MMS - need low-cost means of long range relative nav
•Drives the need to push GPS to its limits
• Span of coverage
•DRACO, MMS - Must cover large spatial region time-synchronously
• Extremely low noise characteristics (high sensitivity of payload)
•LISA - Measurement would be lost in the most minimal gravitational or
seismic disturbances
• Long mission duration
•SI - Must last through entire solar cycle
• “Awkward” Science Sensors
•MAGnetic Imaging Constellation - Each craft has 4 500 meter antennae
• High required angular and spatial resolution
•SI, MAXIM - milli-micro arcsecond line-of-sight requirements
J. Leitner
19
Sunday, May 29, 2016
DSS Technology Development Areas
Goddard Space Flight Center
Formation Sensing and Control
Sensing, actuation, and algorithms required to maintain
and/or understand vehicle position or orientation
Verify Burn
Command
Interface
Verify Burn
Command
Generation
Cold/Warm
Init
Intersatellite Communications
Hardware, software, and advanced coding and compression
algorithms to satisfy unique DSS communications needs
Miniaturized Spacecraft
Technology
Approaches to reducing spacecraft bus
infrastructure requirements in the areas of
cost,mass, volume, and power
SemiAutonomous
4
IDLE
1
Auto Transition
Manual
Commit
Abort
3
Monitor
2
Autonomous
( n burn limit )
Verify Decision and
Planning
Auto Transition
Verify Lights Out
Constellation Management and
Mission Operations
High-level control strategies to enable collaborative multispacecraft campaigns
J. Leitner
Mission Synthesis, Design,
and Validation
The end-to-end DSS systems analysis
20
Data Acquisition, Processing,
Fusion, and Analysis
Data operations of the DSS E2E system
in fulfilling the scientific objectives
Sunday, May 29, 2016
GSFC Distributed Space Systems HIGH-LEVEL DEVELOPMENT ROADMAP
Calendar Year
2001
AM
TRAIN
2
3
4
5
6
7
8
9
10
11
MAGIC
LWS SPIRIT
PM ST5 StarLight COACH MMS GPM Con-X LISA
TRAIN
12
TPF
13
14
15
MAXIM SPECS
PF
16
SI
17
18
SENSOR
WEB
19
20
MAXIM
Real-time wavefront-error-based formation error estimation
Vision-based sensors and algorithms
Laser Interferometry Ranging Systems and Algorithms
Celestial Rel Nav HW & algorithms
Centralized nonlinear control algs.
L2 dynamics and control analysis.
Dispensation system analysis
On-board (OB) Intelligent Constellation Exec
OB High-level Constellation Configuration
OB Adaptive Scheduling
OB Fault Detect.& Res
Autonomous Fault Prediction
OB Automated Data Mgmnt and Delivery
Science Event Detection & On-board Replanning
Constellation and Platform Flight S/W Mgmt
Dynamic Space Networking
Intelligent Retasking
Dynamic Ad-Hoc SensorWeb Mgmnt & Safekeeping
Integrated Science Ops of Heterogeneous Sensors
Adv Const. Data Synth/Vis.
On-Board Distributed Computing
High (ground comparable) capacity processing/memory
(move to DPFA from CMMO?)
Advanced Feature detection
Adaptive calibration/georegistration
On-board science resource mgmt
Data and metadata stds,
Automated multi s/c data dist & analysis
On-board data analysis
UNIX flight environment
ISC
High fidelity sensor modeling and validation
High fid. models of LEO/HEO/GEO/lib. pt orbit envs in integ testbed
Quad precision computing envs and platforms
Development of high precision stochastic integrators in MATLAB
Integrated multi-orbit and launch-to-orbit sim models
RF Comm/ranging for large closely-spaced clusters
Developing HW for new DSS frequency set
On-board communication hub
MST
MSDV
DAPFA
CMMO
FSC
Goddard Space Flight Center
Ultra Low-Power Technology
Miniature High-Bandwidth Star Trackers
Micro and nano wheels
Miniature Sun Sensors
J. Leitner and nanosat packaging, interconnection, and I&T
Microsat
21
Sunday, May 29, 2016
Relative Navigation
Goddard Space Flight Center
Low-cost approaches
GPS Constellation
MAG, MAG+INS, MAG+CEL
Direct Cross-link Ranging
RF/optical/laser
Unaided-GPS, GPS/INS, TDRSS
(Differenced or CDGPS)
Enhanced GPS, GPS/CELNAV, GPS/INS
Enhanced receivers with
CELNAV, WFE sensing
integrated filter and tracking
loops, weak signal
acquisition and tracking
Use sensors already oncapability.
board for attitude, safeJ. Leitner
hold, etc.
22
Good performance at high
data rates
Perhaps the only means of
achieving “optical quality”
figure errors of formations
Sunday, May 29, 2016
AMSAT Phase 3D (AO-40)
Goddard Space Flight Center
Experiment Objectives
• Long term, real time attitude and orbit
determination experiment
• Mapping the GPS constellation antenna
patterns above the constellation
• Understanding the robustness and
limitations of using GPS above the
constellation
Team
AMSAT, NASA GSFC
GPS Hardware
• 2 Trimble Tans Vector Receivers
• 4 patch antennas on perigee side of
spacecraft
• 4 high gain (10 dB) antennas on apogee
side of spacecraft
J. Leitner
23
AMSAT Phase 3D in Kourou
Launch: November 16, 2000
Vehicle: Ariane 5
Orbit: 1000 by 58,800 km, i=6
Sunday, May 29, 2016
Goddard Space Flight Center
AO-40 Orbit with Geosynchronous
& GPS Orbits Superimposed
Y
Z
J. Leitner
24
X
Sunday, May 29, 2016
Goddard Space Flight Center
MEO Test Case
GPS
MEO
42.6 degrees
J. Leitner
25
Visible Region
in Primary Beam
Sunday, May 29, 2016
MEO Relative Position Accuracy
Goddard Space Flight Center
Relative Position Error (meters)
20
Estimation
Span
18
Prediction
Span
16
14
12
10
Maximum
8
6
4
2
RMS
0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Elapsed Days
J. Leitner
26
Sunday, May 29, 2016
HEO Test Case
Goddard Space Flight Center
GPS Side Lobe
GPS
HEO
Visible Region
in Primary Beam
42.6 degrees
GPS Side Lobe
J. Leitner
27
Sunday, May 29, 2016
Goddard Space Flight Center
J. Leitner
HEO GPS Visibility
28
Sunday, May 29, 2016
Goddard Space Flight Center




Lost-in-space/initial insertion
Coarse vehicle placement
Coarse vehicle orientation
Formation initialization






GN&C
VISNAV/CCD/modified star tracker (25 mm lateral motions)
3 color laser interferometer (10 nm distance from hub)
Star trackers on mirror-craft all tracking same guide star (as)
Capture


Wide dynamic range and fine resolution:
formation modes
mirrorcraft-to-mirrorcraft laser ranging required to get from 25 mm to 50 micron
measurement accuracy
Other handoff values must be determined by ISAL analysis based partially on dynamic
range of wavefront error sensing approach.
Calibration (backing out system parameters)
Maintenance



J. Leitner
Real-time wavefront error sensing (e.g., phase diversity)
Mirror motion control
Continuous feep counterbalance on spacecraft
29
Sunday, May 29, 2016
Coarse Formation Alignment
Block Diagram
Goddard Space Flight Center
(5 S/C example)
S/C 1
Actuation
S/C 1
Dynamics
S/C 2
Actuation
S/C 2
Dynamics
S/C 3
Actuation
S/C 3
Dynamics
S/C 4
Actuation
S/C 4
Dynamics
S/C 5
Actuation
S/C 5
Dynamics
Spacecraft
Allocation
J. Leitner
beacon
beacon
beacon
beacon
beacon
beacon
beacon
beacon
beacon
beacon
Formation
Control
Algorithm
30
Laser
Propagation
APS
Formation
Sensor
Relative Navigation/
Relative Attitude
Algorithm
Sunday, May 29, 2016
Goddard Space Flight Center
J. Leitner
APS AutoCAD 3D Model
31
Sunday, May 29, 2016
Modulation Sideband Technology for Absolute Ranging
(MSTAR) Sensor
Goddard Space Flight Center
Product Objectives
Product
Develop a range sensor with nanometer resolution
and multi-kilometer absolute measurement range.
Measurement range enabled by
MSTAR
Proposed
sensor
State–of–
the–art
• A high-precision, high-dynamic range, flightqualifiable interferometric absolute metrology
gauge using Modulation Sideband Technology for
Absolute Ranging (MSTAR) that will bridge the
gap between the existing “fine” and “coarse”
regions.
MSTAR Sensor
Gap coarse: pulsed RF or
fine:
laser rangers
interferometers
RF Mod Sensors
nm
µm
mm
m
• A handoff approach between the interferometric
gauge and the long range “coarse” RF sensor
km
unambiguous measurement range
Participants & Customers
Product Schedule & Funds
•
•
•
•
•
Dr. Serge Dubovitsky, JPL, 346
Dr. Oliver Lay, JPL, 335
Prof. William H. Steier, USC
Dr. Harrold Fetterman, Pacific Wave Industries, Inc.
Primary Enterprise Customer: SSE
Separated Spacecraft Interferometry: Terrestrial
Planet Finder (TPF), Constellation-X, Life Finder
(LI), Planet Imager (PI)
Large Deployable Single Telescopes: Filled Aperture
Infrared Telescope, FAIR), Space UV/Optical
Telescope (SUVO)
• Secondary Enterprise Customer: ESE (EX5)
J. Leitner
32
Product Milestones
02
03
04
Demonstrate full performance X
Demo. path to integration
X
X
and insertion to flight system
Code R ($K)
XXX XXX XXXX
Contracted Support (PWI)
USC
Total ($K)
XXX XXX XXXX
XXX XXXX XXXX
XXXX XXXX XXX
Sunday, May 29, 2016
RF Formation Flying Sensor
Goddard Space Flight Center
Product
Product Objectives
Develop a Ka-band Formation Flying Sensor (FFS)
to measure ranges and bearing angles between
multiple spacecraft to a (2cm, 1 arcmin)-accuracy, at
30-1000m spacecraft separation, with near-4steradican coverage and no ground commands, for
autonomous precision formation flying of multiple
spacecraft.
•FY02: Prototype FFS; demonstrate technology.
•FY03: Develop calibration & acquisition techniques.
•FY04: Enhance formation flying sensor algorithms.
Participants & Customers
Participants:
• Tracking Systems & Applications (335): G. Purcell, J.
Tien, J. Srinivasan, L. Young, M. Gudim
• Spacecraft Telecomm. Equipment (336): L. Amaro
• Comm. Ground Systems (333): M. Ciminera, G.
Walsh, D. Price, C. Foster
Co-funding:
• StarLight Mission
Customers:
• Primary Enterprise Customer: StarLight mission
• Future Customers: TPF, Planet Imager, other future
missions requiring precision formation flying.
J. Leitner
33
Product Schedule & Funds
Product Milestones
02
Prototype sensor Tech demo
Acq. & calibration algorithms
Integrated filtering algorithms
Code R ($K)
X
XXX
Code S ($K)
XXX XXX XXX
StarLight
Total ($K)
03
04
X
XXX
X
XXX XX
XXX XXX
XXX XXX XXX
Sunday, May 29, 2016
Integrated Microthrusters
Products
Goal:
•Micromachined Components
•Highly Integrated Modules
•Minimal External Interfaces
Product Objectives
Goddard Space Flight Center
Integrated High
Voltage Interface
•Develop fully integrated propulsion systems
that combine MEMS-based sub components
with integrated microelectronics control
circuits for future micro/nano Sciencecraft
•FY02: Demonstrate operation of propulsion
components (VLM and MIV) with Driver
Electronics; TRL 3.
•Continued performance mapping of VLM
thruster, MIV filtration tests
Micro-Isolation
Valve (MIV)
Electronics
Isolation Valve
Filter
Thruster Valve
Thruster Chip
Micro-Thruster
Valve
Vaporizing
Liquid MicroThruster (VLM)
Participants & Customers
• Juergen Mueller (PI), Mohammad Mojarradi (Co)
PI Jet Propulsion Lab (JPL). Amanda Green, David
Bame Victor White (JPL). Prof. Harry Li (
University of Idaho), Prof. Ben Blalock (Mississippi
State University)
• Unique facilities: 0.5 µN resolution thrust stand,
Micro Devices Lab, Micropropulsion Design,
Assembly and Test facility (MDAT) (under
construction).
•Primary Enterprise Customer: Code S, Solar System
Exploration Missions to Mars & other planets, SEC
missions (GSFC), interferometry missions
•Secondary Enterprise Customer: Code Y, advanced
sensors
J. Leitner
34
Product Schedule & Funds
Product Milestones
00
Design & Fab Micro Propulsion Comp.
X
Perf. Demo/Charact. of VLM/MIV
Map propulsion Cells into 0.35um
Demonstrate operation of
VLM and MIV with Driver Electronics
CETDP ($K)
Co-Funding ($K), DRDF
Total ($K)
01
02
X
X
X
XXX XXX XXX
XXX XXX XXX
XXX XXX XXX
Sunday, May 29, 2016
Goddard Space Flight Center




Intersatellite Communications Efforts
GSFC/ITT Low Power Transceiver (LPT)
APL Crosslink Transceiver (CLT)
Stanford Transceiver Crosslink System (University
Nanosats)
Visidyne Optical Ranging and Comm System
J. Leitner
35
Sunday, May 29, 2016
Goddard Space Flight Center
•Distributed
systems of
spacecraft
•Distributed
systems for
ground-based
processing
•Need for
integrated
space/ground
data system
DFPA Scenario for DSS
GPS
Constellation
Non-Constellation
Science Spacecraft
Comm Sats
(e.g. TDRS)
Uplink and Sensitive Downlink
via Dedicated Lines, Dedicated
W ANs, or Secure VP Ns
NASA and Commercial
Ground Stations
Control Centers
Home PCs
•Enormous data
volumes
Science Data Centers
Universities
Commercial
Internet
•Management of large constellations – command and control, flight dynamics, trending and analysis
•Collaborative planning and scheduling
•Fusion of dissimilar science data products from diverse instruments, locations
J. Leitner
36
Sunday, May 29, 2016
Decentralized Control Full
Capability
Goddard Space Flight Center
spacecraft position, velocity, attitude, and time
Alpha
Computer
Cesium
RF Gen.
1
STR 4760
Monitor
KB/MSE
GPS 1
RF
signals
RS422
RF Gen.
RF
2
signals
STR 4760
SIMULATOR
FC 1
(GEODE v5)
(GEODE v5)
GPS 2
FC 2
(GEODE v5)
(GEODE v5)
GPS 3
FC 3
(GEODE v5)
(GEODE v5)
GPS 4
FC 4
(GEODE v5)
(GEODE v5)
1-PPS
Oscillator
GROUND
(ITOS)
RF Gen.
commands
1-PPS
10 MHz
into RF
generator
Monitor
KB/MSE
comm
&
telem
SENSOR
E
t
he
r
ne
t
Comparison
Visualization
x
x^
Hu
b
DISPLAY
ENV
DV’s
(VSat)
Digital
Timing
Card
SPACECRAFT
IEEE488
1-PPS
J. Leitner
37
Sunday, May 29, 2016
Goddard Space Flight Center
Full RF Formation Flying Simulation
Nav.
Environment
GPS1
GPS2
GPS RF
Sim
Testport
GSE
ENV
SIM
CLT RF
Sim
On-Board
Processing
GPSn
CLT1
CLT2
FC1
FC2
FCn
Cesium
Source
Testport
GSE
CLTn
XPDR1
XPDR2
TURFTS
Testport
GSE
XPDRn
Mission
Operations
(ITOS)
GCTS
J. Leitner
38
Sunday, May 29, 2016
NASA & the AFRL University Nanosat Program
NASA
Distributed Space Systems Technology Program
(Code R, ESTO, GMSEC, NMP, SBIR, ...)
(relative) navigation system
technologies
fleet and vehicle
control systems
DoD
University Nano-Satellite Program
(AFRL, AFOSR, DARPA)
Santa Clara
New Mexico State
“Emerald”
“3^SAT”
Univ of Colorado
“3^SAT”
Arizona State
“3^SAT”
AFRL
(nanotechnology demo)
inter-spacecraft comm
Stanford
“Emerald”
Carnegie Mellon
“Solar Blade”
GSFC
(formation flying demo)
Univ of Washington
“UofW Nanosat”
Virginia Tech
“VTISMM”
Utah Stat
“USUSat”
Boston U
“Constellation Pathfinder”
University Nano-Satellites
for
Distributed Spacecraft Control
technologies
vehicles
interaction - cooperation - collective behavior

Formation Flying Space
Testbed:
ORION
Operational
Characteristics

Goddard Space Flight Center
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GN2 Propulsion System
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12 thrusters: 4x3 asymmetric
Isp ~ 70 sec
DVtotal: 25 m/s
torquer coils for detumbling
J. Leitner

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40
Mass: ~ 40 kg
Size: 45 cm cube
Tmax: 0.2 N /
thruster
ITB/M: 100 mm/s
MTL/M: 0.01 m/s2
Active station-keeping (cold gas)
and 3-axis stabilization
Advanced inter-spacecraft
communication
Relative sensing and control
(carrier phase differential GPS).
Sunday, May 29, 2016
Goddard Space Flight Center

Provide a comprehensive on-orbit demonstration of
true formation flying spacecraft
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Demonstrate technologies to enable a virtual platform
GPS sensing and fleet control
Significant interest from both NASA & USAF
Demonstrates the key technology element to be used on the TechSat-21
mission (prototype of same hardware, algorithms, and software)
Low-cost to NASA


ORION2 Experiment Objectives
Micro-satellites developed using techniques from the Space Systems
Development Laboratory.
High-risk, but

Most technology developed in-house, so no major investments.
Sunday, May 29, 2016
Integration and Infusion of DSS Technologies
MMS Mission HI-FI E2E
Integrated HWIL Sim
GPS Side Lobe
Goddard Space Flight Center
GPS
HEO
Visible Region
in Primary Beam
42.6 degrees
High-Altitude Relative
Navigation
GPS Side Lobe
Code S Mission with Technologies
Relevant to Code Y
FF Start
Radial Separation (m)
Formation Flying Spacecraft
Reference S/C
Velocity
In-Track Separation (Km)
Ideal FF Location
Landsat-7/EO-1 Formation
Flying
Nadir
Direction
HSS
Ground
GCTS
FF Maneuver
I-minute separation
in observations
Science
Instrument/
Payload
Input
Observation Overlaps
ICS
(comm)
On-Board
GCTS
FFE
GTS
CS
(algorithm)

CS
(actuators)
ES
-
GSFC FFTB
NS
(estimator)
NS
(sensors)
PS
ICS
(ranging)
CEN
GUI Input
External
Testbeds
and facilities
Decentralized Control of
Formations
J. Leitner
DISPLAY
•SOMO
•DDF
•Outside
Partners
University NanoSats &
Intersatellite Comm.
DSS- integrating and validating systems solutions to enable
Enterprise multi-spacecraft
missions
42
Sunday, May 29, 2016
Goddard Space Flight Center



The concept of DSS is opening new possibilities for science exploration
from space
Dozens of missions are in development or proposed to exploit DSS
concepts and technologies
Likewise, DSS technologies are enabling new mission concepts



Summary
Tech push vs requirements pull
DSS cuts across all disciplines and encompasses the spacecraft, the
instruments, the communication network, the ground system, and the
data.
DSS system development requires new processes for systems engineering
and technology development

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J. Leitner
Subsystems have much more significant inherent coupling
In many cases the science instruments and spacecraft bus components are fully
integrated in the form of “sciencecraft”
43
Sunday, May 29, 2016