ST6 ARX Mission & System Overview
Richard Kornfeld
Jet Propulsion Laboratory
Inter-Agency AR&C Working Group Meeting
May 22 - 23, 2002
Naval Research Laboratory
Key Level 1 Requirements
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ARX-100-4.1.1.1: The ST6 ARX shall produce sufficient in-flight data to evaluate the functional
performance of the Autonomous Rendezvous System (ARS).
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ARX-100-4.1.1.2: The ST6 ARX shall produce sufficient in-flight data to evaluate the functional
performance of the Laser Mapper (LAMP) sensor against a representative Orbiting Sample (OS).
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ARX-100-4.1.2.1 Full Project Criteria: Observed Inflight performance of ARX replicates the AR
performance predicted pre-launch.
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ARX-100-4.1.3.1 Basic Project Criteria: Data collected during in-flight operation of ARX is sufficient
to improve the ARX model so as to replicate the in-flight performanceclosely.
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ARX-100-4.3.1: ARS will conform to the launch requirements of the XSS-11 mission.
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ARX-100-4.4.1: ARS will conform to the GDS requirements of the XSS-11 mission.
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ARX-100-7.1: ARX shall utilize the LAMP and OS provided by the Mars Technology Program.
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ARX-100-7.2: ARX shall be hosted on the AFRL XSS-11 spacecraft, launched on the Shuttle, for
access to space.
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XSS-11 Mission Description
Sortie 2 - Rendezvous and RSO Ops
Sortie 1 - OS Proximity Operations
¥ Release OS & Stationkeep w/OS
¥ LAMP Checkout/Characterization
¥ Validate Autonomous Maneuvers
¥ Perform ST6 On-Orbit Operations
¥ Confirm Vehicle Safety Elements
¥ Positive Control
Quiescent
Passive Node Alignment
¥ Images Collected
¥ Payload Operations
¥ Orbit Rendezvous
¥ RSO Rendezvous
¥ RSO Operations
¥ Station Keeping
¥ Natural Motion Circumnavigation (NMC)
¥ Forced Motion Circumnavigation (FMC)
Quiescent
Passive Node Alignment
Sortie 3 - Rendezvous
and RSO Ops (Optional)
Quiescent
¥ Orbit Rendezvous
¥ RSO Rendezvous
¥ RSO Operations
¥ SK
¥ NMC
¥ FMC
Microsatellite
Checkout & Calibration
¥
¥
¥
¥
EPS
ACS
TCS
Prop
De-Orbit
SGLS AFSCN
1-Mbps Downlink
2-Kbps Uplink
¥ 25 year
Imagery, Payload Data,
Mission Plan,
Safety (Positive Control)
Shuttle Hitchhiker
Ejection Launch System
¥ Inert Ejection
¥ Shuttle Flyaway Before
S/C Deployment and Initialization
RSC Facility (Kirtland AFB)
¥ Command, Control, Telemetry
¥ Payload Test Center
¥ Mission Planning,
Simulation, Training
3
Schriever
Remote Ground
Facility (AFSCN)
Partners/Agreements
A partnership between NASA and AFRL
Partner
Contribution
$M
NASA
New Millennium
and Mars
Technology Prog.
ST6 ARX Payload
• LAMP, OS, ARS FSW, ARX PODA
6.7
NMP
15
MTP
AFRL
XSS-11 Prog.
Access-to-space
XSS-11 spacecraft, the assembly, test, launch, and ops
(ATLO) facilities.
35
AFRL
… and a partnership between JPL and SSC, Inc.
An Integrated Product Development Team
SSC provides expertise in all technical areas, especially in S/W Development
and Mission Operations planning/execution.
JPL provides expertise in all areas, especially in System Engr’g, ARC algorithm
design, FP, M&S, as well as I&T. JPL is responsible for delivery of the product.
4
Sortie 1 - Mission Timeline
No.
Event Description
Mission
Elapsed
Time
(days)
Event
Duration
(days)
Delta-V
allocation (m/s
approx)
1
Shuttle release and S/C
initialization; sun-point
1.1
1.1
2
XSS-11 S/C checkout
15
13.9
3
Orbit raising to >400km
15.5
0.5
4
OS eject & LAMP ops
22
6.5
14
5
XSS-11 proximity ops
29
7
30
6
ST6 proximity & AR sequence
36
7
25
5
Sortie 1 Timeline - ST6 AR Experiment
OS
+V-Bar
+V-Bar
OS
+R-Bar
4 km
+R-Bar
(3) AR Demonstration – (a) Proximity Maneuvers
(1) LAMP Characterization
1 km
OS
2 km
∆h = 1 km
+V-Bar
+R-Bar
(2) XSS-11/OS Proximity Operations
(SK/TM, NMC, FMC, Safety Ops)
range = 4 km
(4) AR Demonstration – (b) End-to-end
Terminal Rendezvous Sequence
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LAMP Characterization - Strawman Sequence
(3) Orbit Transfers:
¥ Minimum safe distance for
position control
¥ Lambert x-fers to V-bar
¥ Precision stationkeeping
¥ Collecting LAMP data
(2) Free Drift w/ OS tracking:
¥ Minimum safe distance for
closed-loop tracking
¥ LAMP in track mode
¥ S/C under pointing control
¥ Collecting LAMP data
(4) Orbit Transfer à Long-Range:
¥ Lambert x-fers and station
keeping at various points on the
v-bar
¥ Collecting LAMP data
¥ Transfer to handoff
(1) OS eject + Free Drift:
¥ LAMP acquiring OS
¥ Functionality checkout
¥ Collecting LAMP data
OS
+V-Bar OS Orbit
4 km
Not drawn to scale
Collecting LAMP data:
- rotate S/C +/- 4 deg (TBR)
elevation/azimuth
- translate (6dof) +/- TBD m
R-bar/out-of-plane
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+R-Bar
AR Demonstration: (a) Proximity Maneuvers
- Strawman Sequence
Profile: Stationkeeping à Lambert Transfers à V-Bar Approach à Co-elliptic Separation Maneuver
(3) V-Bar Separation:
¥ V-bar separation
¥3-axis pointing w/ target-track
¥ station keeping
(4) Separation Transfer:
¥Lambert transfer to 500 m coellipse
¥co-elliptic separation to >4 km
(1) Lambert Transfer:
¥ Lambert x-fers
precision stationkeeping
¥ LAMP tracking
+V-Bar
OS
OS Orbit
+R-Bar
Not drawn to scale
(2) V-Bar Approach:
¥ 3-axis pointing w/ target-track
¥ closest approach
¥ station Keeping
8
AR Demonstration: (b) End-to-end Terminal
Rendezvous - Strawman Sequence
Profile*: Co-elliptic Orbit à Football Orbit à V-Bar Approach à ÒAbortÓ Maneuver
(7) V-Bar Approach:
¥ 3-axis pointing
¥ Approach at 20 cm/s
¥ Go/NoGo to closest approach
¥ Closest approach at 3 cm/s
(6) Co-elliptic Approach:
¥ Terminal Phase Initiation
¥ Station Keeping on V-bar
+V-Bar
(5) Orbit Transfer:
¥ Lambert x-fer to co-elliptic
leading orbit at 330 m ∆h
¥ 2-axis pointing
(8) Separation Maneuver:
¥ Separation at 3 cm/s
¥ Abort and recovery to safe
standoff point
(1) Co-elliptic Orbit Adjust:
¥ Lambert x-fer to -1 km co-elliptic
orbit
1 km
∆h = 100 m
2 km
OS
OS Orbit
∆h = 1 km
range = 4 km
+R-Bar
(4) Football Orbit (FO):
¥ FO maintenance
¥ 2 x 4 km
¥ 250 m out-of-plane
(3) Football Orbit Insertion
(FOI):
¥ FOI at R-bar crossing
(2) Co-elliptic Approach:
¥ 2-axis ACS for LAMP tracking
¥ FOI at R-bar crossing
Not drawn to scale
*based on proposed Mars Orbital Rendezvous System (MORS) terminal approach profiles developed by JPL & CSDL..
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Autonomy Concept:
Distribution of Responsibilities
Mission Planner and
Ops Personnel
High-level Goal
e.g. Rendezvous with
the OS
Ground
¥ Decomposition into
sequence of "Macrotasks"
¥ Ground validation
and Go/NoGo
Decision Making
Terminal Approach
Profile (TAP)
e.g
-transfer to V-bar
-acquire LIDAR
On-Board
TLM
Go/NoGo
Rendezvous Payload
Decomposition into
sequence of "Microtasks", execution &
generation of requests
XSS-11
Spacecraft
Execution of Requests
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e.g
- delta-V request
- attitude request
e.g.
- thruster firings
TAP File Example
OS
V-Bar
Preliminary File Format
Step Step Description (not
ID
processed)
Targeting Cmd.
R-Bar
Targeting Parameters
Navigation
Mode
Navigation
Parameter
Ponting
Mode
Pointing Parameter
Start Terminal
Rendezvous Phase
Co-elliptic Approach
LAMP
TWO_AXIS
2
Flyby below OS
LAMP
TWO_AXIS
3
Transfer to Football
orbit
LAMP
TWO_AXIS
4
Football Orbit
Maintenance
LAMP
5
Transfer to V-bar
Station Keeping point
6
Station Keepingon Vbar
station_keep
7
Initiate Closure Phase
9
Closest Point Hold
Backout to Stand-off
Point
Abort Mode
STBY
1
10
MORS/Orbiter
Condition to move
Interface
to next activity
Mode
LINE_OF_SIGHT,
DEADBAND
LINE_OF_SIGHT,
DEADBAND
OBSERVER
Passive
OBSERVER
ground_GO_cmd
Passive
LINE_OF_SIGHT,
DEADBAND
MANEUVER
maneuver_complete
Passive
TWO_AXIS
LINE_OF_SIGHT,
DEADBAND
MAENEUVER
ground_GO_cmd
Passive
LAMP
TWO_AXIS
LINE_OF_SIGHT,
DEADBAND
MANEUVER
maneuver_complete
Passive /
Powered
LVLH_OFFSET,
DWELL_TIME
LAMP
THREE_AXIS
THREE_AXIS_HOLD,
MANEUVER
DEADBAND
ground_GO_cmd,
dwell_time_elapsed
Powered
closure
WAY_POINT,
CLOSURE_VEL
LAMP
THREE_AXIS
THREE_AXIS_HOLD,
MANEUVER
DEADBAND
way_point_achieved
Powered /
Disabled
station_keep
LVLH_OFFSET,
DWELL_TIME
LAMP
THREE_AXIS
ground_GO_cmd OR
THREE_AXIS_HOLD,
MANEUVER
DEADBAND
dwell_time_elapsed
closure
WAY_POINT,
CLOSURE_VEL
LAMP
THREE_AXIS
THREE_AXIS_HOLD,
MANEUVER
DEADBAND
transfer_to_FBO
maintain_FBO
FBO_CENTER,
FBO_ALTITUDE,
FBO_OOP, TRIGGER
FBO_CENTER,
FBO_ALTITUDE,
FBO_OOP
LAMBERT_TRANSFER
transfer_to_V_bar _TIME, TRIGGER,
LVLH_OFFSET, N_MCC
11
way_point_achieved
Disabled
Powered /
Disabled
Access to Space
Shuttle Launched XSS-11 Spacecraft
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•
•
•
•
•
•
Approx 124 kg total (~90 kg dry)
Agile Microsat - 600 m/s ∆V
Hydrazine monoprop system
– One 22 N main engine
– Eight 0.7 N thrusters
– Two 1 N thrusters
3-axis attitude control
– Pointing accuracy to 0.5 deg
– Rate stability to 0.1 deg/sec
Fixed solar panels
Sensors
– IMU, GPS, Sun sensor, Cameras,
LAMP
Constraints on ARX:
12
14 m/s ∆ V for LAMP
Characterization &
25 m/s ∆ V for AR
Demonstration
ARX System Architecture
Timing
ARX Status
Celestial
Sensors
(sun/star
sensors)
Visual
Camera
GPS
Cmds & TAP Files
Abort Profiles
XSS-11
Onboard
GNC
GN&C
GN&C Status
Attitude, Rate Est.
3-axis RCS
Thrusters
Accelerometer Data
Thruster Requests
Autonomous Rendezvous
Experiment (ARX)
LAMP ÒMongooseÓ
Processor
Smart LAMP
Software
XSS-11 MicroSat
Spacecraft
Autonomous
Rendezvous
XSS-11 cPCI-750
Processor
RS-422 Serial Bus
IMU
(accels &
gyros)
cPCI
Bus
LAMP
(Attitude and Delta-V)
Software Interface
Command and Data Handling
Main Engine
(>600 m/s ∆V)
Telecom
RF Link
¥ ARX commands
¥ modes, TAP Files, etc.
¥ S/C target ephemeris updates
¥ S/C cmds (Abort, Safing, etc.)
¥ State Estimates
¥ GNC Status
¥ Sensor Data
LEGEND
LEGEND
¥ ARX status
¥ Lidar data
Ground Control
PODA
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Software
Software
Hardware
Hardware
ARX
ARX (JPL/SSC)
(JPL/SSC)
XSS-11
XSS-11 (AFRL)
(AFRL)
Ground
Systems
Ground Systems
Orbiting
Sample
ARX System Elements
Laser Mapper (LAMP) Optics
Detector
Housing
Laser Mapper (LAMP) Processor
Laser Housing
Telescope
Scan Mirror
Scan Mechanism
Flight Software
ARS Software Module
Attitude
Commander
Trajectory
Commander
RS-422
Serial I/F
State
Estimator
Command &
Data Handling
LAMP
Manager
Fault
Protection
Orbiting Sample
PATCH
ANTENNA
LAMP
Application
LAMP Operating System
VxWorks Operating System
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SOLAR
CELLS
Concept Demonstration Unit (CDU)
Optical Head Assembly
Laser Electronics
15
LAMP Electronics
Laser
Optical Bench &
Thermomechanical Enclosure
Interface Electronics
FPGA-based
I/O Board
Power Supplies &
Conditioning
Mongoose V
& FPGA-based
Processor Brd
Data Processing
VxWorks,
LAMPOS
&
Software
Instrument Control
Electronics
Oulu timing
chip (pulsed)
Signal Detection
&
Timing Circuitry
"NRAO" phase
detector (cw)
Synoptics µC
(pulsed)
Transmit Optics
JDS diode (cw)
Laser Control &
Drive Electronics
Photodetector
Control & Drive
Electronics
C30954E APD
(pulsed)
C30619G (cw)
Photodetector
Electronics Package
16
Scanner Control,
Readout & Drive
Electronics
Dynatherm
Loop Heat Pipe
&
Resist. Heater
Temp. Control
All-aluminum
f/2.5
Cassegrain
telescope
Collector Optics
Transmit
Beam Pointing /
Scanning
Shared az-el
Flex Gimbal
Scan Mirror;
"optical lever"
encoders
Collector
AR Flight Software Context
LAMP ÒMongooseÓ Processor
←LAMP FSW module.
ARC Software
Module
←AR FSW module.
A
A
Attitude
Commander
B ←Indicates control flow (routine A calls B).
B ←Indicates data flow (from A to B).
Trajectory
Commander
AR
Command &
Data Handling
XSS-11 Flight Computer
XSS-11 Flight Software
RS-422
Serial Bus
RS-422
Serial I/F
State
Estimator
LAMP
Manager
Fault
Protection
LAMP
Application
LAMP Operating System
VxWorks Operating System
17
AR G&C Algorithm Functional Block Diagram
XSS-11 S/C
Thruster
Models
Exec / Mode
Commander
Attitude
Commander
Burn
complete
mode,
health,
faults
Thruster
Selection
Logic
Controller
- Delta V
- Attitude
∆v Cmd
Att Cmd,
∆v Mode
Ptg Type,
abort Cmd body Vector,
abort Flag ptg DeadBand
Sensor Models
- Accel
- Gyro
- Tracker
Attitude
Estimator
qEst, wEst
∆vEst
Environment
- J2
- 3rd Body
- Aerodynamics
- Solar pressure
Delta V
Estimator
Attitude
Commander
Trajectory
Commander
Command & Data
Handler
ARS
ARC/FSW
State
Estimator
Mode
Commander
LAMP/Camera
Manager
Fault Protection
ARC Algorithm
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XSS-11 S/C
Dynamics
- Rigid Body
- 6 DOF
LAMP/Camera
Model
OS Dynamics
-Translation
-Point Mass
Backups
LAMP (Functional Overview)
•
Scanning Laser System Characteristics (Hardware)
– Range (time of flight—pulsed system; phase offset—continuous wave
system)
– Azimuth & Elevation (measured from scan mirror)
– Measurement Time (internal electronics counter)
– Measurements made at 10 KHz
– Unit provides processing capability (12 MHz R3000, 128 Mbytes)
– Power Consumption < 25 Watts
– Mass < 4 Kg
•
LAMP Rendezvous Software (LRS)
– Controls Scan (tracks Sample Canister—measurements around object)
– Monitors System Health
– Provides very accurate Range & Bearing information @ 2 Hz from 5 km to
1m
– Controls LAMP, provides processing sub-system resources
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LAMP System – Description
¥
¥
¥
¥
¥
¥
Two boxes: Optical Head Assembly and Electronic Assembly
Mechanically-scanned single beam
Two ranging systems:
Ð Pulsed time-of-flight (long rangeÑ5 km-60 m) 1064 nm
Ð Amplitude-modulated continuous wave (120 m-1 m) 1550 nm
Shared scan and compression optics, processing and I/O electronics, power
converters, etc.
Local processor controls optical head, processes measurements, and
performs I/O operations
Mongoose processor (R3000 architecture) running at 12 MHz
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