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NIAC 8th Annual Meeting: 2006
Photon Tether Formation Flight (PTFF)
Young K. Bae, Ph.D.Bae Institute
Tustin, California, USAwww.baeinstitute.com
NIAC 8th Annual Meeting: 2006
ParticipantsJoseph Carroll, Tether Applications Inc.-- General Tether Aspects and Hardware
Claude Phipps, Ph.D., Photonics Associates-- Nano-Newton Thruster Stand
Eugene Levin, Ph.D., STARS, Inc.-- Dynamics of Tethers and Formation Flying
Bob Scaringe, AVG Communications-- Business Development
NIAC 8th Annual Meeting: 2006
Examples of Revolutionary/Disruptive Technologies
Key Enabling Factor: Orders of Magnitude Enhancement in Critical Parameters
Subatomic Dimension -- Particle AcceleratorsCritical Parameter: Particle EnergyAtomic Dimension – STM/AFMCritical Parameter: Scanning Ability/Noise ReductionMolecular to Daily Life Dimension -- LasersCritical Parameter: Coherence of PhotonsAstronomical Dimension – Precision Formation Flying (?)Critical Parameter: Control Accuracy (?)
NIAC 8th Annual Meeting: 2006
Examples of Precision Formation Flying Concepts
TPF SI MissionMAXIM
LISA
SPECS
NIAC 8th Annual Meeting: 2006Selected Formation Flying Missions
Con
trol
Acc
urac
y
Baseline Distance
>1 km
1 m
1 mm
1 mµ
1 nm
1 m 10 m 100 m 1 km 10 km 100 km >1,000 km
GRACE
LISAPTFF
SNAP 1Tsinghua
ESA Proba-3XEUS
DARWIN GEMINI
MAXIM
TechSat 21
FTXR
SPECS
Control Limitation with Conventional Thrusters?
NIAC 8th Annual Meeting: 2006
Nano-Meter Precision Spacecraft Formation Flying: -- is able to cover most of critical missions planned-- enables many other new missions
• Thus, it is Potentially a Revolutionary/Disruptive Technology of the 21st Century in Astronomical Dimension.
• So far, its Enabling Technology has been illusive.
• We believe that PTFF could be the Enabling Technology,if successfully demonstrated.
• The Primary Goal of this NIAC Phase II is to demonstratea sub-scale prototype PTFF engine.
NIAC 8th Annual Meeting: 2006
Photon Tether Formation Flight (PTFF)
Force Structure: Counter Balance of Two Forces:Contracting Force: Tether TensionExtending Force: Photon Thrust
- Intracavity Arrangement- Thrust Multiplied by Tens of Thousand Times by Bouncing
Photons between Spacecraft
Geometrical Structure: Crystalline Structure
Interspacecraft Distance Accuracy: better than nm
Maximum Operation Range: Tens of kms (Limited by Laser Mirror Size)
Can be Used for both Static and Dynamic Applications
NIAC 8th Annual Meeting: 2006
Major Advantages of PTFFUltra-High Baseline and Pointing Accuracy-- Baseline Accuracy: better than 1 Nano-Meter -- Pointing Accuracy: better than 0.1 micro-arcsec for 1 km baseline system– Enabling Wide Ranges of Imaging Missions
Propellantless-- System Mass Savings, Contamination Free, Long Mission Lifetime
Low Power Consumption
Low Construction Cost
Dual Usage of Photon Thruster Laser for Interferometric Ranging System -- Simplified System Architecture and Control, Low System Weight
Readily Downscalable to Nano- and Pico- Satellites Usage-- Ideal for Sophisticated Fractionated Spacecraft or Space Structures
NIAC 8th Annual Meeting: 2006
PTFF System Architecture
Satellite I Satellite II
Precision Laser Power Meter
HR Mirror HR Mirror
Laser Gain Media
Ultrahigh Precision CW Photon Thrust
TetherTension
Piezo-Translator Stepper Motor
Intracavity Laser Beam
TetherReel
Clamp
Lens
DiodePumpLaser
PumpLaser Beam
HR Mirror
HR MirrorPart al Mirrori
Photodetector
Part al Mirrori
Part al Mirrori
Tether System
Photon ThrusterSystem
InterferometricRanging System
Nano-Precision Formation Flying System Architecture
NIAC 8th Annual Meeting: 2006
Photon Thruster System: TRL 3
Satellite I Satellite II
Precision Laser Power Meter HR Mirror
HR Mirror
Laser Gain Media
Ultrahigh Precision CW Photon Thrust
Intracavity Laser BeamLens
DiodePumpLaser
PumpLaser Beam
Laser System-- Diode Pumped Intracavity Laser-- Lifetime of Diodes
1 Year for Continuous OperationPump Diode Carousel Design – Tens of Years
NIAC 8th Annual Meeting: 2006
10 100 1000 10000 1000000.1
1
10
100
1000
1000010 W System
Intracavity Photon Thrust as a Function of the Mirror Reflectance (R)
Phot
on T
hrus
t (µN
)
11 - R
Off-the-ShelfSuper Mirror
Predicted Capability of the Proposed System
NIAC 8th Annual Meeting: 2006
Specific thrusts as functions of Isp of various conventional and photon thrusters.
Isp (sec)102 103 104 105 106 107 108
Spec
ific
Thr
ust (
mN
/W)
10-7
10-6
10-5
10-4
10-3
10-2
10-1
100
X 1,000
X 10,000
X 100
X 20,000
Electric Thrusters Photon Thrusters
Intracavity Multiplication Factors
NIAC 8th Annual Meeting: 2006
Intersatellite Distance (km)0.01 0.1 1 10 100
Mirr
or D
iam
ter (
cm)
1
10
Photon Thruster System: Mirror Diameter vs. Operation Distance
NIAC 8th Annual Meeting: 2006
Interferometric Ranging System: TRL 5Satellite I Satellite II
Precision Laser Power Meter
HR Mirror HR Mirror
Laser Gain Media
Ultrahigh Precision CW Photon Thrust
Intracavity Laser BeamLens
DiodePumpLaser
PumpLaser Beam
HR Mirror
HR MirrorPart al Mirrori
Photodetector
Part al Mirrori
Part al Mirrori
Dual Usage of Photon Thruster Laser for Interferometric Ranging System Source Laser
-- System Architecture Simplification-- System Mass Reduction
NIAC 8th Annual Meeting: 2006
Heterodyne Interferometric Ranging System Integrated with Photon Thruster System
Satellite I Satellite II
Precision Laser Power Meter
HR Mirror HR Mirror
Laser Gain Media
Ultrahigh Precision CW Photon Thrust
Intracavity Laser BeamLens
DiodePumpLaser
PumpLaser Beam
Part al Mirrori
Beam Splitter
MeasurementDetector Reference
Detector
AOM AOM
Retroreflector
Mirror
ODL
NIAC 8th Annual Meeting: 2006
Tether System: TRL 5
Satellite I Satellite II
Tether
ClampTetherReel Inchworm
Piezo-Translator
Electromechnical Damper
Coarse Control: Reel System-- mm Accuracy
Fine Control: Inchworm or Stepper Motor-- µm Accuracy
Ultrafine Control: Piezo-Translator (off-the-shelf) -- 0.1 nm Accuracy
NIAC 8th Annual Meeting: 2006
Method of Tether Vibration Suppression• Major Tether Vibrations will Result from Reorientation of the Whole Formation Structure, and other Sudden Environmental Perturbations, such as Meteoroid Impacts.
• Longitudinal Tether Wave DampingTether Material Friction/ Modulation of Photon Thruster Power
• Transverse Tether Wave DampingElectromechanical Damper with Impedance Matching
Damping Applied
Electromechanical DampingSimulation by Lorenzini et al.For 1 km Baseline System
NIAC 8th Annual Meeting: 2006
Example I: 10 km 1-D PTFF at L2
NIAC 8th Annual Meeting: 2006
Example II: 1 km PTFF Telescope at L2
NIAC 8th Annual Meeting: 2006
1 km PTFF Telescope:Enables New World Imager Freeway Mission
By Prof. W. Cash – 2005 NIAC Fellow Meeting-- Searching for Advanced Civilization in Exo-Planets
• 300 m resolution at 10 parsecs = 0.02 nano-arcseconds• 500,000 km based line distance between Collectors• Huge collecting area – one square kilometer
NIAC 8th Annual Meeting: 2006
More Advanced PTFF Telescope
James WebbSpace Telescope
Stretched Membrane Mirror (NIAC)Image Processing
With Real-TimeHolographic AberrationCorrection (NIAC)
NIAC 8th Annual Meeting: 2006
Technology Readiness Assessment Summary
Photon Thrusters: TRL 3
Interferometric Ranging System: TRL 5
Tether System: TRL 5
System Integration and Control: TRL 2
R&D3: II - III (moderate -high) (Degree of Difficulty)-- Requires to optimize photon thrust design based on the current laboratory system and system integration, and to develop control system.
NIAC 8th Annual Meeting: 2006
Phase II Work Started Since Sept. 1st 2006Proof-of-Concept Demonstration of Photon Thruster
Construction of a Thrust Stand with nN Accuracy
Overall System Stability and ControlTether Vibration DynamicsEnvironment Perturbation3-D Simulation
Design of Prototype Interferometric Ranging System
Design of Prototype Tether System
Detailed Study of Specific ApplicationsIn-Depth Revisits of Existing Concepts -- SPECS and MAXIMUltralarge Membrane Space TelescopesUltralarge Sparse Aperture Space TelescopesOthers
NIAC 8th Annual Meeting: 2006
Prototype Sub-scale PTFF Engine Demonstration
Laser Power Meter
Concave HR Mirror HR Mirror
Laser Media
TorsionFiber
CounterWeight
Vacuum Chamber
Interference Pattern
Low Power Laser
Corner Cube
Windows
Optical Fiber
Photo Detectorfor Fringe Monitoring
Pump Laser Diode
Piezo-Translator
Tether
Intracavity Laser Beam
Computer
FeedbackElectronics
NIAC 8th Annual Meeting: 2006
Conclusions I
If successful, PTFF technology will be revolutionary/disruptive technology of 21st Century in Astronomical Dimension.
If successful, PTFF technology will open new innovative (revolutionary) ways to implementing new and existing mission concepts at very affordable costs. -- Many applications can be implemented at fractional costs of HST.
Preliminary Studies concluded that PTFF system can be implemented with off-the-shelf technologies – This will be tried to be proved during this study.
NIAC 8th Annual Meeting: 2006
Conclusions II
• Mission Specific Applications
• PTFF Simplifies the Architecture and Reduces the Weight in
Space Interferometery Missions -- TPF, DARWIN, MAXIM,
SPECS, FTXR etc.
• Ultra-large PTFF Space Telescopes -- For New World Imager (300 m Resolution – Freeway
Mission with km Mirror) -- Earth imaging/Monitoring/Surveillance (10 cm
ResolutionMonitoring at GEO with 200 m Mirror)
NIAC 8th Annual Meeting: 2006
“I believe in intuitions and inspirations. I sometimes feel that I am right.
I do not know that I am.”
by Albert Einstein
The Support by NIAC and NASA for this project is greatly appreciated.