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Stratospheric SatellitesStratospheric SatellitesSummary of the Concept including
Simulations
Global Aerospace Corporation711 West Woodbury Road, Suite H
Altadena, CA 91001-5327626-345-1200
http://www.gaerospace.com/
Global Aerospace
Corporation
Global Aerospace
Corporation
SIMULATION VIEWERSIMULATION VIEWER
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Global Aerospace
Corporation CONCEPTCONCEPT
• Tens to hundreds of small, long-life (3-10 years) stratospheric balloons or “satellites”
• Uniform global and regional constellations maintained by trajectory control systems (TCS)
• Flight altitudes of 35 km achievable with advanced, lightweight, superpressure balloon technology
• Provide low-cost, continuous, simultaneous, global and regional Earth observations
• Provides in situ and remote sensing from very low earth “orbit”
BENEFITSBENEFITS
Global Aerospace
Corporation
CONCEPT SCHEMATICCONCEPT SCHEMATICStratoSat™ SystemNorthern Hemisphere
Constellation
383 StratoSat™ Platforms2° Elevation Angle
Max Slant Range of 483 kmCoverage Circle Diameter of 960 km
Snap-shot of Controlled Constellation
Global Aerospace
Corporation
BENEFITS AND THEMESBENEFITS AND THEMES
POTENTIAL COVERAGE BENEFITS• Good diurnal coverage
• Low altitude observations improve remote sensing resolution and/or SNR
• Frequent to continuous measurements
• Provide horizontal gradients in addition to vertical profiles
• Long dwell time over science targets
• Targeted dropsonde opportunities
ADAPTIVE SAMPLINGHURRICANE TRACKING
STRING OF PEARLSSTRING OF PEARLSSTRING OF PEARLSSTRING OF PEARLS
• 20 StratoSats, ~$5-10M• Measurements
– Dropsondes– Wind Lidar– Sea-state – Precipitation Radar– Imager
• Economics– Goal to reduce landfall
uncertainty by 50%– Save ~$150M per
landfall
EARTH SCIENCE THEMES• Climate change studies - ERB, Ice shields
• Ozone studies - Distribution, Loss
• Global circulation - Stratosphere/Troposphere
• Global ocean productivity - Biocycles
• Plate Techtonics - Magnetic field anomalies
• Weather and adaptive sampling - Hurricanes and improved prediction
• Hazard detection and monitoring - Early warning & improved communications
Flight Path GuidanceFlight Path Guidance
Global Aerospace
CorporationSTRATOSAIL®
TRAJECTORY CONTROL SYSTEMSTRATOSAIL®
TRAJECTORY CONTROL SYSTEM
– Wing hanging vertically on long tether in higher density air below balloon system
– Rudder controls angle of attack
15 kmTether
First GenerationTrajectory Control System (TCS)
Global Aerospace
Corporation
STRATOSAIL® TCS FEATURESSTRATOSAIL® TCS FEATURES
Passively exploits natural wind conditions
Operates day and night Offers a wide range of control
directions regardless of wind conditions
Can be made of lightweight materials, mass <100 kg
Does not require consumables Requires very little electrical power Bounded & underactuated control
system
Radio-Controlled Dynamically-scaled Model (1:4) Tested in Natural Winds Suspended From Tethered Blimp,
April 2001
Relative Wind at Wing
Lateral ForceComponent
Drag ForceComponent
ResultantForce
TCSWingAngle of Attack
Wing AssemblyWing Assembly
Winch TestbedWinch Testbed
STRATOSAIL® TCS ROLL OUT
March 16, 2002
STRATOSAIL® TCS ROLL OUT
March 16, 2002
Uncontrolled Trajectory
AliceSpringsLanding
ChristchurchLaunch
• 100-day flight • ~ 60 days at -70° • 35 km Altitude• Launch 11/15/88• Historical Winds• 5 m2 Wing Area• 1st Order Model• Simple Control Strategy
TRAJECTORY CONTROL PERFORMANCE
TRAJECTORY CONTROL PERFORMANCE
Click on the picture to start the movie player
Global Aerospace
Corporation ADVANCED TCS CONCEPTADVANCED TCS CONCEPT
Advanced StratoSail® TCS Design Features
– Lift force can be greater than weight
– Will stay down in denser air
– Less roll response in gusts
– Employs high lift cambered airfoil
– Greater operational flexibility
– Possible Dynamic Power Generation
BalloonBalloon
ADVANCED SMALL ULTRA LONG DURATION BALLOON (ULDB) DESIGN
ADVANCED SMALL ULTRA LONG DURATION BALLOON (ULDB) DESIGN
• Euler Elastica Pumpkin Design
• Volume ~ 70,000 m3
• Advanced Composite Film, 15 g/m2
• 140 Gores ~1.3 m Wide
• Zylon® Load Tendons
• Balloon Mass ~ 250 kg
• Euler Elastica Pumpkin Design
• Volume ~ 70,000 m3
• Advanced Composite Film, 15 g/m2
• 140 Gores ~1.3 m Wide
• Zylon® Load Tendons
• Balloon Mass ~ 250 kg
NASA ULDBScale Model Tests
NASA ULDBScale Model Tests
Global Aerospace
Corporation NASA ULDB FLIGHT TESTNASA ULDB FLIGHT TEST
Stratospheric SatelliteFlight Path Control, Formation Flying
and Constellation Control
Stratospheric SatelliteFlight Path Control, Formation Flying
and Constellation Control
Global Aerospace
Corporation
STRATOSAT™ SYSTEM OVERFLIGHT SIMULATION
STRATOSAT™ SYSTEM OVERFLIGHT SIMULATION
Trajectory Objectives• Achieve overflight of OK ARM site• Avoid overfight of China and Libya
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Global Aerospace
Corporation HURRICANE TRACKINGHURRICANE TRACKING
• Hurricane Alberto• 20 balloons, Advanced TCS (0.5-5 m/s, reel-up capability)• Actual easterly winds at 35 km• 1-day look-ahead• 4 hrs/frame, 31 days• Latitude control strategy
– >90° track lat
– <90° aim eye
Click on the picture to start the movie player
Global Aerospace
Corporation
BEHAVIOR OF NATURAL GROUPS
BEHAVIOR OF NATURAL GROUPS
• Group-level characteristics emerge from individual-level behaviors• Schools/Pods/Flocks
Global Aerospace
Corporation ARTIFICIAL POTENTIALS (APs)ARTIFICIAL POTENTIALS (APs)
• Control derived from a gradient of artificial potentials
• Model local "traffic rules"– Attraction– Repulsion
• Potentials and virtual members produce emergent group behavior
– Manipulate group geometry– Direct group motion
• Useful for stability/robustness proofs
Global Aerospace
Corporation
EXAMPLE HEMISPHERICAL CONSTELLATION MANAGEMENT
EXAMPLE HEMISPHERICAL CONSTELLATION MANAGEMENT
• Constellation– 383 StratoSat platforms, >15° latitude– Gondola altitude @ 35 ± 1 km– StratoSail® Trajectory Control System
(TCS) @ 20 km altitude– Artificial Potentials control algorithm
– ~30 days (start 1 June 2000) • Legend
– Red - StratoSat platform locations– Yellow - 2° elevation– Green - overlaps
• 1 hr/frame, 48 frames/sec, 173,000x faster than reality
• UKMO weather data• Control Model
– Bounded and under-actuated control system
– ∆V proportional to relative wind velocity, Vrel, at 20 km
– Feasible, limited control directions with respect to Vrel
Click on the picture to start the movie
player
Global Aerospace
Corporation
EXAMPLE LINEARNETWORK SIMULATION
EXAMPLE LINEARNETWORK SIMULATION
• Constellation– 100 StratoSat platforms, Overfly 34.5° N
latitude and 69.2° E longitude– Gondola altitude @ 35 ± 1 km– StratoSail® Trajectory Control System
(TCS) @ 20 km altitude– Multiple prioritized objectives: maintain
latitude, equal spacing, overfly target– 15 days (start 15 June 2000)
• Legend– Red - StratoSat platform locations– Yellow - 2° elevation– Green - overlaps
• 4 hr/frame, 12 frames/sec, 173,000x faster than reality
• UKMO weather data
• TCS Model– Bounded and under-actuated control
system– ∆V proportional to relative wind velocity,
Vrel, at 20 km
– Feasible, limited control directions with respect to Vrel
Click on the picture to start the movie player
Global Aerospace
Corporation
POSITIONING OVERDISASTER AREAS
POSITIONING OVERDISASTER AREAS
• Constellation Assumptions– 100 StratoSat™ platforms, +/-20° latitude– Gondola altitude @ 35 ± 1 km– StratoSail® Trajectory Control System (TCS) @ 20 km altitude– Biological group control algorithm (like flocks of birds)– 365 days (start 1 January 2000)
• Cost ~ $44 M
Click on the picture to start the movie player
StratoSat™ Gondola and an Operations Strategy
StratoSat™ Gondola and an Operations Strategy
Global Aerospace
Corporation
EXAMPLE STRATOSAT™ GONDOLAEXAMPLE STRATOSAT™ GONDOLA
StratoSat Mass of 221 kg
Global Aerospace
Corporation
EXAMPLE CENTRALIZED STRATOSAT™ OPERATIONS
EXAMPLE CENTRALIZED STRATOSAT™ OPERATIONS
StratosphericForecastCenter
Gondolacalculates
TCS commands
TWA
Observed Strat.Winds &
In-situ DataConstellationOperations
Center ImprovedStratospheric
Forecasts
TCSCommands
ConstellationGeometry &Atm. Param.
Location &Environment
Standard Sat. & In-situ
Observations
ConstellationGeometry &
Environments
Science Mission Cost EstimatesScience Mission Cost Estimates
Global Aerospace
CorporationCOST SUMMARY OF
ATMOSPHERIC DYNAMICS CONSTELLATION
COST SUMMARY OF ATMOSPHERIC DYNAMICS
CONSTELLATION
Operations about $5M/yr.
SummarySummary
Global Aerospace
Corporation SUMMARYSUMMARY• Stratospheric satellites can provide:
– Low-cost, continuous, simultaneous, global and regional observations options
– Satellite validation and verification
– In situ and remote sensing from very low earth “orbit”
• Global and regional stratospheric constellations will expand scientific knowledge of the Earth system
• Mission definition has progressed on several demonstration science missions
• A demonstration mission is essential first step toward regional and global measurements from 35 km
• A low-cost demonstration flight could leverage ongoing ULDB technology development (balloons, power generation, flight path control)