By Kerry Nock

Global Aerospace Corporationhttp://www.gaerospace.com/

8 February 2001

GLOBAL CONSTELLATIONS OFSTRATOSPHERIC SCIENTIFIC

PLATFORMS

GlobalAerospace

Corporation

Global Stratospheric Balloon Constellations

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Corporation

TOPICS

Concept SummaryPhase II Objectives

Benefits and Science ThemesConstellation Management

Flight SystemsSummary

CONCEPT SUMMARY

Global Stratospheric Balloon Constellations

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Corporation CONCEPT• Tens to Hundreds of Small, Long-life (3-10 years)

Stratospheric Balloons or StratoSats• 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, Globaland Regional Earth Observations

• Provides in situ and Remote Sensing From Very LowEarth “Orbit”

BENEFITS

Global Stratospheric Balloon Constellations

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Corporation CONCEPT SCHEMATICStratoSat Flight SystemGlobal Constellation

Gondola

StratoSail®TCS

SciencePod

35 km Altitude

Dropsonde

Balloon

20 km Altitude

Global Stratospheric Balloon Constellations

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KEYS TO THE CONCEPT

Affordable, Ultra Long-duration StratosphericBalloon and Payload Systems

Lightweight, Low Power Balloon TrajectoryControl Technology

Global Communications Infrastructure

PHASE II OBJECTIVES

Global Stratospheric Balloon Constellations

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PHASE II OBJECTIVES

• Explore and Develop New Earth Science ConstellationApplications and Define a Low-cost Proof-of-conceptMission

• Develop Optimized Control Strategies and Techniques forConstellation Geometry Management

• Extend and Expand the Systems Design Definition andTechnology Requirements of StratoSats

• Understand International Overflight Issues forStratospheric Constellations and Identify Approaches ThatWould Facilitate Their Operation

POTENTIAL BENEFITS ANDSCIENCE THEMES

Global Stratospheric Balloon Constellations

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Corporation BENEFITS OFGLOBAL BALLOON PLATFORMS

• Good Diurnal Coverage of Entire Globe• Low Altitude Observations That Can Improve Resolution

and/or Signal-to-Noise Ratios of Measurements• Provide Frequent to Continuous Measurements• Provide Horizontal Gradients in Addition to Vertical

Profiles• Extended Duration and Low-cost Potentially Provide a

Cost-effective Method for Earth Science and/or SatelliteCalibration and Validation

Global Stratospheric Balloon Constellations

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35 km

700 km

7504 m/s

<50 m/s

Angular Nadir Rate = 11 mrad/s

Angular NadirRate = 1.4 mrad/s

StratoSat vs Satellite Remote Sensing Factors• Surface Image: R - 20-times closer• Surface Emission: R2 - 400-times better• Lidar at 15 km: R2 - 1200-times better• Integration time: ~8-times more

Satellite

StratoSat

´© Global Aerospace Corporation 2000

REMOTE SENSING

Global Stratospheric Balloon Constellations

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Corporation PROMISING EARTHSCIENCE THEMES

• Climate Change Studies– Water Vapor and Global Circulation in the Tropics– Radiative Studies in the Tropics

– Global Radiation Balance

• Ozone Studies– Mid-latitude Ozone Loss– Arctic Ozone Loss– Global Distribution of Ozone

• Global Circulation and Age of Air• Global Ocean Productivity• Weather and Adaptive Sampling

– Hurricane Forecasting and Tracking– Tropospheric Winds– Forecasting Weather from Ocean Basins & Remote Areas

• Hazard Detection and Monitoring

CONSTELLATION MANAGEMENT

GLOBAL CONSTELLATIONMANAGEMENT

FREE FLIGHT SIMPLE CONTROL

ASSUMPTIONS• 100 StratoSats @ 35 km• 82 day Simulation• 5 m/s Control

Global Stratospheric Balloon Constellations

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Corporation CONSTELLATIONGEOMETRY MAINTENANCE

• Balloons Drift in the Typical and Pervasive ZonalStratospheric Flow Pattern

• Trajectory Control System Applies a Small, ContinuousForce to Nudge the Balloon in Desired Direction

• Balloons Are in Constant Communications With a CentralOperations Facility

• Stratospheric Wind Assimilations and Forecasts AreCombined With Balloon Models to Predict BalloonTrajectories

• Balloon TCS Are Periodically Commanded to AdjustTrajectory Control Steering to Maintain OverallConstellation Geometry

Global Stratospheric Balloon Constellations

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FLIGHT SYSTEMS

Global Stratospheric Balloon Constellations

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FLIGHT SYSTEM FEATURES

• Sample Payload for Climate Change Studies in Tropics• ~70,000 m3 Advanced Lightweight Pumpkin Balloon• 5 kW Solar Array Integrated into Balloon Envelope• Satellite Telecommunications at 2.4 Kb/s and 6 Mb/s• Advanced Balloon Trajectory Control System• Tethered Science Pods

ADVANCED TRAJECTORYCONTROL

AD

VA

NC

ED

TR

AJE

CT

OR

YC

ON

TR

OL

SY

ST

EM

BALLOON

Global Stratospheric Balloon Constellations

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Corporation BALLOON VEHICLE DESIGN

• Euler Elastica Pumpkin Design• 68,765 m3, 59/35 m Eq/Pole Dia.,

Equivalent to 51 m dia. Sphere• Advanced Composite Film, 15 µm thick,

15 g/m2 Areal Density• 140 gores each 1.34 m Max Width• Polybenzoxazole (PBO) or Zylon® Load

Tendons At Gore Seams• Balloon Mass of 236 kg

NASA ULDBScale Model Tests

Baseline StratoSat Balloon Design

Global Stratospheric Balloon Constellations

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JUNE 2000 FLIGHT TEST

GONDOLA

Global Stratospheric Balloon Constellations

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Corporation STRATOSAT GONDOLADESIGN

• Designed for Example Climate Change SciencePayload

• 2x1x0.5 m Electronics Compartment With Louvers forDaytime Cooling

• Electronics Attached to Single Vertical Plate• LIDAR Telescopes Externally Attached to WEB• TCS Wing Assembly (TWA) Stowed Below Gondola at

Launch Before Winch-down• Science Pods on Tether

EXAMPLESTRATOSAT GONDOLA

PARACHUTE

SATELLITERADOME

ELECTRONICSCOMPARTMENT

LIDARTELESCOPE

TCS WINGASSEMBLY

SCIENCE PODS

THERMALCONTROLLOUVERS

TCS WINCH-DOWNASSEMBLY

Global Stratospheric Balloon Constellations

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Corporation STRATOSAT FLIGHTSYSTEM MASS

Subsystem Mass, kgBalloon 236Helium 87Power 19Telecomm 5Mechanical 30Guidance & Control 1Robotic Controller 1Trajectory Control 81Science 56Science Reserve 44Total 560

INTERNATIONAL OVERFLIGHTCONSIDERATIONS

Global Stratospheric Balloon Constellations

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Corporation INTERNATIONALOVERFLIGHT

Current Scientific Balloon Flights

Overflight Often Allowed, However Not All Countries Allow Overflightand This List Changes Depending on World Political Conditions

Possible Future Political Pathways

Build on the 1992 Treaty on Open Skies

World Meteorological Organization (WMO) Cooperation

World Pollution Is a Global Problem Which Will Demand GlobalMonitoring Capability That Global Constellations Can Provide

Growing Interest in Providing Method for All Countries of the Worldto Participate in Global Observations

Global Stratospheric Balloon Constellations

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COSTS

Global Stratospheric Balloon Constellations

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Corporation LAUNCH VEHICLE COSTS

0

10000

20000

30000

40000

50000

0 100 200 300 400 500

Launch Vehicle Cost vs. Launch Vehicle Specific CostsSp

ecif

ic C

ost

to 2

00 k

m L

EO

, $/k

g

Launch Cost, FY99$M

Pegasus Xl

Taurus 2110

Athena I

STS

Titan IV B NUS

Atlas IIASDelta II 7320

Athena II

Delta IIIDelta II 7920

Atlas IIIATitan IIGAtlas IIIB

ULDB

Global Stratospheric Balloon Constellations

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Corporation COST ASSUMPTIONS• FY99$• 100 StratoSat Constellation• 133 StratoSats Initially Fabricated and Assembled• 10-year StratoSat Lifetime• 3% Per Year Stratosat Mortality Rate• Commercial Telecom Providers for Data Return at 5 Mb for $1• Balloon Costs Are Function of Material Costs (Proportional to Envelope Area)

and Fabrication Labor (Proportional to Total Gore Seam Length)• Upgrade of Stratospheric Environmental Data Providers Assimilation and

Forecast Systems• Constellation Development Costs Include Stratosat Flight and Operations

Systems Design• Emplacement Requires One Year• Constellation Emplacement Costs Include Stratosat Flight Systems

Procurement, Launch and Operations Costs• Constellation Maintenance Costs Include Stratosat Flight Systems

Replenishment and Operations Costs

Global Stratospheric Balloon Constellations

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COST SUMMARY

SUMMARY

Global Stratospheric Balloon Constellations

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Corporation SUMMARY• The StratoSat System Is a New Class of in situ Platform

Providing:– Low-cost, Continuous, Simultaneous, Global and Regional

Observations Options– In Situ and Remote Sensing From Very Low Earth “Orbit”

• Global and Regional Stratospheric Constellations MayOffer a Unique Opportunity to Expand ScientificKnowledge of the Earth System

• There Has Been Strong Involvement of the NASA EarthScience Community

• International Pathways Exist

• A Proof-of-Concept Mission Is One Essential First Step onthe Path Toward Scientific Balloon Constellations