Space solarpower

Space Solar Power

Thomas Lynch

Boeing

Sun Tower Concept

15 kM bed length3 GW output beam< 5 cents/kW-Hr$125B Fab Estimate

Microwave beam to earth mounted “Rectenna”

Introduction

Laser Beam to Existing Photovoltaic Solar Array

Introduction

1. Concentrator focuses sunlight on space-based PV array

2. PV array powers laser diode

3. Laser diode pumps fibers

6. DC electricityis converted to AC

7. Power is distributed to consumers

4. Light from fibers is fed to optics and transmitted to Earth

5. Terrestrial PV receiver array converts sunlight to DC electricity

Satellite Concept of Operation

•Two robots placed symmetrically on transmitter’s frontside

•Robots move on a rail connected at perimeter and center

Robot assembles and repairs transmitter modules

83,841,250 Radiating Elements2.141 GW Radiated

Transmitter Face and Robot

Microwave (5.8GHz)

Solar Cell Efficiency vs Wavelength

Example: Laser Diode Array achieves 40% with LASER SSP & Photovoltaic ground Array

1kW/m2 ~ Sun on Earth

Typical earth mounted solar array has 14% efficiency

Visible Light(reference)

10SSP Economic & Market Analysis Team

Economic and Market Factors - General Cost Findings

– For 1996, U.S.• Generating costs for new plants averaged about 3.8 ¢/kWh (EIA,

1997)

– For ~ 2020, U.S.• A “reference case” for generation costs in 2020 is ~ 3.2 to 3.3

¢/kWh– World Bank experts suggested an average generating cost, ~

2020, for rapidly growing economics, of ~ 5.5 ¢/kWhUnder following conditions:

• Deregulation of foreign electric power markets • Resource inputs trade in a world market at world prices• Globalization of investment and technology • Interfuel competition holds costs down

14SSP Economic & Market Analysis Team

Preliminary Observations - Market

1,738

6951,043

China OECD Other Developing

World Energy Prospects to 2020, IEA, 1998

Growth In Electric Capacity Supply

1995 - 2020 (GW)

SPG Pointing Accuracy, Structural Control Trades

• Pointing– Off pointing : % of capture (2 degrees of control)– Surface accuracy requires active control – 1-2o for PV concentrator cells– Each concentrator needs its own control– Disturbance while pointing may impact WPT– Station keeping

• Lifetime (40 yrs)– Rotating machinery– Concentrator Materials– Actuator control

Pat George

• SSP must be managed by robotics– Installation – Perform maintenance– Affect repairs

• All are imperative to achieve cost objective of < 5 cents per kW-Hour

Robotics

LEMURLegged Excursion Mechanical Utility Robot

LEMURA new type of autonomous n-pod walker called LEMUR has been developed for assembly, inspection, and maintenance. This robot demonstrates multi-mode operations (mobility, inspection, and manipulation) with a modular and multifunctional toolset.

LEMUR Configuration

4 DOF Hex Driver Leg

4 DOF Gripper Leg w/ in-line camera (Palm-cam) 3 DOF Gripper Leg

Stereo Cameras

– Demonstrated fine manipulation and tool based operations

– Examined payload identification methods

– Implemented fiducial markers for encoding payload identification, orientation, and characteristics

– Performed visual inspection of payloads and robots

LEMURLegged Excursion Mechanical Utility Robot

Three-fingered manipulator with integrated camera optics

Hex driver with retractable foot

• Accomplishments– Designed and integrated LEMUR mobile

platform

– Developed a three-fingered manipulator with compliant grasp adjustment for manipulation of fine/delicate payloads

– Developed a hex driver end-effector with retractable foot

– Developed a miniature macroscopic imaging camera (Palm-cam) for integration into grasping manipulator

– Developed algorithms and computer code for stereo vision and pattern recognition using wavelet decomposition of fiducials

– Demonstrated visual object and self-inspection using the Palm-cam

• Current Work– Developing software for autonomous

navigation, inspection, and manipulation of target

Hyper Redundant Intelligent SystemsDescription•Develop small, identical robotic elements that can accomplish tasks collectively that are well beyond the capabilities of its individual members.

•Approach•Utilize serpentine chain of linkages with integrated computing, sensing, and power as testbed for cooperative robotics executing construction, inspection, and maintenance

ParticipantsNASA - Haith, Wright, Loch, ThomasCMU - Howie ChosetIndustry - Randy Sargent (Newton Labs)

Technology Elements• Mechanism Configuration: advanced actuators,

packaging, lightweight structure, power, biomimetic skin

• Single Robot Control: force and redundancy control strategies, communication, simulation & modelling of hyper-redundant systems

• Cooperative Robot Control: Autonomy;Mobility planning in complex structures, payload strategies, data sharing/sensing

Hyper Redundant Intelligent Systems

• Benefits– Highly Redundant (> 7 DOF) serial

link manipulator chains– Capable of long reach into highly

constrained spaces (trusses, frames)

– Capable of prehensile grasping, limbless locomotion

– Redundant to multiple joint failures

• Research Challenges– Path and motion planning to

arbitrary locations in a complex 3D structure using generalized voronoi graph search

Actual system “flight proven” through successful mission operations

Actual system completed and “flight qualified” through test and demonstration (Ground or Flight)

System prototype demonstration in a space environment

System/subsystem model or prototype demonstration in a relevant environment (Ground or Space)

Component and/or breadboard validation in relevant environment

Component and/or breadboard validation in laboratory environment

Analytical and experimental critical function and/or characteristic proof-of-concept

Technology concept and/or application formulated

Basic principles observed and reported

System Test, Launch & Operations

System/Subsystem Development

Technology Demonstration

Technology Development

Research to Prove Feasibility

Basic Technology Research

TRL 9

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TRL 6TRL 6

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TRL 4

TRL 3

TRL 2

TRL 1

Assessing Technology Readiness Levels