Historical OverviewHistorical Overview

Dry mass trends of NASA science satellites

•1950’s-1990: mass increasing for scientific spacecraft

•90’s: mass decreasing

SMALLSAT SMALLSAT REVOLUTIONREVOLUTION

Smaller Lighter Cheaper Satellites

Technology OverviewTechnology Overview

•Materials and structures have been responsible for major improvements in aerospace systems•For future missions the development of new structures and materials can be a key element in reducing operating cost and gross weight

MultifunctionalStructures

Smart Structures

MFS-Description MFS-Description

•structural composite panel•Multi-ChipModules•Cu/Pi patches•heat-transferring devices embedded•outer surface acting as a radiator•flexible jumpers•electrical circuitry in the Cu/Pi layers•protective coverSynergistic integration of Electronics,

Structural and Thermal control technologies

MFS-BenefitsMFS-Benefits

Traditional Design MFS Design Subsystem Mass(Kg) Volume(in3) Mass(Kg) Volume(in3)

C&DH 10.0 681 0.6 16 Power Distr/Drive Unit 9.3 850

Pyro Initiator Unit 4.0 189 Charge Control Unit 1.2 189

0.6

16

Cabling (Misc.) 18.2 400 1.0 42 •Cable-free S/C with 70% reduction in electronic enclosures and harness•>25% increase in payload fraction•>50% increase in S/C volume available for instruments or propellant tankage•reduced cost as MFS offers modular architecture•reduced “touch labor” needed in the final S/C integration•enhanced robustness and reliability•wide applicability to several missions

Examples of future Examples of future usersusers:•Next Generation Space Telescope

•Space Based Infrared System

•National Polar Orbiting Operational

Environmental Satellite

•Mars missions

MFS-State of the artMFS-State of the art

Current efforts incorporating MFS elements:•New Millenium Program-Deep Space 1 mission•New Millenium Program-Deep Space 2 mission•Mighty Sat SAFI (AFRL)•STRV 1 (DERA/BMDO/JPL)•New Millenium Program-EO1

Technology maturity Description

Component validation Temp and vibe tests on SIES CR&D (AFRL)

System/Substystem or Prototype demonstration

NMP DS1 MFS experiment Development effort

System prototype demonstration NMP DS1 MFS experiment

Flight qualification Test data on DS1

Flight mission success NMP DS1, NMP DS2, STRV

DS 1-Deep Space 1 MissionDS 1-Deep Space 1 Mission

MFS exp

DS1 is managed by NASA\JPL

DS1 GOAL:Validate technologies required for new types of missions

•Oct ’98: launch•Sept ’99: primary mission ended•April ’99: 7 technologies had been successfully tested

MFS experiment had been 100% validatedMFS experiment had been 100% validated

DS 1-MFS ExperimentDS 1-MFS Experiment

Experiment GoalsDemonstrate and validate MFS technology:– Produceability– Flightworthiness– Flex circuit patches and jumpers on structure– Socketed MCM– Distributed temperature measurements – Flex circuit connections – Hybrid cover including composite radiation shielding material

Two validation experiments:•Continuity check: copper polyimide layers and flex jumpers are verified as maintaining integrity•Thermal gradient: cycling the HiLoPDM MCM switching element which powers a thermal simulator and analyzing the thermal gradient on the panel

DS 1-ResultsDS 1-Results

GROUND TESTING:•Random and sine-sweep vibration tests•Thermal vacuum tests

•Mechanical and electrical integrity well maintained•MCM-component temperatures within operational temperature regions

FLIGHT VALIDATION:

•Performance consistent with preflight tests•No degradation in flex conductor performance•No degradation of signal in the flight MCM socket system•No failures in the data collection / interfacing electronics•100% complete (03/99)

Technology effort Technology effort requestedrequestedInnovative technologies are sought in the following areas:

•Techniques for structural integration of low-volume electronics packaging (chip-on-structure, chip-on-flex, imbedded electronics)•Concepts for integrating electronics, thermal management, radiation shielding with lightweight composite structures•Methods to rapidly assemble and disassemble or repair highly integrated multifunctional structures or imbedded electronics•Multifunctional structures that incorporate both power generation and telecommunications functions•Interchangeable structural components that can be used for more than one function•Integration of two or more spacecraft systems functions in miniature components for micro-spacecraft and sensorcraft

ConclusionsConclusions

•Multifunctional Structures methods are valid for flight designs

Design, integration, test, rework, flight and operation all completed successfully

• MFS Technology is a very strong candidate for reducing mass and volume in spacecraft design

Savings from 50% to 80% in both areas

•MFS technology supports mass production of spacecraftCost-effective, modular, reliable and repairable architecture

MFS IS READY FOR USE AS THE PRIMARY LOAD-MFS IS READY FOR USE AS THE PRIMARY LOAD-BEARING AND ELECTRICAL CABLING METHOD BEARING AND ELECTRICAL CABLING METHOD FOR CABLE-FREE SPACECRAFTFOR CABLE-FREE SPACECRAFT

SMART-SMART-DescriptionDescription

A smart material provides a certain function (sensing, actuation) by converting ENERGY from one form to another.

PiezoceramicsPiezopolymersElectrostrictors

Electrorheol. fluids

MagnetostrictorsMagnetorheol. fluids

Shape memory alloysShape memory ceramicsShape memory polymers

Optical fibers

Ionic polymeric gels

SENSING

MECHANICAL FORCE, DISPLACEMENT

Electric variables (C,R,Q)Magnetic variables (R,L)

Resistance

Light intensity

Concentration (PH)

PiezoceramicsPiezopolymersElectrostrictors

Electrorheol. fluids

MagnetostrictorsMagnetorheol. fluids

Shape memory alloysShape memory ceramicsShape memory polymers

Special gels

Ionic polymeric gels

ACTUATION

Electric field

Magnetic field

Thermal energy

Light

Chemical energy

SMART-SMART-BenefitsBenefitsTRADITIONAL

TECHNOLOGIESStres

s (Mpa

)

Strain

Efficiency

Bandwidth (Hz)

Work (J/cm2)

Power (J/cm3)

Electromagnetic 0.02 0.5 90% 20 0.005 0.1

Hydraulical 20 0.5 80% 4 5 20

Pneumatic 0.7 0.5 90% 20 0.175 3.5

Muscle 0.35 0.2 30% 10 0.035 0.35NEW

TECHNOLOGIESStres

s (Mpa

)

Strain

Efficiency

Bandwidth (Hz)

Work (J/cm2)

Power (J/cm3)

Shape memory 200 0.1 3% 3 10 30

Electrostrictive 50 0.002

50% 5000 0.05 250

Piezoelectric 35 0.002

50% 5000 0.035 175

Magnetostrictive 35 0.002

80% 2000 0.035 70

Contractile polymer

0.3 0.5 30% 10 0.075 0.75

• Vibration control• Damage detection• Increasing passengers comfort• Improving precision pointing

•Improving aerodynamics•Reducing manufacturing and assembly costs•Increasing structural life

SMART-State of the artSMART-State of the art1880: Pierre and Jacques Curie discover piezoelectricity

1882-1917: piezoelectric research goes on as a mathematical challenge

1920-1965: first applications (vibration damping, microphones, transducers)

1965-1980: Japanese developments (signal filters, igniters, ultrasonic motors)

Late 60’s: first concept of synthesizing of smart materials and structures

•Early 90’s: work on vibration suppression applications in spacecraft, funded by the Ballistic Missile Defense Organization (BMDO) and the US Air Force

•Since the early 90’s the Army Research Office (ARO), the Air Force (AF), the Defense Advanced Research Project Agency (DARPA), the National Aeronautics and Space Administration (NASA) and the Navy have ongoing programs to demonstrate the application of smart structures in a variety of systems

At present there are three approaches to develop smart materials and structures:

1.Synthesize new materials at the atomic and molecular level

2.Develop systems with actuators and sensors attached to conventional structures

3.Develop new materials by synthesizing composite systems from known materials. These composites contain active constituents and are used to fabricate the structure

SMART-ResearchSMART-Research

Smart materials and structures interest different fields of research:

• active noise control

• active vibration control

• precision machining and micropositioning

• aeroelastic control

• biomechanical and biomedical (artificial muscles, valves)

• process control (on/off shape control of solar reflectors)

• active damage control (detection and control of delamination growth in composite beams)

• seismic mitigation

• corrections in optical systems

• discrete and distributed actuation and control

• ultrasonic motor

Generalized acoustic structure with local panel actuation

SMART-Commercial SMART-Commercial applicationsapplicationsSmart materials have also a wide variety of commercial applications:

• piezo-damped skis and snowboards

• smart-shock for mountain bikes

• piezoelectric actuators for pneumatic valves

• electronic water-skis

• smart baseball bats

• piezoelectric flat speaker technology for computer systems

• omnicom multifunction transducer(provides vibration, tone alert and hands-free loudspeaker functions in one component)

SMART-Ongoing programsSMART-Ongoing programs•SAMPSON: Smart aircraft and marine projects demonstration Shape control and acoustic control (DARPA, Penn State Univ, Boeing Company)

•SMART ROTOR Control of trailing edge flaps and twist control for helicopter rotor blades (MIT, UCLA, ARO, Boeing, DARPA)

• SMART WING Improve aerodynamic performance (lift/drag and maneuver performance) (Northrop, Lockheed Martin, Georgia Tech)

THE NUMEROUS SYSTEM DEMONSTRATIONS RECENTLY COMPLETED OR CURRENTLY UNDERWAY INDICATE THAT SMART TECHNOLOGIES WILL LIKELY PROVIDE NEW AND INNOVATIVE CAPABILITIES IN FUTURE COMMERCIAL AND MILITARY AEROSPACE SYSTEMS

SMART-New technologies 1SMART-New technologies 1

ACTIVE FIBER COMPOSITES

Active fibers introduced into soft polymers; electrode patterns direct field and polarization along fibers. ADVANTAGES: high strength, directional actuation, conformable/large area, high energy densitySINGLE-CRYSTAL PIEZOELECTRICS

Single-crystal piezoelectrics show high strength, large piezoelectric effects (very high electromechanical coupling factors), field-induced strains an order of magnitude greater than strains induced in conventional piezoceramics

TECHNICAL ISSUES

•Fabrication methods

•Reliable materials

•Lightweight materials

•Integrated system design

•Fatigue life characteristics

•Maintenance and repair procedures

SMART-SMART-New technologies 2New technologies 2

MEMS: Microelectromechanical systems

Electrical and mechanical functions on a single chip, realized using techniques utilized in the manufacture of microelectronic devices (micromachining)

APPLICATIONS:•Nozzles and nozzles arrays•Microfluidic systems•Sensors, actuators•Positioners•Pumps, valves

MAD: Meso-scale actuator

Combine MEMS technologies and smart materials to develop a meso-scale large force and large displacement actuator

SMARTSMART-Future 1-Future 1

GOOD PROGRESS IS BEING MADE IN THE DEVELOPMENT OF ELECTRONICS, CONTROL APPROACHES AND ANALYSIS TECHNIQUES. MORE WORK IS NEEDED TO DEVELOP FABRICATION TECHNIQUES TO MAKE SMART SYSTEMS AFFORDABLE. REALIZING MANY OF THE ENVISIONED APPLICATIONS WILL DEPEND UPON THE DEVELOPMENT OF HIGHER AUTHORITY, SOLID-STATE ACTUATORS AND INNOVATIVE CONCEPTS.

Piezo strips

MICRO AIRCRAFT(mass of less than 10 grams)

Project developed at MIT as a mechanical counterpart to biological winged flight; solid state flapping wing propulsion and control using piezoelectric bimorph actuators

Motivations:

•Applications in surveillance operations

•Challenging and exciting

SMART-Future 2SMART-Future 2

SMART-MFSSMART-MFS

New Shape Memory New Shape Memory MaterialsMaterials

Piezo pumpsPiezo pumps

Introduzione alle strutture Introduzione alle strutture intelligentiintelligenti

CSM27 Luglio 2000

Prof. Paolo Gaudenzi

1. Strutture tradizionali e strutture intelligenti

2. Stato dell’arte sulla tecnologia

3. Strutture multifunzionali