Solar Sail
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Transcript of Solar Sail
SOLAR SAIL
SOLAR SAILGeethika MuralidharanB10 ISPCUSATContentsIntroductionHistoryWorkingComponentsSail designsMissionsApplicationsMerits and demeritsconclusion
IntroductionSolar sail is a space craft without engine. It is pushed along directly by light particles from the sun, reflecting off giant mirror like sails. Because it carries no fuel and keeps accelerating over almost unlimited distances, it is the only technology now in existenceIntroduction400 years back Johannes Kepler proposed the ideaIn the 1960s, James Clerk Maxwell predicted that electromagnetic radiation exerts a pressure because of the momentum property of radiation
Sails: using sunlightSail pointed at sun, experiences force Sun pushes the sail directly away Reflected light generates reaction force much like reaction force of rocket
Sailboats: Using windBernoullis principle:Drag when wind moving over the sails (small neglect)Wind flows over airfoil sail receives force perpendicular to wind directionBoat moves forward
Sails: using sunlightLight is made up of packets of energy known as photonsIncident rays of sunlight reflect off the solar sail at an angleChange in momentum pushes the sail
Working Two components of forceIn the direction of incident sunlight In the direction normal to the incident raysComponent tangent to the sail surface cancel outComponents normal to the surface add up to produce the thrust normal to the sail surface
Why solar sails ?Solar sail is effectiveNo noticeable frictionSpace is very empty and clean so there is plenty of roomContinuous supply of energy
Distance v/s time
Comparative studyIn 100 days, a sail-propelled craft could reach 14000 kilometers per hourIn just three years a solar sail could reach over 150000 miles per hour At that speed you could reach Pluto in less than five yearsFar away from the sun, the highly focused beams of lasers can be directed at the sails to boost them onto interstellar trajectoriesComponentsContinuous force exerted by sunlightA large, ultra thin mirrorA separate launch vehicleUltra thin mirror :-large flat smooth sheets of very thin film, supported by ultra light weight structuresSide of film which faces the sun is coated with highly reflective materialSometimes reinforcement are also providedSail parametersSail loading ()(mass/area)Acceleration8.25/ in mm/s2Lightness number=ac/5.93
Sail designsSquare sailLarge, flat reflective film4 spars from hub
Optimum DesignPacking/deployment issuesNo spin to maintain tension
Helio gyro
Plastic-film blades deployed from rollers Film held out by centrifugal forces No mass advantage over a square sailAttractive because the method of deploying the sail is simpler than a square sailSpinning disk sailsPanels are attached to the edge of a rotating spacecraftHave slight gaps, about 1%-5%of the total areaLines would connect the edges of sailsWeights in the middle of these lines would pull the sails tautSail deployment
Essential qualitiesLightweightHighly reflexiveTolerate extreme temperaturesMaterialsAluminiumTitaniumNickelSilicon monoxideboronMissions Cosmos1
Eight triangular sailsMylar thin polyester 30 m wideInsert 825 kilometer near polar orbitMylar suffer high temperature+radiation Worlds first solar sailLaunch planned June 21st 2005Solar sail lost due to booster failure
Missions: Nanosail -DNano satellite or CubesatDesigned to test he potential for solar sails in atmospheric brakingUsed an ultra- thin and light polymer named CP1Deployed in low earth orbit, about 650kmLaunched by falcon -1 launch vehicle in august 2008
JAXA/ISASJapan pursuing solar power sailsSolar sail gathers sunlight as propulsion by means of a large membraneSolar power sail- obtains electricity from thin solar cells on the membrane+acceleration by sunIon propulsion engines accelerate ions driven by solar cells:-hybrid engineAugust 10 2004Deployed on S-310 rocket, first successful one
IKROS (May 20, 2010)
Hybrid solar sail propelled partly by solar pressure, partly by traditional solar pressureH-IIA rocket14X14 m solar sail 307 kgSeparate from rocket spin to unfurl sail Six month mission IKROS headed towards VenusSolar sail powered craft continue even fartherFuture solar sailingHelio storm(2016-2020)150x150mSolar polar imager(2020-2035)150x150mInterstellar probe(2031) 250x250m
ApplicationsSolar weather stationsMonitoring the geomagnetic stormsLaunching small satellitesRemote sensingProbes to the end of milky waySearch for extra terrestrial life
Merits and demeritsMeritsLonger distance can be coveredRequires no fuelFaster than chemical rocketDemeritsDont work well in low earth orbit below about 800km altitude due to erosion or air dragSails have to be physically largePayload size is often smallDifficult to carry manned missions
Solar sail technology is crucial for the next generation of space travelReferenceswww.howstuffworks.comwww.nasa.orgwww.planetarysociety.orgwww.wikipedia.org