Solar Sail Missions That Arent Impossible

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Solar Sail Missions That Arent Impossible

• Mike Souder

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Ph.D Phairly Dumb, Pretty Huge Duh
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• Projected Area
• Area A
• Unit normal n
• Projected in ui direction

n
a
fr
ur
ui
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Outline

• Solar Sail Missions
• LEO
• Deployment tests
• Orbital Maneuvers
• GTO/GEO
• Radiation tests
• Measure magnetosphere
• Spiral to Earth escape
• Lunar
• Lunar Imaging/Communication
• Earth Escape
• Lagrange points

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LEO SailSat 1

• Worlds first solar sailing spacecraft
• Mission Objectives
• Deploy solar sail
• Use SRP force for predicted orbital maneuver
• Monitor sail health/performance

• Specifications
• Orbit
• 800-1000 km
• Terminator
• Mass ? 3 kg
• Sail Area ? 10 m2
• Sail Articulation
• Magnetic torque coils, momentum wheels
• Sensors
• GPS, Sun sensor, Camera

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SailSat 1 - Orbit

• Why 800 1000 km?
• Atmospheric drag
• Van Allen belts
• Why Terminator?
• Destroy Sarah Connor
• Always in the Sun
• Power, Thermal cycling
• Pointing rate requirements

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SailSat 1 Pointing Rate

• Terminator orbit

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SailSat 1 Pointing Rate

• Non-terminator orbit

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SailSat 1 Design

• Why mass ? 3 kg?
• Three CubeSat standard
• Why sail area ? 10 m2?
• What happened to 100 m2?
• 10 m2 raises orbit 1.4 km/day
• ? 0.925
• CD 4

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SailSat 1 - Design

• Sail Design
• Standard square, 3.2x3.2 m2
• 200 g tape measure
• 100 g sail
• Sail Articulation
• Use Earths magnetic field and momentum wheels
• Control during eclipse
• Possible COTS part

• Sensors
• Velocity
• GPS
• Measured from ground
• Sun vector
• Sun sensor
• Solar panel currents
• Sail Health
• Camera
• Measure performance

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LEO Whats been done

• Deployment test
• Feb. 1993
• Russians deploy spinning 20m solar reflector
• May 1996
• Shuttle Endeavour deploys 14m inflatable antenna
• Aug. 2004
• JAXA deploys 2 solar sails from a sounding rocket
• Feb. 2006
• JAXA deploys 15m sail, but it opened incompletely
• Single point failure
• If it deploys in 1-g, itll deploy in µ-g

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LEO Other Missions

• Sail Survivability
• Degradation due to space environment
• Radiation
• Atomic Oxygen
• Micro-meteorites space debris
• Thermal cycling
• Atmosphere???
• Monitor sail
• Camera
• Measure SRP accelerations/perturbations

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LEO Other Missions

• Orbital Maneuvers
• Change any orbital element in a predicted way
• What could you do with unlimited ?V in LEO?
• Government Make it a weapon!
• Solar Sail Microspacecraft
• Zubrin et al. 1999
• Image/Inspect satellites
• Rendezvous/Docking
• Comm. Relay
• Image Earth

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GTO/GEO SailSat 2

• Mission Objectives
• Monitor sail health
• High radiation environment
• Orbital maneuvers
• Circularize to GEO
• Go for Earth Escape

• Specifications
• Orbit
• Apogee 35788 km
• Perigee 200 km
• Mass ? 3 kg
• Sail Area ? 100 m2
• Sail Articulation
• Cm - Cp offset, tiny thrusters
• Sensors
• Star tracker, Sun sensor, Camera

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SailSat 2 GTO Woes

• 200 km radius of perigee is scary
• Current optimal pointing direction not so
  optimal
• Must be edge on

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SailSat 2 Design

• Sail Size
• How long in belts
• Required torque
• Sail Design
• Standard square, 10x10 m2
• 600 g tape measure
• 1000 g sail
• Sail Articulation
• Use Cm - Cp offset
• Control lost during eclipse
• Thrusters
• Finite Fuel

• Sensors
• Velocity
• Star tracker
• Measured from ground
• IMU
• Sun vector
• Sun sensor
• Solar panel currents
• Sail Health
• Camera
• Measure performance

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GTO Other Missions

• Whats been done?
• Solar Kite design study
• Lappas et al. 2005
• 25 m2, 1.75 kg
• GeoSail
• 1444 m2, 80 kg
• Study Earths magneto-tail
• What could be done?
• Radiation environment
• Magnetosphere

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GEO Other Missions

• What could you do with unlimited ?V in GEO?
• Same as LEO
• Boost End of Life GEO satellites to higher orbit
• GEO satellite grim reaper
• Extend GEO satellite life
• GEO Station keeping

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Lunar SailSat 3

• Mission Objectives
• Lunar imaging?
• Lunar communications relay?
• Spiral to Earth escape?

• Specifications
• Orbit
• LTO
• Mass ? 3 kg
• Sail Area ? 100 m2
• Sail Articulation
• Cm - Cp offset, tiny thrusters
• Sensors
• Star tracker, Sun sensor, Camera

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Lunar Whats been thought out

• Solar Kite
• 10 m2, .5 kg
• Lunar Imaging
• Highly elliptical lunar orbit, Low perigee
• Sail continuously compensates for mascons
• Camera resolution 15 cm
• Imagining at high latitudes

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Lunar Whats been thought out

• Lunar Telecomunications
• Comm. relay to polar regions

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Earth Escape SailSat 4

• Mission Objectives
• Create artificial Lagrange point twice the
  distance sunward as L1
• Provide twice the warning time for CMEs (Coronal
  Mass Ejections)

• Specifications
• Orbit
• Halo Orbit about artificial Lagrange point
• Sail Loading Required
• 29.6 g/m2
• 3 kg / 100 m2 30 g/m2
• Sail Articulation
• Cm - Cp offset
• Sensors
• Star tracker, Sun sensor, Magnetometer, Ion
  Plasma Instrument

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SailSat 4 Orbit

• 2x closer to Sun than L1
• Provides 2x warning
• Halo Orbit radius 0.002 AU
• Avoid interference from solar radio noise

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SailSat 4 Design

• Sail Size
• Determined by R3BP
• 29.6 g/m2
• Required rates very slow
• Sail Design
• Standard square, 10x10 m2
• 600 g tape measure
• 1000 g sail
• Sail Articulation
• Use Cm - Cp offset
• No eclipse

• Sensors
• Velocity
• Star tracker
• IMU
• Sun vector
• Sun sensor
• Solar panel currents
• CME
• 2 Magnetometers
• Ion Plasma Instrument

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Earth Escape Other Missions

• Artificial Lagrange
• Polar Observer
• Interplanetary
• NEOs
• Inner Planets
• Solar Observer
• Outer Planets
• Interstellar
• Laser

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Questions?
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STK Orbits

• Terminator
• a 7200 km
• i 95 deg
• Non-Terminator
• Right Asc of asc node 90 deg
• GTO
• a 24372 km
• e 0.730100115
• Arg of periapsis 90 deg
• True anomaly 90 deg