AA 4262 Astrodynamics

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AA 4262 Astrodynamics
Applications of the Rocket-Equation Calculating
the Fuel Budget for an Orbital Phasing Maneuver
of a GeoStationary Satellite
Homework 14_solution
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TTC Satellite
TTC satellite used to monitor pacific coast
battle has failed NACSOC has decided to
transfer the functions of a spare Atlantic
battle group satellite to the pacific until a
replacement can be launched design an
Orbital phasing Maneuver that Allows Transfer of
a GEO Synchronous Communication Satellite from
40.43 west Longitude To 118.15 west longitude
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Phasing Maneuver
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Phasing Maneuver (part 2)
Design a Reverse Orbital Maneuver that Puts
the Satellite Back to the Original Longitude
after Mission has been accomplished
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What To Compute
Compute Phasing Orbit
Parameters Phasing Orbit Period
Required DV1, DV2 Assume Rmin gt
32,000 km (to stay above Van Allen belts)
Note It may take Multiple orbits of
Phasing Orbit to accomplish this task
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What To Compute (contd)
Compute Burn time for Transfer
Orbit Insertion Burn Time for
Final Orbit Insertion Required
Fuel Budget for DV1, DV2
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Parameters of the Problem
Original Longitude 40 deg, 40 min
West Destination Longitude 118 deg, 15 min West
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Parameters of the Problem (contd)
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Parameters of the Problem (Concluded)
Fthruster 0.500 kNt Spacecraft mass
1000 kg Dry
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First Compute Radius ofGeo Orbit
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Next Compute Angular Velocity of GEO Orbit
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Compute Linear Velocity of GEO Orbit
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Compute Required Time of Flight for Phasing
Maneuver
Original Longitude 40 deg, 40 min West Final
Longitude 118 deg, 15 min West
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Use Exterior Phasing Orbit
Positive DV
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Required Period for Exterior Phasing Orbit
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Compute Eccentricity of the Phasing Orbit
Do we need this?
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Compute Perigee Velocity of Phasing Orbit
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Compute DV Required to Insert Spacecraft into
Phasing Orbit
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Compute DV Required to Insert Spacecraft into
Final GEO Orbit
Retrograde Burn
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Return Trip
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Look Interior Phasing Orbit
Retro-grade Burn (Negative DV)
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Required Period for Interior Phasing Orbit
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Next Compute Semi-Major Axis of Phasing Orbit
with Perigee at 32,000 km(as per problem
constraints)
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Compute Period of Phasing Orbit with Perigee at
32,000 km (as per problem constraints)
Allowable Minimum size interior orbit is far
too big
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Must use Exterior Phasing Orbit
Positive DV
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Required Period for Exterior Phasing Orbit
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Compute Perigee Velocity of Phasing Orbit
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Compute DV Required to Insert Spacecraft into
Phasing Orbit
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Compute DV Required to Insert Spacecraft into
Final GEO Orbit
Retrograde Burn
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Delta-Vee Summary for Round Trip Maneuver
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Fuel Budgeting
Spacecraft mass 1000 kg Dry Start at
Burn 4 and Work Backward
Weight of Vehicle at End of Maneuver Series
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Burn 4 Fuel Consumption
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Burn 4 --gt Burn Time
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Burn 3 Fuel Consumptionand Burn Time
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Burn 2 Fuel Consumptionand Burn Time
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Burn 1 Fuel Consumptionand Burn Time
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Propellant Burn Summary
524.1 kg total propellant consumed
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Burn-Time Summary
3187 seconds total burn life of engine expended