AA 4362 Astrodynamics

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AA 4362 Astrodynamics
Newton's Laws as Applied to "Rocket Science" ...
its not just a job ... its an adventure
Week 9
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How Much Fuel?
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Newtons First Law

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Newtons Second Law

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Newtons Third Law

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Newtons Third Law (contd)

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Newtons Third Law (contd)

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Newtons Third Law (contd)

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Newtons Third Law (concluded)

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Before Solving the RocketEquation .. Its
convenient to introduce a Few Additional terms
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Effective Exhaust Velocity


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Effective Exhaust Velocity (contd)


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Total Impulse
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Specific Impulse
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Specific Impulse (contd)
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Specific Impulse (contd)
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Specific Impulse (contd)
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Specific Impulse (contd)
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Specific Impulse (contd)
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Specific Impulse (concluded)
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Relating Isp to Uex
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Maximum Available DV
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Maximum Available DV (contd)
Re-arranging Variables
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Maximum Available DV (contd)
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Maximum Available DV (contd)
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Maximum Available DV (concluded)
Derived for Horizontal Rocket Motion
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What happens on Vertical Launch?
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What happens on Vertical Launch? (contd)
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What happens on Vertical Launch? (contd)
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(No Transcript)
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Required DV to LEO
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Relating DV to Propellant Mass Fraction
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Relating DV to Propellant Mass Fraction (contd)
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Fuel Budget Equation
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Fuel Budget Equation (contd)
A little DV .. Can cost you A lot of Fuel
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Propellant Mass Fraction Example Calculations
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Question What is mean IspOf Shuttle at Launch?
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Shuttle Required Pmf 7.9
How can the shuttle reach Orbit?
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How Can Shuttle Reach Orbit?
Stage 1 SRBs burn for 123 sec.
Stage 1 Effective Isp SRBs
sec
Ignore atmospheric losses
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How Can Shuttle Reach Orbit? (contd)
Stage 1 SRBs burn for 123 sec.
Stage 1 Effective Isp SSMEs
sec
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How Can Shuttle Reach Orbit? (contd)
Stage 1 Compute mean Isp
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How Can Shuttle Reach Orbit? (contd)
Stage 1 Compute available DV
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How Can Shuttle Reach Orbit? (contd)
Stage 2 Mean Isp
Stage 2 Dry mass
264,950 lbs
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How Can Shuttle Reach Orbit? (contd)
Stage 2 Propellant mass fraction
Stage 2 Compute available DV
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How Can Shuttle Reach Orbit? (contd)
Total available DV (ignoring atmospheric
losses)
8380.66 m/sec
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8380.66 m/sec
So thats! how the shuttle reaches orbit
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8380.66 m/sec
7.5 for atmospheric losses (dragengine
performance)
Max shuttle altitude
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Propellant Mass FractionExample Calculations
(contd)
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Propellant Mass FractionExample Calculations
(contd)
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Propellant Mass FractionExample Calculations
(concluded)
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A Real World Example
Mean Isp 453.3
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A Real World Example (contd)
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A Real World Example (contd)
DV required for Orbit
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A Real World Example (contd)
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A Real World Example (contd)
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A Real World Example (contd)
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A Real World Example (contd)
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A Real World Example (contd)
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A Real World Example (contd)
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A Real World Example (concluded)
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(No Transcript)
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AA 4262 Astrodynamics
Homework 14
Applications of the Rocket-Equation Calculating
the Fuel Budget for an Orbital Phasing Maneuver
of a GeoStationary Satellite
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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