Satellite Physics

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Satellite Physics Newton, orbits and DIY Spaceflight January 2009 Morten Jagd Christensen

description

A talk on Satellite orbits and DIY space travel with Orbiter space flight simulator

Transcript of Satellite Physics

Page 1: Satellite Physics

Satellite PhysicsNewton, orbits and DIY Spaceflight

January 2009

Morten Jagd Christensen

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AgendaLaw of gravitation and of motion

Geometry and dynamics of circular orbits

Elliptical orbits

Geosynchronous orbits

Launching a sattelite Hohmann transfer

Re-clocking

Non-spherical mass distribution

Deep space tracking and further complications

Orbit adjustments

DIY space travel with Orbiter

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Newtons laws of motion

)()(

)(22

2

2

trtr

GM

dt

trd

rr

GMmF

dt

VdmamF r

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Differential equations (2D)

)(2)(2)(

)(),()(

)()(

)()(

)()(

)(

)()(

)(

3

3

tytxtr

tytxtr

tvtydt

d

tvtxdt

d

tytr

GMtv

dt

d

txtr

GMtv

dt

d

y

x

y

x

x

yF x(t), y(t)

vx(t), vy(t)

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Solution: EllipseCan be done in Excel

.001

001

etc

tvxx

tavv

x

xxx

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Runge-Kutta method

Adaptive step size

Gnuplot

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From low Earth orbit to GEO

a b

r

arGMv

122

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Rocket Thrust

eee AppvmF )( 0

VF

mTF

T

Vm

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Burn times

Centaur rocket GTODelta V for orbit insertion is ~ 2.4 km/sEngines deliver ~147kNMass: 15000kg prop + 6000kg satBurn time: ~343s

GTO to GEODelta V for circular orbit is ~1.5 km/sMass: 6000kgThrust data for I4 unavailable

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Re-clocking I4 satellitesI4 F2 moves from 53W 25E

Distance travelled:

Time: 30days*86.400s/day

Velocity ~23m/s (80km/h)

New orbit is 650m lower

RL 2460

78

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Re-clocking - finally

78

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Three-body problem

rmsres

msms

sees

es

se rr

mMr

r

mMGrF

33 ||||)(

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Chaotic orbits

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Chaotic orbits?

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Yes really!

y0 = 0.4y0 = 0.4 + Mass

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Non sperical mass distribution

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Non-spherical gravitational field

2

sin1),(n

n

n

n Pr

RJ

r

GMrU

Earth data

J2 = 1082.63 10-6

J3 = -2.51 10-6

J4 = -1.60 10-6

J5 = -0.15 10-6

Earth data

J2 = 1082.63 10-6

J3 = -2.51 10-6

J4 = -1.60 10-6

J5 = -0.15 10-6

...

352

1)(

132

1)(

)(

1)(

33

2

1

0

xxxP

xxP

xxP

xP

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And it gets worse!Relativistic spacetime effects

Earth geometry correctionsTidesPlate techtonicsPole movementsInternal mass shifts

Pico second time resolution

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Satellite tracking - Pioneer 10First probe to visit outer planets

Tracking data from1972 to 2002

Anomalous acceleration8x10-8G

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Space travel with Orbiter

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Orbiter featuresFull solar system dynamics simulation

Including non spherical gravitational fieldsSun, all planets, moons, and other orbiting objectsTimewarp for interplanetary cruisesBroad range of spacecraft

Realism settingsAtmospheric haze, cloudsAerodynamics in earths atmosphereRocket engine exhaust

Launch from Earth, land on moon base

Realistic on board flight software

Star constellation overlay

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Orbiter Demo

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ReferencesJ.D. Anderson, et.al. Study of the anomalous acceleration of

Pioneer 10 and 11

A. Celetti et. al. The Celestial Waltz

Inmarsat

H.Kartunen, et. al. Fundamental Astronomy

NASA Basics of Space Flight , http://www.jpl.nasa.gov/basics

NASA Beginner s Guide to Rocketshttp://exploration.grc.nasa.gov/education/rocket/bgmr.html

M.Schweiger Orbiter - Space Flight Simulator , http://www.orbitersim.com

W.H.Press, et. al. Numerical Recipes in C , http://www.nr.com

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