WHAT I KNOW ABOUT ASTRODYNAMICS (ROCKET SCIENCE)

This is a 22 progress step training, self-assessment

4.5% Progress: The first thing to know about is that space bodies are irregulars. earth looks like a rounded circle...it is a elliptical body.

Meaning: Earth, Moon, Mars..all other space objects are not really perfect rounded objects "round" as they seem to be when we look at them, but more of elliptical objects. What this signifies is that Newton's law of universal gravitation applies with a VARIATIONS introduced to it.

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9% Progress:Rocket science has a mother it is called the “forces of the other”

Meaning: Beside the force of gravity, we have drag force + thrust force + solar radiation pressure force + and perturbation "agitation due to the non-spherical shapes existing in space" force + etc

so,

not only gravity acts force on a space body but also forces of the other:

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13,5% Progress:Orbiting is a small object going around a very much larger object.

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18% Progress:The energy of a satellite in orbit remains constant ( neither increasing nor decreasing) as a result of its motion.

Meaning: The larger object gravitational field is conservative, no mechanical energy is lost or gained. Energy is only exchanged with the satellite. 

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22.5% Progress:The type of the conic orbit (circle, ellipse, parabolic or hyperbolic) is determined by the energy stored in the satellite (negative, zero or positive)

Meaning: If energy is zero >>>>> Orbit is parabola.

If energy is negative >>>>> Orbit is ellipse (or circle).

If energy is positive >>>>> Orbit is hyperbola

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27% Progress:All parabolas have eccentricity of 1 but an orbit whose eccentricity is 1 need to be parabola - it could be a degenerate conic.

Meaning: Eccentricity is a measurement of how much an object or an orbit is away from being a circle. If it is 1 then it can be a parabola, a straight line or a point!

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31.5% Progress: Orbits of all planets in solar system (including earth) are ellipses(closed curve) and turning around it takes time called The period.

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36% Progress: The period of an elliptical orbit depends ONLY on the size of the semi-major Axis (different than radius)

Meaning: Ellipses don't have a constant radius.

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40.5% Progress: To put a satellite into an orbit it is necessary to reach a certain speed  and the launch (from its rocket) in the horizontal Direction at the desired altitude.

Speed with certain direction is called velocity, the greater the radius the less speed is needed to keep a satellite in this orbit.

Escape speed is the necessary speed to overcome gravitational forces

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45% Progress: Interplanetary(between planets or between planet and the sun) probes sent from Earth travel hyperbolic paths relative to earth, this is needed to keep speed leftover after leaving earth.

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49.5% Progress: Sphere influence is there for everybody and once we cross this sphere Edge then Escape happens.

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54% Progress: Earth >>>> Mars

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58.5% Progress: Each object in orbit belongs a "coordinate system".

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63% Progress: Orbital Elements: 6 measures that describe size, shape, orientation of an orbit,and to pin pointing position of satellite @ certain time.

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67.5% Progress:If orbital motion is around the sun " easterly", then it is Direct. Otherwise it is Retrograde

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72% Progress:The beauty in a RADAR lies in the fact that it is able to determine speed plus position.

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76.5% Progress:Determining the orbit of satellite by a preliminary observation involved computing the ephemeris "Table"

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81% Progress:Differential Correction is a famous technique used to improve the accuracy of preliminary orbit observations

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85.5% Progress:Space Surveillance is a tracking system of objects in orbit around earth in population.

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90% Progress:High performance rockets using the principle of "staging" made it

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94.5% Progress: Hohmann Transfer: a manoeuvre to put a satellite in high orbit by using an elliptical jump from a lower "parking " orbit.

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99% Progress:The trajectory of ballistic missile is 3:A. Powered flight: launch until thrust burnout.B. Free flight.C. Re entry: lasts until impact.

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Reference: Fundamentals of Astrodymanics Roger R.Bate * Donald D. Mueller * Jerry E. White

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Self Assessment:
Effort: 1 minimum to 5 maximum
Understanding: 1 minimum to 5 maximum



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Prepared By: Ghassan Samaha 

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