Orbital Mechanics

Ted Spitzmiller

Space… the final Frontier!

How far out from our planet does the atmosphere extend ?

How far out from our planet is the ISS ?

Getting Into

Orbit

Orbital Velocity 17,500 mph

Going to the Moon

Escape Velocity 24,500 MPH

How Far is the Moon?

• 240,000 miles (average)• If the Earth were the size of a basketball

– How big would the Moon be?– How far should we place the Moon?

– Earth 8,000 in diameter (1 foot basketball)– Divide 8,000 into 240,000

Sun

Earth

Earth’s Rotation

Earth OrbitMars

Orbit

Mars

Relative position at time of Viking launch

Going to Mars

93 million miles

142 million miles

Sun

Earth

Earth’s Rotation

Earth OrbitMars

Orbit

Mars

Relative position at time of Viking launch

Path of Viking spacecraft

Going to Mars

Sun

Earth

Earth’s Rotation

Earth OrbitMars

Orbit

MarsMars

Earth

Relative position at time of Viking Arrival at Mars

Path of Viking spacecraft

Going to Mars

Going to Mars

Sun

Earth

Earth’s Rotation

Earth OrbitMars

Orbit

Mars

Mars

EarthRelative position at time of Viking launch

Relative position at time of Viking Arrival at Mars

Path of Viking spacecraft

Review

1. Speed necessary to achieve Earth Orbit?2. Minimum height of a “stable” Earth Orbit?3. Approximate extent of the Earth’s atmosphere?4. Distance to the Moon?5. Relative size of the Earth to the Moon?6. Distance between Earth’s orbit and Mars’ orbit?7. Earth’s gravitational Escape velocity?