1. Orbital Mechanics
Orbital Mechanics refers to the general description of how bodies move in force fields (such as gravity) given that energy and momentum are conserved.
For two spherical objects in which gravity is the only force, this problem is analytic, and both bodies execute elliptical orbits (i.e., they obey Kepler’s laws).

2. Vis-Viva Equation
Gravity is an attractive force. As you fall toward a body of mass, you speed up; as you move away, you slow down.
The Vis-Viva equation is a simple and useful relation describing this interrelation between total orbital speed and proximity to the dominant massive body.

3. Being a Rocket Scientist!
Spaceflight is expensive. Energy is required to lift mass away from the Earth into space ($thousands per kilogram).
Question: What is the minimum energy orbit transfer, requiring the minimum fuel to move from one planet to another?
Ans: Hohmann orbit transfers.
In part, want to take advantage of the fact that the Earth is already moving at about 30 km/sec.

4. Types of Orbit Transfers

5. Transfer Orbits in the Solar System

7. Timing for a Mars Visit

8. Orbit of Voyager

9. Gravitational Boosts for Voyager

10. Geostationary Orbits

11. Issues for Colonizing Other Worlds
TRAVEL - Getting there and back (cost and time).
POLITICS - Who is in charge? Who reaps the benefits? Who “owns”?
GRAVITY - What happens anatomically, physiologically, psychologically, and sociologically in terms of future generations born in different gravity (lower g) environs?
WATER - Finding, bringing, controlling.
ATMOSPHERE - Atmospheres moderate day/night temperature extremes. Also need breathable air. Terra-forming versus building and maintaining specialized habitations.
RADIATION/SOLAR WIND/COSMIC RAYS - What if no ozone? What if no magnetosphere? Might have to live underground.