# Orbital mechanics

## Intro

Most missions to mars are based on a Hohmann trajectory. This trajectory is the fastest trajectory possible that is minimum energy (based on the two body problem). Less energetic trajectories are available using the three body patched trajectories (Interplanetary super highway) but these can take a considerably longer length of time.

For basic mission planning the delta V of the two body problem is used to calculate the mass fraction for the trip between Earth and Mars. The mass fraction tells mission planers how much mass they need to deliver to LEO in order to get a given mass to Mars. For calculating other trajectories Numeric or algebraic techniques can be used.

Some useful algebraic techniques that will be presented shortly are:

Finding the Orbital plane –Useful linear algebra for considering the three dimensional nature of the problem.

Orbital Intersections –Useful geometry for finding where two orbits intersect each other.

## Links to New Mars Discussions

- Orbital mechanics First post: Mon Mar 15, 2004 12:04 pm, Last Post: Sun Jul 10, 2005 2:29 pm
- Zero energy trajectories - a thread to discuss this topic First post, Thu Mar 25, 2004 5:47 pm, Last Post: Fri Apr 02, 2004 6:51 pm

## Online Textbooks

## External Links

Orbital mechanics from: [Rocket and Space technology]

Orbital Mechanics form [The Mars academy]