Celestial Mechanics: Orbits

Interplanetary Spaceflight

When do you launch an interplanetary probe to be sure that it reaches the planet’s orbit when the planet is actually there?

For example, to use the least amount of fuel for a trip to Mars, the situation outlined in the below diagram must hold.  From this information, you should be able to estimate how long a trip to Mars would take, using the least amount of fuel.  Can you?

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