Question

What is an “opportunity” in space navigation? Why is it important in traveling from Earth to another planet?

Anyone who understand this question can help me

Answer 1

As per my think, Here opportunity means the chance we get to get into an orbit or land on a specific planet once in a while. See it in this way - Let's take an example of Mars. It is not like we can launch and go to mars whenever we want . We need to have a specific time of launch so that we reach the mars at the same time Mars reaches a specific point otherwise we will miss the planet and will have to wait again before relaunching. This is also important in terms of energy because if we miss the planet, we will have to use a lot of extra energy, fuel to get back into orbit.

Therefore,

for each and every planet , we wish to travel to, there is an " opportunity" when we can use the minimum energy transfer orbit to reach the planet. For mars, this opportunity comes after every 25 months.