Saturday, August 15, 2009
The best argument for going back to the Moon first before Mars is simply location, location, location. The Moon takes only about three days to reach from Earth and is only a bit over a single light second away, meaning that nearly simultaneous communication is possible. Compare that to Mars where delays take at least four minutes (one way).
Then there's also having to wait for the two planets to be properly lined up in order for there to be a launch window where we can send craft and/or people, with a travel time of some six months one way.
I created a quick map on Google Maps to illustrate the distance between the two. This is a map from my hometown of Calgary, showing the route I took in junior high to get to school - a fairly quick route that involved crossing only a single major street, but still took about 15 minutes or so, pretty much the perfect distance. Lots of squirrels on the path on the way there too, and sometimes cats would sleep in the sun there when it was warm. That's the blue line on the map going to the left, and the total distance is about 800 metres. We'll imagine this to be the distance from the Earth to the Moon.
The next line is red and goes up to the northeast, and this represents the distance from the Earth to Mars when they are particularly close (55 million km), so this is the closest of close distances between the two planets. Even at this distance you can see just how much farther it is. See if you're patient enough to keep scrolling at the same scale as the first blue line until you reach the end of the red one (it may help to bring the map up in a new window instead of staying within this post). Doing so will give you an idea of the difference between the two.
View House to school in a larger map