This is John Batcher, conversation with my good colleague Bob Zimmerman behind the black

about a very geeky subject, Gravity Map of Mars, why do we need such a thing?

This is the first ever, there will be many more iterations. Gravity maps explain where the dense

parts of the planet, where the not dense parts of the planet, and that affects the

ability to stay in orbit around the planet. Bob gives the example of the moon that creates conditions

that are unstable for orbiting and therefore you need to know this to put an orbiter in

place. The gravity map of Mars explained by Bob Zimmerman.

We're going to Mars, this century, and we need all of this data.

It will be the frontier.

More of this later. be the frontier.

More of this later.

This is based on the insight land that has seismology data and earthquake data combined with

orbital data and the orbital

data was how those orbits changed as they

orbited Mars and what that does is it tells you what the densities are

within the planet where you have dense areas and less dense areas. all the black and it shows that the area where all the big volcanoes are is a very dense area.

And it indicates once again something about how the planet formed.

It's also important because orbital mechanics, when you put something in orbit, you want to know how long it's going to be in orbit, and knowing these slight changes is very important data. You have to have it. For example, the moon has very wide swings of density underneath the

surface. They call them mass cons, these mass concentrations. It makes almost

all lunar orbits unstable and so if you want to put something in

orbit that you really got to know that underground density map and so they now

produce their first density map of Mars using the inside seismology data and they'll refine this over the years.

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