L4, L5 Gravity Wells

Remember that the L-4 / L-5 points themselves are NOT stable.

There is a large kidney shaped stable orbit around each of these points.

>
> Good questions Chad!
> Here are my two cents. Assumeing that we have launched a probe for the
> purpose of mapping the L5 gravity gradient, my first question is how do

I am not sure why we need to do this...the orbits are well understood.

> we measure the gravity gradient? I seem to remember that gravity
> mapping of the moon used variations in the orbit of the probe to detect
> variations in the density of the moon. Not much use when sitting in an

That works in very low lunar orbits, less than 1000 km above the Moon.

Those mascons have no detectable effect out at the L-4 / l-5 region.

> L5 location. My first design would be a tetrahedon of long spines and
> use some sort of very sensative flex measurement.(I have got to get
> spell checking back on this email tool.) Design of this probe would be
> a good InnerTransit.org project.
>

Sounds rather complicated. At the L-4/5 region the gravity differences
are tiny, the spines would have to be kilometres in size to get useful
measurements.

Why not simply toss out some reflective metallic foil chaff and track
them with radar ?

There is one practical problem with that approach which will make the
collected tracking data rather difficult to analyze....

The person who figures out that problem gets 5 points :-)