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| Credit: NASA/GSFC/MIT/SVS |
We have been mapping the moon for a long time now,
but the latest results from NASA gives us more detail than ever before (1). For
the past year NASA’s lunar orbiter has be steadily going round and round the
moon shining a light into every nook and cranny it can see. It’s by no means
finished yet and will be plugging away for the next two years as it goes round
and round in its polar orbit.
The satellite is equipped with a laser altimeter
firing laser pulses at the surface. The single pulses are split into five so
that when they are reflected back, their different arrival times indicate the
distances that they have travelled. So if they are reflected from a high point,
the light gets back sooner than the beam from a slightly lower point from an adjacent
part of the surface.
The spatial resolution is around the 100-foot mark
and will be better in the polar parts as these are directly under the orbital
track. The images are stunning. The coloring is used to indicate the height of
the features, so red is high and green is low. Measurementwise, the height
resolution is around 3-feet.
Why do we earthlings care about such detail? When
we get back up there to set up mining camps to exploit the resources, we will
need to know how easy it will be to get machinery to where we want to go, best
route, and where the most shaded and coldest spots occur as there might be some
ice around. That would be particularly handy. Not just for our gin and tonic,
but for fuel.
Above all, it will be nice to have a hi-res picture
before we’ve had a chance to spoil it, don’t you think?
