Mark Thornton wrote:

The imagers on space probes are usually designed for scientific
purposes and not generating eye candy. This usually means a sensor
with a colour filter wheel. Creating colour images requires post
processing which isn't trivial --- with the probe moving you have to
align the images for each colour. The colour response is also often
not well suited to producing what our eyes would interpret as true
colour. I think NASA has admitted that this last aspect results in
poor PR and that future sensors might include more suitable filters in
the set.


In the case of MESSENGER, the photos are across a wide part of the
optical spectrum via several filters.
So they will be putting together color images of the planet from this
data fairly shortly.
The main point of the mission is to determine the elemental make-up of
the surface of Mercury by how the various minerals and rocks reflect
sunlight in various parts of the spectrum, via multiple images of the
same area through all of the optical filters This allows maps to be
generated, such as Clementine generated of the Moon using the same
technique. You can look at the Clementine lunar mineral maps he
http://www.lpi.usra.edu/lunar/missio...entine/images/

Pat