"TVDad Jim" wrote in message
oups.com...
Quoting from http://www.spaceref.com/news/viewnews.html?id=1057 :

"Along with a CEV that carried the flight crew and their support
equipment and propulsion system package, a Lunar Surface Access Module
(LSAM) which was designed to undock from the CEV and take the entire
crew to land upon the moon's surface. Upon completion of the mission,
part of the LSAM would launch off the surface and rendezvous and dock
with the CEV, orbiting unmanned following departure of the flight crew
to the surface. The CEV and LSAM would use a similar approach to the
Apollo CSM/Lunar Module/S-IVB complex to get to and from the moon."

Questions:

What are the risks of having an unpiloted CEV in orbit, rather than
leaving a pilot onboard while the LSAM lands?

Docking might be a problem if the LSAM has instrumental failure. I would
imagine that there would be a provision for a "rescue" mission if the CEV
failed during the lunar stay. (The LSAM will be capable of a much longer
stay than the LM.)
How have these risks changed since the days of manned lunar CSMs? Is it
just better automation available? Was having a CMP onboard just a
"consolation prize" in case the LM didn't make it back for a LOR?

Much, much, much better automation. The CMP was responsible for performing
orbital science (primarily photography), and the final phase of docking was
performed by the CSM.
How do four astronauts on the Moon make it a "better" mission than
three astronauts on the Moon? It sounds like a lot of ballast (both in
body mass and support materiel) to land and re-launch.

First, you should compare four with two. Second, the primary reason why it
is a better mission is that there will be a longer stay. Secondly, IIRC, the
new proposal calls for two rovers. I would imagine that a single one of the
new missions would cover as much ground as all the Apollo missions. (IIRC,
Apollo 15 alone covered more than all three of the successful non-LRV
missions).