LSAM and an unmanned CEV in lunar orbit?

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?

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?

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.

"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).

TVDad Jim wrote:

Questions:

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



That depends on if you leave the CEV under the command of a slightly
defective HAL-9000 series computer while the crew is not aboard it. ;-)

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?



Well, you did get the advantage that either the Apollo or the LM could
do the docking procedure if one suffered some sort of RCS problem. It
will be interesting to see if they go with manual or automatic docking
on this design. Knowing NASA, it will be manual- which pretty well
botches using the CEV as a unmanned cargo craft the way Soyuz got turned
into Progress.

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.



They had to show some improvement over Apollo, or there would be no
apparent point to it all.
There still is no apparent point to it all, but it carries twice as many
people to the Moon's surface as Apollo did on each flight.

Pat

Ami Silberman wrote:



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).



Longer stay means more EVAs on the Lunar surface, and that means we need
beefed-up spacesuits to deal with the abrasive Lunar dust...have they
started working on those yet?

Pat

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

Would seem to depend on whether the whole post-Columbia NASA safety culture
sticks around for a while, or a little Kranz-type editorial boldness
previals. Can the the already mentioned advantage of having a piloted
capability for either vehicle to be the active rendezvous platform basically
trump any other lunar surface advantages? At least in the minds of mission
mode planners?

We got LOR down reasonably well 30 years ago, but age old ideas of minding
the store, keeping the watch, and having someone left to debrief if
something goes wrong... do those supercede our trust in 21st Century
spacecraft that haven't been built?

JW

On 11 Aug 2005 09:36:16 -0700, "TVDad Jim" wrote:


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

Somewhat higher, I suppose. Especially in lunar orbit with no magnetic
field to protect electronics from solar flares and what-not.

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?

No, even human piloted dockings were new and risky at the time of
Apollo (only, what... five or six dockings before Apollo 9?) and
automatic dockings were way beyond the state of the art at the time.
So one astronaut stayed behind to run the CSM.

Not so today, although NASA has yet to achieve it. We'll need
autodocking anyway for the unmanned cargo version of CEV.

How do four astronauts on the Moon make it a "better" mission than
three astronauts on the Moon?

Four crew on the surface means you can have two outside pretty much
all "day" except during crew sleep. Double the productivity versus two
man or even three man, as 16 hours is too long for one person to be in
a spacesuit outside, and safety will call for at least two astronauts
outside at a time (spacewalks are always at least 2 people, too.)

Brian

On 2005-08-11, TVDad Jim wrote:

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.

Four people means you can potentially operate two teams of two, which
allows for more activity to be done within the limited surface time
(since you're not constrained by things like daylight, which helps). If
you just have three people on the surface, then you're effectively
limited to one operating team, since you wouldn't want anyone to be
working solo if possible.

One of the major advantages of having a CMP in Apollo was that he could
do "orbital work" - photographing landing sites, that sort of thing -
whilst he was on his own. A lot more of this "routine science" can be
automated now, lessening the requirement for a human in the loop. A CEV
is also likely to be a lot less "maintainable" than a CSM was, meaning
that fewer potential problems would be helped by having a person handy.

It actually reads a lot like the current Mars Reference Mission -
lander, unmanned orbiting return vehicle - in some respects, and I
suspect there may have been cross-pollination of ideas there.

Also, consider longer missions - a solo flight for the *CMP is fine for
a few days, but once it stretches to significantly longer than that
he'll be bouncing off the walls, which may adversely impact the mission.

--
-Andrew Gray

"Pat Flannery" wrote in message
...

Well, you did get the advantage that either the Apollo or the LM could
do the docking procedure if one suffered some sort of RCS problem. It
will be interesting to see if they go with manual or automatic docking
on this design. Knowing NASA, it will be manual- which pretty well
botches using the CEV as a unmanned cargo craft the way Soyuz got turned
into Progress.


It'll likely have both automatic and manual docking modes. It's also quite
possible that the docking procedure can be partly or fully teleoperated from
Earth.

Dr. P. Quackenbush wrote:

It'll likely have both automatic and manual docking modes. It's also quite
possible that the docking procedure can be partly or fully teleoperated from
Earth.



Easy enough in Earth orbit- but at lunar distances, given the time delay?

Pat

"Pat Flannery" wrote in message
...


Dr. P. Quackenbush wrote:

It'll likely have both automatic and manual docking modes. It's also
quite
possible that the docking procedure can be partly or fully teleoperated
from
Earth.



Easy enough in Earth orbit- but at lunar distances, given the time delay?

Pat


1.2 second one way light speed delay? No big deal if you're moving slowly
and the machine you're controlling is somewhat intelligent. I think the old
Soviet Lunakhod rovers were teleoperated.