Jeff Findley wrote:

In article . com,
says...

On 2017-12-14 13:54, Greg (Strider) Moore wrote:

As others have pointed out, Congress has to allocate the money.

Is there any indication that pressure/suggestions will be made to
Congress to fund a lunar lander? I take it this would come from NASA who
would point to Trump's memo as justification?


Doubtful. As I said, every Administration after Reagan announced plans
to go to the moon and/or Mars. No funding of any significance was ever
allocated to develop a full scale manned lander.


This is somewhat different, in that this isn't a space policy produced
by a NASA Administrator, but rather comes from a group headed by the
Vice President.



In a normal situation, would funding for the lander have been made at
the same time as funding for Orion and the Service module as both were
part of a new plan to return to the moon? Or do these first 2 normally
get started years ahead of the lunar module ?


This is a normal situation. Following the politically motivated (Cold
War) Apollo/Saturn program, NASA's funding has not gone up much, except
in rare instances where Congress is convinced that NASA won't come back
to Congress for more and more money. Most proposals for manned moon or
manned Mars missions in the past have fallen on deaf ears in Congress.


The "won't come back and ask for more money" thing is well known by
NASA, too, and has led to a number of bad decisions (like the Space
Shuttle).


The exception is SLS/Orion. They were funded by Congress to keep the
pork flowing to former space shuttle districts after the cancellation of
Ares/CEV.


"The pork must flow."



(Obviously updated electronics/software, updated batteries).
Other than pretty much updating everything, it'll be exactly the same.


Jeff Findley wrote:
Pretty much updated everything. Plus it "needs" to be bigger, because
we plan on staying much longer. You're not going to "dust off" the old
LEM design, build it, and fly it. Today's NASA engineers and managers
would never accept such a "marginal" design. The walls were thin
enough aluminum in spots that you could literally jam a pencil right
through the wall of it with one hand.

How different COULD a lander be considering technology advancements.
(aka: weight limits to get something to and from the moon).

Few suppliers of the LEM hardware exist today as they did in the mid
1960s. It's been half a damn century! You can't just build new copies
to the old plans because there is a hell of a lot more to it than that.
Many of the then "off the shelf" parts aren't made anymore! The
electronics in particular only exist in museums. No one makes parts
like them anymore!


Even for things that we're building constantly we have to obsolescence
updates to designs because we don't have the parts to build more.



Won't "new" requirements such as redundancy, thicker walls, bigger
module for longer stay make the lander weight more than can be launched?


Possibly. Making it more redundant and safer (higher margins in things
like structural design) will add mass. But the opposing "force" is
improvements in materials, manufacturing, electronics (lighter),
batteries, solar cells, fuel cells, and etc. will tend to reduce mass of
certain systems.


Altair was bigger because it was intended to carry a crew of four.
Whatever they do will probably look sort of similar to a LEM, since
form tends to follow function.


For a "flags and footprints" style mission, it might be a push. But,
for a "moon village" program, you're going to want a bigger lander to
land payloads on the moon which are bigger than the old LEM ascent
stage.


You'll probably wind up with two different landers, one for people
that works like a LEM and one for cargo that's just a big pod that
sets down and stays. Or you could, of course, go the BFR Spaceship
route and build a real spaceship.



Secondly, since the Service module is designed and being built before
the lander, wouldn't a service module need to know the weight of the
lander which it needs to push to the moon?


Chicken and egg problems abound. But they're all driven by budget and
what the goal is. If the goal is repeat of flags and footprints, that's
a lander maybe a tad bigger than the LEM. If the goal is a lunar
"base", that would drive the lander design to be bigger than the LEM.


And it doesn't really 'need to know'. It just needs to be 'big
enough'. The main driver will be the EUS rather than the relatively
small engine on the Service Module.


Either way, I doubt we'd even use the old two stage LEM architecture. I
find it far more likely that a reusable lunar lander (single stage)
would be developed, especially if a lunar base/village is the goal. We
simply can't afford to keep disposing of such expensive hardware after a
single use. That's just insane.


I think that NASA will want to build something very like the LEM, but
larger. But if you look at NASA's plans, they don't need a lander for
a good long time yet. By then they'll be able to contract SpaceX to
use BFR Spaceship.


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw