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Old May 23rd 19, 12:06 PM posted to sci.space.policy
Jeff Findley[_6_]
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Default NASA?s full Artemis plan revealed: 37 launches and a lunar outpost

In article ,
says...

On 2019-05-21 06:42, Jeff Findley wrote:

Nope. In order to have enough political support in the Congress, the
pork-lifter will be part of the plan. Note that each of its planned
launches are specifically (prominently, actually) shown in the graphic.


When I saw the graphic, I had i my mind the SLS "icon" as being generic
since I was thinking NASA was open to using commercial rockets to get
this done by 2024.


Nope. NASA Administrator Bridenstine has assured the SLS/Alabama mafia
that SLS/Orion are integral to NASA's plan to return US astronauts to
the lunar surface.

So the graphic shows they can land a man on moon by 2024 by using only 3
porklifter flights (12 of 16 engines). Also shows that each of the 3
components of the LEM will be sent to orbit separately (I guess this is
where the commercial launchers come into play) and I would assume much
of the testing will be done on flights that don't involve SLS.


The graphic doesn't seem to show much in the way of testing for
SLS/Orion, so I'm not sure how much in space testing they're allocating
for the other components. My guess is they aren't. The plan doesn't
have time for much testing, does it?

The graphic shows all of the SLS/Orion flights on it including the
"test" flights. There are no more. There is no money nor the time for
more (if the 2024 date is to be believed).


But the graphics also show generic rockets lifting the 3 components of
the "LEM". So I have to assume that there would be some earth orbit
flights in the 2021-22-23-24 time frame to test the LEM prototypes. (not
sure if manned or not).


I wouldn't necessarily assume that. Just like NASA isn't requiring an
in flight abort test for Boeing's Starliner, today's NASA seems to rely
on piles of paperwork to "prove" something safe to fly. This is
misguided, IMHO, but that's where we are.

Does Orion have a hatch compatible with Dragon2/station ? If so, could
they send crews on Dragon2 to dock with the "LEM" in LEO for humans to
test the lander and then return to earth in a Dragon? (or Constellation).


By "hatch", I assume you mean docking system. Yes, Orion, Starliner,
and Dragon 2 will all use the same mechanism.

Same thing will happen for SRB segments too. It's not yet clear

what
will happen when those run out.


I was always under impression that only the engines were leftover
inventory from shuttle and limited in supply, and that the core stage
and SRBs were built new, based on designs for shuttle.


Nope. They're building the five segment SRBs for SLS from the leftover
steel space shuttle SRB casings. When those are gone, they're gone. I
have not seen any news article saying they've gotten a contract to build
more steel SRB casings. And even if they did, I'm not sure the original
supplier is still around because I don't know off the top of my head who
that was.



Did you even read the article? No, the LEM design won't be "dusted
off". It can't operate at sea level internal pressures, which is the
standard today.


Why would LEM-2 need to operate at 1ATM since it will never operate on
earth?


Because with the advent of the space shuttle, NASA standardized on 1 atm
80% N2, 20% O2 atmosphere in its spacecraft, just like the Russians have
used all along. This is best for long term missions.

Its walls are horribly thin and would not have the
factor of safety required today.


So what magic has happened to allow a lunar lander to now have much
heavier structure t please NASA standards? At the end of the day, won't
they be working with the same limitations on mass/fuel for the lander?


Things that are different just aren't the same. Different requirements,
different designs.

I am sure NASA wanted more shielding for the Apollow ERA LEM, but when
engineers come back with "no can do, all we can afford in the mass
budget is aluminium foil walls", then NASA has to bend the rules,
doesn't it?

That is why I asked if engine efficiently had radically changed since
then to allow much heavier vehicle to land on moon.


No, engine efficiency has not radically changed. Physics today is the
same as it was in the 1960s.

And most importantly, the suppliers
are all gone. So you'd have to re-certify everything anyway!


Put blueprints on the RFP and suppliers able to build what is already
designed will bid and get contract. You save the years needed to design
something. The LEM's design was tested and went through all that
certification back in the 1960s.


Having a "design" isn't enough. You have to be able to manufacture
everything to spec. And much of the manufacturing knowledge has likely
been lost. We don't machine things by hand much anymore. The LEM was
not designed to be produced using modern manufacturing techniques.

If you built a LEM today to the old specs, you'd still have to certify
every single part just like a new vehicle. Again, the original
suppliers are long gone. And even if they weren't, the original
machinists and other people who built it all are all retired and many
have passed. No one has the type of knowledge that was simply assumed
at the time anymore. So anything that wasn't written down has been
lost.

Jeff
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