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Old May 21st 19, 11:42 AM 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 2019-05-20 12:56,
wrote:
"In the nearly two months since Vice President Mike Pence directed NASA to return
to the Moon by 2024


Unless MASA is given unlimited budgets, could it do this by 2024?


Nope. I give this "plan" zero chance of achieving the Administration's
aspirational date.

A while back, NASA signalled that it isn't opposed to commercial rockets
and mentioned Falcon Heavy. Could this be the perfect excuse to put SLS
out of its misery and redirect budgets towards building a moon lander
ASAP and launch using Falcon Heavy or some other commercial rocket?


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.

Would NASA require a sequence of flights similar to those that
preeceeded Apollo 11? Or would it compress the testing into fewer
flighst? Combine 9 and 10 together and test the LEM in Earth orbit, and
eliminate 8 which was a sightseeing flight.


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).

If NASA insists on SLS, would it compress the testing to culminate onto
the pne flight to the moon on the last set of SSMEs they have left? Or
would this trigger the contract to actual build more of them instead of
just studying how to build new SSMEs ?


Congress insists on SLS. NASA obliges. We've already discussed new
build RS-25 engines. You can look that info up again if you'd like.

Same thing will happen for SRB segments too. It's not yet clear what
will happen when those run out. But Northrup Grumman Innovation Systems
has already designed composite wound casings of the same diameter for
their Omega launch vehicle, so it's likely they'll pitch them as a
replacement. So likely a new contract will go to them to test a five
segment SRB with composite wound casings. Because opening up something
like this to competition would not help with the time-line.

In terms of a lunar lander, considering the time frame, is NASA's only
option to dust off the LEM plans and just update avionics? (Or even
build an emulator on an iPhone and have it run the original software).


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. Its walls are horribly thin and would not have the
factor of safety required today. And most importantly, the suppliers
are all gone. So you'd have to re-certify everything anyway! So it
would be treated as a new design. So you gain nothing by starting
there.

In terms of hypergolic engines, has efficiency changed much since the
last Apollo missions, (aka: mass of new lander would have to be as
limited as it was for Apollo missions) or have significant improvements
happened since then to allow far more mass (shielding etc) to be loaded
onto the lander?


Nope. Physics is physics. Look at the engine in Orion. Look at where
it came from and where that engine came from. Then look at the specs of
each engine in its lineage and compare them.

Jeff
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