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NASA’s full Artemis plan revealed: 37 launches and a lunar outpost



 
 
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  #11  
Old May 22nd 19, 09:02 PM posted to sci.space.policy
Fred J. McCall[_3_]
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Default NASA's full Artemis plan revealed: 37 launches and a lunar outpost

JF Mezei wrote on Wed, 22 May 2019
15:21:39 -0400:

On 2019-05-21 22:42, Fred J. McCall wrote:

You're a bit confused. There are five LaGrange points, not just one.


https://space.stackexchange.com/ques...ear-halo-orbit


Thanks.

I take it this L2's advantage is that it gets closer to the moon from
time to time, giving opportunities to have less beefier transfer/landers?


It's covered in the cite I gave.


From a requirements perspective, would the actuial lander (without
transfer) be required to be able to rejoin the Gateway at any altitude,
or only when it makes a low pass (since we're talking direst ascent)


You've asked this before and it's been answered before. Neither the
Lander Element nor the Transfer Element could reasonably be required
to "be able to rejoin the Gateway at any altitude". I wish to God you
would learn even a little bit about orbital mechanics. Think about
what you're asking.

I'm missing something in your thought process here because the
preceding doesn't make sense. The Gateway is going to make its fast
and low north to south orbital segment around the Moon about every six
days.


I was thinking in terms of a static distance between Gateway and Moon.
If it varies, then this changes things.


You need to take notes or something. This has been explained to you
several times. At some point it ought to stick, Mayfly. Regardless,
the same thing applies if the Gateway is in a fixed lunar orbit. Once
a Transfer Element has dropped a Lander Element it is pretty much free
to return to Gateway, drop more Lander Elements, and eventually still
be available for the first Lander Element to meet with it. There is
no requirement for a Transfer Element to 'loiter' once it drops a
Lander Element.

does that because we want the Lander Element to spend roughly a month
on the surface. So they refuel it, mate with a new Lander, and 6 days
later (12 from the first Lander) it repeats and deploys a second
Lander. Another 12 days later and it deploys a third Lander. This
time instead of returning to the Gateway, it waits around. The first
Lander is 24 days into its mission.


Does this limit where the various landers can land in order to ensure a
lander can rejoin a transfer vehicle that is in the orbit that dropped
off another lander ?


No.


If the lander has to wait X time to take off so it can rejoin the
transfer element in orbit, does that make it harder to time it so that
once joined, they are in good position to ascend to Gateway?

No.


I can see why direst ascent makes sense since you don't have to wait for
the right time to launc to transfer element.


But now your Lander Element would need sufficient grunt to get from
Lunar surface into the appropriate NRHO to meet the Gateway. And you
still have to wait for the right time to Launch to Gateway.

Or you don't do that at all (remember, we're talking about L2 here),
which is why I said there was something like a 20% 'cargo penalty'


Just wanted to make sure I understood correctly. 20% is pretty
significant, isn't it ?

In terms of going to Mars and beyond, with that Gateway's L2 orbit have
any advantage over an L1 orbit ?


Yes.

Shuttle couldn't get to the Gateway orbit even if it was still flying.


Come on, I saw a documentary (Airplaine II) where the Shuttle ended up
crash landing on the moon and couldn't stop in time and hit the control
tower with Captn Kirk in it :-)


Mayfly, there are times when your output could lead someone to believe
that the preceding paragraph is about the level of your thinking.


I used the shuttle since we have experience with the main ISS resupply
vehicle being grounded for a long time.


Nope. Main ISS resupply was always Progress.


If Gateway needs to be refueled once a year, how many rockets can bring
sufficient fuel mass to an L2 orbit? Is it only SLS?


Anything that can get mass to that orbit can do the job. Gateway will
use ion engines that are pretty stingy insofar as fuel use goes. It
doesn't take huge amounts of thrust to maintain an L2 NRHO. Go read
the cite I gave again. So no, it is not only (or probably even
mainly) SLS that will be doing that job.


So if this thing gets built, doesn't it prevent SLS from ever being
cancelled?


Perhaps until Falcon Super Heavy, New Armstrong, or other vehicles are
flying, but not for the reason you're concerned with above.

Other than that you would need (and throw away) a much larger and more
capable Descent Element because now it needs the 'grunt' to get from
NRHO to LLO in addition to what it needs to get from LLO to the
surface.


So you have Gateway, designed to support multiple missions to the moon,
right? And an architecture that allows re-use of the Transfer element,
right?


Gateway is INTENDED to support both Lunar missions and deep space
missions. Other than that, essentially correct.


But if the landers ditch the descent stage when they ascend, won't they
have to ship a new descent stages for every weekend camping trip to the
moon? Seems to me like more than one resupply mission per year to Gateway.


Again you're confused. First, shipping vehicles for Lunar missions
out to Gateway is not 'resupply' any more than boosting up a new
module for ISS is 'resupply'. Second, there will be multiple types of
landers and each may (probably will) require it's own unique Elements.

And weren't you the guy proposing to just use LEM, which leaves its
descent stage on the Moon?


If this project is to support only one mission to Moon, is this Gateway
thing not only a waste of money, but also not providing any advantage to
the logistics?


If cows can fly, shouldn't you carry an umbrella? That question is
the same form as yours, above. Start with a false conditional premise
("cows can fly") and then ask a question that assumes the premise is
true. In your case, the falsehood is "this project is to support only
one mission to Moon". Since that premise is false, your question is
moot.


--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
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  #12  
Old May 23rd 19, 12:19 AM posted to sci.space.policy
[email protected]
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Default NASA’s full Artemis plan revealed: 37 launches and a lunar outpost

I have a continuing suggestion. Put a ground robot station
on the Moon's surface below L2. The robots could be made
more fault tolerant there, while they construct ultra-light
solar sails. I am talking about multi-Kilometer sized sails.

At L2 there is a vertical climb from ground, no Moon circling.

I believe that robots with a ground construction base frame
would be able to recover from faults easier than free fall.
Free-fall sail oscillations would not exist also.
  #13  
Old May 23rd 19, 05:11 AM posted to sci.space.policy
Fred J. McCall[_3_]
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Default NASA?s full Artemis plan revealed: 37 launches and a lunar outpost

JF Mezei wrote on Wed, 22 May 2019
15:36:18 -0400:

On 2019-05-21 23:08, Fred J. McCall wrote:

Except it doesn't work that way. Try to buy an Intel 80486 processor.
You can't. And that will apply to almost every part in the LEM
blueprints.


Since they need hardened CPUs and RAM, they'll use whatever is available
on the market (usually older vintage) or special order some.


Yes, they will, which means all the avionics (including heat
dissipation, which affects structure) will be a clean sheet design.


I am not
advocating they use the same computers as on the 1960s LEM. I even
mentioned they could run this on an iPhone if they wanted it.


What you were advocating was, as usual, unclear, then.


But for structures, I have to wonder why they wouldn't re-use the
general design of the LEM, as ugly as it was since it fit the purpose.


Probably because they don't want the limitations of that design. Why
do you think Blue Origin didn't just do that for their Blue Moon
lander? Are they so much stupider and so much more inexperienced than
you? Somehow I just don't think so.

But all your parts are going to be from new vendors using new assembly
lines. You're going to have to certify everything as if it was a
brand new vehicle.


Yes, but re-using a design you know has worked well saves you on the
design stage.


Not really, no. Whatever you build needs to interface with boosters
in a standard way and be of a size to fit inside the payload fairing
of whatever rockets you plan on using to get it out to Gateway. You'd
like to use modern alloys to build the thing. It needs to provide
power and heat dissipation for all the electronics you stuff in it.
You'd like to use modern, more efficient engines that use propellants
that you can make in situ out of water ice. I could go on.

Now lets see how the old LEM stacks up. It's too physically large to
fit inside the payload fairing of anything other than SLS or Falcon
Super Heavy. It relies on a docking adapter that doesn't exist
anymore. It's battery powered and only has power for a 75 hour
duration. It's made largely out of, well, tissue paper. Atmosphere
is pure oxygen at 5 PSI or so. It uses old hypergolic engines fueled
by Aerozine 50 and using dinitrogen tetroxide as the oxidizer.

See what a poor fit that is for what we actually want to do?


When totally new, you have to certify the design will work and then
certify the hardware as built meets the design. When re-using an
ecxisting design, you only have to certify the new hardware fits the design.


You've never actually been exposed to engineering, have you?


--
"Ignorance is preferable to error, and he is less remote from the
truth who believes nothing than he who believes what is wrong."
-- Thomas Jefferson
  #14  
Old May 23rd 19, 05:48 AM posted to sci.space.policy
Fred J. McCall[_3_]
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Default NASA's full Artemis plan revealed: 37 launches and a lunar outpost

JF Mezei wrote on Wed, 22 May 2019
16:34:48 -0400:

On 2019-05-22 16:02, Fred J. McCall wrote:

It's covered in the cite I gave.


You explain the orbit, I asked if the orbit having periods where it is
close to moon was the main advantage or if there are others.


No, I didn't. I provided a cite which explained what an NRHO is and
what the advantages are. Did you read all the papers it linked to?
Did you understand it all?

You've asked this before and it's been answered before. Neither the
Lander Element nor the Transfer Element could reasonably be required
to "be able to rejoin the Gateway at any altitude".


I originally asked in a context where I thought Gateway would be in a
lunar orbit. So I asked again, now that I know it is in L2 location.


And when you originally asked I described the orbit (so you should
have known what it was by now) and why your 'desirement' was not
feasible or reasonable. Mayfly, is your long term memory defective or
do you just not bother to read and understand the answers when you ask
questions?

be available for the first Lander Element to meet with it. There is
no requirement for a Transfer Element to 'loiter' once it drops a
Lander Element.


Didn't you mention the transfer would have to wait for Gatway to again
be close which happens every 6 days ?


It doesn't have to 'loiter' WAITING FOR THE ASCENT ELEMENT TO COME
BACK UP, YOU NINNY!

Anything that can get mass to that orbit can do the job. Gateway will
use ion engines that are pretty stingy insofar as fuel use goes.


But Gateway will still need to be refueled so that it can refuel
trasnfer element and landers, right?


Right. And the long term goal is for that fuel to be produced on the
Moon, not on Earth.


The whole point of Gateway is a refueling station, isn't it?


No.

And weren't you the guy proposing to just use LEM, which leaves its
descent stage on the Moon?


Yes. I propose this in the context of a 2024 deadline where NASA is
unable to deliver anything new in such time frames.


Wrong. Landers and such will be commercial, not 'NASA delivered'.
Blue Origin, for example, says that their Blue Moon lander can be
ready for use by 2024.


And in a context
that this is a political one-off mission not some long term endeavour.


Wrong. Pull your head out of your TDS asshole.

("cows can fly") and then ask a question that assumes the premise is
true. In your case, the falsehood is "this project is to support only
one mission to Moon". Since that premise is false, your question is
moot.


I asmed about missions to Mars. Does this Gateway provide any advantage.


Yes, if you buy into NASA's architecture for this sort of thing. I
answered that already.


For Moon, I gave see resupply dicking when Grateway is "high", and
Gateway launching landers to Moon when it is low. But for missions to
Mars, is there any Advantage?


Asked and answered. REPEATEDLY. The answer hasn't changed. Write it
the **** own and stop asking.


Also, assuming Gateway is to be built is wrong. With a goal of landing
on Moon in 2024, all efforts will be amde to make it happen once. Only
after, if funds aren't pulled, would they start thinking about a Gateway
thing to support multiple missions.


Again, pull your head out of your TDS ass. Your preceding paragraph
is bull****. NASA has put forward a plan. You claim to have looked
at it. It involves Gateway.


--
"Ignorance is preferable to error, and he is less remote from the
truth who believes nothing than he who believes what is wrong."
-- Thomas Jefferson
  #16  
Old May 23rd 19, 11:29 AM posted to sci.space.policy
Scott Kozel
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Default NASA?s full Artemis plan revealed: 37 launches and a lunar outpost

On Thursday, May 23, 2019 at 12:11:18 AM UTC-4, Fred J. McCall wrote:

Now lets see how the old LEM stacks up. It's too physically large to
fit inside the payload fairing of anything other than SLS or Falcon
Super Heavy. It relies on a docking adapter that doesn't exist
anymore. It's battery powered and only has power for a 75 hour
duration.


What is proposed for longer stays ... an APU, solar arrays?

It's made largely out of, well, tissue paper. Atmosphere
is pure oxygen at 5 PSI or so. It uses old hypergolic engines fueled
by Aerozine 50 and using dinitrogen tetroxide as the oxidizer.


The main advantage being non-cryogenic. What fuel and oxidizer would
be superior for a LEM today?
  #18  
Old May 23rd 19, 12:06 PM posted to sci.space.policy
Jeff Findley[_6_]
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Posts: 1,881
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
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
  #19  
Old May 23rd 19, 12:09 PM posted to sci.space.policy
Jeff Findley[_6_]
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Posts: 1,881
Default NASA?s full Artemis plan revealed: 37 launches and a lunar outpost

In article ,
says...

On 2019-05-21 22:21, Greg (Strider) Moore wrote:

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


For the same reason ISS operates at 1 ATM. It makes some parts of the
operations easier.


Ah so this 1 ATTM was meant as cabin pressure. When I read it, I was
thinking about engines for sea level vs vacuum, hence my questioning
requiremenet to operate a LEM at 1 ATM.

If the cabin moves from 5PSI to 14.7, does that change much in terms of
thickness of walls/windows needed ? Or is the change fairly minimal?


Cabin pressure. The US has used standard sea level pressure and N2/O2
mixture since the space shuttle. The Russians have used that standard
from the very beginning.

The pure O2 atmospheres in early NASA spacecraft simply isn't acceptable
to the medical people for long term spaceflights. It was a kludge early
on so US spacecraft could be made lighter. I doubt any future US
spacecraft, aside from EVA suits, will use that kludge again.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
  #20  
Old May 23rd 19, 12:13 PM posted to sci.space.policy
Jeff Findley[_6_]
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Posts: 1,881
Default NASA?s full Artemis plan revealed: 37 launches and a lunar outpost

In article ,
says...
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.


I believe you're correct here. I think the original intent was to use
SRB segments that were identical to those used with the Shuttle, but I
think that intent changed.



Unless something has changed, they've been using shuttle SRB components
from the very beginning for the 5 segment SRBs:

https://www.space.com/28775-worlds-l...nasa-test.html

From above:

The individual segments though, use the same case parts that
were recovered and reused during the space shuttle program.
As such, the first SLS qualification motor (QM-1) being
tested on Wednesday is comprised of hardware with a historic
past.

Do you have a cite for the assertion that new casings have been made?

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
 




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