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



 
 
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  #21  
Old May 23rd 19, 12:16 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 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. 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.

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.


So you're advocating for a new LEM, not one that is made to the exact
specs of the 1960s. Do you see how you're already sliding down a
slippery slope? By the time you're done replacing old parts with new
ones made with modern manufacturing techniques, your "proven" LEM design
will actually be a completely new design!

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.

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.


Bull****. You have to also certify the entire *system* design will work
with all those new parts. It's not good enough to design and test the
components and *hope* that they all work together. Almost all of the
hard problems in engineering are at the system level, not the component
level.

Jeff

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  #22  
Old May 23rd 19, 12:18 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 , lid
says...
See:

https://arstechnica.com/science/2019...lunar-outpost/


Plans are easy. They've been told they need to get back to the moon
quickly, so they've produced a plan to do so.

Doesn't mean it will happen, or even that the people at NASA think it
will happen.

It's a good way of telling contractors to increase their prices though.


Also doesn't mean Congress will fund any of this. They'll be suspicious
that the early funding requests are just the tip of the iceberg and that
huge increases will be looming in the years ahead. This has doomed
every single "plan" that NASA has had to go beyond LEO since the 1970s
to today.

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.
  #23  
Old May 23rd 19, 12:19 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 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?

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)



There is no real advantage to L2, IMHO. This is necessary because Orion
is simply not capable of getting to a low lunar orbit and getting back
to earth. It's too heavy and lacks the necessary delta-V to do so.

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.
  #24  
Old May 23rd 19, 07:22 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 Thu, 23 May 2019
01:23:23 -0400:

On 2019-05-23 00:11, Fred J. McCall wrote:

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


Consider when they upgraded the Shuttles to glass cockpit. They also
updated the flight computers with 386s with more RAM but the core
software was preserved. (they would have had to add the LCD screen
drivers to emulate the old analogue gauges).


OK, I've considered. What the hell is your point?


With the modest advances in computing since the 1960s, it would be
rather easy to host computing power needed to run the LEM software
unmodified im emulation with less weight, less heat dissipation, less
power.


Everything is always "rather easy" until you actually have to do it.


However if you remove the huge challenge of fitting all the logic onto
the limited LEM computer, is the actual logic of landing a craft on the
Moon very difficult to write?


That depends. LEM, for example, was always flown manually, so
'auto-landing' would be difficult because it wasn't built for that.
And don't think that writing the software is the difficult part.
Remember, SpaceX did away with powered landings for Crew Dragon
because CERTIFYING it was too difficult to be worth the trouble to
them, not because of concerns about difficulty writing the software.

Meanwhile, Blue Moon is designed for automated landings going in,
since it's supposed to be able to be used as an unmanned cargo lifter.


Just curious of what sort of challenge exists to write one from scratch
to be ready by 2024.


Depends on the vehicle. Certification will be anywhere from difficult
to impossible, since all the testing will be done in Earth orbit. It
wouldn't surprise me to see manual control required for the landing
unless you're going to run an unmanned test flight to landing.

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?


Have they landed on the moon?


Of course not. Don't be an idiot. Your 'new LEM' hasn't ever landed
on the Moon, either.


or is this just a proposal on paper?


No. It's well beyond that, unlike your 'new LEM'.


And
was that plan devised before there was a 2024 deadline imposed by a
politician?


Of course it was. Otherwise it would just be some napkin doodles.
However, the company says it can be ready to put humans on the Moon by
2024, so who cares that their development effort started years ago?


Of course if you are asked to get to the Moon or Mars, your initial
thoughts are to create a clean sheet design and take whatever time it
takes.


Yeah, because that's going to be faster and cheaper than trying to
update some half century old design to try to make it work.


But when one imposes a 2024 deadline, you have to wonder if a clean
sheet design can meet that deadline and if not, whether you could re-use
older proven designs.


You cannot use "older proven designs" BECAUSE YOU CANNOT GET THE
BLOODY PARTS AND HAVE TO RECERTIFY EVERYTHING. Which part of that
don't you get? Bezos says that the Blue Moon lander can be ready to
put people on the Moon by 2024. How long would it take to recruit and
recertify vendors for your 'new LEM'?

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


Would any commercial rockets be able to launch a LEM ?


To the Moon? No. Insufficient grunt. The baseline LEM (good for 48
hours on the lunar surface) weighs in at a bit over 15 tonnes. Falcon
Heavy can get around 20 tonnes to TLI if you fully expend the vehicle.
Nothing else can, so that's the only commercial launcher that could do
that job. Then you have the problem of the LEM being a dead hunk
until people board it and power it up.

Note that that mass doesn't get you any people out there. That
requires an SLS launch.


Saturn5 had 3rd stage width of about 6m. Falcon 9 has 5.2m (4.6 usable
by payload).

reading Wikipedia for the LEM, it appears it had 4.22m width with
landing gear retracted. So it would fit with the right adaptor.


But you cannot get it to anywhere because it's too heavy for anything
but Falcon Heavy expended or SLS. And if you could get it to anywhere
it would be just a big dumb rock until people could get to it and
power it up.

of whatever rockets you plan on using to get it out to Gateway. You'd
like to use modern alloys to build the thing.


Wouldn't modern version of aluminium just be lighter and stronger and
thus can be easuly meet requirements of the older aluminium used?


Of course, but that's all new design, new heat dissipation studies,
new structural studies, etc.

It needs to provide
power and heat dissipation for all the electronics you stuff in it.


Surely a modern version would need less power and dissipate less heat?


You don't know that until you do the studies. This is engineering.
You're not allowe to just reach into your ass and pull out a "surely"
or an "easy".


Its batteries might be much lighter than the ones used in Apollo era?


Maybe yes, maybe no. However, you're now also replacing the whole
power system in your 'new LEM'. More studies and more certifications.


Seems to me this is one area where meeting the needs of the LEM is much
easier today than it was back then, AND same on power and heat dissipation.


This is engineering. You cannot just reach into your ass and pull out
a "much easier" based on how things "seem to you".

You'd like to use modern, more efficient engines that use propellants
that you can make in situ out of water ice.


Yeah, as if fuel production on the moon will happen by 2024 so that the
first mission can land there with a ready-made fuel refinery that is
operating and they just have to use their credit card to buy the guas at
the pump.


You need to pull your head out of your TDS ass. Despite your inane
idiocy in insisting that it is, this is NOT supposed to be a 'one off'
mission after which you throw away all the hardware and start over.


If hypergolics are so "old" why is SpaceX using them for Dragon1 and 2?
Japan is using them for HTV, right?


Stop being so ****ing stupid. None of those vehicles are landing and
taking back off. None of those vehicles are using hypergolics to land
payloads, which is sort of the goal of the exercise. More efficient
engines and propellants means more mass up and down. It's really that
simple and even you ought to be able to wrap your head around it.


Has anyone gone to actual orbit with de-orbiting as part of mission
without hypergolics?

Super Heavy. It relies on a docking adapter that doesn't exist
anymore.


Should be pretty easy to fit the standard docking adaptor that is used
for station, Dragon2 and Orion. Is it much different in diametre than
the original Apollo one?


Again, this is engineering. You don't get to pull a "pretty easy" out
of your ass and claim you're done. There is a lot more to any docking
mechanism than 'diameter'. The more Rube Goldberg **** you have to
string together the heavier **** is.

It's battery powered and only has power for a 75 hour
duration.


Obviously, one would use different batteries today.


This is engineering. You can't just reach into your ass and pull out
an "obviously" and declare that you're done.


And would solar
panels be usable in flight considering whyat happens when you land? Or
just something you deploy once you have landed? Those would just be
cosmetic add-ons to the structure, and probably could have easily been
added by NASA on the LEMs if it had access to current solar panel tech.


This is engineering. You can't change the power system and claim it's
"just cosmetic add-ons". You can't just pull an "easily" out of your
ass and declare the problems solved.

Note that Blue Origin's plan for Blue Moon is to use boil off from the
LH2 tanks to run hydrogen fuel cells for power. This gives you weeks
(not days) of stay time on the surface.


But in the end, how much autonomy do you really expect the ship that
lands in 2024 to really have? not just power, but also ECLSS, food, water?


Contrary to your TDS delusions, this is not intended to be a 'one-off'
mission after which we throw all the hardware away. With your 'new
LEM' you get four days on the surface with two people. Or you could
do the 'extended' LEM, which gets you up to 75 hours but adds several
tonnes to the mass.

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


Sicne they are trying to do the exact same thing, why is it a poor fit
for the 2024 mission ?


Because you're not "trying to do the exact same thing". "Flags and
footprints" is not the goal here. Blue Origin started developing
their lander some three years ago and says it will be ready for use in
2023. A year later their Ascent Element will be ready for manned
landings in 2024.

NASA has asked for crews of up to four people (twice your 'new LEM'
capability). The Blue Moon Ascent Element weighs in at around 6.5
tonnes, which is almost half again as heavy as the LEM Ascent Element.
Want to guess why?


--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
  #25  
Old May 23rd 19, 07:53 PM posted to sci.space.policy
[email protected]
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Default NASA’s full Artemis plan revealed: 37 launches and a lunar outpost

There seems to be a lot of concern in the thread on
the landing vehicle. The original must have used an
inertial guidance system. But these days we have
work going on for GPS airliner landing systems.

It might be worth the effort to put a GPS constellation
around the moon. The question would then be to
use an automated monitoring system or make an earth
moon network connection.

The goal is to allow zero-zero airliner landings.
So why not moon landers.
  #26  
Old May 23rd 19, 11:28 PM posted to sci.space.policy
Jeff Findley[_6_]
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Posts: 1,974
Default NASA?s full Artemis plan revealed: 37 launches and a lunar outpost

In article ,
says...

There seems to be a lot of concern in the thread on
the landing vehicle. The original must have used an
inertial guidance system. But these days we have
work going on for GPS airliner landing systems.

It might be worth the effort to put a GPS constellation
around the moon. The question would then be to
use an automated monitoring system or make an earth
moon network connection.

The goal is to allow zero-zero airliner landings.
So why not moon landers.


We'd have to be landing hundreds of craft on the moon in order to
justify GPS on the moon, IMHO. Besides, we had instrument landing
technology on aircraft long before GPS. We can apply similar techniques
today.

Since the moon has no weather, clouds, or even air to obscure the
surface, we can do precision landings based on imagery. For height
above the surface, radar and laser range-finders will suffice (both on
the landing craft and on the surface). For things like a lunar base,
you could put laser retro-reflectors around the landing pad to allow for
precise positional landings.

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.
  #27  
Old May 24th 19, 04:33 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

Scott Kozel wrote on Thu, 23 May 2019 03:29:15
-0700 (PDT):

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?


Fuel cells. You need something that can get you through lunar night.
Blue Origin's Blue Moon will use hydrogen fuel cells powered with boil
off from the propellant tanks.

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?


Blue Origin is using LH2/LOX, with the idea that eventually lunar ice
can be used to make the propellants rather than shipping them all the
way from Earth.


--
"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
  #28  
Old May 24th 19, 04:42 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

Jeff Findley wrote on Thu, 23 May 2019
06:52:56 -0400:

In article ,
says...

On 2019-05-20 22:05, Fred J. McCall wrote:

You understand that the Gateway isn't in an orbit around the Moon,
right? It's in a LaGrange halo orbit.


Was not aware of that. I was under the impression it was in lunar orbit.


Orion has nowhere near the delta-V capability of the Apollo CSM.


True, but I don't see why it matters since the CSM had about twice as
much delta-v as required. Orion has about a third less than the
Apollo CSM, so it still has enough to do the missions that Apollo did.
And I'm not sure that getting into an L2 NRHO is that much 'cheaper'
when it comes to delta-v.


--
"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
  #29  
Old May 24th 19, 05:05 AM posted to sci.space.policy
Fred J. McCall[_3_]
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Posts: 10,018
Default NASA?s full Artemis plan revealed: 37 launches and a lunar outpost

Jeff Findley wrote on Thu, 23 May 2019
07:13:11 -0400:

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?


Turns out that a lot of Shuttle legacy parts are used in the SLS SRBs.
They're different, though. The big difference is that SLS SRBs have
an extra segment over the Shuttle SRBs (5 vice 4). So they will
eventually run out of those legacy parts (but not until well after
they run out of RS-25 engines).


--
"Millions for defense, but not one cent for tribute."
-- Charles Pinckney
  #30  
Old May 24th 19, 05:14 AM posted to sci.space.policy
Fred J. McCall[_3_]
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Posts: 10,018
Default NASA's full Artemis plan revealed: 37 launches and a lunar outpost

Jeff Findley wrote on Thu, 23 May 2019
07:19:43 -0400:

In article ,
says...
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?

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)


There is no real advantage to L2, IMHO. This is necessary because Orion
is simply not capable of getting to a low lunar orbit and getting back
to earth. It's too heavy and lacks the necessary delta-V to do so.


I don't believe that's the case. I don't believe Gateway (nee Lunar
Orbital Gateway (nee Deep Space Gateway)) really reared its ugly head
until the asteroid recovery missions were planned. Apollo CSM only
needed about 50% of its delta-v capability to do the lunar missions.
Even Orion has more delta-v than that (around 65% or so of Apollo
CSM).


--
"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
 




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