A Space & astronomy forum. SpaceBanter.com

Go Back   Home » SpaceBanter.com forum » Space Science » Policy
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

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



 
 
Thread Tools Display Modes
  #31  
Old May 24th 19, 05:32 AM posted to sci.space.policy
Fred J. McCall[_3_]
external usenet poster
 
Posts: 10,018
Default NASA's full Artemis plan revealed: 37 launches and a lunar outpost

wrote on Thu, 23 May 2019 11:53:23 -0700
(PDT):

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.


The 'original' used a radar altimeter and eyeballs to land manually.
You bring up GPS airliner landing systems like that means something in
this discussion. It doesn't.


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.


So your 'idea' is to build a GPS constellation around the Moon (yeah,
how many years is THAT going to take?) and then construct a bunch of
carefully surveyed landing sites with terminal instruments on the Moon
so that you can then land. Except you have to land to do that. Then
build and certify specialized 'Moon GPS receivers'.


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


You really don't have a clue about how GPS actually works, do 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
  #32  
Old May 24th 19, 06:53 AM posted to sci.space.policy
Fred J. McCall[_3_]
external usenet poster
 
Posts: 10,018
Default NASA?s full Artemis plan revealed: 37 launches and a lunar outpost

JF Mezei wrote on Thu, 23 May 2019
23:28:35 -0400:

On 2019-05-23 07:06, Jeff Findley wrote:

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 basically test everything on commercial and keep the few SLS lainches
you have for the bare minimum dress rehersals and first flight to moon.


Congratulations on finally catching up. It won't last, though. I'm
sure you'll forget everything in a few days.

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


If Orion is deemed too heavy, how difficult would it be to put a Dragon2
on top of the european service module so that it would be a Dragon2 and
the new LEM that go to the moon in 2024?


You'd have to invent a new forward adapter for the SM. You'd have to
reengineer Dragon to be able to use it. You'd have to retest
everything, including abort tests. It would probably be faster and
cheaper to have SpaceX design something clean sheet. And you still
don't have a 'LEM'.

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.


Wow. this SLS thing is much worse than I though. They need 10 segments
per launch. How many are leftover from Shuttle programme?


They've got more SRB sets than they have Shuttle Engine sets. Note
that the Service Module is ALSO using legacy engines from the Shuttle
program and there are only like four of those.

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


Saturn V had 140t to LEO.
SLS starts with 95T with dreams of going to 130t.

Is this a case of not worrying about mass too much because they are
planniong on having multiuple launches to LEO to assemble/fuel before
the "ship" leaves to the moon ?

As I recall, for Apollo, they were paranoid about cutting every gram
thet could to make it. So I am puzzled why with the same laws of
physics, they now think they can sent luxury payloads to the moon even
if SLS has less capacity.


Because payload to LEO is irrelevant. Payload to TLI is what matters.
Orion plus service module weighs in at just under 26 tonnes. SLS
Block 1B can do 37 tonnes to TLI. So for an Apollo-style mission that
leaves around 10 tonnes for the Lander + Ascent Element and that's
just not enough. The original LEM weighed in at a bit over 15 tonnes
(or over 16 tonnes for the extended version). Saturn V could get 48.6
tonnes to TLI. And this is why Gateway makes sense to them. You can
send Orion, Descent Element, and Ascent Element all on separate
launches out to Gateway.

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.


Whether you create new design or re-use antique one, they need to create
the tooling and program the CAD/CAM machines to build the parts.
Building something in the shape of the old LEM shouldn't be more
difficult than building something of another shape.


This is engineering. You cannot just reach into your ass and pull out
a "shouldn't be more difficult" and declare things a non-problem.


The difference is that by re-using LEM desiogns, you can give the
drawings to manufgacturers much more quickly so they can start to
built/test/certify their parts. Starting from scartch means a delay of
when manufacturers can do that.


LEM drawings are paper. You can't run CAD/CAM machines off of that.

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.


But of the laws of physics haven't not changed, and gravity on the moon
hasn't changed, why would the design concepts of the LEM not be as valid
today as they were back then?


They are, but so what? The mission is different this time around.


Or do they expect a ship large enough to have separate airlock, a couch
for crew to sit on, and a 60" TV so they can watch Netflix while on the
moon?


They expect someone with a brain in the loop to be involved in the
decision. This lets you and your recommendations right out.


--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
  #33  
Old May 24th 19, 08:32 AM posted to sci.space.policy
Fred J. McCall[_3_]
external usenet poster
 
Posts: 10,018
Default NASA?s full Artemis plan revealed: 37 launches and a lunar outpost

JF Mezei wrote on Thu, 23 May 2019
23:51:02 -0400:

On 2019-05-23 14:22, Fred J. McCall wrote:

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.


What I am trying to understand is how, with SLS having less payload than
Saturn V, one can talk about several more tonnes to the moon than they
were able to do with Apollo/Saturn V.


Why are you trying to 'understand' something that no one ever claimed?

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.


Yep. and Dragon 2 was ready on time, so was every module on the ISS.


So since nothing can ever meet schedules your claim is that nothing
can meet this one, either?

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?


I will let you, the expert, explain how you can have 4 people, and
consumables for 75 hours in a ship that is half the mass, yet has the
shielding that the LEM didn't have, and structural strength to have 14.7
psi cabin pressure instead of 5


Simple. "Half again as heavy" is not the same as "half as heavy".
"Half again as heavy" means 1.5 times the mass, not 0.5 times the
mass.


If it is because the transfer element does part of the job of dropping
the "LEM" to the moon, consider that this transfer element still has to
be brought there from Earth, so it still mass you need to carry from
Earth surface.


It's because you apparently can't read simple declarative English
sentences. It doesn't matter that much how much mass you have to get
out there if you can get it out there in small pieces. You cannot get
your 'new LEM' out there in any smaller pieces than the Lander Element
and Ascent Element as one piece. Meanwhile, the Gateway architecture
says that a 'mission' gets out there as four discrete pieces; Orion,
the Lander Element, the Ascent Element, and the Transfer Element.


--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
  #34  
Old May 24th 19, 11:28 AM posted to sci.space.policy
Jeff Findley[_6_]
external usenet poster
 
Posts: 2,307
Default NASA's full Artemis plan revealed: 37 launches and a lunar outpost

In article ,
says...

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.


Orion simply does not have the delta-V to enter a low lunar orbit and
then get back to earth and have the margins that NASA requires. This
fact is all over all of the online space forums. But I've done a quick
search for an actual NASA study. This looks promising:

Options for Staging Orbits in Cis-Lunar Space
https://ntrs.nasa.gov/archive/nasa/c...0150019648.pdf

LEO was ruled "infeasible" for use by Orion by NASA. See Table 6 on
page 8 of the above document.

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.
  #35  
Old May 24th 19, 11:34 AM posted to sci.space.policy
Jeff Findley[_6_]
external usenet poster
 
Posts: 2,307
Default NASA?s full Artemis plan revealed: 37 launches and a lunar outpost

In article ,
says...

On 2019-05-23 14:22, Fred J. McCall wrote:

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.


What I am trying to understand is how, with SLS having less payload than
Saturn V, one can talk about several more tonnes to the moon than they
were able to do with Apollo/Saturn V.


Because if you look at the damn picture of the proposed time-line that's
all over online, *none* of the stages of the lunar lander are launched
by SLS. They're *all* launched on *separate* commercial launch
vehicles. So NASA is using *distributed* launch in order to do a much
bigger mission using a heavier lander.

You keep thinking that the commercial launches are for tests and that
the lander will fly on SLS. That's not true. SLS will launch Orion and
little else. Everything else flies on many more commercial launch
vehicles.

All of your other strange "conclusions" keep happening because you're
just not understanding how these missions will be flown. The three
pieces of the lander will be launched on three separate commercial
launch vehicles. They will rendezvous with Gateway where they'll all be
docked or berthed together to form the three stage lander. Orion will
be launched on SLS (perhaps with some cargo to resupply Gateway).

So each crewed landing mission will take at a *minimum* 4 launches, of
which only one will be SLS.

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.
  #36  
Old May 24th 19, 11:37 AM posted to sci.space.policy
Jeff Findley[_6_]
external usenet poster
 
Posts: 2,307
Default NASA?s full Artemis plan revealed: 37 launches and a lunar outpost

In article ,
says...

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


Agreed. What's not clear to me is what happens when they run out of SRB
segments. The press hasn't reported on this much.

Next time I meet up with someone from Northrup Grumman Innovation
Systems, I'll ask. But I don't think that will be for a while since
they only come to where I work less than once a year for beta testing
our products.

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.
  #37  
Old May 24th 19, 11:39 AM posted to sci.space.policy
Jeff Findley[_6_]
external usenet poster
 
Posts: 2,307
Default NASA's full Artemis plan revealed: 37 launches and a lunar outpost

In article ,
says...

In article ,
says...

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.


Orion simply does not have the delta-V to enter a low lunar orbit and
then get back to earth and have the margins that NASA requires. This
fact is all over all of the online space forums. But I've done a quick
search for an actual NASA study. This looks promising:

Options for Staging Orbits in Cis-Lunar Space
https://ntrs.nasa.gov/archive/nasa/c...0150019648.pdf

LEO was ruled "infeasible" for use by Orion by NASA. See Table 6 on
page 8 of the above document.

Jeff


Ugh, I said LEO above when I meant LLO (low lunar orbit). Oops.

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.
  #38  
Old May 24th 19, 06:13 PM posted to sci.space.policy
Fred J. McCall[_3_]
external usenet poster
 
Posts: 10,018
Default NASA's full Artemis plan revealed: 37 launches and a lunar outpost

Jeff Findley wrote on Fri, 24 May 2019
06:28:51 -0400:

In article ,
says...

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.


Orion simply does not have the delta-V to enter a low lunar orbit and
then get back to earth and have the margins that NASA requires. This
fact is all over all of the online space forums. But I've done a quick
search for an actual NASA study. This looks promising:

Options for Staging Orbits in Cis-Lunar Space
https://ntrs.nasa.gov/archive/nasa/c...0150019648.pdf

LEO was ruled "infeasible" for use by Orion by NASA. See Table 6 on
page 8 of the above document.


Note that the figures they used to rule out LLO underestimate the
capability of the Orion/SM combination. It has about 12% more fuel
than they state (9 tonnes vice 8 tonnes) and more delta-v than they
say (1800 vice 1650). Note that with 1800 m/s delta-v LLO changes
from infeasible to feasible.


--
"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
  #39  
Old May 24th 19, 06:41 PM posted to sci.space.policy
Fred J. McCall[_3_]
external usenet poster
 
Posts: 10,018
Default NASA?s full Artemis plan revealed: 37 launches and a lunar outpost

Jeff Findley wrote on Fri, 24 May 2019
06:37:22 -0400:

In article ,
says...

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


Agreed. What's not clear to me is what happens when they run out of SRB
segments. The press hasn't reported on this much.


I think the original plan was that they'd switch to 'advanced
boosters' at that point, but I think those may be too far out now to
make the timeline. Also the original plan was to have a Block 1A
vehicle that got the new 'advanced boosters' before the Block 1B EUS
milestone (which at that point would have been Block 2). Block 1A was
cancelled, adding EUS became Block 1B, and Block 2 was moved to after
that.

A little poking around tells me that there is enough SRB hardware for
8 SRB sets, which will carry them through 2027 or so. They currently
have 4 RS-25 engine sets and contracts for another set and a half of
'new' RS-25 engines. This gets them into 2026. Another half engine
set (2 more engines) would get them through 2026. There are
apparently 3 AJ10-190 engines available for use on the Orion Service
Module. That gets them through 2024 and the first landing, at which
point they'll have to change engines. There are engines currently in
production that they could use, like the AJ10-118k used on Delta II.

So in summary the real long pole is the SRB hardware. There are
contracts and contingencies in place for the other two pieces of the
system that are limited by availability of old Shuttle hardware, but
once those SRB components are gone, they're GONE and the program to
replace those boosters is way out there.


--
"Millions for defense, but not one cent for tribute."
-- Charles Pinckney
  #40  
Old May 24th 19, 06:42 PM posted to sci.space.policy
Fred J. McCall[_3_]
external usenet poster
 
Posts: 10,018
Default NASA's full Artemis plan revealed: 37 launches and a lunar outpost

Jeff Findley wrote on Fri, 24 May 2019
06:39:00 -0400:

In article ,
says...

In article ,
says...

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.


Orion simply does not have the delta-V to enter a low lunar orbit and
then get back to earth and have the margins that NASA requires. This
fact is all over all of the online space forums. But I've done a quick
search for an actual NASA study. This looks promising:

Options for Staging Orbits in Cis-Lunar Space
https://ntrs.nasa.gov/archive/nasa/c...0150019648.pdf

LEO was ruled "infeasible" for use by Orion by NASA. See Table 6 on
page 8 of the above document.


Ugh, I said LEO above when I meant LLO (low lunar orbit). Oops.


That's OK. I misread it as LLO. :-)


--
"Adrenaline is like exercise, but without the excessive gym fees."
-- Professor Walsh, "Buffy the Vampire Slayer"
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
NASA's new focus plan revealed Pat Flannery Policy 11 February 27th 10 05:32 PM
NASA's new focus plan revealed Jorge R. Frank History 0 February 27th 10 05:32 PM
Bush administration to adopt Artemis Society plan for moon mission... Dholmes Policy 1 January 13th 04 03:11 PM


All times are GMT +1. The time now is 05:43 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 SpaceBanter.com.
The comments are property of their posters.