totm dec 2023 Artemis Discussion Thread

[Exoscientist]

21 hours ago, tater said:

Initial talks about what a Gateway lander might look like (Gerst presented this):

36t min. 43t max.

Doesn't list requirements, just min masses for components tells us something. The Ascent Element is at min 2X the mass of the Apollo LM, nearly 3X at max.

…

 

 

 This can’t be correct for a minimal lander to and from low lunar orbit since we know Apollo LEM was able to do it at ca. 15 tons gross mass.

 

  Bob Clark

[Codraroll]

25 minutes ago, Exoscientist said:

This can’t be correct for a minimal lander to and from low lunar orbit since we know Apollo LEM was able to do it at ca. 15 tons gross mass.

You're using the wrong value of "it" in this sentence. The Apollo lander only managed the equivalent of pitching a tent on the Moon's surface. Artemis asks for much more capability [Snip]

Edited May 9 by James Kerman
Redacted by a moderator

[sevenperforce]

16 minutes ago, Exoscientist said:

Quote

 This can’t be correct for a minimal lander to and from low lunar orbit since we know Apollo LEM was able to do it at ca. 15 tons gross mass.

Well, it's NOT a lander to and from low lunar orbit.

If you mean that the numbers are off-base for a minimal lander that WOULD be going to and from low lunar orbit...that depends on what you mean by minimal.

The ascent element denoted above needs to get from the lunar surface to Gateway. Technically, going between LLO and the Gateway should only cost 730 m/s, but the ascent element above has additional Δv to handle phasing and other issues for abort situations. Assuming the minimal mass of 9 tonnes above and hypergolics at ~318s, we're looking at a notional 5.4 tonnes of propellant. (This means a dry mass of 3.6 tonnes.) Reducing the required Δv to the bare 1.87 km/s to go from the lunar surface to LLO allows the total props to drop to just 3 tonnes, trimming the ascent element to a wet mass of 6.6 tonnes. Let's say the reduced tankage weight and getting rid of reusability/refillability can trim it to 3.2 tonnes dry and 5.9 tonnes wet. The Apollo LM ascent module had a dry mass of 2.15 tonnes, so ~49% dry mass growth for double the crew is pretty good. No reason to think this "can't be correct".

With an ascent module wet mass of 5.9 tonnes (compared to the 4.7 tonnes of the LM), using the gross mass ratio of the LM descent and ascent elements, you'd need a descent module of 12.9 tonnes, for a total gross mass of 19 tonnes. That's what the above figures suggest for a minimal lander going to and from low lunar orbit. 19 tonnes.

Of course that wouldn't satisfy any of the program requirements of Artemis.

[tater]

55 minutes ago, sevenperforce said:

Well, it's NOT a lander to and from low lunar orbit.

Exactly, since to be an LLO lander, it needs to be at the larger size of that range, ~45t because it needs to be able to brake itself and Orion into LLO, which means the lander and Orion need to be sent to TLI together... huh.

Let's go back in time to before SLS, in the days of Constellation!

Orion was launched to LEO on top of the cursed Ares I. The cargo-only Ares V was designed to send 71t to TLI (~188t to LEO). 71 tons to TLI, wonder why they pulled that random number out of a hat?

Altair was ~45t. Orion was ~26t. 45+26=71

Note that if they had put Orion on top of Ares V, it would have had a lower throw to TLI, it got to 71t to TLI by launching with just Altair, then docking with Orion (sent to LEO with the cursed Ares I (the "cursed" part is required!)). It was never a single stack vehicle for multiple reasons. Everyone at NASA (and presumably Ballast, the current NASA Admin knew in Senate when he championed SLS) knew this. So a vehicle that can never get more than 40-something tonnes to TLI has been useless from day 1. This was always the primary beef with SLS/Orion, it is, and always has been a rocket to nowhere. The Artemis lunar architecture is basically Constellation's—because it has to be. The problem is that SLS is completely incapable of filling the hole left by canceling Ares V (which was not gonna work anyway of course, it had its own problems). Earlier make-work concepts for SLS/Orion was lousy missions like ARM, because that was all they could think of it doing. Bridenstine was making lemonade with the lemon that is SLS, using the only tool he had that could help, commercial providers. Since that was on the table, why not make sure the mission has good long term goals? Decent duration stays? Check! Incorporate in-space reuse of mission elements for a more sustainable program, and some TRL bumps? Check! More humans to the surface? Check! JB is smart enough to know that the proposals that came out of Artemis actually kill SLS. Any that can possibly work obviate SLS in the long run.

The sooner, the better.

 

Edited May 9 by tater

[Terwin]

Being able to parlay a project to support a funding-required but poor capability component into multiple systems with superior capabilities sounds like quite the coup to me .  

[Exoscientist]

 The concept of Artemis being “better” than Apollo based on cost grounds comes from this assessment of Apollo’s costs in inflation-adjusted dollars:

How much did the Apollo program cost?
The United States spent $25.8 billion on Project Apollo between 1960 and 1973, or approximately $257 billion when adjusted for inflation to 2020 dollars. Adding Project Gemini and the robotic lunar program, both of which enabled Apollo, the U.S. spent a total of $28 billion ($280 billion adjusted). Spending peaked in 1966, three years before the first Moon landing. The total amount spent on NASA during this period was $49.4 billion ($482 billion adjusted).
https://www.planetary.org/space-policy/cost-of-apollo

The max expenditure in a single year was ca. $45 billion in 2020 dollars. And the total cost of the lunar lander alone was ca. $20 billion in 2020 dollars. 

The total cost of Artemis so far is ca. $50 billion:

The Cost of SLS and Orion
From its inception in 2011 through the year of its first flight, the Space Launch System rocket program has cost $23.8 billion. The Orion deep space capsule has cost $20.4 billion since the program began in 2006. Related ground infrastructure upgrades cost an additional $5.7 billion since 2012. In total, NASA spent $49.9 billion on these programs between 2006 and their first test launch in 2022.
https://www.planetary.org/space-policy/cost-of-sls-and-orion

 But how much cheaper Artemis is than Apollo exemplifies another key advantage we have now over Apollo that we must make use of: the plentiful commercial launchers, in-space stages, and spacecraft already operational and in regular use.

 Then USE that advantage. Construct your lander, small like Apollo’s, from EXISTING components, not developing the lander from scratch. Knowledgeable observers of the space program are aware of the fact development costs for entirely new systems from scratch incur ballooning costs. 

There are multiple ways of following this approach. 

Here’s one:

Possibilities for a single launch architecture of the Artemis missions, Page 3: Saving the lander mission for Artemis III.
https://exoscientist.blogspot.com/2023/08/possibilities-for-single-launch_11.html

 

  Bob Clark

 

 

[tater]

33 minutes ago, Terwin said:

Being able to parlay a project to support a funding-required but poor capability component into multiple systems with superior capabilities sounds like quite the coup to me .  

Yep.

[RCgothic]

There's no such thing as a minimum viable commercial off the shelf lunar lander made from existing parts.

And even if there were, SLS couldn't send it.

And even if it could, starting from now would only incur huge delays.

And even then it'd only get a very very poor excuse for a lunar mission. 

If value for money is the concern, then the Landers should be at the very bottom of the list of things to change, right behind *gestures at literally every other thing in the Artemis program and very specifically at SLS/Orion*.

Any criticism of Artemis on cost grounds that doesn't want HLS but does want SLS is completely devoid of credibility IMO.

Edited May 9 by RCgothic

[RCgothic]

Image won't link properly. Oh well.

Edited May 9 by RCgothic

[tater]

9 minutes ago, RCgothic said:

Any criticism of Artemis on cost grounds that doesn't want HLS but does want SLS is completely devoid of credibility IMO.

Yeah, hard to imagine anyone making that argument given the black hole of funding SLS/Orion is. What's more odd right now is not a call for a rerun of Artemis 1. The heat shield has nontrivial issues. Yes, it will likely survive Artemis II/III as initially envisioned, but it smacks of defining deviancy down. I'dve expected any of the loons who misunderstand iterative design to be all over Orion to retest the heat shield before any crew mission is flown.

4 minutes ago, RCgothic said:

Image won't link properly. Oh well.

What's the image of? Or could we google it using your search terms?

[RCgothic]

Aha! Fixed! It was importing cropped for some reason.

Edited May 9 by RCgothic

[Flavio hc16]

Ooofff size: GIGANTIC

( Ars Technica article about the Orion heat shield problem and how to resolve/retest it).

 

 

So.... You are telling me that the HLS Is not really the thing  that's holding back the Artemis program? Call me shocked! Shocked!

And to me it's utter insanity to have Artemis 2 astronaut be either the guinea pig for a current solution that "might work" or a revised solution that has never been tested.

They say that SpaceX has go fever...but I smell it more from NASA, considering also the last report where NASA said that " they didn't like the GAO being nosy on NASA's matters".

The most cost effective solution would be putting a boilerplate Orion with the new heat shield on a falcon heavy, send it to TLI and make it do a real test of the return from the moon, then if the test goes as expected, go on with Artemis 2. The current plan is insane and a good way to kill 4 astronauts.

 

Heritage strikes again.

 

NASA strongly considered going with PICA for Orion which was being used for Curiosity at the time (since then it has been used on Dragon and Perseverance). Instead they decided to use a modified Avcoat since it was a heritage Apollo material and was considered to be lower risk. Except the material does not seem to match the Apollo performance. Why? Because we have actually lost the full list of "ingredients" to make AVcoat.

[RCgothic]

Oof indeed. That definitely deserves a fresh uncrewed test flight IMO.

Falcon Heavy should be able to send an Orion boilerplate with the right shape, entry mass, and heat shield on a free-return trajectory around the moon if it doesn't need to send ESM as well.

The problem is they don't have a spare Orion hull they can quickly convert, because they're hardware-poor. Shuttle, Apollo, and the earlier spacecraft all had multiple test articles that could be repurposed in situations like this (or even pressed into operational service, like Endeavour was from structural spares).

And apparently any solution that involves demounting the Orion for Artemis II and modifying the heat shield will incur at least a year of delay because they're incapable of doing it any faster. It's inexplicable to me why mounting/demounting a spacecraft takes them so long.

Edited May 10 by RCgothic

[tater]

21 hours ago, RCgothic said:

Aha! Fixed! It was importing cropped for some reason.

?

2 hours ago, Flavio hc16 said:

( Ars Technica article about the Orion heat shield problem and how to resolve/retest it).

[tater]

https://ntrs.nasa.gov/api/citations/20190001310/downloads/20190001310.pdf

Old article about improvements after EFT-1.

[darthgently]

2 hours ago, tater said:

?

That seems like enough lost to have made a measurable difference in cabin temperature.  That could make an astronaut a little nervous.  Aren't heat shields for capsules a fairly mature technology generally speaking?  Are the trying something relatively new?

[AckSed]

Looking over that paper, I don't see any show-stoppers on the new block-by-block placement. In fact it was made to be more easily checked. I note that the rectangles, edge pieces and curved parts have been replaced with curved parts and edge pieces on the Artemis 1 HS.

I wonder if LOFTID could be adapted?

Edit: I have been told that Apollo 4 used an elliptical trajectory and the Saturn upper stage to simulate lunar re-entry speeds. The velocity was 11,168 m/s, close to the proposed 11,111 m/s of Artemis 1. Of course Orion's heavier, so it's striking the atmosphere with greater energy, but we've seen that the shield is thicker.

Edited May 10 by AckSed

[magnemoe]

46 minutes ago, darthgently said:

That seems like enough lost to have made a measurable difference in cabin temperature.  That could make an astronaut a little nervous.  Aren't heat shields for capsules a fairly mature technology generally speaking?  Are the trying something relatively new?

I'm more concerned about burning trough. That is unless this is damage from capsule hit water but then it would not been an concern. 

4 hours ago, RCgothic said:

Oof indeed. That definitely deserves a fresh uncrewed test flight IMO.

Falcon Heavy should be able to send an Orion boilerplate with the right shape, entry mass, and heat shield on a free-return trajectory around the moon if it doesn't need to send ESM as well.

The problem is they don't have a spare Orion hull they can quickly convert, because they're hardware-poor. Shuttle, Apollo, and the earlier spacecraft all had multiple test articles that could be repurposed in situations like this (or even pressed into operational service, like Endeavour was from structural spares).

And apparently any solution that involves demounting the Orion for Artemis II and modifying the heat shield will incur at least a year of delay because they're incapable of doing it any faster. It's inexplicable to me why mounting/demounting a spacecraft takes them so long.

Don't they have boiler plates from parachute tests? Granted its not space rated, and this need all the flight systems including RCS for fine control coming back. 

And that trajectory reminds me of an KSP 2 mission, Mun free return but I had 3 km/s in upper stage who I burned to simulate an high speed Kerbin intercept.  It worked. 

Edited May 10 by magnemoe

[Exoscientist]

 The concept Artemis is cheaper than Apollo was in response to this video:

NO WAY we’re landing on the moon in 2026.
https://youtu.be/pQufaHiAark?si=gYJKXgzQf-hjkuiv

 About at the 5:25 point is mentioned a NASA lunar lander might normally be developed for $10 to $20 billion. And in this link about the cost of Apollo, the total costs of the Apollo lunar lander over the entire Apollo program adjusted to 2020 dollars did indeed cost ca. $20 billion:

https://www.planetary.org/space-policy/cost-of-apollo

 For the seven Apollo lander missions that’s in effect ca. $3 billion per mission. The contract NASA gave SpaceX for the Starship HLS  totals about $4 billion for two lander missions, or $2 billion per mission. That’s not a terribly great saving over what we did during Apollo. Even worse, that’s the same as the cost for the entire SLS rocket, with the two SRB’s, the core stage with the four over-priced reincarnations of the SSME’s, and interim upper stage.

 But the key point I’m making is considering how much the space program in general has developed world-wide now, with a wide variety of launchers, in-space stages, and spacecraft, we can use essentially off-the-shelf components to construct a lunar lander. And as SpaceX has shown costs are cut drastically if the spacecraft is privately funded. So don’t construct the lander from scratch, which as experienced space observers we know makes costs balloon greatly, and don’t use the typical government financed approach, which we also know make costs balloon greatly, instead use already existing and operationally in use components and use private funding to construct it.

 In this, way the lander might only cost in the tens of millions range, instead of billions.

 Dave Masten gave another interview where he discussed his Centaur-derived lunar lander:

Spacevidcast Live - What if Apollo never happened?
https://youtu.be/oQ4lLTblx5M

About 30 minutes in, he suggests its costs would be ca. $50 million to purchase the Centaur, and only a few more million to add on Masten’s side thrusters for horizontal landing. Plus, some millions more for testing. The host suggests under $200 million total, and Masten responds, “Oh, easily.”

  Bob Clark

 

[tater]

I think it's deeply concerning that they don't understand what's causing the spalling.

[darthgently]

1 hour ago, tater said:

I think it's deeply concerning that they don't understand what's causing the spalling.

The thing that jumps out starkly is that some polygon sections are clearly affected strongly while neighbors are not.  I hope the are tracking each section individually through manufacture so as to ID a particular batch of resin, or when a "minor" design change occured, or even to find correlations to inadvertent but slightly different installations techniques from one tech to another.  It's all about the data 

[RCgothic]

2 hours ago, Exoscientist said:

For the seven Apollo lander missions that’s in effect ca. $3 billion per mission. The contract NASA gave SpaceX for the Starship HLS  totals about $4 billion for two lander missions, or $2 billion per mission. 

 In this, way the lander might only cost in the tens of millions range, instead of billions.

Sure, with dev costs ammortised over only 2 missions it comes out expensive. But I'd keep an eye on how much is contracted for subsequent missions. 

On the second point there's not a chance in hell any human lander has a dev included cost over 2 missions of just tens of millions. NASA can't even buy a single unintegrated rocket engine for that little. The paperwork alone for crew rating would blow that figure into smaller pieces than Orion's ablated heat shield.

Edited May 10 by RCgothic

[RCgothic]

For a similar comparison, the first two full flight lunar modules were probably delivered around the end of 1968. LM-1 flew in Jan 68 on Apollo 5, LM-2 became a test article, and LM-3 flew Mar69 on Apollo 9. Earlier LMs that flew were various degrees of boiler plates and test articles (dev).

From what I can tell, 75% of the total funds allocated to lunar modules were disbursed by the end of 68.

That would put a 2nd flight dev-inclusive cost for Apollo at $15B in 2020 dollars, or $7.5B per flight.

That's rather more favourable to SpaceX's starship's $2B. And that's before considering Starship is VASTLY more capable.

Over 10x as much downmass, over 35x as much downmass per dollar.

[AckSed]

https://spacenews.com/how-artemis-astronauts-protected-solar-storms/

tl;dr Orion's upgraded protection, greater prediction capabilities with algorithms and the coronagraph on the GOES-U and Space Weather Follow On Lagrange 1 satellites. And if it gets bad, astronauts retreat to their inner sanctum and stack luggage on themselves.

Spoiler

 

 

Edited May 30 by AckSed

[darthgently]

7 hours ago, AckSed said:

https://spacenews.com/how-artemis-astronauts-protected-solar-storms/

tl;dr Orion's upgraded protection, greater prediction capabilities with algorithms and the coronagraph on the GOES-U and Space Weather Follow On Lagrange 1 satellites. And if it gets bad, astronauts retreat to their inner sanctum and stack luggage on themselves.

  Hide contents

 

 

Luggage full of lunar and asteroid dust samples gathered for priceless research back on Earth?  Whatever it takes